Die Casting Sessions by dandanhuanghuang


									     Die Casting Sessions
          Monday, September 19                                                    nent mold casting applications. This paper has measured the loss
                                                                                  constant k for both strontium and magnesium in the equation
          Advanced Technologies                                                   C(t) = C(0) exp[ -kt ] and has demonstrated that the frequency
                                                        8:30 am - 10:00 am        of adding strontium to avoid strontium from falling below the
                                                                                  0.05% Sr level for good die soldering resistance can be ties to the
          The Influence of Ultrasonic Vibration on the                            well established frequency practice of adding magnesium to avoid
          Microstructure of A380 Alloy                                            magnesium from falling “out of specification” for magnesium
                              – Jie Song & Qingyou Han, Purdue University         for 367.0, 368.0, XK360.0 [a proprietary alloy] and B360.0 [an
                                                                                  unregistered and proposed alloy for an Aluminum Association
          A380 alloy is one of the widely used diecasting alloys for au-          designation]. The frequency will be shown to depend on both the
          tomotive application. Formation of globular grains during the           k-value of the species, the composition levels of the species and
          solidification process of this alloy will allow the alloy to be die     the width of the composition ranges of the species, and thus the
          cast at much lower temperatures and thus improve its mechanical         frequency will be alloy dependent.
          properties. This article reports our experiments on the influence of
          high-intensity ultrasonic vibration on the microstructure forma-        Effect of Heat Treatment and Chemical Composition on the
          tion of A380 alloy in metal molds. We have found that high-             Mechanical Properties of a 357 Semi-solid Alloy using SEED
          intensity ultrasonic vibration can be used to significantly alter the
          microstructure of A380 alloy. Dendritic aluminum grains became                 – Ehab Samuel & Chang-Qing Zheng, National Research
          globular and eutectic silicon plates were modified. The sizes of                      Council of Canada, Aluminum Technology Centre
          the primary grain and eutectic particles decreased with increasing      The ability of aluminum-silicon alloys to be cast into complex
          intensity of ultrasonic vibration. Two regions with distinct mi-        shapes has been well-documented. However, fewer studies have
          crostructural feature were formed near the ultrasonic waveguide/        devoted themselves to the use of semi-solid Al-Si alloys as an al-
          radiator which was placed in direct contact with the solidifying al-    ternative to conventionally cast alloys. Semi-solid alloys have been
          loy. Region I occurred near the ultrasonic waveguide where blocky       reported to demonstrate ease of material flow and good die-filling
          hypereutectic silicon particles and small globular aluminum grains      capabilities, owing to their dual liquid-solid nature and character-
          were formed. Hypoeutectic structure occurred in region II away          istic globular network. In recent years, the Aluminum Technology
          from the ultrasonic waveguide. The globular aluminum grains in          Centre has investigated the use of semi-solid aluminum alloys, no-
          Region II were larger than those in Region I. Finally, the effect of    tably 357, using the novel SEED rheocasting method. The SEED
          mold material on the microstructure of A380 alloy is discussed.         (Swirled Enthalpy Equilibration Device) process, as developed
                                                                                  by Rio Tinto Alcan in collaboration with the National Research
          Measurement and Use of Oxidation Loss Constant for                      Council Canada – Aluminum Technology Centre, is a rheocasting
          Strontium and Magnesium in Determining the Frequency                    technology yielding semi-solid slurry from the mechanical swirling
          for Strontium Additions to Various Alloys                               and cooling of molten aluminum. The resulting semi-solid billets
                                           – Ray Donahue, Mercury Castings        demonstrate a homogeneous, globular microstructure. These bil-
                                                                                  lets are subsequently fed into a high pressure die cast press for part
          A new third generation of die casting alloys for crash worthy           production. Typical mechanical property values observed for this
          applications that rely on strontium [at 0.05-0.07% Sr levels]           SEED processed 357 alloy include yield strength, ultimate tensile
          instead of iron [at 1-2% levels] for die soldering resistance was       strength and percent elongation values of 210-250 MPa, 300-320
          been developed. Since this new generation of die casting alloys do      MPa and 12-17%, respectively. In the current work, this semi-
          not require iron for die soldering resistance, these new die casting    solid 357 alloy is subjected to several heat treatments and chemical
          alloys are low in iron and have superior mechanical properties,         composition changes, in our attempt to further maximize the
          particularly much higher ductility, and are recyclable with sand        rheocast alloy`s already favorable mechanical properties.
          casting and permanent mold casting alloys with huge savings
          in energy and CO2 emissions, compared with conventional die
          casting alloys. Two of these high performance die casting alloys
                                                                                  Cast Materials I: Aluminum (Special Format)
          are registered with the Aluminum Association and have the                                                             10:15 am - 11:45 am
          Aluminum Association designations of 367.0 [8.5-9.5 Si, 0.25
                                                                                  Aluminum Alloy Development
          max Fe, 0.25 max Cu, 0.25-0.35 Mn, 0.30-0.50 Mg] and 368
          [8.5-9.5 Si, 0.25 max Fe, 0.25 max Cu, 0.25-0.35 Mn, 0.10-                             – Libo Wang, Diran Apelian & Makhlouf Makhlouf
          0.30 Mg]. The perceived problem with these new die casting                                              ACRC - Metal Processing Institute
          alloys is with strontium, which is a very reactive metal, and its use   The chemistry limits specified for die casting alloys are generally
          at 0.05-0.07% levels [i.e. 500-700 ppm] is relatively uncommon          wide, which can cause large variations in the mechanical proper-
          relative to its common use at 0.01-0.03% levels [i.e., 100-300          ties of die cast components. In many cases, there is a strong need
          ppm] to modify the eutectic silicon in sand casting and perma-          to minimize these variations in properties in order to enable cast-

                    : Cast Metals Coalition         : Defense Logistics Agency         : Department of Defense            : Department of Energy
                                                   : American Metalcasting Consortium           : NADCA

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September.indb 65                                                                                                                                 8/10/2011 9:37:20 AM
           ing conversions to meet the demands of the application. In many         A good example of this type of state-of-the-art technology is the
           other cases, the requirement of the application necessitates the use    water-cooled, 250 cm3 cylinder block manufactured using the
           of a premium grade high performance alloy. Therefore, the objec-        vacuum assisted High Pressure Die Casting (HPDC) technology
           tive of this work is twofold: (1) to tighten the chemistry specifica-   using DiASilTM alloy.
           tion of 380 alloy in order to minimize variation in its mechanical         This hypereutectic Al-20% Si alloy heated to 785 and 850oC
           properties, and (2) to develop new premium grade aluminum-              followed by rapid solidification exhibited refinement of the
           based die casting alloys that have enhanced mechanical properties.      primary Si (~15m) while heating to 735oC produced coarse and
           In this paper we report on the initial stages of the work, which        heterogeneous primary Si crystals (~40m). The solidification rate
           involved the use of i-Select Al software to optimize the chemical       determined based on laboratory experiments was between 45
           composition of four aluminum-based die casting alloys.                  to 85oC/s depending on thickness of casting section. Increase in
                                                                                   cooling rates produced better primary Si refinement and mini-
           Calculation of Aluminum Alloy Properties                                mized its variation caused by the melt temperature. The SDAS
                      – Libo Wang & Diran Apelian & Makhlouf Makhlouf,             was not affected by the melt temperature and was a function of
                                        ACRC - Metal Processing Institute          the cooling rate for the given experimental conditions.
                                                                                      Cylinder block rapid solidification created a desired structure
           The chemistry limits specified for die casting alloys are generally     for subsequent energy efficient heat treatment processing offer-
           wide, which can cause large variations in the mechanical proper-        ing ~ 70% reduction in heat treatment time while maintaining
           ties of die cast components. In many cases, there is a strong need      and/or improving the cast component’s characteristics including
           to minimize these variations in properties in order to enable           hardness. A revised T6 temper resulted in a hardness of 77.2
           casting conversions to meet the demands of the application. In          HRB which is 3.7 divisions higher than the conventional T6
           many other cases, the requirement of the application necessitates       temper currently used for the vacuum HPDC engine blocks
           the use of a premium grade high performance alloy. Therefore,           (HRB = 73.5). The total process duration for the conventional
           the objective of this work is twofold: (1) to tighten the chemistry     T6 temper was 9 hours and 10 minutes, while the modified
           specification of 380 alloy in order to minimize variation in its        T6 temper’s total duration was 2 hours and 55 minutes. Tensile
           mechanical properties, and (2) to develop new premium grade             testing confirmed that for both analyzed tempers it is feasible to
           aluminum-based die casting alloys that have enhanced mechani-           maintain comparable mechanical properties (UTS~260MPa).
           cal properties. In this paper we report on the extensive measure-       The presented results were used to optimize the casting process
           ments of mechanical properties and the characterization of the          and improve the service characteristics of the vacuum assisted
           microstructure of alloys that were developed to meet these goals.       HPDC motorcycle engine blocks.
           Proposed “Environmentally Green” High Pressure Die                      Panel Discussion: Diran Apelian, WPI; Makhlouf Makhlouf,
           Casting Alloys with Low Iron for Improved Mechanical                    WPI; Ray Donahue, Mercury Marine
           Properties and Strontium for Die Soldering Resistance
                                             – Ray Donahue, Mercury Marine         Cast Materials II: Zinc
           This paper describes a new die cast alloy technology that relies on                                                   2:00 pm - 3:30 pm
           strontium instead of iron for die soldering resistance and provides
           specific compositions that can replace all current conventional         Environmentally Friendly Finishes for Zinc Die Castings
           die cast alloys. These proposed alloys have the same Aluminum                          – Frank Goodwin, International Zinc Association
           Association numeric designations, except for a different letter des-
                                                                                   The environmental performance of zinc die castings has been
           ignation, as the Aluminum Association die cast alloy it is replac-
                                                                                   improved with the availability of new surface finishes that reduce
           ing. As such these new die cast alloys are low in iron, like sand
                                                                                   occupational and environmental effects. Results of a survey of
           cast and permanent mold cast alloys, because iron is not needed
                                                                                   literature and industrial activity will be presented together with
           for die soldering resistance. These alloys are recyclable with sand
                                                                                   laboratory results of corrosion testing of selected new finishes.
           cast and permanent mold cast alloys and are thus “environmental
           green” and capable of decreasing the “carbon footprint” of the die
                                                                                   Aging Properties of Zinc Alloys
           cast industry. It is estimated the annual CO2 emission savings
           from the complete conversation of the die cast industry to these        – Frank Goodwin, International Zinc Association; Walter Leis &
           “low iron - high strontium” die cast alloys amount to approxi-                     Lothar Kallien, Aalen University of Applied Sciences
           mately 23 million tons [i.e., 46,000,000,000 pounds] CO2                Natural aging of zinc diecasting alloys results in changes in
           emissions annually. Similarly, the energy savings are estimated as      their mechanical properties. However, artificial aging treat-
           21,800,000,000 kWh - the environmental equivalent of provid-            ments can stabilize these properties. The relationship between
           ing enough energy to power 2 million households for a year.             casting wall thickness, alloy copper content and resulting
                                                                                   properties has been statistically analyzed for different aging
           Optimization of the Al-Si Hypereutectic HPDC                            treatments and related to microstructural changes.
           Cylinder Block Casting Process and its Heat Treatment
                    – Wojciech Kasprzak, Natural Resources Canada, CANMET          Mechanical Properties of High Fluidity Zinc Die
                              Materials Technology Laboratory; Jerry Sokolowski,   Casting Alloy for Thin Wall Applications
                               University of Windsor; Hirotaka Kurita, Yamaha      – Frank Goodwin, International Zinc Association; Keith Zhang &
                             Motor Co. Ltd.; Hiroshi Yamagata, Gifu University               Daniel Liu, Teck Resources Product Technology Centre
           Aluminum cast alloys are successfully used for a variety of light       A high fluidity (HF) zinc die casting alloy, containing 4.5%Al,
           weight powertrain components in high performance motorcycles.           0.01%Mg and 0.03%Cu, was developed at Teck’s Product

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September.indb 66                                                                                                                              8/10/2011 9:37:21 AM
          Technology Centre in a project sponsored by NADCA. This hot              Die Castable Aluminum Metal Matrix Composites by
          chamber die casting alloy possesses up to 40% better fluid-              Self-propagating High-temperature Synthesis
          ity than ZAMAK™ Alloy 7. Mechanical properties of the HF
                                                                                       – William Garrett, Jacob Nuechterlein, Ilguk Jo & Avraham
          alloy have been systematically evaluated and the results will be
                                                                                    Munitz, Colorado School of Mines; Christopher Rice, VForge Inc.
          reported in this paper. In particular, the creep resistance of the
          alloy, which was recently measured, will be discussed in detail.         Self-propagating High-temperature (combustion) Synthesis
                                                                                   (SHS) has successfully been used at the Colorado School
                                                                                   of Mines (CSM) to make die castable particulate titanium
          Cast Materials III: Metal Matrix Composites                              carbide reinforced aluminum. Previous experiments with
                                                           3:45 pm - 5:15 pm       traditional aluminum die casting alloys revealed that sili-
                                                                                   con will react with the TiC phase and form an undesirable
          Production Process Standardization of Selective Short                    Al3Ti intermetallic that increases the melt viscosity and
          Ceramic Fiber Reinforced Al12SiCuMgNi Aluminum Piston                    decreases the mechanical properties. Thixocasting experi-
              – Karuppa Chinnathambi, Teledyne Continental Motors, Mobile          ments were performed at VForge in Denver, CO. Cast
                                                                                   components include automotive engine brackets, wedges,
          The piston is one of the most stressed components of an internal-
                                                                                   military sight mounts, and mechanical test specimens.
          combustion engine. The power increase of diesel engines entails
          an increased thermal and mechanical loads resulting from the
          higher ignition pressure, the increased combustion temperatures
          of about 320 – 3500 C at the edge of piston combustion cham-             Tuesday, September 20
          ber, higher thermal gradients are also observed in the piston on         Die Materials
          top ring groove and pin hole. Therefore to enhance the perfor-                                                      8:30 am - 10:00 am
          mance of existing aluminum alloy piston has been selectively
          reinforced with short ceramic fiber in the hot and stressed areas.       High Thermal Conductivity Tool Steels for Die Casting
          Among the different technologies used to produce near net                of Light Alloys: Benefits and Potentials
          shape selectively ceramic reinforced aluminum piston, indirect
          squeeze casting process has been well proven for commercial                                   – Anwar Hamasaiid, Rovalma S.A., Spain
          scale production. This paper deals with the step by step process         This work deals with the application of High Thermal
          for realizing a reliable manufacturing method and sustained              Conductivity Steel (HTCS(R)) as die for High pressure
          selective ceramic fiber reinforced Al12SiCuMgNi piston through           die casting of aluminium alloys. The HTCS(R) grades have
          standardization. From the published literature, it is understood         been recently developed and patented by the company of
          that the properties of short ceramic fiber reinforced aluminum           Rovalma. In this work, prototype dies and a production
          composite depend on the matrix, fiber type, % Volume fraction,           dies were investigated. For each die the thermal behav-
          average fiber length and cleanliness(free of shots) in as cast or heat   iour of the conventional H11 and the new developed
          treat. The published details on the above topic has been analyzed        HTCS(R), during production cycles, were closely studied
          to determine the appropriate indirect squeeze casting process            and compared. The dies were instrumented by heat transfer
          parameters to ensure stable quality and productivity of mass             gauges that allow for measuring; the temperature profiles
          produced selectively ceramic fiber reinforced Al12SiCuMgNi               of the parts and of the die and evaluating the interfacial
          aluminum piston at a competitive cost.                                   heat flux density and the die surface temperature dur-
                                                                                   ing casting cycles. The results showed that the heat flux
          Effect of High-Intensity Ultrasonic Vibration on the
                                                                                   density was higher by around 20-50% and the die surface
          Microstructures of in Situ Particulate Reinforced
                                                                                   temperature was lower by around 10% with HTCS(R) dies
          Aluminum Matrix Composites
                                                                                   compared to H11 ones. By adapting the process parameter
                                – Zhiwei Liu, Shanghai Jiaotong University;        on HTCS(R) material, the cycle time was reduced by 16-
                                           Qingyou Han, Purdue University          20% with HTCS(R). The simulation work validated by the
          Clusters of reinforced particles and high porosity are usually           experimental thermal parameters shows further potentials
          present in the in situ particulate reinforced aluminum matrix            of HTCS(R) in particular for improving the efficiency of
          composites fabricated by conventional stir casting technique.            the cooling system and further increase in productivity.
          For the first time, we studied the effect of ultrasonic vibra-
          tion on the microstructures of in situ particulate reinforced            Laser Deposited Cores for Increased Production Rates
          aluminum composites. The process involved the addition of                in Aluminum Die Casting
          titanium and graphite powders into the molten pure alumi-
                                                                                       – David Schwam & Richard Tomazin, Case Western Reserve
          num at 850oC. In the meantime, high intensity ultrasonic
                                                                                                   University; Yaou Wang, Ohio State University
          vibration was applied into the melt to disperse in situ formed
          particles into the matrix. Comparision of microstructures of             A key parameter that determines cycle time in die casting
          samples without and with ultrasonic vibration was studied in             is the capability of the tooling to extract heat from the
          our research. Microstructural characterization indicated that in         solidifying aluminum alloy. The thermal conductivity of
          situ formed Al3Ti and TiC particles were distributed uniformly           tool steels is less than 20 BTU/ft*hr*F compared to copper
          in the matrix and a homogeneous microstructure with a low                alloys with over 100 BTU/ft*hr*F. Water-cooled copper
          porosity was gotten due to the effects of ultrasonic stirring and        cores are therefore very attractive as a means to shorten
          degassing. An effective approach using high intensity ultrasonic         cycle time. However, if unprotected, copper dissolves in
          vibration to optimize the microstructure of in situ particulate          molten aluminum making it inappropriate for die casting
          reinforced metal matrix composites was given firstly.                    tooling. In the current study, a 0.100” layer of H13 tool

           www.diecasting.org/congress                                               2011 1DIE CASTING CONGRESS & TABLETOP /                  67

September.indb 67                                                                                                                            8/10/2011 9:37:21 AM
           steel was laser-deposited over a water-cooled copper core
                                                                                   Die Surface Engineering
           to protect the core from direct exposure to molten alumi-
           num. A 27% reduction in cycle time was demonstrated                                                                 10:15 am - 11:45 am
           in production, by replacing a tool steel core with the H13              The Influences of Deposition Parameters on the Texture
           laser deposited core. Finite Element Analysis was under-                of a Sputtered, ‘Smart’ AlN Thin Film to be Used in Die
           taken to optimize the thickness of the laser deposited layer.           Coatings for Al Pressure Die Casting
           This analysis predicts a thinner layer of H13 can lead to an
           improvement in the thermal fatigue resistance and extend                                      – Masood Hasheminiasari, Jianliang Lin &
           core life. However, decreasing the thickness of the H13                                          John J. Moore, Colorado School of Mines
           layer will reduce the creep strength of the core. An inter-             Pulsed-DC closed field unbalanced magnetron sputtering (P-
           mediate, 0.050”-0.750” H13 layer thickness is predicted                 CFUBMS) system was used to deposit piezoelectric aluminum
           as optimal for this core configuration. A new core with a               nitride thin films in a reactive nitrogen atmosphere with different
           0.075” thick H13 layer has been fabricated and is being                 under layer (seed layer) compositions and varying substrate heat-
           evaluated in production. An added benefit of the enhanced               ing temperatures in the range of 200 to 700oC. The preferred
           heat extraction by the laser deposited cores is a faster                (002) orientation, microstructure and piezoelectric properties of
           cooling rate in the aluminum casting, leading to higher                 AlN films were characterized by means of x-ray diffraction, field
           mechanical properties.                                                  emission scanning electron microscopy and a Michelson laser in-
                                                                                   terferometry. It is found that seed layer structure/orientation and
           Using 3-D Laser Scanning to Measure Distortion of Die                   substrate heating significantly affect the (002) orientation and the
           Inserts During Heat Treatment – An Initial Feasibility Study            piezoelectric response of AlN thin films.

               – Stephen Midson, The Midson Group; Brad Johnson, Konica            Soldering Analysis of Core Pins
           Minolta Sensing Americas; Thomas Heider, Twin City Die Casting
                                                                                                     – Jie Song & Qingyou Han, Purdue University;
           Distortion of die inserts occurs during heat treatment primar-                                       Tony DenOuden, Chrysler Company
           ily due to the phase changes occurring during heating to
                                                                                   Soldering of a core pin is associated with the failure of the
           the austenitization temperature and subsequent quenching.
                                                                                   ceramic coating, the dissolution of the pin matrix metal, and
           Obtaining an accurate estimate of the amount of distortion is
                                                                                   chemical reaction between the molten aluminum and the
           important, as a suitable amount of machining stock needs to             matrix metal. Methods that prevent coating failure, retard
           be left on the rough machined tool. If the tool maker leaves            dissolution and reaction of core pin material with molten alu-
           insufficient machining stock, the tool will not clean up after          minum can be used for reducing soldering failure of core pins.
           heat treatment. Leaving too much machining stock means                  This article describes experimental results on coating failure
           that large amounts of steel needs to be removed from the fully          and dissolution rates of alloys using an accelerated method. The
           hardened tool, increasing costs and lead-times.                         method involves the use of high-intensity ultrasonic vibration
              Previous attempts to estimate the amount of distortion               to simulate die casting conditions such as high alternating pres-
           occurring during heat treatment has used Coordinate Mea-                sure and high alternating molten metal velocity on core pins.
           suring Machines (CMMs). The approach used has been                      Three types of coatings on H-13 steel have been examined for
           to measure the positions of discrete points on the surface              their failure rates and three types of core pin material (H13
           of an insert both before and after heat treatment, and the              steel, Niobium and Tungsten) have been tested for their disso-
           amount of distortion estimated by subtracting the original              lution rates in molten A380 alloy at 650°C under high-intensi-
           measurements made before heat treatment at each position                ty ultrasonic vibration. Our initial results indicate that coatings
           from their position after heat treatment. The drawback                  present barriers between H-13 steel and molten aluminum
           of the CMM approach is that it only provides data at the                alloy and retard the soldering process. As soon as coating failure
           locations measured – it does not provide any information                occurs, the dissolution rate of H-13 steel is extremely high. The
           about the remainder of the insert.                                      dissolution rate of niobium in molten aluminum is at least 3
              3-D laser scanning is an alternative approach that can pro-          orders of magnitude slower than that of H-13 steels.
           vide distortion data over the full surface of an insert. It is a non-
           contact technology that digitally captures the shape of physical        A Review of Industrial Trials Testing Coatings
           objects using laser light. A laser probe projects a line of laser       for Extended Tool Life
           light onto a surface while cameras continuously triangulate the                               – Tom Heider, Dave Kelzer & Chris Harris,
           changing distance and shape of the laser line as it sweeps along,                                  Twin City Die Castings Company Inc.
           digitizing the object in three dimensions. The 3D laser scanner
                                                                                   Twin City Die Castings Company have undertaken many
           creates a point cloud of data samples from the surface of the
                                                                                   coating trials in an effort to increase tool life. Many differ-
           object from which a digital CAD model can be made.
                                                                                   ent people offer many wonderful claims when it comes to
              The objective of the NADCA-sponsored project described
                                                                                   coatings and TCDC have found one of the easiest and most
           in this paper was to examine the feasibility of using 3-D laser         economically viable ways to test coatings is to use them on
           scanning to accurately measure distortion of die inserts during         cores. You can test different coatings in the same tool at the
           heat treatment. Two inserts were measured before and after              same time or multiple sets of coatings in sequential order.
           heat treatment using both 3-D laser scanning and a CMM.                   In some instances TCDC found a 5-10 fold increase in
           The results from the two measurement methods will be pre-               core life due to the application of the coatings. When tak-
           sented, and an analysis performed of the applicability of the           ing into account reduced replacement costs this represents
           3-D laser scanning for estimating die distortion.                       huge savings when rolled out to applicable tools.

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September.indb 69                                                                                                                               8/10/2011 9:37:22 AM
            This paper will detail the results of the trials which TCDC           In the third part, a die coated with BALINIT Lumena
          Inc. have undertaken. This will include the most recent               Duplex was evaluated. Wear and tear was documented
          results comparing two coatings, one generated through                 and compared with previous dies without coating. It was
          physical vapor deposition and one through chemical vapor              concluded that the coating was interesting and has great
          deposition. The results of these tests are compared against           potential, but it needs to be evaluated further.
          uncoated cores in two different tools.
                                                                                Proper Cooling Line Diameter in a High Pressure
                                                                                Die Casting Die
          Process Control & Engineering: Die Thermal Aspects                                     – Ralf Kind, Magma Foundry Technologies, Inc.
                                                        2:00 pm - 3:30 pm       This article discusses why simply opening the water chan-
                                                                                nel diameter for better die cooling has not the promised
          Optimization of Die Casting Processes Using                           effect and will be worse in the most cases.
          Infrared Thermography
                            – Daniel Simon, General Motors Corporation;
                             John Lafeber, North Coast Industrial Imaging       Cast Materials IV: Magnesium (Special Format)
          A very critical point to reach in any die casting process                                                           3:45 pm - 5:15 pm
          is thermal balance. This steady state thermal equilibrium
                                                                                Magnesium Alloy Systems & Classification
          point is arrived at by the die casting machine in conjunc-
          tion with all of the other parameters which can affect the                                                       – Diran Apelian, WPI
          process. Parameters include molten metal temperatures, die            An overview of magnesium die casting alloy systems and
          lube spray amounts and location, cycle times, die cooling             classification will be presented as the introduction to the
          systems, machine down times, etc. In this paper, the uses             special format session on magnesium. (Presentation only).”
          of infrared thermal vision systems capable of radiometric
          measurements are discussed as applied to several differ-              Production and Characterization of a Thixomolded
          ent die casting processes supplying parts for the auto                Magnesium Component
          industry. Key to these many uses are the goals of reduced
          cycle times, low scrap rates and maximized up time of the                       – Kumar Sadayappan, CANMET Materials Technologies
          die casting process in supplying quality parts on time. In                     Laboratory; Himesh Patel, Daolun Chen & Sanjeev Bhole,
          addition, die cast machine reliability and maintainability                         Ryerson University; Mike Vassos, Magna International
          will be discussed with respect to infrared thermal imag-              Thixomolding is a semi-solid metal molding process, extensively
          ing. Items such as electrical supply, motor control centers,          used to produce magnesium alloy components, with very high
          hydraulic systems, hot oil baths, insulation breakdown can            component quality. This is attributed to the low speed non-
          all be observed and optimized for maximum throughput.                 turbulent filling experienced in the thixomolding process. In this
          Finally, the idea of tying these measurements together into           publication the tensile properties, strain hardening, strain rate
          die cast process control using a dedicated robust infrared            sensitivity, and fracture mechanisms of thixomolded magnesium
          thermal machine vision system will be discussed.                      alloy AM60 were measured. Also, in this manuscript the develop-
                                                                                ment, of a large automotive component, Ford F-150 shotgun,
          Prediction of Die Casting Die Life Using Computer Modeling            the structural connection between the A-pillar and the radiator
                                                                                support structure, and produced by G-Mag International, is
                    – Frida Hallström & Sargon Jidah, Swerea SWECAST            presented. Evaluation of this component including structural
          For a die caster to be competitive in today’s market it would be      integrity and mechanical strength was undertaken. Results were
          a great advantage to be able to determine the optimal cycle time      correlated to microstructural features. Also, the properties of the
          and process parameters since it would lead to increased die life      shot-gun casting were compared to those of experimental plate
          and profitability. In order to achieve that, a vast amount of work    castings. Properties of the large casting were found to have a
          is needed in the field of thermal balance in dies for high pressure   higher level of scatter compared to plate castings which can be
          die casting. This paper describes a small part of that work.          attributed to the gas entrapment and oxide inclusions.
             Fatigue simulation in the software nCode is a part of de-
                                                                                Keynote: Advanced Magnesium Alloys and Processes
          veloping a computer model to calculate at what positions die
                                                                                for Weight Reduction
          wear will occur. The software can also predict the number of
          cycles after which the wear occurs. In the current situation it                                      – Alex Monroe & Steve Udvardy,
          is possible to analyse various times, temperatures, velocities                                North American Die Casting Association
          and design suggestions. This paper compares fatigue simula-           Conventional magnesium alloys have provided light-weighting
          tion to actual die wear.                                              benefits in many applications. Their property limitations
             Furthermore, the effect of using oil or water in the cooling       however, have precluded their use in many other applications,
          channels was evaluated by practical experiments. The advantage        especially those where iron-based alloys continue to be utilized.
          of oil over water is that the die reaches higher temperature with     This presentation will identify opportunities that are provided
          oil. The benefit of using water is that the die reaches the peak      by cast magnesium matrix composites which yield properties
          temperature fast and even faster to bring the temperature of the      similar to those of cast iron-based alloys. Automotive related
          die surface down. In addition, the use of water is less hazardous     and other components targeted for weight reduction by conver-
          and more environmental than oil.                                      sion to magnesium matrix composites will be sited.

           www.diecasting.org/congress                                             2011 1DIE CASTING CONGRESS & TABLETOP /                    71

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           SHS Die-Casting (SHS-DC) of Magnesium Metal                              of the thermocouple inside the cavity. The depth at which the
           Matrix Composites (MMCs)                                                 thermocouple cavity was modeled was found to be the prevailing
           – Ilguk Jo, Jacob Nuechterlein, Michael Kaufman & John Moore,            feature affecting the coefficients.
                           Colorado School of Mines; Ken Young, VForge Inc.
                                                                                    Integration of Coupled Casting and Structural Simulation
              SHS Die-casting of metal matrix composites (MMCs) is                  into the High Pressure Die Casting Development Process
           a novel process that couples rapid ceramic particle synthesis
           in-situ within molten metal during casting process. Process-                        – Sam Scott & Adi Sholapurwalla, ESI North America;
           ing of Mg metal matrix composites using self-propagating                            Ole Koser, Calcom ESI; Moritz Wuth, Takata-Petri AG;
           high temperature synthesis (SHS) was investigated and                                                     Elke Lieven, Adam Opel GmbH
           implemented to produce Mg MMCs billets as a function of                  In part design, a component typically must meet structural design
           processing parameters and different volume fraction of TiC               criteria of loadings expected when the part is in use. Initial designs
           reinforcement. Powder chemistries were optimized to reduce               must use assumptions regarding material properties, such as a
           the ignition temperature of the SHS reaction for coupling                typical strength and homogeneity throughout the component.
           with ignition of the powder pellets in molten Mg.                        However, cast parts rarely have such a consistent microstructure
              Billets of Mg-TiC MMCs were successfully semi-solid die               and material continuity as the design assumptions. Therefore,
           cast into lightweight automotive parts and wedge test specimens          parts may display a different performance than expected, such as
           which can be used for mechanical testing specimens. Microstruc-          part shape, durability or strength under loading.
           tural development and Mechanical properties of the Mg-TiC                   Ideally, design would factor in such inconsistencies and local
           MMCs are investigated by X-ray diffraction (XRD), Scanning               metallurgical characteristics to ensure an expected performance.
           electron microscopy (SEM), Rockwell Hardness test, compres-              Structural simulations used in the design stage need the as-cast
           sion test, wear test and Chevron notch 4 point bend test.                morphological characteristics and defects to provide a viable and
              SHS-DC techniques provide a feasible way to produce in-situ           perhaps optimized design. Takata-Petri and ESI have determined a
           and net shaped Mg-TiC MMCs product. Microstructural analy-               method to “couple” structural and high pressure die casting simu-
           sis shows favorable microstructures with uniform particle size and       lation to chain the material history from the casting process, using
           distribution in product. The mechanical testing results show that        the commercial software ProCAST, into the structural test analy-
           the in-situ formed TiC reinforcement can increase the hardness,          sis, which significantly increases the correlation accuracy between
           tensile strength and wear resistance of the Mg MMCs.                     analysis and destructive test results. In this paper, simulation and
                                                                                    experimental results of a magnesium steering wheel are presented
           Panel Discussion: Diran Apelian, WPI; Alex Monroe, NA-                   to demonstrate and validate this simulation coupling capability.
           DCA; Michael Kaufman, CSM
                                                                                    Modeling Dynamic Pressure in High Pressure Die
                                                                                    Casting Using a Lumped Parameter Model
           Wednesday, September 21                                                                       – Hongyu Xue, Khalil Kabiri-Bamoradian &
                                                                                                              Allen Miller, The Ohio State University
           Computer Modeling I
                                                                                    A large dynamic pressure spike due to the rapid deceleration
                                                          8:30 am - 10:00 am        of the liquid metal, plunger, and hydraulic oil is experienced at
           Process Parameters and Modeling Features Affecting                       the end of injection in high pressure die casting and plays a key
           Interfacial Heat Transfer Coefficients in the Casting                    role in die flashing. The fact that the cavity pressure and plunger
           of a Semi-Solid 357 Aluminum Alloy                                       speed are tightly coupled makes prediction of transient cavity
                                                                                    pressure extremely difficult using current fluid flow simulation
           – Claudia Sheehy & Dominique Bouchard, Aluminum Technology               approaches. The purpose of this research is to develop a simple
                Center - National Research Council Canada; André Charette,          model that can predict transient cavity pressure, gain insight
                                         Université du Quebec à Chicoutimi          about the influence of the shot profiles on the cavity pressure
           A study was carried out to identify process parameters and mod-          spike, and also can be used as an input for die distortion model-
           eling features affecting interfacial heat transfer coefficients in the   ing. A multi-degree of freedom lumped-parameter model that
           casting of a semi-solid 357 aluminum alloy. A 2-level screening          represents the injection system and die casting machine was
           design was created to evaluate the effect of 5 process parameters        developed and implemented in MatLAB’s Simulink. This model
           on these coefficients. The varied parameters were the following:         addresses the coupling issues between plunger speed and pressure
           set die temperature, intensification pressure, plunger velocity,         and predicts the transient cavity pressure during cavity filling in a
           lubricant type and lubricant quantity. The interfacial heat transfer     fast and inexpensive way. Different shot plunger deceleration pro-
           coefficients were calculated with an inverse heat conduction             files were studied and useful insights into the die responses were
           method using as inputs the measured die temperatures obtained            achieved. The factors included in the study are deceleration start
           from the various casting conditions in the screening design. The         time, plunger position when velocity is zero, plunger position
           effects of these process parameters were quantified considering 2        when controller switches to pressure control, and hydraulic pres-
           response variables: the peak value of the coefficients and the time      sure rise time to full accumulator pressure. The maximum cavity
           the coefficients decreased to 5 % of their peak value. The inten-        pressure was predicted with the aid of above lumped-parameter
           sification pressure was found to be dominant for both response           model. A design of experiments study was performed in which
           variables. It was also observed that features in the finite element      both linear and quadratic regression models were used to evaluate
           model used to solve the inverse heat conduction problem affected         the effect of these factors on the cavity pressure spike. The results
           the coefficients. The features investigated in the model were: the       show quantitatively that a decelerated plunger shot profile can
           thermocouple cavity, its depth, its base angle and the presence          dramatically decrease the impact pressure spike.

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September.indb 72                                                                                                                                  8/10/2011 9:37:23 AM
                                                                             complex. Thin wall castings, in combination with new
          Computer Modeling II
                                                                             materials, offer weight reduction with increased strength.
                                                    10:15 am - 11:45 am      These significantly increase the application fit in functional
          Runner Design Optimization of a Thin Walled                        assemblies for pressure die castings.
          Aluminum Casting                                                      Secondary operations like welding, riveting, and heat
                                                                             treatment have raised quality requirements for these highly
                    – Deepika Gaddam, Magma Foundry Technologies, Inc.;      engineered castings. In order to achieve the greater struc-
                                       Tom Malicki, Empire Die Casting       tural uniformity, high efficiency vacuum systems are rou-
          Die casting is a dynamic process and a well designed tool is a     tinely used on die cast dies. We have found that standard
          necessity. A simulation analysis of the tool design can prove      vacuum valves did not provide adequate size for the gas
          to be a cost effective approach for efficient production with      ventilation in our systems. Rather than adding second and
          required casting quality. Foundries can now integrate the opti-    third valves to our die systems, with the associated added
          mization tool in the engineering phase to obtain the optimum       operational complexity, we have showed that size of ven-
          casting design and process much quicker.                           tilation system could be tripled to meet vacuum require-
             Empire Die Casting has incorporated such methods in their       ments of the die cast process in a single valve. Through
          engineering department recently for efficient production with      numerical analysis, utilizing general CFD capabilities of
          higher quality castings. Empire Die Casting specializes in
                                                                             Flow3D, a standard vacuum block was modified to achieve
          aluminum and zinc casting for a very diverse range of industries
                                                                             calculated size of cross-sectional area of the ventilation
          and applications. One of their manufactured castings is a thin
                                                                             channel. Subsequent production runs determined that the
          wall aluminum part with approximately 3.5 “ high wall and
          0.07” grove machining application. The main fall out cause was     numerical calculations were in good correlations with the
          gas porosity and the production ran with high scrap rate.          results generating the improvements predicted.
             As part of their learning process, they utilized MAGMA-
          frontier to design the runner system for the thin walled alu-
          minum casting. The autonomous optimization tool utilizing          Equipment: Metal Melting (Special Format)
          the genetic algorithms selected the best design with lower                                                      2:00 pm - 3:30 pm
          air entrapment within the defined range of parameters. The
          optimized runner has been cut into the tool and the scrap          Keynote - Electric Melting: The Most Efficient
          rate has been significantly reduced. Integrating the optimiza-     Means of Melting Aluminum
          tion tool has helped them in attaining good quality castings                               – David White, The Schaefer Group, Inc.
          in a cost effective way with in the allowed time frame.
                                                                             This paper will give you all the pros and cons to electric
          Runner Design Optimization Based on CFD Simulation                 melting of aluminum. It will include the latest technology for
          for a Die With Multiple Cavities                                   electric reverbs and Immersion element furnaces that both
                                                                             melt and hold metal. There will be a portion on Solar electric
                    – Yaou Wang, Allen Miller & Khalil Kabiri-Bamoradia,     melting the latest in Green technology melting and holding
                                                The Ohio State University
                                                                             of aluminum. Discussions on ROI and actual energy savings,
          As part of the NADCA HyperCast project, computational              metal melt loss and maintenance will be covered.
          fluid dynamic (CFD) methods were applied to analyze a
          high pressure die casting (HPDC) die containing six cavities       Bringing Back Electric Melting
          producing various test specimen. As is typical, each specimen
          cavity is connected to the main runner by a separate brunch               – Robert P. Dathe, A&B Die Casting; Frank B. Smith &
          runner. The connection of the brunch runners to the main                                             Matthew R. Smith, Rayteq
          runner strongly influences the filling ability of each specimen    Since the early 1980s many die casters have come to appreci-
          cavity. The purpose of this study was to analyze the influence     ate the quality advantages of clean electric melting at the die
          of the runner trajectory and directional change on the ability     casting machine, particularly wherever machined castings are
          to smoothly fill the cavities. CFD simulation was used and         involved. They’ve also learned that electric melting can greatly
          different runner designs are compared. An optimized design         reduce air quality problems while improving the working
          is proposed and some general observations about the effects of     environment by eliminating excessive heat stress and noise.
          runner geometry on pressure and fill are provided.                 As a result, many die casters installed electric melting at the
                                                                             machine to gain these advantages while reducing plant energy
          Optimization of the Die Cast Die Vacuum System
                                                                             costs compared with fuel fired melting.
          Using Numerical Simulation
                                                                                However, in the past decade some electric utilities have
               – Alexandre Reikher & Harold Gerber, Albany Chicago LLC       worked at cross purposes to the die casting industry by
          Numerical analysis has become an integral part of pro-             increasing electricity cost, particularly with respect to kW
          cess development in the die cast industry. With more               demand charges, making electric power less competitive with
          economical and faster computers, and more efficient and            fuel fired melting. This led some die casters to return to fuel
          accurate numerical approximations, engineers can examine           firing at the price of forfeiting their gains in casting quality,
          more design options and achieve better results in a much           air cleanliness and improvements in working environment.
          shorter time. This numerical simulation coupled with the              But now, new technology has arrived that reduces electric
          efforts to reduce energy consumption, reduce mass, and             utility charges so electric melting at the machine once again
          achieve greater efficiency, die cast parts have become more        makes economic sense. While this technology does include

           www.diecasting.org/congress                                          2011 1DIE CASTING CONGRESS & TABLETOP /                   73

September.indb 73                                                                                                                        8/10/2011 9:37:23 AM
           improved furnace design for better thermal efficiency and             The bottom line is that an atomizer for each point of spray
           new, higher performance electric heating elements, the main         will result in lower lube usage and increased part quality.
           focus is on bringing down the aggregate kW demand of a
           group or fleet of electric melting furnaces with a novel closed-    Die-Casting Magnesium with a Dry Powder
           loop central energy management system (EMS) to interact             Lubrication System
           with and synchronize each furnace’s power demand.
                                                                                       – Chris Harris, Greg Tryman, Ed George & Tom Heider,
             This interactive EMS effectively holds total fleet kW de-
           mand to the minimum required to meet production melting                                      Twin City Die Castings Company Inc.
           needs without adversely impacting die casting cell perfor-          Lubricants are applied to the tool in high pressure die cast-
           mance. Each furnace features unique digital/analog hybrid           ing to aid the release of the part, minimize soldering, add
           power controls that maintain two-way digital communication          cooling and generally to extend the life of the die through
           with the central EMS while avoiding outdated, failure prone         better running conditions. However, there are issues with
           and waste-heat generating solid state SCRs or thyristors.           traditional lubricants which tend to be water-based. They
                                                                               are notoriously wasteful, they sometimes have special
           Waste Heat to Energy for Aluminum Furnaces                          disposal requirements, they can be costly and most impor-
                                  – David White, The Schaefer Group, Inc.      tantly raise safety concerns due to the proximity of water
                                                                               to molten metal which is always undesirable.
           This paper will deal with the reality of trying to produce
                                                                                  There exists another lubricant which is both novel in
           elctricity fomr the exhaust stacks of large melting furnaces.
           Real numbers to compare with existing and future ROI for            formulation and application. It is a dry powder applied
           coverting waste heat to electricity will be presented. Com-         electrostatically to the surface of the tool. Applied in the exact
           parisons will be made to the additional qualified staff to          same manner as powder painting the powder lubricant wraps
           the amount of potential savings per year. Ohio has created          around features on the tool.
           real incentives for utilities to accept co-generated electric-         Runs of this dry powder lubricant during the die casting
           ity. Attend this paper and see how it can be done.                  of a magnesium bicycle fork have shown the powder to
                                                                               extremely cost effective. This has occurred at no detriment
           Panel Discussion: David White, The Schaefer Group, Inc.;            to part quality. In addition there are significant safety
           Frank B. Smith, Rayteq; Steve Udvardy, NADCA                        improvements from decreasing exposure of the molten
                                                                               metal to water and great environmental benefits due to less
                                                                               waste during application. This paper details the trials and
           Die Lubricants & Die Preparation                                    implementation of this new system at TCDC Inc.
                                                        3:45 pm - 5:15 pm
                                                                               Moving Out Of The “Stone Age”
           Improving the Efficiency of Die Spraying
                                                                                        – Jerald Skoff & Tim Newman, Badger Metal Tech, Inc.
                            – Jason Hoffman, Mark Riekert & Jerry Osborn,      In the past 20 years, major advances have been made in man-
                                                        Rimrock Corporation    ufacturing tooling. With today’s technology, very few tools
           Balancing simplicity and functionality in a spray manifold          fail the PPAP process for geometry reasons. We can attribute
           presents challenges for every die casting manufacturer – a          this to better steels, better heat treatment, solid models, mold
           challenge that some die casters often struggle with.                flow modeling, high speed spindles with 5 axis technology,
              In an effort to keep initial costs low, many companies           cutter path logic control, new cutter coatings and EDM’s with
           take the simplest approach, which is to utilize systems             advanced minimum white layer controls. The advances are so
           which distribute the spray from a single atomizer to mul-           dramatic that they require us to take a look back and question
           tiple spray tips. Although this may at first seem to be the         the logic for still doing some of the steps.
           most cost effective approach, it can be much more costly               This paper will present an analysis of these methods, what
           in the long-term when variables such as lube consumption
                                                                               effect they are having on tool life and conclude with a suggested
           and costs of poor quality are considered.
                                                                               logic that makes more sense when all of the facts are considered.
              A more effective approach to the spray challenge, and one
                                                                                  We begin with a study of the complete tool building pro-
           that deserves consideration, is to utilize one atomizer for every
           point of spray required. This approach reduces the amount of        cess, questioning why it is counter productive to wait until
           lube required as well as placing each atomizer as close as pos-     final sampling. Concentration will be in the area of stoning
           sible to the desired point of spray.                                and polishing. Our studies and experience involving over
              Because the lube is metered into the air stream for each         100,000 die failures show that draw polishing with a 180 to
           individual point of spray instead of metering the lube into the     320 grit stones is actually cutting stress risers into the surface
           air stream and then dividing that mixture into several points       and fillets/radius of the steel. It is in these fillets/radius where
           of spray, the lube stays atomized and distribution is improved,     the first signs of heat checking and fatigue cracking occur. In
           thereby optimizing spray consistency. Furthermore, by im-           the past it was necessary, however, stoning for the draw polish
           proving the distribution and metering of lube to each unique        finish today is, in most cases, not necessary and is actually
           spray point, less lube is wasted by over-spraying areas of the      a major leading cause for crack and heat check propagation
           die in the effort to adequately spray the rest of the die.          leading to reduced tool life. We will then shake the core of
              In addition to reduced lube usage, die temperatures can be       this “old logic” replacing it with “modern concepts” embrac-
           held more consistent and the possibility for excess lube, which     ing the “New Build Technologies” that will not only reduce
           causes part porosity, is reduced.                                   overall tooling cost but also extend tool life.

           74/DIE CASTING CONGRESS & TABLETOP 12011                                                                www.diecasting.org/congress

September.indb 74                                                                                                                           8/10/2011 9:37:23 AM

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