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									                         Louisiana Team AgEd
              Louisiana Agriscience Education Curriculum
Course:           Agriscience I

Unit:             8. Agricultural Mechanics

Lesson:           7. Arc Welding


LOUISIANA CONTENT STANDARDS AND GRADE LEVEL EXPECTATIONS

Content Standards:
   1.   Identifying careers and appropriate work behavior in the welding industry.
   2.   Identifying and applying skills in welding safety.
   3.   Demonstrating basic competencies needed for applying welding skills.
   4.   Demonstrating shielded arc welding skills (stick).
   5.   Identifying and applying the safe set up, lighting, adjusting and usage of oxyfuel
        equipment.


Grade Level Expectations (GLE)
   1. Listen to detailed oral instructions and presentations and carry out complex
      procedures, including: reading and questioning, writing responses, forming
      groups, taking accurate, detailed notes (ELA-4-H2).
   2. Use counting procedures and techniques to solve real-life problems (D-9-H).
   3. Differentiate between accuracy and precision and evaluate percent error (PS-H-
      A1).
   4. Evaluate diagrams of series and parallel circuits to determine the flow of
      electricity (PS-H-G2).
   5. Identify evidence of chemical changes (PS-H-D1).


PERFORMANCE-BASED LEARNING OBJECTIVES. Instruction in this lesson should
result in students being able to:

        1.   Successfully strike an arc.
        2.   Demonstrate procedure for cutting metal with oxy-acetylene.
        3.   Successfully run a stringer bead.
        4.   Identify careers associated with welding.




                Louisiana Team AgEd - Agriscience Education II Curriculum - Page 1 of 28
LIST OF RESOURCES. Teachers may find the following resources useful in planning
and teaching this lesson:

Textbooks
      Herren, Ray V. Agricultural Mechanics Fundamentals and Applications 6th Edition. Clifton Park:
       Delmar, 2010.

      Herren, Ray V. Lav Manual to Accompany Agricultural Mechanics Fundamentals and
       Applications 6th Edition. Clifton Park: Delmar, 2010.


Web Sites
    http://www.lsu.edu/lata/ag1.htm
    http://aged.ces.uga.edu/Browseable_Folders/Curriculum/Lesson%20Plans/index.
       htm


Other Resources. The following resources will be useful to students and teachers:
    www.nccer.org
    www.aws.org
    www.ansi.org
    CEV Multimedia Shielded Stick Metal Arc Welding
    Lincoln Electric Technical Training Department DVD’s


TERMS. The following terms are presented in this lesson:
  1. Weld                                         11. Flash burn
  2. Welding                                      12. Arc
  3. Shielded metal arc welding                   13. Electorodes
      (SMAW)                                      14. Slag
  4. Welding shop supervisors                     15. Duty Cycle
  5. Welding engineers                            16. Amperage
  6. American Welding Society (AWS)               17. Conductor
  7. Entry Level Welder                           18. Voltage
  8. Ultraviolet                                  19. Wattage
  9. Infrared                                     20. Alternating Current
  10. Visible                                     21. Direct Current




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LIST OF EQUIPMENT, TOOLS, SUPPLIES, AND FACILITIES
     .Arc Welder                         Welding gloves
     Electrodes                          PPE
     SMAW                                Chipping Hammer
     Oxyacetylene Torch                  Pliers
     Valves                              Wire Brush
     Regulators                          Soap Stone
     Hoses                               Grinder
     Striker                             Water
     Tip Cleaners                        Supplied PowerPoint
     #5 Shade goggles


INTEREST APPROACH.
   1. Bring students into shop and explain some of the safety procedures that need to
      be in place for a safe welding experience.
   2. Group and ask them to make a list of 5 things that are welded together and 5
      things that could not be made without being welded together.
   3. Have students make a graphic organizer listing all PPE that needs to used after
      walking them through shop and explaining welding safety.



SUMMARY OF CONTENT AND TEACHING STRATEGIES
NOTE: You may notice the Objective numbers out of order. These objectives were
rearrange according to way they should be taught. Numbers match LDE and
BESE approved objectives.


   A. Objective 2: Demonstrate procedure for cutting metal with oxy-acetylene.

      Anticipated Problem: What three things must react for you to have a fire?




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CONTENT

  1. What is OFC?
        a. OFC = Oxygen Fuel Gas Cutting
  2. OxyFuel Gas Cutting
        a. A group of oxygen based cutting processes that uses heat from an oxyfuel
            gas flame to bring up to the kindling temperature and helps maintain the
            cut on steel. Severing of the material is achieved by the oxygen jet which
            burns the iron in the steel, which has been heated to kindling temperature
            by oxyfuel preheat flames.
  3. Advantages
        a. No Electricity Required
        b. All Position Cutting
        c. Extremely Portable
        d. Low Cost Equipment
        e. Suitable for Cutting Thick & Thin Materials
        f. Can be Readily Used Underwater
        g. Requires Moderate Operator Skill Level
  4. Limitations
        a. Materials Limited, Primarily Ferrous
        b. Additional Operator Protection Necessary
        c. Must Operate under “Hot Zone” Concept
        d. (Fire Hazard)
        e. Various Hazards Associated with Handling of Fuel Gases and High
            Pressure Gases
        f. Flashbacks and Backfires
  5. Safety Precautions
        a. Wear safety goggles and face shield at all times
        b. Obtain instructor’s permission before using any gas
        c. Store fuel gas cylinders and oxygen cylinders separately
        d. Keep cylinders upright and chained at all times
        e. Store cylinders in well-ventilated areas
        f. Do not put pressure on the hoses or equipment connected to cylinders
        g. Always check for leaks before using
        h. Never use equipment exposed to grease or oil
        i. Follow specific on/off procedures
        j. Work only in areas free of flammable materials
        k. Always have fire extinguishers nearby
        l. Wear leather gloves and apron
        m. Always screw on caps when cylinder is not in use
        n. Always point equipment away from people and clothing


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       o. Never leave clothing where it can be saturated by fuel gases or oxygen
       p. Learn to recognize combustible fuel odors
       q. Protect gas cylinder storage areas with locked fences or concrete
          enclosures
6. Safety
       a. Eye & Ear Protection
       b. Welding Goggles with Proper Lens Shade Number
       c. Welding Gloves & Optional Covering
       d. Proper Attire for OFW, OFC, OFB, & AFS
       e. Eye & Ear Protection
       f. Headgear
       g. Optional Covering
       h. Proper Attire
7. Fumes & Gases
       a. Welding or Cutting May Produce Hazardous Fumes & Gases
       b. Leaking Gases May Cause Injury or Death
       c. Use Ventilation To Keep Air Breathing Zone Clear & Comfortable
       d. Use Special Care When Welding or Cutting In a Confined Area or on a
          Container
       e. Do Not Weld or Cut Near Flammables
8. Oxyacetylene Equipment - Slides
9. Leak tests should be performed when
       a. equipment is first set up
       b. cylinders are changed
       c. odor of acetylene is present
10. To test
       a. Put a small amount of water in a jar or can
       b. Add a drop or two of non-detergent hand soap
       c. Use a 1'' paintbrush to get a soapy lather and apply gently around each
          fitting or any connection where gas can escape
       d. Bubbles will form if there is a leak
11. Terms
       a. Weld: to join by fusion
       b. Fusion: to melt together
       c. Gas: any fluid substance that expands without limit
       d. Compress: to reduce in volume by applying pressure
       e. Flammable: burns easily
       f. Apparatus: objects necessary to carry out a function
       g. Important Terms (continued)
       h. Manifold: a pipe with two or more outlets



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      i.   Rig: a self-contained piece of apparatus assembled to conduct a specific
           operation
       j. Oxyacetylene: oxygen and acetylene
       k. Torch: assembly that mixes gases and discharges them to support a
           controllable flame
       l. Cylinder: long, round tank with extremely thick walls built to contain gases
           under great pressure
       m. Valves and regulators: devices that control or regulate the flow of a gas
       n. Gauge: measures the gas pressure in a hose, tank, or manifold
       o. Hoses: flexible lines that carry gases
       p. Crack the cylinder: turning the gas on and off quickly to blow away any
           dust from the opening
       q. Purge the lines: remove undesirable/leftover gases in the welding hoses
       r. Carbonizing flame: excess acetylene present in the flame
       s. Neutral flame: correct balance of acetylene and oxygen in the flame
       t. Oxidizing flame: excess oxygen in the flame
       u. Tip cleaners: rods with rough edges designed to clean the hole in the
           welding tip
       v. Bleeding the lines: removing gases from all lines and equipment
12. Which Fuel Gas?
       a. Acetylene
       b. Methylacetylene-propadiene
       c. MAPP
       d. Propylene
       e. Propane
       f. Natural Gas
       g. Methan
13. Cylinders
       a. Oxygen Cylinder Valves
       b. Acetylene Cylinder Valves
       c. Regulators
14. Torch types
       a. welding
       b. cutting
15. Regulator types
       a. Single Stage Regulator
               i. Use When Slight Rise in Delivery Pressure from Full to Empty
                  Cylinder Condition Can Be Tolerated
       b. Two Stage Regulator




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             i. Use When a Constant Delivery Pressure from Full to Empty
                Cylinder Condition is Required
16. Have student complete a cut in the welding shop.




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  B. Objective 1: Successfully strike an arc.

     Anticipated Problem: What does it take for an electrical circuit to be complete?


CONTENT:

  1. Shielded Metal Arc Welding

         a. Welding process that uses electrodes

         b. Also called arc welding or stick welding

  2. Advantages

         a. Electricity and welders relatively inexpensive

         b. Works with ordinary 240-volt wiring

         c. Available in a portable form

         d. Fast and reliable

         e. Can also be used for heating, brazing, and hard surfacing

  3. Electricity for Welding

         a. Ampere or amp: rate of flow of electrical current in a conductor

         b. Conductor: material that permits electrical current to move through

         c. Volt: measure of electrical pressure

         d. Watt: measure of energy available

         e. Formula: W × V = A or W = V/A

                  i. Know as West Virginia Formula

         f. Transformers: convert high voltage and low amperage to low voltage and
            high amperage

         g. Alternating current: reverses direction of flow cyclically

         h. Generator: produces direct current

         i.   Direct current: flows in one direction only


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     j.    Polarity: the direction of the flow of electricity in the welding circuit

     k. Straight polarity: DC current flowing in one direction

     l.    Reverse polarity: DC current flowing in opposite direction

4. Welding Equipment

     a. Valves

     b. Regulators

     c. Hoses

     d. Striker

     e. Tip Cleaners

     f. #5 Shade goggles

     g. Welding gloves

     h. PPE

     i.    Chipping Hammer

     j.    Pliers

5. NEMA Color Coding

     a. NEMA: National Electrical Manufacturers Association

     b. Colored markings are placed on electrodes in three areas: the exposed
        end of metal rod, exposed surface, flux near exposed rod

     c. Most manufacturers stamp the AWS classification number on each
        electrode instead of using the color-code system

6. AWS Numerical Code

     a. AWS: American Welding Society

     b. Code condenses information into a four- or five-digit number for mild steel
        electrodes

7. Terms

     a. Slag: layer of burned flux and impurities



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      b. Duty cycle: percentage of time that a welder can operate without
         overheating

      c. Chipping hammer: steel hammer with a sharp edge and/or point

      d. Tensile strength: the amount of tension the finished weld can withstand

      e. Safety Procedures

8. Welding area should consist of

      a. metal benches

      b. booths made of fireproof or fire-resistant materials

      c. fire extinguishers for class a, b, and c fires

      d. safety equipment, first-aid kit, and wool fire blanket

      e. buckets of water

      f. no oil, grease, paper, sawdust, rags, or other flammable materials

9. Personal protection equipment (PPE)

      a. #10 shade lens with flip-up lens or auto darkening hood and safety
         glasses

      b. Fire-resistant coveralls

      c. High leather shoes

      d. Leather gloves

      e. Cover all exposed skin

10. Setting Up

      a. Pick appropriate electrode

      b. Eliminate fire hazards

      c. Gather all necessary materials

      d. Make sure the welding machine has suitable welding cables

      e. Put on safety clothing including helmet

      f. Select your amperage


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       g. Be sure the metal is clean and free of any oil, grease, or rust

       h. Strike the arc

11. Have students try striking an arc in a welding booth.




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  C. Objective 3: Successfully run a stringer bead.

     Anticipated Problem: What is the purpose of a flash light? Why do women
     generally make better welders?

CONTENT:

  12. Beads

        a. A bead is produced by handling the electrode so that there is a proper mix
           of base and filler metal

        b. Stringer bead: made without weaving

        c. Weaving: moving the electrode back and forth (side to side) to create a
           wider bead

        d. Running a Bead

  13. Electrode angle

        a. Lean slightly in the direction of travel; usually a 75° to 80° angle (or 10° to
           15° from vertical)

        b. Obtain correct arc length

        c. Move across metal at a uniform travel speed

        d. Check for correct amperage setting (semicircles should be wider than they
           are long)

        e. If weaving for the first time, start using a circular pattern

  14. Butt Welds

  15. Butt joint: pieces placed end to end or edge to edge

        a. Leave a gap between the two pieces that is about the thickness of the
           electrode core

        b. Be sure all slag is removed between beads to ensure a solid weld without
           voids

  16. Fillet Welds

        a. Fillet joint: two parts come together to form a 90-degree angle


           Louisiana Team AgEd - Agriscience Education II Curriculum - Page 12 of 28
              i. Be sure to prepare the vertical piece so the weld metal will fuse
                 both pieces completely

             ii. Follow a procedure similar to butt welds

             iii. Remember that heat rises, so watch the top piece for overheating

17. Welding Positions

      a. Horizontal: moving horizontally across a vertical piece of metal

      b. Vertical: moving up or down across vertical piece of metal (weaving is not
         recommended)

      c. Overhead: the metal is positioned above the welder




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     D. Objective 4: Identify careers associated with welding.

        Anticipated Problem: How far are you willing to go to make money? Could your
        job affect your life expectancy?

CONTENT

1.      Industrial Revolution (1750 – 1850) forge welding

        a. Also known as hammer welding

        b. A forge was used to heat metal

        c. The ends of the iron were hammered together

2.      Elihu Thomson - resistance welding (1886)

        a. Faster, more reliable

3.      Riveting was replaced by fusion welding

4.      Welding considered vital to military security

5.      Welding repairs to ships damaged during World War I were done in secrecy

6.      Uses of Welding

        a. Ships, bridges, recreational rides, machines to manufacture new products

        b. Commercial and military aircraft

        c. The space program

               i. Modern techniques enabled space exploration

               ii. The space shuttle's construction required the improvement of welding
                   processes

7.      Welding Processes

        a. The number of welding processes has grown recently

        b. Processes differ in the manner in which heat, pressure, or both are applied

        c. Popular welding processes:

               i. Oxyacetylene welding (OAW)



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             ii. Shielded metal arc welding (SMAW)

            iii. Gas metal arc welding (GMAW)

            iv. Flux cored arc welding (FCAW)

            v. Torch brazing (TB)

8.    Shielded metal arc welding (SMAW)

      a. Makes high-quality welds rapidly

      b. Excellent uniformity

9.    Gas tungsten arc welding (GTAW)

      a. Provides high- quality welds

      b. Requires little or no postweld finishing

10.   Gas metal arc welding (GMAW)

      a. Easily used for thin-gauge metal and heavy plate

11.   Flux cored arc welding (FCAW)

      a. Does not use an external shielding gas

12.   GMAW and FCAW most commonly used

13.   Selection of the joining Process

14.   Selection depends upon many factors

      a. Availability of equipment

      b. Repetitiveness of the operation

      c. Quality requirements

      d. Location of work

      e. Materials to be joined

      f. Appearance of the finished product

      g. Size of the parts to be joined

      h. Time available for work


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      i.   Skill or experience of workers

      j.   Cost of materials

      k. Code or specification requirements

15.   Selection of the joining Process (continued)

16.   The welder must also select the application method:

      a. Manual – the welder manipulates the process

      b. Semiautomatic – filler is added automatically

      c. Machine – done mechanically under observation

      d. Automatic – no interaction with the operator

      e. Automated – performed repeatedly by a robot programmed for multiple tasks

17.   Occupational Opportunities in Welding

      a. Welders perform the actual welding

      b. Tack welders make small welds to hold parts in place

      c. Welding operators operate automatic equipment

      d. Welders' helpers clean slag, position weldments

      e. Welder assemblers position the parts

               i. Interpret blueprints and welding procedures

              ii. Knowledge contraction and expansion of metals

      f. Inspectors hold a special certification

      g. Shop supervisors have good management skills

      h. Salespersons have understanding of welding and marketing skills

      i.   Shop owners are often skilled welders with knowledge of small-business
           management

18.   The test for welding inspector certification covers:

      a. The welding process, blueprint reading



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      b. Weld symbols, metallurgy

      c. Codes and standards, Inspection techniques

19.   Training for Welding Occupations

      a. Both school and work experience are required

      b. An entry-level welder must have workplace skills

      c. Some welding jobs require theoretical knowledge

      d. Robotics and computer-aided manufacturing (CAM) require computer literacy

      e. Employers prefer high school or vocational training in welding processes

      f. A formal apprenticeship is usually not required

20.   The American Welding Society (AWS)

      a. Three levels of certification for welders

      b. Entry Level Welder ids for beginner welders

      c. Level II and Level III for more skilled welders

21.   FFA

      a. Sponsors welding skill competitions for students

      b. Emphasizes community service and citizenship


Bibliography
Herren, Ray V. Agricultural Mechanics Fundamentals and Applications 6th Edition.
Clifton Park: Delmar, 2010.

Lincoln Electric. Shielded Metal Arc Welding. Cleveland, December 2004.




            Louisiana Team AgEd - Agriscience Education II Curriculum - Page 17 of 28
ASSESSMENT / CRITICAL THINKING SKILLS

After student have completed a bead, have them self-evaluate themselves as well as
one other student in the class.

ANALYSIS:
   1. Students should be able to recognize relevant components a good/acceptable
      bead.
         a. Is the bead acceptable according to AWS standard?
   2. The student will uses logic to support the conclusion of their answer to number
      one?

         a. How did you come to this conclusion of it being a good or bad weld?

   3. Students will differentiate among facts, opinions, and assumptions within the
      conclusion on the weld.
         a. If you had to choose between your weld or the other weld, which one
            would you choose?
EVALUATION:
      1. Student will assess people’s general acceptance of the conclusion as being
         correct of whether their weld is good or not.
             a. Does your partner agree with your conclusion and what is their
                argument either way?
      2. Student will offers supplementary information that may strengthen the
         conclusion?
             a. What could have been done better to improve the weld? What
                conditions?
      3. Student will determines the significance of the conclusion based on future
         implications of their weld

             a. If you had to use the weld that you presented, where would be best be
                 suited? Where object could your weld hold together?

INFERENCE:
      1. Student will develop possible alternative conclusions to consider.

             a. Would other consider you and your partners weld to be sufficient?

      2. Student will identify specific implications as a result of the given conclusion.


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              a. If your weld had to be used as a safety device would it be advised and
                 why or why not?

       3. Gives recommendation or a plan to gather more information.

              a. What practices could you do to help hone your welding skills?


REVIEW/SUMMARY. Use the student learning objectives as the basis for review and
summary. (Discussion, Q&A, examples of observed methods, etc.)

One of the most important tools for use in working metal is that of oxyacetylene. Using
these gases, metal can not only be cut, but can also be joined. The use of oxyacetylene
can be safe if the proper procedures are followed There are several types of arc
welding. All involve the use of an electrical current that melts the metal. The correct type
of welder, electrode, and technique should yield a strong, attractive weld. With this skill
comes many career options that can lead to lifelong employment.

APPLICATION

Have students complete a cut on mild steel. After completing the process of being able
to maintain an arc, have student weld a stringer bead, and evaluate the result.

Showing the welding video from CEV or Lincoln Electric would be HIGHLY
suggested. These are available for purchase from those vendors.




             Louisiana Team AgEd - Agriscience Education II Curriculum - Page 19 of 28
                           Sample Welding and Oxyfuel Test

Multiple Choice. Identify the choice that best completes the statement or answers the
question.

____1. Brazing is the process of ____ with metals and alloys that melt at or above
       840°F.
       a. gluing                              c. bonding
       b. heating                             d. shaping


____2. What device converts high voltage and low amperage to low voltage and high
       amperage?
       a. generator                          c. transformer
       b. welder                             d. electrode holder


____3. A welder puts out high amperage, so it needs
       a. large electrical cables             c. long electrical cables
       b. small electrical cables             d. no electrical cables


____4. A carbon arc torch is a device that holds two carbon sticks and produces a
       ____ from the energy of an electric welder.
       a. current                              c. stream
       b. flame                                d. spark


____5. What is the temperature of the arc created by a welder?
       a. 1000°F                              c. 9000°F
       b. 212°F                               d. 5000°F




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Completion. Complete each statement.

6.   Since the 1800s, ____________________ gases have been combined with
     oxygen for the purpose of welding metals.

7.   Slag is a good ____________________.

8.   Brass is a mixture of ____________________ and ____________________.

9.   The fuel most suitable for gas welding is ____________________.

10. ____________________ and ____________________ are used extensively for
    general heating.

11. ____________________ is the distance from the metal to the torch tip.

12. A machine that produces current for welding is known as an
    ____________________.

13. An ____________________ is the discharge of electricity through an air space.

14. The ____________________ is the percentage of time that a welder can operate
    without overheating.

15. Any material that permits current to move through it is a ____________________.

16. A ____________________ is a measure of electrical pressure.

17. A ____________________ is a measure of energy available.

18. A ____________________ is a machine that produces direct current.

19. ____________________ refers to the amount of tension or pull the weld can
    withstand.

20. In terms of gauge for electrical wiring, the lower the gauge, the
    ____________________ the size of the wire.




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Matching.   Match the following flame cutting terms to their descriptions.
       a.   preheat                              d. gas pressure
       b.   clearance                            e. correct cut
       c.   speed

____21. distance from torch tip to metal

____22. straight and square with smooth face

____23. too high will produce a dish shape near the top of the kerf

____24. too much makes incomplete cut with rough edges

____25. if too hot or too slow, the surface melts before the metal is heated through

True/False. Indicate whether the statement is true or false.

____26. There is one gas used for welding that is safer and superior to all others.

____27. Metals do not mix during the brazing process.

____28. Oxygen is not a fuel gas, but it will burn.

____29. Oxygen must be 99.5% pure to support the combustion of iron.

____30. The higher the pressure a gas is used or stored at, the more stable it is.

____31. It is more difficult to attain a neutral flame with a welding torch than a cutting
        torch.

____32. If the preheat flame is too hot, the surface melts before the metal is heated
        through.

____33. Moving the torch too slow across the metal results in an incomplete cut and
        rough edges.

____34. You should not cut galvanized pipe with oxyfuels.

____35. When heating, melting takes place as the temperature rises.




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Short Answer

36. Name the product formed during the oxyfuel cutting process.

     37.      If using a welder to cut pipe 3 inches or less in diameter, what is done
     first?

38. When using a welder to cut, what should the metal be placed over?

39. To what temperature must iron be heated before it will burn in the presence of
    oxygen?

40. List the four uses for oxyfuels.

41. What is oxyfuel?

42. Explain the process of oxyfuel cutting.

43. What is MAPP gas and what is it used for?

44. What is a backfire and how is it caused?

45. Define oxyfuel cutting.

46. Explain a flashback and what should be done if one occurs.

47. What problems are encountered in cutting aluminum, copper, and stainless steel?

48. What process is used to cut nonferrous metals?

49. Identify the five welding positions.

50. Name the three areas used for marking an electrode.

51. What are on the free ends of the two cables of a welder?

52. The exact temperature of an arc varies according to what?

53. What is the formula for figuring out the number of watts consumed?

54. What is polarity?

55. What kind of AC welder is popular for farm use?

56. What are DC welders driven by?




              Louisiana Team AgEd - Agriscience Education II Curriculum - Page 23 of 28
57. Why should you have a booth when welding?

58. What is a chipping hammer?

59. Where are electrode markings placed?

60. What advantage(s) does E6011 have over E6013?

61. Define shielded metal arc welding.

62. List the four pieces of information used in the numerical coding for electrodes.

63. What are two other names for shielded metal arc welding?

64. Arc welding is used extensively in agricultural mechanics. Name three advantages
    of arc welding.




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                                      Answers

MULTIPLE CHOICE

1.    ANS:   C
2.    ANS:   C
3.    ANS:   A
4.    ANS:   B
5.    ANS:   C

COMPLETION

6.    ANS:   combustible
7.    ANS:   insulator
8.    ANS:   copper, zinc
9.    ANS:   acetylene
10.   ANS:   Propane, natural gas
11.   ANS:   Clearance
12.   ANS:   arc welder
13.   ANS:   arc
14.   ANS:   duty cycle
15.   ANS:   conductor
16.   ANS:   volt, voltage
17.   ANS:   watt, wattage
18.   ANS:   generator
19.   ANS:   Tensile strength
20.   ANS:   larger

MATCHING
21. ANS: B
22. ANS: E
23. ANS: D
24. ANS: C
25. ANS: A

TRUE/FALSE
26. ANS: F
27. ANS: T
28. ANS: F
29. ANS: T
30. ANS: F
31. ANS: F
32. ANS: T
33. ANS: F
34. ANS: T
35. ANS: T


             Louisiana Team AgEd - Agriscience Education II Curriculum - Page 25 of 28
SHORT ANSWER

36. ANS:   slag

37. ANS:   A hole is pierced in the top of the pipe.

38. ANS:   a slag box

39. ANS:   between 1600°F and 1800°F

40. ANS:   welding, brazing, cutting, heating metals

41. ANS:   Oxyfuel is the combination of pure oxygen and a combustible fuel gas to
           produce a flame.

42. ANS:   Oxyfuel cutting is a process in which steel is heated to the point that it
           burns and is removed to leave a thin slit.


43. ANS:   MAPP is a formulated mixture of methylacetylene and propadiene gases.
           Its high temperature flame is suitable for brazing, cutting, heating, and
           metallizing.

44. ANS:   Backfire is a loud snap or popping noise that generally blows out the
           flame of a torch. It may be caused by touching the tip against the work,
           overheating, incorrect torch adjustment, a loose tip, a dirty tip, or
           damaged valves.

45. ANS:   Oxyfuel cutting is a process in which steel is heated to the point where it
           burns and is removed to leave a thin slit called a kerf.

46. ANS:   A flashback is burning inside the torch causing a hissing or squealing
           noise. Quickly turn off the torch oxygen valve and then the torch
           acetylene valve. If fire is suspected in the hoses, rush to close the
           acetylene valve and then the oxygen valve at the tanks.

47. ANS:   These metals are nonferrous and don’t react the same way as ferrous
           metal to oxygen.

48. ANS:   plasma arc cutting that uses electrical current with argon gas

49. ANS:   flat, horizontal, vertical up, vertical down, overhead

50. ANS:   exposed end of the metal rod, exposed surface of the metal rod, flux near
           the exposed rod


           Louisiana Team AgEd - Agriscience Education II Curriculum - Page 26 of 28
51. ANS:   One ends in an electrode holder, and one ends in a ground clamp.

52. ANS:   The exact temperature of arc varies according to the length of the arc,
           size of the electrode, and amperage setting.

53. ANS:   The formula for figuring out the number of watts consumed is: W = V X A.
           Watts = volts multiplied by amperes.


54. ANS:   Polarity refers to the direction of the flow of electricity in the welding
           circuit.

55. ANS:   AC welders rated at 180 and 225 amperes are popular for farm use.

56. ANS:   DC welders are driven by electric motors.

57. ANS:   A booth is good to have when welding because it protects the other
           workers from blinding light flashes.

58. ANS:   A chipping hammer is a steel hammer with a sharp edge and/or point.

59. ANS:   Electrode markings are placed on the exposed end of the metal rod, the
           exposed surface of the metal rod, and the flux near the exposed rod.

60. ANS:   E6011 is better to use because the deep penetration it provides generally
           results in a stronger weld than can be obtained by the E6013.

61. ANS:   Shielded metal arc welding is a process using flux-coated metal welding
           rods called electrodes. The heat for arc welding is obtained by using
           electricity.

62. ANS:   The four pieces of information on the electrode are "E" for electrode,
           tensile strength, welding position, and welding current and/or depth of
           penetration.

63. ANS:   Two other names for shielded metal arc welding are stick welding or arc
           welding.

64. ANS:   Advantages of arc welding are that electricity is relatively inexpensive;
           electric welders for farm welding are relatively inexpensive; welders are
           available that work on ordinary 230-volt household or farmstead wiring;
           engine-driven portable welders are available; arc welding is fast and
           reliable; agricultural students and workers can become good welders
           quickly; and an arc welder can be used for brazing, heating, and
           hardsurfacing as well as welding.


           Louisiana Team AgEd - Agriscience Education II Curriculum - Page 27 of 28
65. ANS:   AC welders use alternating current. Transformers in these welders
           convert high voltage and low amperage to low voltage and high
           amperage. Alternating current (AC) is current that reverses its direction of
           flow frequently. DC welders use direct current. Direct current flows in one
           direction only in accordance with how the welder is set. A generator
           produces the direct current.




           Louisiana Team AgEd - Agriscience Education II Curriculum - Page 28 of 28

								
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