FATIGUE BEHAVIOR OF DUPLEX THERMAL SPRAY COATINGS ON STEEL by shuifanglj

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									Sliding Wear of Tungsten-Carbide
     Thermal Spray Coatings
Standard Grind and Superfinished

               HCAT Meeting
            August 28 – 30, 2001
           Toronto, Ontario, Canada




          SOUTHWEST Aeroservice, Inc.
                   Outline

•   Objectives
•   Experimental Procedure
•   Wear Test Schematic and Machine
•   Specimens
•   Results


              SOUTHWEST Aeroservice, Inc.
               Objectives
• Compare sliding wear characteristics of
  standard grind thermal spray coatings to
  superfinished coatings.
• Compare sliding wear characteristics of
  thermal spray coatings to chrome plating –
  standard grind and superfinished.



             SOUTHWEST Aeroservice, Inc.
      Experimental Procedure

• Perform sliding wear test according to
  ASTM G77 standard
• Quantify wear for each coating type and
  chrome plating (standard grind and
  superfinished) against Al-Ni-Bz bearing
  material
• Standard grind finish defined as 16 –32 Ra
• Superfinish defined as 4 Ra or less
              SOUTHWEST Aeroservice, Inc.
     ASTM G77 Wear Test Schematic




                                          w



    The thermal spray coated test ring rotates against a stationary
Al-Ni-Bz test block with a 15 1b contact force. Boeing grease
BMS 3-33 was used as lubricant between block and ring.
                        SOUTHWEST Aeroservice, Inc.
Wear Test Machine



                                 Load Cell




                Block
    Ring




   SOUTHWEST Aeroservice, Inc.
        Wear Test Procedure
• Weigh ring and block before test
• Install ring, block, and grease feeder
• Run test for 30 min with load applied –
  6.8 kg (15-lb)
• Clean off grease from ring and block
• Weigh ring and block after test
• Measure volume loss from blocks
              SOUTHWEST Aeroservice, Inc.
           Wear Test Procedure

• Quantify volume
  loss from block
  by measuring
  width of scar




                    SOUTHWEST Aeroservice, Inc.
          Wear Test Specimens

SW Coating #    Coating Type                  Spray gun
                 83WC-17Co
 SWATS 125                                     Jet Kote
               High Comp Stress
                 83WC-17Co
 SWATS 076                                     Jet Kote
                 Tensile Stress
 SWATS 139     86WC-10Co-4Cr                   Jet Kote
 SWATS 141       83WC-17Co                    Diamond Jet
 SWATS 140     86WC-10Co-4Cr                  Diamond Jet
                SOUTHWEST Aeroservice, Inc.
          Wear Test Specimens

• Rings (1.377 in dia. coated on O.D.)
  – Coatings
     •   SWATS 125
     •   SWATS 076
     •   SWATS 139
     •   SWATS 141
     •   SWATS 140


                SOUTHWEST Aeroservice, Inc.
         Wear Test Specimens
• Blocks (0.625 x 0.40 x 0.25 in)
  – Al-Ni-Bz (Common aircraft bearing material)
  – Also Coatings
     •   SWATS 125
     •   SWATS 076
     •   SWATS 139
     •   SWATS 141
     •   SWATS 140


               SOUTHWEST Aeroservice, Inc.
                                          Wear Test Results
                                             Volume Loss of Al-Ni-Bz Blocks

                    2.4E-05
                               Measurement                                                   Std Finish
                               Accuracy +/- 2.0e-7 in^3                                      Superfinish
                    2.0E-05
Volume Loss, in^3




                                                                                           125 = WC-Co JK
                    1.6E-05                                                                (Compressive)

                                                    Error bars indicate                    076 = WC-Co JK
                    1.2E-05                         range of data                          (Tensile)

                                                                                           139 = Co-Cr JK
                    8.0E-06                                                                (Compressive)

                                                                                           141 = WC-Co DJ
                    4.0E-06                                                                (Compressive)

                                                                                           140 = Co-Cr DJ
                    0.0E+00
                                                                                           (Compressive)
                              SWATS      SWATS            SWATS   SWATS   SWATS   Chrome
                               125        076              139     141     140
                                                           Coating Type

                                                   SOUTHWEST Aeroservice, Inc.
                                       Wear Test Results
                                         Volume Loss of Self-Test Blocks

                  7.E-07

                  6.E-07                                                                          Std. Finish
                                       Error bars indicate          Measurement
                                                                                                  Superfinish
                                       range of data                Accuracy +/- 1.5e-8 in^3
                  5.E-07
Vol. Loss, in^3




                                                                                               125 = WC-Co JK
                  4.E-07                                                                       (Compressive)

                                                                                               076 = WC-Co JK
                  3.E-07                                                                       (Tensile)

                  2.E-07                                                                       139 = Co-Cr JK
                                                                                               (Compressive)
                  1.E-07

                  0.E+00
                           SWATS 125       SWATS 076         SWATS 139            Chrome
                                                    Coating Type

                                             SOUTHWEST Aeroservice, Inc.
                                             Wear Test Results
                                         Ring Weight Change against Al-Ni-Bz Blocks

                       0.005
                                                                                                         Std. Finish
                       0.004                                                                             Supefinish
                                                                       Measurement
                                                                                                      125 = WC-Co JK
                                                                       Accuracy +/- 0.5 mg
Weight Difference, g




                       0.003                                                                          (Compressive)

                                                                                                      076 = WC-Co JK
                       0.002                                                                          (Tensile)

                                                                                                      139 = Co-Cr JK
                       0.001                                                                          (Compressive)

                                                                                                      141 = WC-Co DJ
                           0                                                                          (Compressive)
                                SWATS 125 SWATS 076 SWATS 139 SWATS 141 SWATS 140            Chrome
                       -0.001                                                                         140 = Co-Cr DJ
                                                                                                      (Compressive)

                       -0.002
                                                        Coating Type

                                                   SOUTHWEST Aeroservice, Inc.
                                            Wear Test Results
                                       Ring Weight Change against Self-Test Blocks

                       0.005

                       0.004                                                                         Std. Finish
                                                                          Measurement
                                                                    Accuracy +/- 0.5 mg              Superfinish
Weight Difference, g




                       0.003

                                                                                                   125 = WC-Co JK
                       0.002                                                                       (Compressive)

                                                                                                   076 = WC-Co JK
                       0.001                                                                       (Tensile)

                           0                                                                       139 = Co-Cr JK
                                                                                                   (Compressive)
                                SWATS 125      SWATS 076      SWATS 139                   Chrome
                       -0.001

                       -0.002
                                                     Coating Type

                                                 SOUTHWEST Aeroservice, Inc.
This is a preliminary report of
findings. T.U. will be presenting
the complete results at the ASM
International Materials Solutions
Conference in Indianapolis on
Wednesday November 7, 2001.

          SOUTHWEST Aeroservice, Inc.

								
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