CHAIN 8T8001 - Caterpillar

TENSILE STRENGTH 480 MPa (70 KSI)
YIELD STRENGTH 400 MPa (58 KSI)
ELONGATION 22%
IMPACT TOUGHNESS 20 FT LBF @-20F (27J@-18C)
These are low hydrogen electrodes and mustbe stored in an electrode oven at 120 degrees C (250 degrees F) when notin use. If the electrodes get damp, scrap or recondition to manufacturer'sspecifications.The following chart relates to the electrodediameter and approximate current settings for welding:
DIAMETER AMPS
3.2MM (0.125") 1/8" 70-140
4.0MM (0.156") 5/32" 110-180
4.8MM (0.166") 3/16" 190-270
Use the direct current electrode positive (DCreverse polarity) polarity setting and remove the slag after every pass.The weld pass shall not exceed two times the electrode diameter.
As an alternative process the FCAW processmay be used with E71T-1 (ANSI/AWS A5.20) welding electrode and the manufacturersspecified shielding gas(es). The weld deposited by these electrodes willhave the following mechanical properties:
TENSILE STRENGTH 480 MPa (70 KSI)
YIELD STRENGTH 400 MPa (58 KSI)
ELONGATION 22%
IMPACT TOUGHNESS 20 FT LBF @-20F (27J@-18C)
Welding parameters will vary due to weld positionand manufacturer of the welding electrode. For 1.3mm (0.052 inch) diameterelectrode typical welding parameters should be:
WIRE FEED SPEED VOLTAGE APPOX. AMPERAGE
MIN 200 IMP 24 210
OPT 275 IMP 28 250
MAX 325 IPM 29 300
Use the direct current electrode positive (DCreverse polarity) setting and remove the slag after every pass.
PRECAUTION/PRECLEANINGThe base metal shall be preheated to at least225 degrees F (unless otherwise specified) and this minimum temperaturemaintained during cutting or welding.Clean the area to be welded of oil, grease,paint, and dirt. Attach the welding ground cable directly to the frameassembly. Protect all machined surfaces from sparks or spatter producedby the welding, chipping, and/or grinding operations.
QUALITY/INSPECTIONThe weld shall be free from cracks, porosity,undercut, and incomplete fusion. All weld quality shall conform to ANSI/AWS14.3 or Caterpillar Engineering Specification 1E99. All groove welds areto be ultrasonically inspected to factory specs.
!THE COUNTERWEIGHT MUST BE REMOVED PRIOR TO PERFORMING THIS WELD REPAIRPROCEDURE. ENSURE PRECAUTIONS ARE MADE DURING THIS REMOVAL PROCEDURE SUCHTHAT THE MACHINE DOES NOT BECOME OFF BALANCE OR TIP
PROCEDUREDuring the following procedure the inner-mosthole attaching the counter-weight to the swing frame will be destroyed.It will need to be redrilled.Preheat the region to be repaired to 225 degreesF. Ensure enough soak time that the entire thickness of the member is at225 degrees F and is maintained during the entire repair.Using the carbon arc gouging process removethe crack in the lower portion of the swing frame as seen in Figure 1.
Grind such that all carbon and dross remainingfrom the carbon arc gouging process is removed and the surfaces are inspectableby the Liquid Dye Penetrant Process.
Perform a Liquid Dye Penetrant inspection procedureensuring the crack has been entirely removed.
Ensure the liquid dye penetrant, developerand cleaner are removed prior to performing the welding operation.Attach runoff tabs along the edge of the grooveas seen in Figure 2.Weld the groove ensuring the 225degree F minimuminterpass temperature is maintained.Upon completion of the welding operation thechamfered edge will need to be re-contoured eliminating the sharp transitionthat originally existed. See Figure 3.Allow the swingframe to cool, re-inspect usinga liquid dye penetrant inspection process and drill the hole welded closed.