Workscope: Babbitted Bearings Inspection and Repair

• Perform complete visual inspection of bearing and hardware
• Perform complete dimensional inspection, including ball diameter, bore and oil seal diameters and dowel pin fits
• Evaluate babbitt bond by ultrasonic inspection as per GE specifications
• For insulated bearings, perform a 500 VDC Megger check

• Perform visual inspection
• Record as found dimensions
• Blue check bearing ball to ring
• Torque check bearing ball to ring
• Perform minor hand scraping of spherical surface of ring or ring horizontal joint, to obtain proper torque
• Record final values of torque clearance and contact

• Remove all babbitt by machining
• Skim cut machine bearing casing ID surfaces, including dovetails, to expose new metal on all surfaces
• Clean, prepare and tin bearing casing in fixture for spin casting
• Rebabbitt the bearing casing by spin casting, using ingots of certified composition with the GE-prescribed overpour
• Machine out any low density babbitt from the bore
• Perform ultrasonic inspection of the babbitt bond
• Handwork the horizontal joint of the casing to improve joint contact, and perform blue check of joint
• Replace bent or galled casing dowel pins, if required
• Replace or repair aluminum oil seals*
• Finish machine the bearing bore to applicable GE drawing configuration (or customer-supplied drawing configuration, if non-GE), providing design oil clearance over a specified journal diameter
• Perform red dye inspection of babbitt bond and bore surface
• Perform final dimensional inspection

• Machine the bore surfaces to remove damaged, oil impregnated and otherwise contaminated babbitt
• Build up the bore surfaces through the application of certified babbitt weldments
• Machine the bearing bore, leaving stock for finishing
• Handwork the horizontal joint to improve joint contact, if required, and perform blue check of contact
• Replace bent or galled dowel pins, if required
• Finish machine the bearing bore to applicable GE drawing dimensions (or customer supplied drawing configuration, if non-GE), providing design oil clearance over a specified journal diameter
• Perform red dye inspection of babbitt bond and bore surface
• Perform final dimensional inspection

• Grind outside spherical diameter to obtain specified finish
• Replace dowel pins, if required
• Fit bearing ring by removing material from horizontal joints
• Blue check bearing ball to ring
• Torque check bearing ball to ring
• Skim cut ring shim pads

• Perform incoming inspection on all bearing parts
• Check seal teeth diameters
• Disassemble bearing
• Inspect bearing pads, anti-rotation pins, dowel holes, and dowel pins
• Ultrasonic test babbitt bond line to shell
• Blue check and scrape the babbitt liner to the bearing mandrel
• Pinch check the assembled bearing to the mandrel
• Reassemble bearing

• Install new pads
  

  -	Remove existing bearing pads
  -	Set up and secure the new pads into the casing
  -	Reassemble bearing, finish machine the babbitt bore for design clearance
  -	Machine overshot groove

• Repair existing pads
  

  -	Dimensionally inspect the bearing pads
  -	Remove shims - leave shims designated by drawings in place
  -	Set up and secure the pads into the casing
  -	Reassemble bearing and prepare the babbitt surfaces for TIG weld
  -	Babbitt weld pads
  -	Finish machine the babbitt bore for design clearance
  -	Disassemble bearing
  -	Hand blend babbitt on pads at radii and edges

• Remove seal teeth, weld and machine grooves
• Install and machine two seal teeth
• Drill corner jack screw holes per drawing (set of pads)
• Blue check pads to mandrel and perform minor scraping as necessary
• Hardened bushing modification
• Furnish material and manufacture mandrel

• Receive visually and dimensionally inspect thrust plates. Record incoming flatness and land geometry
• Perform ultrasonic inspection of babbitt bond
• If the ultrasonic test results are acceptable, machine each thrust plate to restore flatness and geometry to factory specifications
  Note: If porosity is detected in the babbitt during machining, the thrust plate must be rebabbitted
• If the ultrasonic test results are not acceptable, or porosity is detected in the babbitt while machining, repair each thrust plate as follows:
  

  -	Machine out old babbitt
  -	Prep and rebabbitt each thrust plate
  -	Machine to restore flatness and geometry to factory specifications

• Perform final inspection and record flatness and land geometry

For More Information

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