analysis of journal repairs
TRANSCRIPT
The importance of analyzing journal repairs
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Why to analyze journals for repairs
� To determine if fits have been previously repaired.
� Why was the fit was previously repaired.
� To determine proper way to repair journal if needed.
� To aid in the quoting process if repair is required.
� To help educate customer if there are any issues.
� To help determine structural integrity of journal.
� To prevent catastrophic failures from occurring.
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Types of journal repairs to be analyzed
� Thermal sprayed fits
- metal spray
- brass spray
� Electroplated fits
- nickel
- copper
� Sleeved fits
� Welded split sleeves
� Welded fits
� Ground bearing fits
� Unique repairs
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Visual clues a fit has been repaired.
� Odd colored fit.
� Irregular step on back of taper fit.
� Widened thread relief.
� Swirled polishing marks.
� Hydraulic assist groove modified.
� Hydraulic assist hole modified.
� Hydraulic assist groove, and or hole edges – chipping, or porosity .
� Porous seam lines on fit, by leading edge, and by hydraulic assist groove.
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� Edges of fit – both IB, OB – chipping, flaking or porous.
� Porosity in the fit.
� Overspray – threads, radiuses, edges of fit, ect.
� Rough matte finish in hydraulic assist groove, and edges of fit.
� Pins or dowels in fit, face of journal, or hydraulic assist groove.
� Sleeve seam lines at IB,OB edge of fit, and or face of journal.
� No radius IB bearing fit.
� Seam line at step or radius.
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� Grinding chatter marks on fit.
� Horizontal weld seam - shiny spots / lines (heat).
� Weld pitting at seams and other places on fit.
� Weld irregularities (voids from slag) on face of journal, edges of fit, keyway, and/or adjoining fits.
� Threading pattern under surface of bearing fit.
� Remember an experienced machinist, and your NDT technician are your greatest allies.
� NEVER PUT A REPAIR ON TOP OF ANOTHER REPAIR !
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� Fit may show discoloration.� Edges of fit – both IB, OB – chipping, or porosity.� Porosity in spray material itself (thermal spray porosity).� Overspray – threads, radiuses, edges of fit, ect.� Seams were spray starts IB, and OB.� Threading pattern visible under surface of fit.� Hydraulic assist groove edges – chipping, or porosity.� Hydraulic assist hole edges – chipping.� Hydraulic assist hole –enlarged, off centered, chamfered, or
angled. � Hydraulic assist has been widened or deepened, or location looks
off (typically the groove is 1/3 distance from leading edge). There is a specification on this.
� NDT may pick up seams.
Thermal sprayed fits – metal spray
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� Clues a fit was previously thermal sprayed – metal spray
Hydraulic assist groove edges – chipping, or porous.
Edge of fit flaking, and porous.
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� Clues a fit was previously thermal sprayed – metal spray
Edges of fit flaking.
Groove deeper than normal, and hole is off centered.
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� Clues a fit was previously thermal sprayed – metal spray
Outboard seam
Inboard seam
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� Clues a fit was previously thermal sprayed – metal spray
Overspray in radius.
2 Spray jobs on top of each other with porosity, and flaking.
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� All of the same characteristics of “ metal thermal spray “.
� Dull brass colored fit.
Thermal sprayed fits – brass spray
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Electroplated fits - nickel
� Bearing fit has a golden colored hue.
� Look for “break thru” or discoloration by hydraulic assist groove, and keyways on thin plaiting jobs.
� Dull matte finish in hydraulic assist groove, and edges of fit.
� Swirled polish marks are common.
� Hydraulic assist hole edges may have chipping.
� Hydraulic assist hole may appear oversized, or undersized.
� OB edge of fit may have chipping.
� NDT may pick up roughness by edges of fit.
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Bearing fit has a golden colored hue.
“Break thru” or discoloration by hydraulic assist groove, and keyways.
Swirled polish marks.
� Clues a fit was previously electroplated – nickel
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� Clues a fit was previously electroplated – nickel
Heavy plating deposit
Dull matte rough finish in hydraulic assist groove, and edges of fit.
Hydraulic assist groove appears narrowed, and hole is undersized.
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� Clues a fit was previously electroplated – nickel
Bearing fit has a golden colored hue.
Flaked plating from disassembly tearing.
Swirled polish marks.
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� Clues a fit was previously electroplated – nickel
Bearing fit has a golden colored hue.
Dull matte finish in hydraulic assist groove.
Swirled polish marks.
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Electroplated fits - copper
� All of the same characteristics of “ nickel plating “.
� Semi - bright copper color.
� Copper fits are often flashed up with nickel on top. These fits may show copper at the edges of the fit, and or the hydraulic assist groove. Typically this is a sign there is a lot of plating present.
� Copper plating is softer than nickel plating, scratching fit with scribe will leave very noticeable shiny scratch.
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� Clues a fit was previously electroplated – copper
Copper plated internal bearing bore.
Semi - bright copper color.
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� Clues a fit was previously electroplated – copper
Scratch test with scribe left very noticeable shiny scratch.
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� Dutch dowels in face of journal.
� Pins in fit itself.
� Pins in hydraulic assist hole.
� Seam lines at beginning, and end of sleeve.
� Seam lines on face of journal will be visible.
� No radius present on IB side of bearing fit.
� NDT will show seam lines.
Sleeved fits
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� Clues a fit was previously sleeved
Dutch dowels in face of journal on seam line.
Seam line on face of journal.
Seam line at end of sleeve.
No radius.
5/8” Pin in bearing fit itself.
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� Clues a fit was previously sleeved
Seam line at end of sleeve.
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� Clues a fit was previously sleeved
Seam line on face of journal.
Seam line at end of sleeve, and no radius.
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� Clues a fit was previously sleeved- On a large press roll journal
Seam line at end of sleeve, and no radius.
Sleeved area.
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� Clues a fit was previously sleeved
Seam line on journal face with small void.
Pin in hydraulic assist hole.
- On same large press roll journal
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� Weld seam (horizontal) shiny spots (heat).
� Weld pitting at seams.
� Weld irregularities (voids from slag) on face of journal, edges of fit, keyway, and/or adjoining fits.
� Pins in hydraulic assist hole.
� Possible seams lines will be visible.
� Radius may not be present on IB side of bearing fit.
� NDT should show seam lines, and stress cracking from welding.
� Stowewoodward recommends replacement of any welded journals, and will not warranty any previously welded journals.
Welded split sleeve fits
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� Clues a fit has a welded split sleeve on the fit.
Pin in hydraulic assist hole.
Widened thread relief.
Horizontal weld seam.
Modified radius on IB edge.
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� Weld pitting.
� Weld irregularities (voids from slag) on end face of journal, edges of fit, keyway, snap ring grooves, and/or adjoining fits.
� NDT should show stress cracking from welding.
� Stowewoodward recommends replacement of any welded journals, and will not warranty any previously welded journals.
Welded fits
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� Clues a fit has been repaired by welding the fit.
Weld irregularities on IB edge of fit.
Weld irregularities on OB edge of fit.
Weld irregularities in radius of keyway.
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� Clues a fit has been repaired by welding the fit.
Weld irregularities on IB edge of fit.
Golden colored hue.
Dull matte finish in hydraulic assist groove.
Edges of hydraulic assist hole has chipping.
- Nickel electroplating on top of a welded fit.
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Ground fits
� Possible grind chatter marks in fit.
� Sizes possibly undersize.
� Bearing centerline possibly shortened.
� Check for smooth transition point at IB edge of fit.
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� Clues a fit has been repaired by grinding the fit.
Grind chatter is evident across the fit.
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� Look for seam lines at steps or radiuses.
� Look for “no radiuses” were there should be ones.
� Look for repairs on top of old repairs.
� NDT may detect seams.
Uniquely repaired fits
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� Clues a fit has a unique repair.
Threads welded, and re machined.
Thermal sprayed fit, which is lifting.
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� Clues a fit has a unique repair.
Journal that was partially replaced from the OB edge of the bearing fit out. It was machined off, and bored out. A new section was threaded and installed, then finish machined.
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NDT pictures
Relevant indications.
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Catastrophic failures
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Why to analyze journals for repairs
� To determine if fits have been previously repaired.
� Why was the fit was previously repaired.
� To determine proper way to repair journal if needed.
� To aid in the quoting process if repair is required.
� To help educate customer if there are any issues.
� To help determine structural integrity of journal.
� To prevent catastrophic failures from occurring.
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Please feel free to send any pictures of journal repair work, with a detailed description to:
Wayne S. Millard
Mechanical Quality Assurance Manager
Stowewoodward Neenah, WI
(920)729-7013