04:31 Jan-09-2003 Milan Rastislav NDT Inspector U.S.Steel Kosice s.r.o, Slovak Republic, Joined Aug 2002 4
Hello . I have some troubles with testing bearings. I need testing inner ring in bearing.I need strike off every cracks.Diameter of ring is 150mm.Which ndt method is best. I m working with ultrasound, penetrant and magnetic testing. Thank you for every advice. Milan Rastislav Sorry for my english.
04:47 Jan-09-2003 Godfrey Hands Engineering, PRI Nadcap, United Kingdom, Joined Nov 1998 281
Re: testing bearing : Hello . : I have some troubles with testing bearings. : I need testing inner ring in bearing.I need strike off every cracks.Diameter of ring is 150mm.Which ndt method is best. I m working with ultrasound, penetrant and magnetic testing. : Thank you for every advice. : Milan Rastislav : Sorry for my english. . Dear Milan, It depends on the origin of the cracks. Is this a bearing that has been in service and has cracked, or are they bearings being manufactured ? Probably best technique is Magnetic Particle Inspection with a Threading Bar technique, which will detect cracks parallel to the bearing axis (i.e. Transverse). Alternative is to place the ring between the jaws of a MPI bench and magnetise that way to detect circumferential defects. Turn the ring through 90 degrees and make a second test. Circumferential defects are the least likely problem in manufactured rings (main problem is raw material seam causing transverse defect). Wear in the bearing will cause a random orientation of defects or "spalling". Threading bar should find this. Alternative cause of very small cracks in manufacturing is grinding burning, causing cracks sometimes less than 1mm long on the raceway.
For mass produced inspection, please contact me and I can send details of automatic machines to test these.
Can you please suggest me best way to check crack testing for inner and outer races of bearings. We do turning on cnc machines and need to check it on mass production basis. So we need a fast way to check rings.
Like 12 years old whisky, Godfrey's post has rewardingly matured so there is no reason to discount his excellent advice. Read it Atul.
A tip to remember in MPI the orientation of detectability is that detectable flaws will always lie in the same direction as the current flow. So with components tested with a threader bar (TB), defect detectability is transverse to the item's circumference.
Your need to test large quantities is best addressed by TB method and try to use one with a diameter that allows internal viewing whilst as close as possible to the component ID.