Crack detection in 430FR bars
Crack detection in 430FR bars
(OP)
Search is down at the moment so I'm starting a new thread even though I'm sure there have been relevant posts in the past.
We buy parts machined from solenoid quality 430FR (ASTM A 838 alloy type 2) bar. Several parts have cracked completely through from one end to the other right through the center axis of the bar. There is one large flange on the part which the crack does not go completely through the OD. There is no doubt in my mind that the crack is a seam in the bar stock which was present before machining. We are 100% sorting parts at the moment but would like the supplier to check their remaining bar stock inventory.
What sort of non destructive testing is available to find an internal crack in magnetic material like this? The bar stock is approximately 7/8" OD.
We buy parts machined from solenoid quality 430FR (ASTM A 838 alloy type 2) bar. Several parts have cracked completely through from one end to the other right through the center axis of the bar. There is one large flange on the part which the crack does not go completely through the OD. There is no doubt in my mind that the crack is a seam in the bar stock which was present before machining. We are 100% sorting parts at the moment but would like the supplier to check their remaining bar stock inventory.
What sort of non destructive testing is available to find an internal crack in magnetic material like this? The bar stock is approximately 7/8" OD.





RE: Crack detection in 430FR bars
Regards,
Cory
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RE: Crack detection in 430FR bars
RE: Crack detection in 430FR bars
The steel supplier is doing metallurgical tests on the cracked parts and we don't have the results yet. However, in a phone conversation, they said the cracks could have been created when some of the bar stock was straightened. I don't see how straightening could create centerline cracks. The centerline is the neutral axis during a straightening operation and there should be zero stress & strain. Any cracks from straightening should be on the surface in my opinion. I'm no metallurgist, but I think centerline cracks would be more likely do to improper heating/cooling during hot rolling. Any comments?
RE: Crack detection in 430FR bars
Regards,
Cory
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.