y2clay
Mechanical
- Mar 16, 2005
- 2
I have a product made out of 17-4 PH. We centerless grind the surface down to the O.D. of the part and heat treat is as a rod. After this, we get the hardness up to about 37±4 RC and make three bends to it. We havent had any problems until recently. The material is starting to crack and fold. We are thinking it was the material to begin with, so we take a couple of samples, and clean them and bend them. Nothing happens. No cracks, no splinters, nothing. So now I'm at the point of what do I try next.
NOTE: There were two heats of material due to availability. 1) was a Ø.130 material c'grinded to a Ø.128
2) was a Ø.140 material c'grinded to a Ø.128
Could the aditional .010 inches of material harden the material enough that it when it went to Heat treat, it was made harder than expected and made more brittle.
ALSO, when we sent the 1st batch to Heat treat and came back it had a RC of 35-37 and when we got it back the 2nd time, it came back at the hire end, round 38-40.
Question: Could the additional C'grinding have made the material harder and more brittle that when it bends it cracks? Or could it have been in Heat Treat where something happened, where it wasn't quenched rapidly enough to get full austenite? Please help, I'm curious as to what to look into next. I also want to pot and section a couple of sample to see its structure and see what happened. Would this be also a good idea?
NOTE: There were two heats of material due to availability. 1) was a Ø.130 material c'grinded to a Ø.128
2) was a Ø.140 material c'grinded to a Ø.128
Could the aditional .010 inches of material harden the material enough that it when it went to Heat treat, it was made harder than expected and made more brittle.
ALSO, when we sent the 1st batch to Heat treat and came back it had a RC of 35-37 and when we got it back the 2nd time, it came back at the hire end, round 38-40.
Question: Could the additional C'grinding have made the material harder and more brittle that when it bends it cracks? Or could it have been in Heat Treat where something happened, where it wasn't quenched rapidly enough to get full austenite? Please help, I'm curious as to what to look into next. I also want to pot and section a couple of sample to see its structure and see what happened. Would this be also a good idea?
