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12-03-2009, 11:38 AM #1
material shrinkage during heat treat?`
I have a job made out of a material called "custom 455 stainless steel". We had a heat treat op. (heat treat to condition H-1000) done to these parts and we experienced quite a bit of shrinkage on all od diameters and growth on all id diameters. the print says "all dimensions apply before heat treat" but the customer is claiming there is no way these parts could shrink this much. ALL dimensions on the part have changed by .002-.003 total. could someone tell me that this is a possibility. these parts were checked by 4 different people, documented in process, 1st pc, and final inspection before leaving the building. Multiple gaging was used for all dimensions. whats up? thanks.
12-03-2009, 11:47 AM #2
I'm not gunna say that growth as well as shrinkage doesn't happen in HT - b/c Shirley it does.
But I really hafta when you say that you lost material.
Bore grew .002 and OD shrank .002?
Where'd the extra go?
I ran 450 before, but a long time ago and only a tapped hole, so .... ???
Think Snow Eh!
12-03-2009, 12:19 PM #3
I do know that 13-8 shrinks .0008" per inch. Lost .018 on a 26" long part, and had a first article become scrap at HT(.0005 total). So if your ID/OD was bigger than a couple of inches, very possible.
And hey, what do you know, looks very similar to 13-8 and
Custom 455 shrinks -.001/in/in.
12-03-2009, 12:40 PM #4
Wrapped or in an atmospheric furnace?
What condition before HT?
For most of what I've been around, I've never seen anything grow or shrink more than 0.001" per inch. Most of the time, it's in tenths.
12-03-2009, 12:51 PM #5
Pretty unusual to grow an ID and shrink an OD simultaneously. The inside and outside are gonna tend to follow each other. Now, if it's a 1" bore in a 5" part, then the ID and OD can acto more independently and maybe there was a bunch of compression stress on the inside and tension on the outside, and it all just relaxed? In general, something with a hole in it ends up with a slightly smaller hole when it shrinks -- the void behaves as if it was solid.
Ida Know though, .002-.003" is a lot(unless it's 60" part ). Can you check for roundness? Maybe it went oval, and they're measuring the ID and OD 90* apart?
12-03-2009, 01:02 PM #6
Looks like it shrinks a little more than 0.001 inches per inch with H1000 heat treat
You wouldn't need a very big part to see the levels of shrinkage you are describing.
I didn't post everything on the page out of respect for the copyright notice on the page . . .
12-03-2009, 01:31 PM #7
Etched after heat treat and they forgot to take it out of the tank over the weekend?