intergranular failure of 420ss (martensitic)
intergranular failure of 420ss (martensitic)
(OP)
Anyou have any solid info or references they could point me towards for causes of inter granular failure in bending of 420 stainless (with 1%Mo addition)?
Nick
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RE: intergranular failure of 420ss (martensitic)
I have two decent references - "Physical Metallurgy Handbook" by Sinha and "Handbook of Stainless Steels" by Peckner and Bernstein.
They both address ductility and notch sensitivity problems with the higher carbon martensitic grades of stainless (including 420) during forming. Can you provide more specific information, like;
What was the heat treatment condition or hardness of the 420 stainless steel when it was subjected to bending? Was the bending performed cold?
RE: intergranular failure of 420ss (martensitic)
More details would be very helpful.
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RE: intergranular failure of 420ss (martensitic)
I was unable to get reliable chemistry data from the fracture surface. Some indications of S being present. (EDS)
Both trans and intergranular fracture noted on the fracture surface.
Thanks for the references, everything in my references deals with austenitics.
I'll see if I can get a copy of the ASM Handbook, but $ is tight at the end of the year.
Thanks
Nick
RE: intergranular failure of 420ss (martensitic)
You might ask your management to pay for ASM Handbooks online. For only a few hundred dollars per year (instead of thousands of dollars all at once), you have full access to all volumes.
I know you are in Metro Detroit. If you can't get your own access, use the library of the nearest university (UM Ann Arbor, UM Flint, UM Dearborn, Wayne State, Oakland).
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: intergranular failure of 420ss (martensitic)
RE: intergranular failure of 420ss (martensitic)
RE: intergranular failure of 420ss (martensitic)
Did these part fail during forming? or after?
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Rust never sleeps
Neither should your protection
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RE: intergranular failure of 420ss (martensitic)
(I'm trying to avoid too many details about our process, there is nothing new, and no process changes have been implemented.)
I looked at an older (blue books) volume of the Failure Analysis handbook. No information given on this specific steel type, nor any info on intergranular failure in martensitic stainless.
RE: intergranular failure of 420ss (martensitic)
These alloys are very strain rate sensitive. If you have speeded up an operation even slightly, or if the material may have been a little cold, or a stamped edge was a little rough, any of these could push you over into problems.
= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm