Welding after heat treating

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Can you tell me if I heat treat 17-4 PH Stainless then weld it, will I have to heat treat again or will the weld not affect the hardness?
Reply:i'm pretty sure welding heat and the rate of cooling will have an affect on a heat treated part. how large/thick is it?i.u.o.e. # 15queens, ny and sunny fla
Reply:The part being welded to is .750. The other parts is .100
Reply:Generally, from what I understand, any time you weld heat treated material it has to be normalized after welding.  Expensive, and cumbersome for large parts."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by MossyCan you tell me if I heat treat 17-4 PH Stainless then weld it, will I have to heat treat again or will the weld not affect the hardness?
Reply:Naw, I think I'm wrong, have to research it"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Looks like it involves stress relieving at high temps, and long soak times http://www.azom.com/article.aspx?ArticleID=1141Least it's a start, maybe point you in the right direction (big shrug)"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Excellent, Thanks Guys!
Reply:Here's some in depth discussion of welding 17-4 PH SS.  I've only given it a quick once over so far but it looks like I may have been wrong (shudder the thought) about it not being very weldable in the hardened condition.http://www.aws.org/wj/supplement/WJ_1995_05_s153.pdf
Reply:Ha!  Thanks HT2
Reply:Mossy,What is it you're building?   The parts intended purpose and any codes or standards that might be involved will have a lot to do with what it will be acceptable to do welding wise.   If it's some thing critical you might want to make sure you have the customers engineering approval before you go doing some thing you're not entirely sure of.   These parts are 17-4 and are part of door closure mechanisms for military aircraft.  In the annealed condition 17-4 welds beautifully.  They went out for heat treat after all the machining and welding was done.
Reply:This is informative as to the different heat treat conditions of 17-4 and what they do for it.http://www.aksteel.com/pdf/markets_p...Data_Sheet.pdf
Reply:This big thing I'll point out is 17-4 PH is not comparable to things like 316. You can heat treat 17-4 and make it softer. (I'm not talking about annealing) H1150 is softer than Condition A. It's precipitation hardened. I've machined 17-4 a number of times and often when I got advice online about it, people were flat wrong because they used their knowledge of working with other stainless as a basis. PH steels are their own thing and really behave differently. Like the fact they machine better post heat treat. (Though tons of people will claim you never machine heat treated steel as it's harder) I really have a horribly limited knowledge of the steel to help you other than to warn you it's just very different and I hope you get advice from someone who welds it all the time and knows PH steels.
Reply:This is a surgical instrument. The forces it will encounter are light but the corrosion resistance must be maintained. Thank for all the info guys.
Reply:Originally Posted by MossyThis is a surgical instrument. The forces it will encounter are light but the corrosion resistance must be maintained. Thank for all the info guys.