17-4 stainless heat treat custom hand wrenches ANY post treatment?

PDXconcepts · Jul 10, 2018

Hello All!

I have seen some great info about 17-4 in these forums and would love an expert to offer feedback.

Current Project: I have some 17-4 investment casted custom hand wrenches ( similar to basic combo wrench).

Question: Do you guys think these need to be heat treated post casting?

If YES: Do you guys recommend any additional post heat treat steps, such as a temper? I have them hardened to 42 HRC currently.

Thanks! hoping to have a properly set of treated wrenches done the right way according to the pros.

plastikdreams · Jul 10, 2018

42rc is about normal for h900 heat treatment. This condition is going to give you the strongest outcome with no further treatment needed.

Bobw · Jul 10, 2018

plastikdreams said:
42rc is about normal for h900 heat treatment. This condition is going to give you the strongest outcome with no further treatment needed.

You really can't tell what the H# is by a hardness test on 17-4.. Could be anything from a 1050 to a 900.. I've
seen H900's come in in the low 50's a couple of times..

As for the wrenches.. Do you know what condition they are in?? I'm assuming you know what happened
to them. If they just knocked the sand off and threw them in a box, then they need to be solution
treated to bring them to a "condition A", 1900-1950 and air cool.. Then precipitation hardened
(thats what the PH means with THIS material).. Pick your H# and go. 4 hours at the H#, except for
900, thats only an hour for some reason. Then air cool.

Never hurts to passivate afterwards if you are really worried about corrosion.

JRIowa · Jul 10, 2018

What Bob said
JR

plastikdreams · Jul 10, 2018

Bobw said:
You really can't tell what the H# is by a hardness test on 17-4.. Could be anything from a 1050 to a 900.. I've
seen H900's come in in the low 50's a couple of times..

As for the wrenches.. Do you know what condition they are in?? I'm assuming you know what happened
to them. If they just knocked the sand off and threw them in a box, then they need to be solution
treated to bring them to a "condition A", 1900-1950 and air cool.. Then precipitation hardened
(thats what the PH means with THIS material).. Pick your H# and go. 4 hours at the H#, except for
900, thats only an hour for some reason. Then air cool.

Never hurts to passivate afterwards if you are really worried about corrosion.

I used to heat treat 17-4 parts daily to h900, random tests showed them to be between 41 and 45 rc. Now while I never treated to the other h conditions by ams 5604 standards 42rc is the high side of h1025.

The op mentions he had them hardened to 42... Does that mean it was an after process or as cast, that's a clarification he needs to make.

I've never seen over 45, doesn't mean it can't happen. We delt with mostly flat bar up to 3" thick.

Bobw · Jul 10, 2018

plastikdreams said:
I used to heat treat 17-4 parts daily to h900, random tests showed them to be between 41 and 45 rc. Now while I never treated to the other h conditions by ams 5604 standards 42rc is the high side of h1025.

---> The op mentions he had them hardened to 42... Does that mean it was an after process or as cast, that's a clarification he needs to make.<-----

I've never seen over 45, doesn't mean it can't happen. We delt with mostly flat bar up to 3" thick.

1x3 rectangular bar. H900.. Did that job 3 times, had the customer heat treat it (I don't deal
with the BS and certs).. 50-51, every time.. Still cut nice.. I don't know if there is something
different that happens, processing, rolling, whatever with rectangular bar...

I did some H900 a few weeks ago in house(Ag stuff, NO CERTS.. :willy_nilly:

). 45-46. About where I
expected it.. Granted, I haven't calibrated the oven in YEARS and YEARS..

I don't know if there is something different with rectangular bar... And I do have certified standards
for the hardness tester.

17-4 is a strange one..

plastikdreams · Jul 10, 2018

Bobw said:
1x3 rectangular bar. H900.. Did that job 3 times, had the customer heat treat it (I don't deal
with the BS and certs).. 50-51, every time.. Still cut nice.. I don't know if there is something
different that happens, processing, rolling, whatever with rectangular bar...

I did some H900 a few weeks ago in house(Ag stuff, NO CERTS.. ). 45-46. About where I
expected it.. Granted, I haven't calibrated the oven in YEARS and YEARS..

I don't know if there is something different with rectangular bar... And I do have certified standards
for the hardness tester.

17-4 is a strange one..

Yes it is, our oven was calibrated once a year as it was for non production use.

PDXconcepts · Jul 10, 2018

plastikdreams said:
I used to heat treat 17-4 parts daily to h900, random tests showed them to be between 41 and 45 rc. Now while I never treated to the other h conditions by ams 5604 standards 42rc is the high side of h1025.

The op mentions he had them hardened to 42... Does that mean it was an after process or as cast, that's a clarification he needs to make.

I've never seen over 45, doesn't mean it can't happen. We delt with mostly flat bar up to 3" thick.

Yes this heat treat was post casting. The casting was investment. Heated up and held to achieve 42hrc by a heat treat company.

You guys are great, talk about quick responses.

So is the consensus to do the solution bath then heat treat or with ok to go straight to heat treat post casting.

Hoping to do a run of these if the samples come out nice.

PDXconcepts · Jul 11, 2018

plastikdreams said:
I used to heat treat 17-4 parts daily to h900, random tests showed them to be between 41 and 45 rc. Now while I never treated to the other h conditions by ams 5604 standards 42rc is the high side of h1025.

The op mentions he had them hardened to 42... Does that mean it was an after process or as cast, that's a clarification he needs to make.

I've never seen over 45, doesn't mean it can't happen. We delt with mostly flat bar up to 3" thick.

what is: " then they need to be solution
treated to bring them to a "condition A" Is this required? It sounds like most guys are going straight to the oven. Do you have a link I could check into it? I went straight to the oven and did not do this "solution treatment". What is the side effect of skipping this step?

Thanks for the help fellas.

Bobw · Jul 11, 2018

PDXconcepts said:
Yes this heat treat was post casting. The casting was investment. Heated up and held to achieve 42hrc by a heat treat company.

You guys are great, talk about quick responses.

So is the consensus to do the solution bath then heat treat or with ok to go straight to heat treat post casting.

Hoping to do a run of these if the samples come out nice.

I am completely confused... What are you trying to do????

You already have heat treated castings... I don't understand what you are
trying to accomplish..

Triaged · Jul 11, 2018

Solution treat to condition A is the first step of the heat treat and done in a furnace. If the heat treat was done by someone who knew what they were doing it has already been performed.

To keep them from rusting you will want to have them "Passivated". This is dunking the parts in a nitric acid solution.

I think I can see how the word "solution" in both steps could be confused. They are completely different things.

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