Annealing and stabilization heat treatment

[Moh.Ibra]

Can anyone please help me to clearly explain the meaning of the following sentence mentioned in received datasheet for ASTM B407 material (Alloy 800H)
"Material shall be procured in solution annealed and stabilized condition at 982 C for 3 hrs"

What i got from ASTM standard is that minimum annealing and heat treatment temperature shall be 1120 C and datasheet mentioned 982 C so, is it considered as a deviation from ASTM standard?

 

[EdStainless]

After the required high temperature anneal you can add another heat treatment. This does not void the compliance with the spec.
Some of the specs have this option built in (A249 S4).
I have seen stabilization added to the common grades (321 or 347) and 800, 625, and a few others over the years. This is important if the operating temp is near the bottom edge of the sensitization range. The funny thing is that we still see a lot of 321 and 347 used where using low C 304L would work just as well if not better. Often those these are aerospace and changing 40 year old specs is nearly impossible. But if you can suing 0.018% max C in 304 makes you nearly immune to sensitization.
We always made it clear to people that the properties and dimensions apply BEFORE the stabilization. They are doing it at their own risk (unless it is actually part of the spec).

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P.E. Metallurgy, consulting work welcomed

 

I agree EdS, I would never spec a stabilized grade where an L grade would do the job. Lower cost and reduced risk is a win-win.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[mfgenggear]

Very informative post from every one.
You guys are all pro's.

All from my interpretation to the answer from the OP question.

A)material purchase to the ASTM B407
Has been both annealed and stabilized.
And meets his ASTM requirements.

B) unless forming is required the it needs to be solution annealed. Then after forming , re anneal & re-stabilize.
Correct?

Which answers his questions, yes

 

[Moh.Ibra]

EdStainless

I got your point about stabilization required after annealing but my question is:

ASTM clearly defined the minimum temperature for final heat treatment shall be 1121 C as per paragraph no. 5 so, may be stabilization or re-annealing shall be done at 1121 C as per ASTM requirements, can you please confirm my understanding?

ASTM B407 defined two kind of temperatures as following:

1- Final heat treatment temperature: 1121 C min as per para 5.1
2- Annealing temperature: 1120 C min as per para 7.4

So, annealing shall be done on 1120 C and any final heat treatment will be required whether stabilization or re-annealing shall be done at 1121 C

 

[EdStainless]

A) There is no reason that this isn't true. People add additional requirements all of the time.
B)If it is going to formed (I think that there is a strain limit) it could be stress relieved or annealed, you have an option. There are two reasons for needing some HT. You don't want to leave high residual stresses. One risk is that with high temp exposure and high enough stresses you can get re-crystallization and then you would end up with fine grain material with poor creep resistance.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed