Impact Test for SA268-410 Smls tubes

[Aodwan]

Dear All,

We are discussing the requirement of impact testing on SA268-TP410 u bend tubes OD 3/4'' x 0.083''thk with our mill.
After bending we need to perform heat treatment on bending area. (temp around 650 deg C as per mill)

As per ASME VIII -1, UHA51 C (4) martensitic stainless steel needs to perform impact testing if temp is between 425-730 deg C.

Now mill is saying that they do not need to perform impact testing as it is for thermally treated
means thermally affected area due to weld assembly work.

So do we need to perform impact testing ? ( MDMT of exchanger is 10 deg C)

 

[david339933]

"Thermally affected area due to weld assembly work"?
End Note 81 - "Thermal treatments of materials are not intended to include warming to temperatures not exceeding 600F, thermal cutting or welding".

 

[weldstan]

I think the material is too thin to require impact testing under ASME VIII guidelines. Unfortunately I do not have access to the Code to better my analysis.

 

[EdStainless]

And it makes me wonder why you are having the u-bends heat treated at all.
This is commonly done in austenitic grades to lower residual stress.
My guess is that your 410 is low enough in C that it is actually ferritic, not martensitic.

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P.E. Metallurgy, Plymouth Tube

 

[SnTMan]

So, Ed, can you enlighten me, what processes do you think are intended to be included in "thermal treatments"? Mill heat treats, PWHTs, other? Not being a metallurgist, I find the term ambiguous. I have not seen it applied as to mean impacts are required when SS u-bends (of any flavor) are stress relieved.

Regards & TIA,

Mike


The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[r6155]

1) See API 660
9.6.5 For ferritic and martensitic stainless steels, stabilized austenitic stainless steels, duplex stainless steels,
copper, copper-nickel, and high nickel alloys (Ni > 30 %), heat treatment of U-tubes shall be applied if cold working
can induce susceptibility to stress corrosion. The purchaser shall specify when heat treatment is required in such
cases.

2) Impact test: not applicable

Regards
r6155

 

Not being a metallurgist, I find the term ambiguous.

Being a metallurgist, I find the term ambiguous!

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

 

[SnTMan]

IM, thanks for clearing that up

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[EdStainless]

Tubing is considered material, so any mill HT is not a subsequent thermal treatment.
Since a ferritic is not susceptible to SCC I don't see any reason to HT the u-bends.
Unless of course the mill can't hold the required bend tolerances without it.
You have specified the tolerance and testing from A803 haven't you?

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P.E. Metallurgy, Plymouth Tube