Crack in forming of A240-304l dished head

[MFQC]

Dear friends
As you know minimum tensile of A240-304l is 485Mpa ,its yield is 170Mpa and minimum elongation is 40%.
We purchased a plate with the below specifications for dished head and the dished head has 2 weld lines.
Tensile:779Mpa
Yield: 584Mpa
Elongation :46%
Our process for production of dished head is dishing & flanging.
During flanging the weld lines cracked.
According to standard our material, chemically and mechanically is in accordance with A240- 304l.
Does anybody has some experience like this matter?
Do we have to purchase material with lower mechanical properties or higher elongation?
Thanks

 

[Dhurjati Sen]

Dear FZQC,

Did you send the failed plate to some lab for chemical analysis and mechanical tests?

Regards.

DHURJATI SEN

https://www.nace.org/people/dhurjatisen

 

[MFQC]

Dear dehurjati sen
Yes. The numbers which I mensioned above for mechanical properties are according to lab tests.
Thanks

 

[EdStainless]

You need material that is softer to start with.
This plate does not look well annealed to start with.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[weldstan]

Agree with Ed.

 

[EdStainless]

with strength that high I am guessing that you can measure a difference between the L and the T values.
Values of 600/300 would not be uncommon, but the elong should be >55% if this is truly annealed 304L.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[MFQC]

Dear Edstainless
What do you mean by L and T values?
Thanks

 

[EdStainless]

Longitudinal and transverse to the rolling directions.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[MFQC]

Dear Edstainless
Thanks for your valuable post. Have you any Idea about the ideal difference between L and T values?

 

[Don56]

You say the fracture was in the weld lines. Did it break in the weld metal, HAZ, or base metal. Did it break in all 4 locations where the welds are in the knuckle? What is the nominal thickness? Thickness in the area of fracture? What shape head is being made? What is the KR? Grade of SS? Weld process? Filler metal?

 

[NUFITPIPINGSOLUTIONS]

Plates need to be soft & annealed to manufacture the dish end/cap. This kind of issue was never found when we manufacture it. NUFIT PIPING SOLUTIONS is my company name, if in any case we can help you with with any fittings, flanges, fasteners, Valves, pipes, plates, bar etc then you can contact us.