SS410 cracked while dish forming.

[amsomu04]

Hello all,

Recently we sent the dish blank for forming operation. While forming the dish end, the base material was broken up to 1 feet from 4 inch away from the weld joint. The condition of received plate was HOT ROLLED, ANNEALED AND PICKLED. Plate Thk.10mm. Welding consumable used E309/E309L. No pre heat given since the PQR passed without preheat.

Request all to give your feedback of what could be the reason for this failure.

Thank you..

 

Pictures would help.

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

 

[SnTMan]

cold formed? hot formed?

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

 

[amsomu04]

It's cold formed since the material was annealed condition...

 

[EdStainless]

What C level?
What strength?
What was the temperature when you were forming?

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

 

[amsomu04]

Here with image of the base metal failure

 

[amsomu04]

Carbon 0.127, UTS as per MTC 518MPA, Hardness 160BHN and Cold formed..

 

[weldstan]

The cut edge appears to have been flame cut. It would appear that fracture initiation occurred at the flame cut edge. Check the hardness there.

 

[amsomu04]

The cutting was made using plasma arc cutting. Will check the hardness. Thank you..

 

[amsomu04]

Which cutting process to choose to avoid this fracture..How to prevent this failure if we use plasma arc cutting...

 

[DVWE]

You will only be able to effectively use plasma arc, your only real viable alternative is water jet cutting.

Grind the edges 1/16" minimum to remove the hardened edge when using plasma cutting.

The devil is in the details; she also wears prada.

 

[chicopee]

"Grind the edges 1/16" minimum to remove the hardened edge when using plasma cutting" I believe that DVWE has it correct.

 

[Don56]

Also any torch cut notches precipitate this type of cracking during cold forming.

 

[amsomu04]

Thank you all for your much valuable responses. Is Cold forming recommended for annealed 410 materials.??

 

[r6155]

Can you tell us diameter?
IMO the reasons are:
1) Required lubricant for forming is not showed
2) I can see a laminar fracture near the weld –HAZ-
3) May be spring effect near crack
4) May be brittle fracture.
5) Poor fabricator experience in SS410

More information in

http://www.ssina.com

Regards
r6155

 

I'll throw in my own speculation: what is the impurity content and inclusion distribution?
A proper failure investigation instead of speculation is recommended, or the outcome could be repeated.
A bit expensive, but not as expensive as speculation or trial and error.

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

 

[weldstan]

The plasme cutting appears to have been hand done. Machine cutting is much preferred followed by grinding to both remove the hardened layer and provide a smooth notch free edge surface. Greater grinding will be incurred to provide the same edge surface as previously stated.










your

 

[amsomu04]

Is Cold forming recommended for annealed 410 materials.??

I did the trial dish with preheated up to 150 deg C and got the formed dish end without any failures..

So I concluded that the cold forming is wrong for 410 annealed plates. Whats your thoughts here please..