Cold Stretching vs Hydrostatic Test

[victorpbr]

Hi,

When performing cold stretching on austenitic steels to improve my allowable stresses in cryogenic aplications. Do I still need to perform an hydrostatic test?

Also, can someone with knowledge on cold stretching check which one of the below is correct, procedure 1,2 or 3.

Procedure 1:
1- Design and fabricate using allowable stress AFTER cold stretching
2- Perform cold stretching
3- MAWP is set based on thickness and allowable calculated on 1, and not on the actual final thickness.

Procedure 2:
1,2 - same as above
3- Check thinning on thickness
4- Recalculate MAWP based on the final thickness

 

[ConstantEffort]

Under what code of construction?

Sec 8 Div 1 MA 44 answers your questions as directly as a design code can... if that code applies.

 

[jtseng123]

I have purchased cryogenic dual-wall bullet with cold stretching years ago from an Australian company. They are expert in this area that will be able to answer your questions. I am not sure if it is ok to give company name and contact in this forum.