Specifications for ERW/HRW pipes with PWHT

[afstructures]

Hi,
I am selecting welded pipe material for an offshore structure and came across a requirement that if ERW/HRW pipes are used they have to subjected to heat treatment to relief stresses caused by this welding technique.

I was wondering if the required heat treatment is there (by default) EN 10225 , EN 10210, EN 10219 and API 5L.

 

[blacksmith37]

At least for API 5L and 5CT, the HT requirements for ERW are not for stress relief : the HT is to recrystallize the grain/fiber flow at the weld. This is an induction HT , normally in line with the ERW. There is also a metallographic requirement to check grain flow and HT. For poor quality mills ,one of the most likely shortcomings is inadequate control of this HT. All API grades do not have the same req'ts; the mills were able to exclude some of the lower grades. If this is an important structure, there should be a metallurgist involved with material selection.

 

[afstructures]

blacksmith37
Many thanks for the response.

I am actually selecting the material based on the project specification.

The reason i raised the question is that one paragraph of the material specification stated that ERW pipes are not allowed, yet it called for the usage of several pipe grades of EN 10225 which are ERW pipes. So i was trying to figure out why.