Weld toe to toe distance requirements

[ricellis]

In API 650 and 653 the minimum weld toe to toe requirement is 250mm. We would like to cut out a 16mm butt weld on a 30 yr old grade 250 steel precipitation tank, and place a new weld only 100mm from where the old weld was. What factors are involved in this 250mm weld distance? We can test a sample of the weld and plate around the HAZ; do we need to look for metallography changes and residual stress only, or are there other factors that influence weld toe to toe distances?

Thanks

 

[JoeTank]

The weld spacing is for the new weld to other welds that remain in the tank. The distance between removed welds and the new weld seem to not matter at all.

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com

 

[ricellis]

I thought the weld distance specified is to keep away from HAZ.

The problem is on our tank I'm not sure if we're cutting out all of the HAZ (or other effects) from the previous weld?? because we're only cutting 100mm away from it.

Thanks,

Richard

 

[JoeTank]

The HAZ is on the order of 1/8" wide.

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com