Distance Between Welds to Avoid Overlapping HAZ's?

[KernOily]

Hi guys. I know there is a rule of thumb out there someplace for spacing between adjacent buttwelds so as to avoid overlapping the HAZ's. I seem to remember it being one inch or one diameter. This is for P1 materials. What do you all say? Thanks guys! Pete

 

[SJones]

I say use the search function:

http://www.eng-tips.com/search.cfm?q=weld spacing&action=search

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[BigInch]

Now that you've searched the forum (HAZ comes up every 6 months), you probably see its more closely related to wall thickness than diameter.

Independent events are seldomly independent.

 

[LittleInch]

As an absolute minimum I'd go for 4t (min 25 mm) as suggested by someone on a previous post as it least it has a back-up from code AS xxxx. This issue generates some forceful views and personally I would always look at anything less than a 1D or 300mm pup(whichever is smaller) as an error in design or manufacture. Any piping run should have freedom in x,y and z for "green lenghts" to be the final as measured legnth (I usually showed it as xxx*) of at least this to avoid these small annoying pups which are of dubious long term strenght.

It normally comes down to the judgement of the metalurgist / welding engineer depending on the material, size, wall thickness and design code or instalation specification.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[KernOily]

Guys thanks for the replies and thanks for the admonishment to use the search function... <facepalm>