Cadweld failures pipelines

[brimmer]

Has anyone had experience where a cadweld on a pipeline has caused a failure (leak or rupture)? If so what was the cause, cracking from hard spot, etc..

(Not trying to spark a debate about cadwelding to pipelines in general, but what failure mechanism were involved)

Thanks

 

[BigInch]

Never. What about you?

Let your acquaintances be many, but your advisors one in a thousand’ ... Book of Ecclesiasticus

 

[brimmer]

I am investigating one at the moment...

 

[GregLamberson]

Very interested to know more - never seen or heard of it happening either.

Could be poor coating around the cadweld leading to excessive localized corrosion? Must be thin wall pipe?

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[BigInch]

Very thin pipe and when they did the "hit the cadweld with a hammer test" it broke the pipe ???

Let your acquaintances be many, but your advisors one in a thousand’ ... Book of Ecclesiasticus

 

[stanweld]

As memory serves and at this point maybe loss of memory, I seem to recall reading about an incident ocurring in the early 1970's. you might try the Office of Pipeline Safety or Batelle for further info.

My only problems encountered with cadwelding involved the use of molds too many times resulting in the exothermic puddle depositing on the pipe (still reactive), melting the copper wire resulting in no connection. I investigated for copper migration into the pipe but found none in a few such incidents.

 

[BigInch]

Exactly, its always the copper wire, not the pipe, that fails. The melt temp are just too far apart to affect the steel.

Let your acquaintances be many, but your advisors one in a thousand’ ... Book of Ecclesiasticus