API 5l Grade X70 56" longitudnal seam Pipe ruptured along the seam

[goodbadgood]

Dear All,

I have encountered an issue during production, one of the pipes rupture after hydrotest beside the longitudinal seam
Pipes were made of API 5L Grade X70 and contains longitudinal seam weld. It seems that ruptured occurred from an area beside the weld you can also say at HAZ from the ID side of the pipe. Did you guys have encountered any problems like this.

hydrogen cracking may have been the cause of this rupture which usually develops in HAZ area in SAW pipes.

Any help in finding the cause will be appreciated.

 

[EdStainless]

What does your metallurgist say? I presume that he has details on the material and samples of failed and intact material.
Why, there are about a dozen possible reasons.
I won't speculate from here.

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P.E. Metallurgy, Plymouth Tube

 

[goodbadgood]

we havenot doen full fledged investigation on it . will update you by looking at the microcircuit. however the fracture surface is brittle with some flat fracture surface on the ID side of the welded Pipe. a long centre line is also observed which also points towards pre existing defects inside the weld which may have helped in crack initiation

 

[metengr]

Have a proper metallurgical analysis performed. If necessary use an independent lab.

 

[racookpe1978]

Verify your hydrostatic pressure: Check pump logs, check gages and gage calibration, pressure recorders. If the pipe were overpressurized, the pipe weld may not have been at fault.
Did temperature change or test fluid oscillate or hammer?