Conducting NDT (UT,MT,PT) before heating (firing for dimensional correction)

[Arif]

Hi All

I have a problem during fabrication of steel structure
We are using carbon steel and we conduct UT just after welding
The problem is after UT we usually do some correction in dimensional with heating
Is there any affect to that weld?I was afraid heating raise some defect and we could not found it.
any of you has experience with my problem, was it better to conduct UT after heating?

Thanks before

[shovelon]

Hi All

I have a problem during fabrication of steel structure
We are using carbon steel and we conduct UT just after welding
The problem is after UT we usually do some correction in dimensional with heating
Is there any affect to that weld?I was afraid heating raise some defect and we could not found it.
any of you has experience with my problem, was it better to conduct UT after heating?

Thanks before

You know you do all NDT after any operation or process that can alter the physical properties of the structure.

You have it correct. Unless the print or engineering says otherwise.

[lotechman]

Some types of failure such as underbead cracking on very thick section do not happen until many hours after the weld has been completed. Some inspection procedures require that the UT be done 24 hours after. So if you are heating and straightening after welding yes you could cause failure by stressing the material past the yield point. If you are talking material under half inch thick and low carbon alloy then it would not be a concern. The old A 36 structural steel is rarely used on larger structures and higher yield point steels are being chosen for weight savings. These new steel alloys do not like excessive heats or built in stresses.