Crashproj,
What are you actually asking ?
"are you guys really doin this kind of stuff..."
"Us guys" generally follow the clients specifications, the codes / standards and good work practices.
A good welder can usually weld a fillet weld (eg. reinforcing pad) on the outside of a stainless pipe without causing oxidation on the inside of a pipe.
A less competent welder may weld too hot and cause oxidation.
Cheers,
Shane
The thickness of the pipe wall and the welding process (heat input) will influence the maximum temperature attained on the pipe ID. Temperatures above 400 degrees F will typically result in some level of discoloration.
Whether the discoloration is unacceptable is determined by the customer and what is specified in the project specification.
Best regards - Al
Al,
I agree with you Al.. when heat input is the one will influence the discoloration and not the purging gas.
thanks and regards,
shane sorry...
What i mean , is it necessary to have a back purge when welding on stainless pipe with a fillet weld?
"A good welder can usually weld a fillet weld (eg. reinforcing pad) on the outside of a stainless pipe without causing oxidation on the inside of a pipe."
So it is not mandatory to have a back purge on a fillet weld, actually the thickness of the run pipe is 7.9 mm same thickness for the reinforcement pad we completed 2 spools without back purging and no oxidation on the inside of a pipe.
regards