Welding procedure for pipe couplings

Date 01-04-2004 23:18

I'm welding forged couplings into sa 106 gr B pipe. My question is, will a single fillet weld around the coupling be sufficient for my application.
This vessel I'm fabricating is a miniature water tube boiler with 30 sqft of heating surface using the above grade pipe for steam and mud drums.
It will have an operating pressure of 200psi and a safety factor of 5:1.
The couplings are for generating tube connections which will be grade "L" copper tubing.
I suspect fillet welds from both sides or a full penetration weld is needed, as I do not have access to ASME section 1.
much appreciated
Skip

By pipewelder_1999 (****)

Date 01-04-2004 23:41

I cannot say anything regarding your application. The strength of the weld will come from the size. As far as how many passes, usually a two pass minimum is performed. The chance of leaks is greatly reduced. Single pass fillet welds can be made that are watertight.

If my memory suits me a 1.09t leg size is usually specified. I have also seen this specified as 1t x 2t leg size.

These sizes would usually be left up to the designer (You). The theory behind how and why a weld is a certain size is beyond my training however it is much more simpple than the design of a boiler. I have never seen a socket weld in a boiler.

ASME Sec I would be highly recommended along with your local jurisdiction requirements before undertaking design of a boiler. Im pretty sure many boiler failures have resulted from low pressure boilers built without proper design.

I'm not doubting your expertise, just letting my thoughts flow.

Gerald Austin
Have a good day