What Consumable would you use?

[iam42]

I have a joint that is a single v between two pieces of carbon steel pipe. Inside the pipe is a stainless steel nozzzle which is incorporated into the weld like a backing material.

My question is..... should this be classified as a P1 to P1 weld or a P1 to P8 weld, secondly, what consumable classification would you use to weld it. 309 or 70XX?

I have attached a sketch which may help in understanding my poor description above.


Thanks

 

[weldstan]

Use E/ER309.You have a carbon steel to carbon steel weld and a carbon steel to stainless weld.

 

[metengr]

Using your referenced sketch this would be a combination weld with the root being P1 to P8 and the fill would be P-1 to P-1. The filler metal would be 309 stainless for the entire joint, if the service temperature is below 700 deg F. If above, I would use Inconel 82/182 to weld the entire joint.

Although, I have an alternate option for your consideration. I would consider machining a recess (about 3/8" wide and 3/16" deep approximate dimensions, and radius the corners) into the 316 stainless steel nozzle which will be located at the weld root region. Shrink fit a carbon steel strap into the recessed region of the stainless steel nozzle. Once this is completed you have a carbon steel backing to weld against and the entire weld joint can be made using E7018 weld rod. The carbon steel insert will be held in place by the recess in the stainless steel nozzle.

 

[iam42]

Thanks guys,

you confirmed my own opinions about using the 309 consumable. The reason this question came up is I have a customer who is not accepting my WPS which I have used for successfully for many years.

Thanks again.