Inconel pipe test

Date 05-13-2004 13:55

Hi everyone,

I need some pointers. The company I am working for has a hydrogen plant we are building and we have about 40 4'' sch. 160 inconel butt welds to do all to ASME B31.3 and 100 percent x-ray. They have asked me to take a 6G test to certify on this, and I had never touched the stuff till yesterday, I ran one out yesterday and the top sides the stringer bead of it came out great, the bottoms had a small amount (1/32) of suck-back in 2 spots, I have been feeding the wire in the puddle more than normal (compared to stainless and carbon), I was told to turndown the purge to about 5 and push it up on the hot pass with the wire, this didn't work it actually made it worse then, it also turned the inside of the bead gray. I have been using a sharp edged bevel, and running 110-140 amps on the stringer 5/32 gap using 1/8 filler, and a gas lense number 6 cup, with 40 for flow out of it. The filler I am using is 617 ErNiCrCoMo.
Thanks in advance.
Mike

By G.S.Crisi (****)

Date 05-13-2004 18:32

Welding Inconel isn't easy. My advice to you is to train and train until you've got confidence in your skills. Don't run the test until you're sure to succeed.
Inconel is manufactured by a company whose name was International Nickel and now changed to Special Alloys. They're in Huntington, Alabama. They're very kind people and willing to help anybody who needs help on their products.
Try to get into contact with them either by telephone or e-mail.
Giovanni S. Crisi
Sao Paulo - Brazil

By Jim Hughes (***)

Date 06-15-2004 00:31

Piece of cake. Set your cupon up with a 3/16" GAP. (Make sure the wps allows this) Turn your heat way down and use a tech. called bridging. You will back feed the wire by letting it hang in the pipe. This is the best procedure for welding Inco's and S.S. Sounds like they are using ASME B31.3 Severe Cyclic for the production welds. It is a very tight code to weld to. Make sure you buff after every pass and anytime you touch your tungsten, grind. Use 3/32" wire and as long as you can feel the purge on your lips its high enough. Make sure your test coupon has a weep hole. If it's starts to drop in on you, your too hot.

By srw2506 (*)

Date 06-23-2004 00:50

I have welded cryogenic pipe,x-ray inconel and we used a J bewel so the root was thin,butt the pieces together no gap,then purge,remember when you purge to have the same size hole out as you do in,your replacing the air not pressurizing the tube,1/4" in = 1/4" or larger out.Adjust your pressure so air cant be sucked back in the outlet from turbulance,put the inlet on the bottom and the outlet on the top,remember argon is heavier than air and fills a pipe like water,if you wanted to put water in thats how youd do it,if you line the hole both at the top the inlet will blow through the pipe and go out without filling the whole pipe.Start your weld at about 4 o'clock weld up past the top and then weld the other side,a hot root about 90 amps or so and a little filler metal(the thinnest rod you have)move fast enough to penetrate but not keyhole,then the next pass weave from side to side,keeping the heat off the center of the root bead,to prevent suckback.Keep filling till done.If your good you can butt the joint and blow a keyhole through it and weld with the keyhole method,most have trouble with that.

By welder03 (*)

Date 06-27-2004 19:00

Thanks guys for all the tips, I got all of the inconel finished on the job just down to a few carbon welds and we will be all done.