When welding stainless, how do you guys get the rainbow of colors in the welds? I am using 304SS and ER308L, and the welds are silver (like regular mild steel welds)?

 

The color is the temp that the weld was when the gas shield was uncovered. Silver is OK, and usually you see it at the end of the weld. But the color isn't a sign of penetration. If you are butt welding, you will not see the pretty colors everyone loves. The heat has no where to go. More likely to see Salmon and purple until you do thick to thin like welding to the header flanges. Then you will see the colors you are thinking of.

 

I think you even posted the merges that you sell, and you had some pretty colorful welds on the tubing that merged together (thin -to-thin).

If you are welding 16ga 304SS, how many amps are you using? I was told I am using too much (60A).

 

Ah, the merge I had was thick to thin on the shiny stuff, at the base. The tubing was mild, but still isn't shiny. Only at the base on the thick stuff. 60 on butting 304 together is way too hot. I like to start at about 43 amps on colder days. 60-65 might be good for thin to a T4 or T6 flange.

 

Thanks for the advice. I'll have to play around some more

 

Actually a silver to light goldish tint would be ideal in terms of least contamination with in the weld. I would concentrate more so on proper pen, backpurging, heat control and machine/flow settings. One thing I don't see mentioned would be the use of a large gas lense. This will promote a much more laminar gas flow, and overall better argon coverage. I'll usually use a #7 gas lense with a 3/32nd tungsten. Gas flow is is important in terms of too little or too much... Yes, too much. Thin wall tubing or sheet metal tends to heat soak very quickly, so you may find yourself working around the part to keep heat soak down. Always remember and keep mental note of the expansion rate of stainless, to cut back on warpage or shifting.
One more important thing to remember is Argon post flow, and it's importance.

With practice, and a little knowledge, it'll come to you.

 

Do you have any pics with a cut to check for full penetration ?

 

Yea, that's a good idea... a clear photo of the welds your refering to would be usefull for critiquing.

 

I meant you.

I've done LOTS of testing and butt welding with back purge and can get the nice colors, but not full penetration. If I get full penetration, it's not straw or blue. Now if I weld anything else like to hear flanges or V-bands it's fine. Just butt welding when it has nowhere to run is becomes salmon colored.

 

When talking about color, you've got to remember color is part of the air born contamination, after the weld is out of the sheilding gas. Atmosphere contaminates the weld for the most part. The color issue could also be your travel speed. A gas lens will help significantly. But it's NOT a requirement. It's just much much better.
Try fusing first to get the feel for speed. By fusing, this means no filler. Once you get the hang of it, start adding filler in. For thin wall tubing, try MIG welding wire to get the feel of it. Then move up in size of filler if necessary. The smaller filler seems to give a better feel and freedom, but you'll have to feed it in quicker.

It's all in the fit up, prep work, and process. Like I mentioned, it really depends on the part, if full 100-90% pen is necessary. On the intercooler piping, full pen is not necessary, which means fusion welding is not out of question for these parts. On the thick wall Sch 10/40, full pen is a process of proper bevel/landing, spacing, and heat/torch control. This all becomes second hand when you have experience. Now this is nothing new to you, as a professional, but more so directed towards the original poster.

I could go on and on, but I don't have time to rewrite the books here... Study up on the process, take a course or two at your local collage, practice, and continue improving... It'll come with time if your dedicated.

Also, 10sec...To answer your original question, no I do not have any photos, but I may be able to get something for you, if I remember to pick up the camera. I'm not on here too often, but I'll see what I can do for you.

 

Yeah, they've got the color broken down with color being heat once the argon is removed, and even PPM. I've talked to guys who do 16 and thin stainless for a living pretty much all of them said on thin stainless with a butt weld like this, you aren't going to get the color. Butting thin is the only time I don't get that pretty color.Not burnt though. Anything else is gold,blue and pink.

 

I am going to try the gas lense idea.

Magicbus - What amps do you use for butt welding 16ga?

 

I set my course to about 80A but use quite a bit less than full power...Ideally, you should be 63 or less amps.

 

Less than yes, but that's way too high to even start. I'd probably start at 40