.035 chromoly amperage

By - Date 12-15-2000 01:37

Have any of you guys, gals, welded on .035 chromoly tubing using the TIG process? All I need to know, is what was the average of your amperage? Where did it hang around mostly? I'm starting a new project, and was wondering if my machine has too high of amperage. It's lowest setting is 40 amps. I'm guessing it will work, but might be a little too hot and possibly have an unstable arc. If I had some material in hand, I'd experiment for myself, but I also figured some of you might have some pointers as well. I've TIG welded plenty, just not on 20 gauge chromo.

Thank you. Slagman

By awill4x4 (**)

Date 12-16-2000 11:58

Slagman, you may just get away with welding .035 Cr/Moly at 40 amps.
We regularly weld 1"X.049 4130 Cr/Moly tubing and our amperage is just on or just below 50 amps.
It welds beautifully, no sizzle like carbon steel. It almost welds like Stainless.
It's worth giving it a try.
Regards Andrew.

By Mike Brace (**)

Date 12-16-2000 14:35

As Slagman stated it can be done with 40 amps. There are somethings that come into play though. What is your skill level? What is the part fit up? If you are just starting Tig welding, 40 amps might be to much. This current level will require faster travel speeds that may take time to master. If fit up is not tight and consistant again it could be difficult. What machine are you using? Some amperage drop can be obtained by putting an inductor in the weld cable. This can be done by rapping the work cable tightly around a large (6" or larger solid piece of metal) to choke down the output of the machine. Start with 8 to 10 raps and see if how much it helps. I would not go more that 15 raps. The side effect of this is it lowers the duty cycle of the machine.

By - Date 12-17-2000 06:11

Skill level is not a problem. I have experience in building boiler parts, mainly .035 stainless tubing to 3/8 inch black iron plate, with the TIG process. The thing of it is, I was using a Lincoln Square Wave TIG 355. Now I own my own business and don't have access to that machine. The machine I will be using is my field service rig's TIG unit. The reason being, I do proto type project welding for an engineering business, on occasion, that is out of my home state. Well, this project has me traveling some 300 miles to do this project. The reason being, they don't have any welding machines. GOOD MONEY for me to do it!! So, I will be using my Miller Trailblazer 251nt. Park the truck outside, fire it up, and drag my TIG welding stuff into the shop. I love this 3 phase machine, and that's what I'm stuck with because I'll be nowhere near my shop. Duty cycle is not a problem, as it is 100% at 250 amps, and I think it is safe to say that I won't be welding that high on .035 material. Fitup WILL be tight and consistent, as the joints will be end milled. Thanks for your response.

Slagman

By Mike Brace (**)

Date 12-18-2000 12:46

Have you though of using a small invertor machine? Miller makes a Maxstar 140 that will do the job vely well. It runs on 120 or 240 and has a range on 110 of 1 to 100 amps and on 240 1 to 140. It only weights about10 lbs and is the size of a lunch box. Info on it can be seen at millerwelds.com. It is an excellent machine.