4130 Prep

[Rob]

Well, this is my first post, but likely won't be my last. I have more questions than answers, so running across this message board while looking at the Miller site was a pleasant find.

I'm using my old 330AB/P to weld up some 4130 tubing, mostly .058 wall thickness. I had been cleaning the tubing with lacquer thinner, but some of the welds had not been as clean as I would like. Just noticed a recommendation elsewhere on the miller site to use isopropyl alcohol or acetone to preclean, and plan to try both.

My question (finally) is whether 4130 requires cleaning with sandpaper or other mechanical cleaning process prior to TIG welding? I'm using 2% thoriated 3/32 tungsten, 15 cf/h argon, and 50 amps.

By the way, any of you know what my old welder might be worth if I get to trade it in on one of the new pulse machines?

Rob

[Kevin Disney]

Rob,

Prior to solvent cleaning (ie. lacquer thinner, acetone, alcohol) it is a good idea to power clean several inches around the area to be welded. Use a clean wire wheel to remove any debris or mill scale on the tubing surface. I prefer to use 100% isopropyl alcohol to solvent clean as it leaves no residue, and it is a little safer to handle.

What filler metal are you using ER70S-6? You may also want to try increasing you gas flow to about 20cfh.

Can't help you with the value of your machine, you'll need to check with your local distributor.

[Rob]

Thanks Kevin, I'll give the wire brush a shot. Yes, I'm using ER70S-6 1/16" filler, but that brings up another question. One supplier I've bought 4130 from recommended a Oxweld #65, which I have not been able to find locally. Any idea what that might equate to under another brand or standard designator?

[BugEyedValiant]

I believe that the Oxweld 65 is the same as RG 60 (Gas welding rod). I do know that the recommended rod is actually ER80-sd-2 if you dont do the postheat treat. I was also known as Linde 83 or now ESAB 83 at my welding shop.

[Sean Brown]

Try pulling the copper off the rod before you start with sandpaper and cleaning it with the same chemicals you're using on the base metal. You might try going down to a 1/16" tungsten and using a gas lens also. I've noticed that these tricks can help.

I've used actual 4130 rod from the US Welding Corp (and liked it), but I've also read that you should use ER70-S2 or the ER80-sd-2 if the parts are not going to be normalized and heat treated. I would really like to know more about this subject because I don't necessarily buy all the explanations I've heard.

Sean

[BugEyedValiant]

I agree with Sean, I use scotch brite to rub the copper off of the rod.