4130 wire choice

By paulpollaccia Date 12-02-2007 02:14

I have been told that i can weld chrome-moly tubing .083 1", using the mig process. I am building kart frames. I was told that i could use ER70S-2 wire, but ER80S-D2 would be a better choice to use for strength. I will be preheating the tubing prior to tacking and welding. Some of my concern are this, I will be welding mild steel tabs for seat bracket and throttle linkage to the 4030 tubing . I was told to use 75/25 )AR/CO2). Would there be any problem using this wire and shielding gas. By the way I want to use .030 wire. I did find it in the ER80-D2, but not in the ER 70-2 wire. Any help would be very appreciated. Thanks in advance for your comments and suggestions.

By smallcastle Date 12-02-2007 23:21

Have mig welded allot of 4130 base material with .035" & .045" ER80S-D2 filler wire. 300 to 350 preheat is what we use. Never have used 75% argon - 25% Co2. Always have used 98% argon & 2% oxygen. We have a mig welding procedure that was qualified on 3/8" 4130 plate in 1G. Hard to believe but the tensiles came in at over 115 KSI. Biggest problem we have with this procedure is porosity on x-ray welds. But most of that seems to have to do with problems that the welder can control. A far as welding lower alloy steels to 4130, I can't help you. Maybe someone else will chime in on that one.

By bozaktwo1 (***)

Date 12-03-2007 17:48

80S wire will work just fine. Preheat might not even be required for that wall thickness, although it can't hurt anything.