TIG Welding queries

By teamunwired Date 06-25-2009 14:36

Hello!
We students here at NIT Calicut,India are competing for a vehicle design & fabrication contest- Baja SAE Asia 2010. We have chosen 4130 Chromoly Alloy Steel tubings/pipes as the material for our Roll Cage(Chassis). The following are the specs:

Tubing Material: 4130 Chromoly Alloy Steel
Outer Dia(OD)= 1.25 inch
Wall Thickness= 0.065 inch (1.65 mm)

The roll cage has to survive the harshest of punishment of a 4 hour endurance race on an off-road track. I would really appreciate if answer the following queries:
1. Does TIG Welding have a clear advantage over MIG and Arc Welding in our case? If so, what are the advantages?
2. Does TIG Welding require stress relieving/ heat treatment?

Thanking you in anticipation

Kind Regards
Prateek Kalyankar
NIT Calicut,India

By Kix

Date 06-25-2009 16:53

I'd say that TIG welding will give you consistently good qaulity and nice cosmetic welds. Mig welding can be used, but tie in's and restarts are not going to have the quality that the TIG will give you in a consistent manner. MIG is harder to get into tight places and it's harder to maneuver than a TIG torch around the radius of the pipe.
All our big motorsport teams here in the states TIG weld 4130 chassis with ER70S-2 tig wire or a ER80S-D2 wire. More and more race teams are going back to the ER70S-2 wire for it's ductility and the flex it allows in the joints during a crash or over harsh terrain.

By teamunwired Date 06-25-2009 17:47

Thank you so much for the prompt and may i say encouraging response.
Could you please answer the query on whether stress relieving is required? If yes, does it require local or global stress relieving?

By Kix

Date 06-26-2009 12:09

Some may take it to the level of stress relieving, but some do not. For your application, I'd say to weld it up and run er.;-)