MIG welding chromoly

I'm a little confused on this module MIG vs TIG in this course at 4:19... Please correct me if I'm wrong... So chromoly steel can't be mig welded, but yet that's what's used a majority of time in cages? So you can't use chromoly steel and mig weld it? That's where I'm confused... Because what if some of us don't own a tig welder... I thought you can mig weld chromoly, just don't burn it because of the heat temperature of the material and how it's cured. Also of course, how it's welded. Any help, and wisdom is deeply appreciated! -AAL

I'm surprised you haven't received an answer in a week. I am not signed up for the Roll Cage Fabrication course, so I don't know exactly what was presented. I can think of two reasons why MIG shouldn't be used for chromoly tubing. One, it is too easy to produce welds that look very good but do not have enough penetration to get full strength from the weld. The second reason I can think of is there are different sanctioning organizations for various types of racing and some of them do not like MIG welding, probably for the reason I stated above. That is about all I can contribute and maybe my response will trigger some more answers.

Bob

Hi Adarrio, thanks for the question, the problem with chromoly is the elements in the material that make it strong also get adversely affected by heat, depending on where you are in the world its commonly outlawed for MIG welding due to the high amount of heat in the MIG weld, the TIG welding method controls this and produces less heat making for a more ductile joint. The problem isn't in the weld itself its the heat affected zone next to the weld and when its overheated it becomes too brittle and can snap in an accident. It is common to see MIG welded chromoly in the USA but but you will more often than not find its thick wall which reduces the chances of it breaking in the heat effected zone. The only benifit to chromoly over DOM is the weight saving it can bring to reduce the wall thickness, if your using Chromo over Dom in the same wall thickness then your really just wasting money IMO. Thanks for the question and sorry for the delay in the reply.

Nigel you're a busy man as I could only imagine so no worries on the delay, I'm a patient guy. I do thank you and Robert T. for helping me get a better understanding on chromo with mig welding. I guess it's time to get into the tig welding course so may better myself with the fundamentals of the skill. Glad I'm asking way ahead of time so I'm not wasting money, material, and time. Nor putting anyone's life in danger! Thank you Nigel P. again for the solid information, I do appreciate it sir! Glad to learn every time I get on here! 🤙🏼⚡🤘🏼

My pleasure, you will love TIG welding, it's a skill that will open up so many opportunities to build better components. All the best.