Low Thermal Input MIG Welding Processes???

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Good afternoon Gents,What a wonderful, invaluable forum this is that we can draw on the knowledge and experience of such a vast audience of forum members.I am investigating GMAW process equipment that will exert the least amount of thermal input into welding a .750" thk rolled CS flange to a .375" thk SS plate.I have limited experience with Pulse Arc and was disappointed with the results in that heat input was still to high for my desires.Although on the expensive end, the Fronius Cold Metal Transfer MIG welding process seems ideal and may be contacting such for a demonstration at our facility.Would like to query all as to their experience and comments on this or any other MIG welding process that could produce the results I desire.Thanks in advance.......
Reply:Originally Posted by sooeey2uGood afternoon Gents,What a wonderful, invaluable forum this is that we can draw on the knowledge and experience of such a vast audience of forum members.I am investigating GMAW process equipment that will exert the least amount of thermal input into welding a .750" thk rolled CS flange to a .375" thk SS plate.I have limited experience with Pulse Arc and was disappointed with the results in that heat input was still to high for my desires.Although on the expensive end, the Fronius Cold Metal Transfer MIG welding process seems ideal and may be contacting such for a demonstration at our facility.Would like to query all as to their experience and comments on this or any other MIG welding process that could produce the results I desire.Thanks in advance.......
Reply:Controlled short-arc processes like Fronius' CMT or Lincoln's STT are mostly used for thin metal and for root passes in pipe welding. I'm not sure they are suitable for metal that thick, but consulting with the manufacturers would provide answers.OTOH, joint design and welding technique are more important than process for minimizing heat input.309L wire, BTW.JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:I think you might strike out on a CMT or similar process, since inherently they are best suited for thinner materials.  Even conventional short circuit processes would need to be ran at the limits for the joint in question simply due to the mass of the parts.It may be wise to look into a laser hybrid process, which fronius specializes in.  This process can use a laser to either aid in weld fusion or droplet detachment, allowing higher travel speeds which will greatly reduce your heat input.If you notice in most heat input formulas used in industry, travel speed is typically the denominator. A small change to this variable will make the largest impact in your overall heat input.  It might even be beneficial, though counter intuitive, to look at increasing volts/amps in order to gain a significant increase in travel speed.Have we all gone mad?