What is the proper filler to use when mig welding a 4140 weldment. We need to weld end plates and a axle in a 1" wall 4140 steel tube for a 15" long roll. I have been told to use an e80s material because e70s would crack, and I have been told e70s would be fine by another reliable source what is the correct answer or does it matter? Plan on 035 wire using 75/25 argon co2 mix
thanks
John