hi, we are developing a WPS for Welding AISI 4145 (TS: 140,000 psi) to AISI 4130 (TS: 95,000 psi), what kind for welding consumable we can use as the highest AWS electrode (E12018-G) available still not match the required tensile strength,
If you are welding 4145 to 4130 you do not need to match the highest TS. If your weld metal is stronger than the weakest TS then the weak point of the joint is obviously the 4130 NOT the weld metal. But before you go welding on this stuff you need to understand fully the ramifications of the 45 in 4145.
js is correct if it was me I would rethink this whole thing bad design and engineering (no surprise there) too much difference in strengths setting this up for failure, from the start just IMHO I might be wrong, not the first time sincerely, Kent
kent makes a good point. The large difference in strength can cause testing issues as well. I'd consider longitudinal bends instead of transverse. With transverse the 4130 part of the joint will take the brunt of the bend and create conditions in which you have excessive fiber elongation. This may fail the test when in reality it would be a good joint.
We have to use this materials as it's a product requirements, The mechanical tests has been done using ER 80b-2 & E11018M electrode and the results for macro, tensile bend tests was satisfactory, the the hardness values were less (179 to 195 HV) and we did PWHT.