Welding of 17-4 PH 630 1.4542 Stainless Steel

Arc and resistance welding processes used on standard grades of stainless steel are applicable to 17-4PH stainless steel. The low hardness enables sections, up to 100mm, to be welded without requiring pre heating.Alloy 17-4 PH can be welded by the following welding processes: SMAW, GTAW, PAW and GMAW. SAW should not be used without preliminary testing (to check freedom of cracks and toughness of the weld metal).

Successfully welded by common fusion and resistance methods, this alloy should not be joined by oxyacetylene welding. AWS E/ER630 filler metal is recommended if required.Due to a ferrite delta primary type of solidification, the hot cracking risk of the weld metal or the HAZ is reduced.

Generally, no preheating must be done and interpass temperature must be limited to 248°F (120°C). The better toughness is obtained in the weld after a complete heat treatment (solution annealing + precipitation hardening).

Due to the martensitic microstructure, a low oxygen content in the weld metal is preferable to increase ductility and toughness. To avoid cold cracking, the introduction of hydrogen in the weld must be limited. Alloy 17-4 PH can be welded with homogeneous filler metals such as E 630 (AWS A5.4) electrodes and ER 630 (AWS A5.9) wires.

Austenitic filler material can be used when the mechanical properties of 17-4 PH steel are not required in the weld and, in this case, no post-weld heat treatment must be applied.