904L also is called as Nr. 1.4539  (DIN EN X1NiCrMoCu25-20-5) or UNS S08904.

904L is a high alloy austenitic stainless steel with outstanding corrosion resistance in aggressive environments, specially to sulfuric acid, phosphoric acid, acetic acid and chloride-induced pitting/crevice corrosion.

It remains austenitic and non magnetic even after cold working or printing. It can reach tensile strength 600-750MPa. yield strength (0.2%) 300-450MPa, elongation 30-45%, and hardness 150-200HB in the state of as-printed + annealed.

Its typical solution annealed condition is 1050-1100℃ and then water quench to restore corrosion resistance. Its strength comes from solid solution and grain refinement, no precipitation hardening, so offering exceptional acid resistance as the bridge between stainless steel and expensive nickel alloy.

904L powder produced by gas atomization, but also can by PREP for better sphericity and lower hollow particles, typically is used in additive manufacturing, particularly Laser Powder Bed Fusion (LPBF) and electron bean melting.