Stainless Steel

Stainless steel is the appropriate material when aluminum lacks the corrosion resistance, elevated temperature capability, or surface hardness the application requires, and when the application does not yet demand the extreme conditions that push into nickel superalloy territory. We source 304, 316, and 17-4PH in plate form for qualifying programs. Each grade represents a fundamentally different approach to the stainless design problem.

304 is the most widely produced stainless steel in the world. Its 18 percent chromium and 8 percent nickel composition (the basis for the 18-8 shorthand) produces excellent corrosion resistance in a broad range of environments at low cost. It is used for food processing equipment, architectural applications, and general chemical service. 316 adds 2 to 3 percent molybdenum, which dramatically improves resistance to chloride pitting and crevice corrosion. In marine environments and pharmaceutical applications where 304 would pit, 316 is the correct choice. Neither 304 nor 316 is hardenable by heat treatment; strength comes from cold work in the rolled plate.

17-4PH (UNS S17400) is a different class: a precipitation-hardened martensitic stainless that can be delivered in Condition A (solution annealed, relatively soft) and then aged to high hardness and strength after machining. This allows complex parts to be machined in the soft state and then aged to achieve tensile strengths from 115,000 psi (H1150) to over 200,000 psi (H900) depending on the aging cycle. The combination of high strength, corrosion resistance, and hardness makes it the standard for aerospace structural brackets, downhole tool bodies, and defense hardware where stainless is required but austenitic grades cannot provide adequate strength.