ISO 5832-9 Stainless Steel Bars ISO 5832-9 Rods ISO 5832-9 Rings ISO 5832-9 Round Bar

Product Description

ISO 5832-9 defines the international standard for wrought high-nitrogen, high-purity austenitic stainless steel used in surgical implants, medical instruments, and critical non-magnetic hardware. Standardized globally under UNS S31675, ASTM F1586, and European designation DIN Werkstoff Nr. 1.4472 (X4CrNiMoN21-9-4 or X2CrNiMoN21-16-5-4), this material is commercially produced under trade names including Rex 734, UGIPURE 4472, and Chronifer M-1586. Manufactured via vacuum-arc remelting or electroslag remelting processes, ISO 5832-9 steel relies on a controlled solid-solution nitrogen addition to deliver superior yield strength, fatigue endurance, and pitting corrosion resistance compared to standard implant grade 316L stainless steel.

Standards and Designations

Primary governing specifications include ISO 5832-9 for surgical implants, ASTM F1586 for wrought nitrogen-strengthened stainless steel, UNS S31675, and European standard DIN Werkstoff Nr. 1.4472.

Chemical Composition Limits

The alloy composition mandates 19.50 to 22.00 percent chromium, 9.00 to 11.00 percent nickel, 2.00 to 4.25 percent manganese, 2.00 to 3.00 percent molybdenum, 0.25 to 0.50 percent nitrogen, and 0.25 to 0.80 percent niobium. Maximum impurity limits require no more than 0.030 percent carbon, 0.75 percent silicon, 0.025 percent phosphorus, 0.010 percent sulfur, and 0.25 percent copper, with iron providing the balance.

Physical Properties

ISO 5832-9 material exhibits a density of 7.88 grams per cubic centimeter (0.285 pounds per cubic inch) and a tension modulus of elasticity of 200 gigapascals. Its calculated Pitting Resistance Equivalent Number ranges between 33.0 and 38.0. Due to its nitrogen-stabilized austenitic structure, the alloy maintains a magnetic permeability below 1.005, remaining non-magnetic even after heavy cold deformation or forging.

Mechanical Properties

Mechanical requirements vary depending on product form, cross-sectional thickness, and thermal processing condition across round bar, rod, and ring stock.

In the solution-annealed state, bars and forgings specify a minimum tensile strength of 740 megapascals (107 ksi), a minimum 0.2 percent yield strength of 430 megapascals (62 ksi), a minimum elongation of 35 percent, and a hardness between 200 and 250 Brinell.

In the cold-worked or high-strength forged condition, minimum tensile strength increases to 1000 megapascals (145 ksi), minimum 0.2 percent yield strength increases to 750 megapascals (109 ksi), minimum elongation is 10 to 15 percent, and hardness reaches 30 to 38 Rockwell C.