Stainless Steel grades

Nickel-bearing martensitic stainless steel with higher corrosion resistance than 410/420. Highest strength of the standard martensitic grades (up to 1100 MPa). Used for marine shafts, propeller shafts, high-strength fasteners, valves, and pump components.

17% Cr Ti-stabilized ferritic stainless. Cost-effective alternative to 304 for many applications — no Ni means ~30-40% lower cost. Immune to chloride SCC. Used for automotive exhaust systems (downstream), kitchen sinks, washing machine drums, heat exchangers, and architectural trim.

High-carbon martensitic stainless steel with molybdenum and vanadium. Hardenable to 58+ HRC while maintaining moderate corrosion resistance. Used for cutlery, surgical instruments, valve components, bearings, and pump parts where hardness and corrosion resistance are both needed.

Highest-hardness standard martensitic stainless steel. Achieves 57-60 HRC — the hardest commonly available stainless grade. Excellent wear resistance from chromium carbides. Used for bearings, races, valve components, surgical instruments, high-end cutlery, and precision molds.

Stabilized ferritic stainless steel with Mo addition. A cost-effective alternative to 316L for applications where austenitic properties are not needed. Excellent resistance to chloride stress corrosion cracking. Used for hot water tanks, solar collectors, automotive exhaust, and catering equipment.

Precipitation-hardening martensitic stainless steel — the highest-strength stainless in common use. Solution anneal at 1040°C then age at 480-620°C for UTS >1300 MPa. Corrosion resistance similar to 304. Cu+Nb precipitation hardening. Trade names include 17-4PH, SUS630. Used for aerospace structural parts, turbine blades, valve components, nuclear waste casks, medical instruments, and oil/gas equipment.

Super-austenitic stainless steel with high Mo and Cu content. Excellent resistance to sulfuric acid, phosphoric acid, and chloride environments. Bridges the gap between standard austenitics (316L) and nickel alloys (Inconel/Hastelloy). Used in chemical processing, oil & gas, and pharmaceutical.

Soft martensitic (supermartensitic) stainless steel with good corrosion resistance and high toughness. Low carbon prevents embrittlement. The standard material for hydraulic turbine runners, pump impellers, compressor components, and offshore valves.

The most widely used duplex (austenitic-ferritic) stainless steel. Balanced 50/50 microstructure provides twice the yield strength of 304/316L with superior chloride and stress corrosion resistance. Used in oil & gas, chemical processing, marine, and pulp & paper industries.

Lean duplex stainless steel with minimal Ni and Mo — the most cost-effective duplex grade. Uses Mn and N instead of expensive Ni for austenite stability. Double the yield strength of 304 (450 MPa vs 190 MPa). Used as a direct replacement for 304/316L where higher strength or better SCC resistance is needed.

Lean duplex stainless steel with low Mo content. More economical than 2205 with better corrosion resistance than 304/316L. Developed for construction, water treatment, and storage tanks where full duplex properties are not required.

Premium aerospace precipitation-hardening stainless. Al-precipitation for the highest transverse toughness and most uniform properties of all PH stainless grades. SCC-resistant in marine environments. Used for landing gear, structural airframe parts, nuclear components, and high-performance shafts.

Super duplex stainless steel with PREN >40. Superior corrosion resistance to standard 2205 duplex, especially in chloride and H₂S environments. Used for subsea pipelines, offshore platform components, desalination plants, and chemical processing equipment.

Japanese martensitic stainless steel — the higher-carbon variant of the 420 family (C 0.26-0.40%). Achieves HRC 50-55 after heat treatment. Very good corrosion resistance for a martensitic grade. THE budget knife/cutlery steel worldwide. Also used for surgical instruments, haircutting scissors, and industrial blades. ≈ EN X30Cr13 (1.4028) / Chinese 3Cr13.

Work-hardening austenitic stainless — AISI 301. Higher C (0.05-0.15%) than 301LN enables extreme cold-work strengthening to UTS 1300+ MPa in full-hard temper. THE spring-temper stainless: used for flat springs, retaining clips, conveyor belts, automotive structural parts, and rail car body panels. Corrosion resistance similar to 304 in annealed state.

Free-cutting ferritic stainless — AISI 430F equivalent. S 0.15-0.35% + Mo 0.2-0.5% for machinability and slight improvement in pitting resistance. THE ferritic Automatenstahl for CNC screw machines. Used for screws, nuts, bushings, fittings, and automotive components where ferritische Korrosionsbeständigkeit with machinability is needed. Magnetic, not weldable.

Heat-resistant 25Cr-21Ni austenitic stainless — AISI 310S (low-C variant). Oxidation resistance to 1050°C continuous, 1150°C intermittent. Higher Cr+Ni than 304/316 = much better high-temperature scaling resistance. Used for furnace parts, radiant tubes, heat treatment fixtures, kiln linings, and thermocouple protection tubes. Also used in petrochemical cracker tubes.

Martensitic stainless for steam turbine blades and discs — 12Cr-3Ni-Mo-V. Higher Ni (2.5-3.5%) than X20Cr13 gives better toughness and corrosion resistance. V addition for creep strength at elevated temperatures. Used for LP/HP turbine blades, compressor discs, pump shafts, and valves in power generation. Service temperature to ~550°C.

Heat-resistant duplex (austenitic-ferritic) stainless — 25Cr-4Ni-1.5Si. Si addition improves oxidation resistance at high temperature. Used for furnace components, burner nozzles, heat treatment fixtures, and kiln supports operating at 800-1000°C. Higher strength than fully austenitic heat-resistant grades at intermediate temperatures due to duplex structure.

Martensitic CrNi stainless — AISI 431. Best corrosion resistance of ALL martensitic stainless steels due to high Cr (15-17%) + Ni (1.5-2.5%). Hardenable to HRC 46-50. Used for shafts, bolts, valve stems, pump components, fasteners in marine/offshore environments. Also aerospace (WL4044) and medical instruments. Service to 400°C.

6% Mo super austenitic stainless steel — trade name 254 SMO (Outokumpu). PREN 42-44, equivalent to super duplex but fully austenitic = non-magnetic, better weldability, wider temperature range (-196 to +300°C). Strength nearly 2× that of 300-series stainless. Used for seawater systems, offshore oil/gas, FGD scrubbers, bleach plants, and desalination where super duplex is limited by temperature or magnetic concerns.

Super austenitic 6Mo+Cu stainless — Alloy 926 / Incoloy 25-6MO. Enhanced version of 904L with higher Mo (6-7%) and N (0.15-0.25%). PREN 41-48 — rivaling super duplex but fully austenitic. Ni 24-26% eliminates stress corrosion cracking. Used for seawater systems, FGD, phosphoric acid production, offshore hydraulics, and salt extraction. Service -196 to +400°C.

Basic martensitic stainless steel — 0.16-0.25% C + 12-14% Cr. Hardenable to HRC 48-52. THE workhorse martensitic stainless: cheap, available, and adequate corrosion resistance for mild environments. AISI 420 equivalent. Used for cutlery, surgical instruments, shafts, valve spindles, bolts, and turbine blades. Better corrosion resistance than X12Cr13 (1.4006/410) due to higher C and slight Cr advantage.

Ti-stabilized ferritic stainless with Mo — 18% Cr + 2% Mo + Ti. Best pitting resistance in the ferritic family (PREN ~25, comparable to 316L austenitics). Ti stabilization prevents sensitization after welding. Used as cost-effective replacement for 316L in hot water systems, solar collectors, catering equipment, and automotive exhaust heat exchangers. No Ni = lower cost than austenitic.