Stainless Steel

Nitrogen-alloyed work-hardening austenitic — AISI 301LN. Lower Ni (6-8%) than 304 makes it metastable: cold work transforms austenite to martensite → UTS up to 1400 MPa in full-hard condition. N addition compensates low C for corrosion and strength. Used for rail car bodies, springs, structural parts requiring high strength-to-weight ratio, and architectural cladding.

Lean duplex stainless steel (SAF 2304 / UNS S32304) with reduced Mo and Ni content compared to 2205. Cost-effective alternative to austenitic 316L with ~2× yield strength (400 MPa) and good stress corrosion cracking resistance. No Mo addition — relies on Cr+N for corrosion resistance (PREN ~25). Used for storage tanks, water heaters, transport tanks, structural applications in construction (e.g. reinforcing bar), and swimming pool structures. The budget-friendly duplex option.

Titanium-stabilized ferritic stainless steel with 12% chromium, often called the muffler grade stainless steel. Ultra-low carbon (max 0.03%) with Ti stabilization prevents sensitization during welding. Excellent formability for stamped and deep-drawn components. Primary material for automotive exhaust systems (manifolds, catalytic converter housings, mufflers), hot water heaters, and welded tubes. Cost-effective alternative to austenitic grades. Service temperature up to 600°C.

Ti- and Nb-stabilized ferritic stainless steel with very low carbon (max 0.03%) and 17.5-18.5% Cr. The dual stabilization with Ti and Nb provides excellent resistance to intergranular corrosion and superior high-temperature oxidation resistance. Non-hardenable. Used extensively for automotive exhaust manifolds, catalytic converter housings, heat exchangers, furnace parts, and kitchen equipment. More economical than austenitic grades for high-temperature applications.

Martensitic chromium stainless steel with moderate carbon content (0.26-0.35%) and 12-14% Cr. Part of the AISI 420 family. Can be hardened to approximately 50-52 HRC. Good balance of hardness, toughness, and corrosion resistance. Used for cutlery, kitchen knives, scissors, springs, surgical instruments, and pump shafts. Better toughness than higher-carbon variants X39Cr13 and X46Cr13.

Martensitic chromium stainless steel with medium-high carbon content (0.36-0.42%) and 12.5-14.5% Cr. Higher hardness potential than X30Cr13 (up to 54 HRC) but slightly reduced toughness. Used for high-quality cutlery, cutting tools, scissors, surgical instruments, and measuring tools requiring both corrosion resistance and good edge retention.

Hardenable martensitic stainless steel with Mo addition for improved corrosion resistance and hardenability. Higher Cr (15.5-17.5%) than basic Cr13 grades. Achieves 220-275 HB after QT. Good resistance to nitric acid, water, steam, acetone, alcohol, and glycerine. Used for pump shafts, valve components, springs, fasteners, turbine blades, and food processing equipment requiring both hardness and corrosion resistance.

Low-carbon martensitic stainless steel with nickel (3.5–4.5%) and molybdenum (0.3–0.7%) for improved toughness, weldability, and corrosion resistance. Available in QT650, QT780, and QT900 conditions. Primary material for hydraulic turbine runners (Francis, Kaplan), pump impellers, compressor components, and offshore parts. Service range -60°C to 300°C. Also known as F6NM (ASTM cast) and UNS S41500.

Austenitic CrNiMo stainless — AISI 316 variant with higher Mo (2.5-3.0%) and Ni (10.5-13.0%). Better pitting resistance than standard 316 (1.4401) due to higher Mo minimum. C max 0.05% (not L-grade, so slightly higher strength than 316L). Used for chemical plant, textile dyeing equipment, and applications requiring guaranteed higher Mo than 316 minimum.

Martensitic chromium stainless steel with high carbon content (0.43-0.50%) and 12.5-14.5% Cr. The highest carbon grade in the basic Cr13 martensitic series. Achieves hardness up to 56 HRC. Good compromise between hardness and corrosion resistance. Equivalent to AISI 420C/420HC. Used for knife blades, surgical instruments, razor blades, CO2 capture pipes, and precision cutting tools. Good polishing capability.

Free-cutting high-carbon martensitic stainless steel. Sulfur-enhanced variant of X46Cr13 (1.4034) for automated production of knife blades and cutlery. Combines the high hardness of X46Cr13 (up to 54 HRC) with excellent machinability for mass production on automatic lathes and CNC machines. Used for industrially manufactured knife blades, scissors, and cutting tools.

Austenitic Cr-Ni stainless with higher Ni (11-13%) than 304 (8-10.5%) — AISI 305. The higher Ni content lowers work-hardening rate, making it ideal for severe cold forming and deep drawing operations where 304 would crack. Same corrosion resistance as 304. Used for deep-drawn sinks, pots/pans, complex stampings, and cold-headed fasteners where minimum work-hardening is needed.

Supermartensitic stainless steel with high Ni and Mo. Excellent combination of high strength (up to 1000 MPa) and good corrosion resistance. Superior to CA6NM (1.4313). Used for offshore flow lines, subsea Christmas trees, hydraulic cylinders, and pump shafts.

Premium martensitic stainless steel with 0.50% C, 15% Cr, Mo and V additions. The signature blade steel of German knife manufacturers (Wüsthof, Zwilling J.A. Henckels, Victorinox Swiss Army). Mo and V improve corrosion resistance, hardenability, and toughness beyond basic Cr13 grades. Achieves 55-57 HRC. Excellent rust resistance, easy sharpening, and good edge retention. Also known as Krupp 4116. Equivalent to 5Cr15MoV (Chinese).

High-carbon martensitic stainless steel with Mo addition for blades and cutting tools. Higher carbon (0.48-0.60%) than X50CrMoV15 with similar Cr and Mo but without V. Achieves high hardness (56-58 HRC) with excellent wear resistance. Used for premium knife blades, scissors, surgical instruments, and industrial cutting tools. Popular in Japanese-influenced European knife manufacturing.

THE most widely used stainless steel worldwide — the original "18/8" austenitic (V2A). Good corrosion resistance in natural environments (water, humidity, weak acids). Non-magnetic when annealed. NOT resistant to intergranular corrosion after welding — use 1.4307 (304L) or 1.4541 (321) for welded service. PREN 17.5-21.1 — not suitable for chloride/seawater. Used everywhere: kitchen equipment, food processing, architecture, chemical tanks, automotive, medical devices.

Austenitic stainless steel similar to 1.4301 (AISI 304) but with higher nickel content (11-13% vs 8-10.5%) for improved austenite stability and better resistance to stress corrosion cracking. The higher Ni also provides better formability and deeper drawability. C ≤0.06% reduces sensitization risk. Used where enhanced SCC resistance is needed: chemical processing, food industry equipment, pharmaceutical vessels, and heat exchangers in chloride-containing environments.

Standard molybdenum-bearing austenitic stainless steel, known as AISI 316. Similar to 1.4404 (316L) but with higher carbon content (max 0.07%) providing slightly better high-temperature strength. Not resistant to intergranular corrosion after welding — for welded constructions prefer 1.4404 (316L). Used in chemical processing, marine environments, and applications requiring improved pitting resistance over 1.4301 (304).

THE standard ferritic stainless steel — 16-18% Cr, no Ni. Non-hardenable, magnetic, lower cost than austenitic grades. Good corrosion resistance for indoor/mild environments. Used for kitchen sinks, automotive trim, washing machine drums, architectural panels, and catering equipment. Not suitable for welding thick sections (grain coarsening). AISI 430.

Ferritic chromium-aluminum stainless steel with good oxidation resistance up to 850°C. The aluminum addition (0.10–0.30%) improves scaling resistance at elevated temperatures by forming a protective Al₂O₃ layer. Non-hardenable by heat treatment. Used for furnace parts, burner nozzles, heat exchangers, and automotive exhaust system components.

Niobium-stabilized austenitic stainless with Mo — 316+Nb. Nb stabilization prevents sensitization (like 347) PLUS Mo gives pitting resistance (like 316). Best of both worlds for high-temperature welded chemical plant. Used for welded pressure vessels, heat exchangers, and piping operating at 400-800°C in mildly corrosive environments.

Titanium-stabilized austenitic Cr-Ni-Mo steel — AISI 316Ti. THE German standard industrial stainless (known as "V4A"). Ti prevents Cr-carbide precipitation at 450-850°C giving intergranular corrosion resistance after welding. Better high-temp stability than 316L (up to 550°C). PREN 23-27. Used extensively in chemical/pharmaceutical plants, pressure vessels, food processing, apparatus construction, and shipbuilding.

Niobium-stabilized austenitic stainless — European equivalent of AISI 347. Nb (10×C min) binds carbon to prevent Cr-carbide precipitation during welding or service at 400-800°C ("sensitization"). Same base composition as 304 but immune to intergranular corrosion after thermal cycling. Used for welded constructions in chemical plant, nuclear reactor internals, exhaust manifolds, and any 18/10 austenitic application with repeated heat exposure.

Titanium-stabilized austenitic stainless — AISI 321. Ti (5×C min) prevents Cr-carbide sensitization during welding or service at 400-800°C. Same approach as Nb-stabilized 347 (1.4550) but with Ti instead. Better creep resistance than 304/304L at elevated temperature. Used for exhaust manifolds, aircraft exhaust systems, expansion bellows, and high-temperature chemical plant (to ~800°C).