Materials database

Lean ferritic stainless with just 12% Cr and ~1% Ni — the cheapest stainless option. Also called "utility ferritic" or 3CR12. Lower corrosion resistance than 304 but much better than carbon steel. Magnetic, weldable (with precautions), and formable. Used where mild corrosion resistance at lowest cost is the goal: railway wagons, coal trucks, bus chassis, sugar mills, and architectural cladding in mild environments.

Low-cost utility ferritic stainless steel (12% Cr). A cost-effective alternative to 304 where full corrosion resistance is not required. Good weldability for a ferritic grade. Used for railway wagons, bus bodies, sugar industry, mining equipment, and structural applications.

Low-carbon 18/10 austenitic stainless — AISI 304L. C max 0.030% prevents sensitization after welding without stabilizing elements. THE welding-grade 304. Slightly higher Ni (10-12.5%) than 1.4301 (304) for better austenite stability. Used for welded vessels, piping, food equipment, and any 304 application requiring post-weld corrosion resistance without solution annealing.

High-Mo, high-Ni variant of 316L. Often specified for pharmaceutical and biotech cleanroom applications where delta-ferrite must be minimized (high Ni ensures fully austenitic structure). Also used in chemical processing and offshore. Often dual-certified with 1.4404.

Higher-alloy variant of 316L — Ni 12.5-15.0% (vs 10.0-13.0 for 1.4404) and Mo 2.5-3.0%. Guaranteed delta-ferrite free (essential for pharmaceutical/biotech electropolished surfaces). THE pharma and biotech process equipment stainless. Also used for chemical plant and food processing where maximum pitting resistance in the 316-family is needed.

Super duplex stainless steel — SAF 2507 / UNS S32750. PREN >40 giving outstanding resistance to pitting, crevice corrosion, and stress corrosion cracking in chloride environments including hot seawater. 50/50 austenite-ferrite microstructure. UTS >800 MPa — roughly 2x the strength of 316L. Used for offshore oil/gas, desalination, chemical tankers, flue gas desulfurization, and subsea equipment.

Super duplex stainless with W + Cu addition — trade name Zeron 100 (Rolled Alloys). PREN >41 — even higher than SAF 2507 (1.4410) due to tungsten contribution. Outstanding pitting, crevice, and stress corrosion cracking resistance in hot seawater and aggressive chlorides. Used for subsea oil/gas equipment, seawater desalination, FGD systems, and chemical tankers in the most aggressive chloride environments.

Low-carbon nitrogen-enhanced austenitic Cr-Ni-Mo steel — AISI 316LN. Nitrogen (0.12-0.22%) boosts yield strength above 316L while maintaining weldability. Higher PREN than 316L for better pitting resistance. Charpy impact compliant to -196°C. ASME Section III approved for nuclear pressure boundary. Used for nuclear power piping, LNG cryogenic vessels, pharmaceutical equipment, and chemical plants.

High-Mo austenitic stainless — 4-5% Mo (vs 2-2.5% for 316L). N addition for strength and PREN. Superior pitting and crevice corrosion resistance in chloride environments compared to 316L/317L. PREN ~34-38. UNS S31726 / AISI 317LMN. Used for chemical plant, pharmaceutical equipment, pulp bleach plants, and FGD systems where 316L would fail. Resistant to intergranular corrosion even after welding.

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.

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.

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.

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.

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.

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).

THE free-cutting austenitic stainless — AISI 303. Sulfur 0.15-0.35% for short-breaking chips and excellent machinability. Not weldable (hot cracking risk from S). Reduced corrosion resistance vs 304 due to sulfide inclusions. Used for high-volume CNC screw machine production of fittings, shafts, bushings, valves, and any turned stainless part where machining cost dominates.

High-carbon martensitic stainless steel — 0.9% C + 18% Cr. Achieves HRC 58-60 after hardening — among the hardest stainless steels. Better corrosion resistance than 440C (1.4125) due to higher Cr (17-19% vs 16-18%). THE premium European cutlery/surgical instrument stainless. Used for kitchen knives, surgical scalpels, razor blades, ball bearings in corrosive environments, and valve seats.