Stainless Steel

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.

Nitrogen-strengthened low-carbon austenitic stainless steel — essentially 316LN. The N addition (0.12–0.22%) raises yield strength to ≥280 MPa (vs 200 for 316L) without sacrificing corrosion resistance or weldability. Preferred over 316L for pressure vessels and cryogenic applications where higher design stress is needed. Approved for ASME Section VIII. Used for chemical reactors, pharmaceutical vessels, cryogenic storage (LNG) and high-pressure piping.

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-molybdenum austenitic stainless steel with 4.0-5.0% Mo — significantly higher than 316L (2.0-2.5%). Provides substantially improved resistance to pitting and crevice corrosion in chloride environments (PREN ~35, vs ~25 for 316L). Low carbon (≤0.03%) and N addition for sensitization resistance and strength. Used for chemical processing in aggressive chloride media, flue gas desulfurization, pulp & paper bleach plants, and seawater-cooled heat exchangers where 316L is insufficient but duplex is not desired.

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.

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).

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).

Heat-resistant austenitic stainless steel with 25% chromium and 21% nickel. Maximum continuous service temperature up to 1050°C in oxidizing atmospheres. Standard material for furnace construction, heat treatment baskets and fixtures, radiant tubes, muffles, and high-temperature chemical processing. Good resistance to sulfur-containing atmospheres. Equivalent to AISI 310S.

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.