Materials database

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.

12% Cr martensitic creep-resistant steel for steam turbine applications. Operates to ~580°C continuous. Combines corrosion resistance of 12% Cr with creep strength from Mo+V. Used for steam turbine blades, bolts, discs, and high-pressure steam piping in fossil power plants.

High-carbon high-chromium cold-work tool steel. Excellent wear resistance and dimensional stability after heat treatment. Used for blanking and forming dies, drawing mandrels, gauges, shear blades, and thread rolling dies. Not suitable for impact loading.

Martensitic creep-resistant stainless steel for high-temperature applications up to 600°C. V and Mo additions provide excellent creep rupture strength and high-temperature oxidation resistance. Hardenable to approximately 280 HB. Used for steam and gas turbine blades, high-temperature bolts, valve spindles, and fasteners in power generation. Standardized in EN 10302 (creep-resistant steels) and EN 10269 (high-temp fasteners).

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.

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.

Low-carbon austenitic stainless steel with 2.5-3.0% Mo — the higher-Mo variant of 1.4404 (316L). The increased Mo (vs 2.0-2.5% in 1.4404) provides superior pitting and crevice corrosion resistance in chloride environments. Ultra-low carbon (≤0.03%) prevents sensitization during welding. Used for chemical processing equipment, pharmaceutical vessels, offshore piping, marine hardware, and pulp & paper digesters where 1.4404 is borderline. Often specified in pharmaceutical/biotech where maximum corrosion resistance is required.

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.

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.

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.

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.

The most widely used duplex stainless steel worldwide (SAF 2205 / UNS S31803/S32205). Austenitic-ferritic microstructure provides ~2× yield strength of 304/316 (≥450 MPa) with excellent resistance to stress corrosion cracking, pitting (PREN 33-38), and intergranular corrosion. Service temperature -50°C to 300°C. Used for oil & gas production tubing, chemical processing vessels, desalination plants, pulp & paper digesters, heat exchangers, and bridge structures. Weldable with ER2209 filler.

Super duplex stainless steel (SAF 2507 / UNS S32750) with 25% Cr, 7% Ni, 4% Mo, and high N for PREN ≥42. The highest corrosion resistance and strength among standard duplex grades — YS ≥550 MPa is ~2.5× that of 316L. Service temperature up to 300°C. Used for subsea oil & gas equipment (manifolds, trees, risers), desalination plants, flue gas cleaning, chemical tankers, and mining equipment in severe chloride environments. Requires careful welding to avoid sigma phase.

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.

Tungsten-alloyed hot work tool steel (AISI H21) with 9% W for exceptional high-temperature strength and resistance to tempering. Low thermal conductivity makes rapid cooling unacceptable — tools must be preheated to ~300°C before use. Achieves 44-50 HRC. Used for die casting dies for copper alloys (brass/bronze), hot forging dies, hot extrusion tooling, hot shear blades, and mandrels. The go-to steel for copper alloy die casting where H13 would soften. JIS: SKD5.