Steel

High-chromium austenitic stainless for high-temperature service. Better oxidation resistance than 304 due to higher Cr (22-24%) and Ni (12-14%). Maximum service temperature ~1000°C (intermittent). Used for furnace parts, heat exchangers, fluidized bed combustors, kiln liners, and boiler baffles.

Low-to-medium carbon Cr-Mo QT steel — lower C than 34CrMo4/42CrMo4 giving better weldability and toughness. THE gas cylinder and pressure vessel grade in Europe (EN ISO 9809). Good hardenability for medium sections. Also used for automotive crankshafts, gears, and high-pressure hydraulic components. AISI 4130 equivalent.

THE Cr-Mo-V nitriding steel — Cr 2.3-2.7% forms hard CrN nitrided case (800 HV surface). V addition for secondary hardening. Core QT to UTS 1080-1270 MPa before nitriding at 570-580°C. Used for piston rods, valve stems, cylinder liners, turbine parts, and any component needing extreme surface hardness + fatigue resistance without distortion (low nitriding temp).

High-strength quenched and tempered Cr-Ni-Mo steel for very large cross-sections. Even better hardenability than 34CrNiMo6 due to higher Cr and Ni content. Used for large shafts (>200mm diameter), heavy-duty gears, turbine rotors, and critical aerospace components.

Boron-alloyed QT steel — between 22MnB5 (press hardening, UTS ~1500 MPa) and 38MnB5 (UTS ~1800 MPa) in the B-steel range. C 0.27-0.33%. Used for high-strength fasteners (class 10.9), chain links, agricultural machinery, and some press-hardened components. Good cold formability before heat treatment.

High-chromium, high-nickel austenitic for the highest service temperatures among standard austenitics. Oxidation resistance to ~1100°C (continuous). Higher Cr/Ni than 309S. Used for furnace parts, radiant tubes, heat treatment baskets, kiln liners, and high-temperature flue gas equipment.

Standard-carbon austenitic stainless steel with molybdenum. Higher C than 316L (max 0.07% vs 0.03%) giving slightly higher strength. Same corrosion resistance as 316L. Used where welding is not required or post-weld solution annealing is possible.

Low-carbon austenitic stainless steel with molybdenum addition. Superior corrosion resistance to 304, especially against chlorides and pitting. Standard choice for chemical processing, marine, medical implants, and pharmaceutical equipment.

Nitrogen-enhanced low-carbon version of 316. The N addition (0.12-0.22%) increases yield strength by ~30% over 316L without losing corrosion resistance or weldability. Used for pressure vessels, nuclear components, and structural applications requiring higher design stress.

Titanium-stabilized austenitic stainless steel with molybdenum. Stabilization prevents sensitization during prolonged high-temperature exposure. Very popular in Germany for chemical, pharmaceutical, and food processing. Being replaced internationally by 316L (1.4404) for most applications.

Low-carbon austenitic with 3-4% Mo — higher Mo than 316L (2-3%). Better pitting and crevice corrosion resistance (PREN ~30 vs ~25). Used in aggressive chemical environments where 316L is borderline: pharmaceutical, dye production, and organic acid processing.

Deep nitriding steel with 3% Cr — the highest Cr content in the EN 10085 nitriding series. Produces the deepest and hardest nitrided case (surface hardness >900 HV, case depth >0.5mm). Core strength 800-1000 MPa QT. Used where maximum surface hardness and wear resistance with a tough core is needed: large gears, cylinder liners, spindles, precision measuring tools, and heavy-duty sliding components.

THE standard nitriding steel — Cr-Mo-V combination optimized for gas nitriding. Vanadium refines grain and forms hard VN nitrides (surface >750 HV). Better core toughness than 31CrMo12 at similar strength. THE default choice when "nitriding steel" is specified without further detail. Used for crankshafts, gears, spindles, extrusion screws, and precision machine components.

Heavy-duty NiCrMo quenched & tempered steel with high Ni (3.0-3.5%) — maximum hardenability in the QT range. UTS 1100-1300 MPa. Used for the most heavily loaded shafts, crankshafts, and structural components where 34CrNiMo6 hardenability is insufficient. Large cross-sections up to 250mm. Aerospace landing gear, heavy mining equipment, and large hydraulic press components.

Titanium-stabilized austenitic stainless steel. Similar to 304 but with Ti addition to prevent carbide precipitation during welding and high-temperature service (up to 800°C). Used for aircraft exhaust manifolds, boiler casings, jet engine parts, and chemical processing.

Premium CrMoV nitriding steel with highest Cr (3%) and Mo (1%) in the nitriding series — designed for maximum core strength after nitriding. Higher strength than 31CrMoV9 and 31CrMo12. AMS 6481 for aerospace. THE gun barrel material. Nitrided surface reaches 860+ HV while maintaining tough core at 415 HV. Used for gun barrels, high-performance gears, ball bearing races, crankshafts, and components requiring the ultimate combination of core strength + surface hardness.

Boron-alloyed case hardening steel with higher C (0.30-0.36%) than typical case-hardening grades. B addition for cost-effective hardenability. After carburizing: HRC 58-62 surface with tough core. THE chain link and chain pin steel — also used for agricultural equipment, earth-moving parts, and wear-resistant components requiring surface hardness with impact resistance.

Niobium-stabilized austenitic stainless steel. Nb forms NbC instead of CrC, preventing sensitization during welding or high-temp service (425-860°C). Alternative to 321 (Ti-stabilized). Used for welded structures in chemical processing, aircraft exhaust systems, and high-temp piping.

Medium-carbon chromium steel with moderate hardenability. Used for components requiring moderate through-hardening: axles, shafts, connecting rods, bolts, and general machine parts. Less expensive alternative to 41Cr4 for smaller cross-sections.

THE classic aluminum-containing nitriding steel — Al 0.8-1.2% forms extremely hard AlN nitrided layer (900-1100 HV surface). Cr 1.0-1.3% + Ni 0.85-1.15% provide core strength. Highest achievable surface hardness of all nitriding steels. Used for cylinder liners, piston rings, crankshafts, spindles, and gauges where maximum nitrided hardness is critical. Also known as 34CrAlNi7-10.

Medium-carbon Cr-Mo quench and temper steel. Lower C than 42CrMo4 for better weldability and toughness. Used for welded pressure vessels, seamless tubes for high-temperature service, bicycle frames, and moderately stressed machine components.

Free-cutting variant of 34CrMo4 (1.7220) — S 0.020-0.040% for improved machinability on CNC automatics. Same Q&T properties. Used for high-volume CNC production of shafts, connecting rods, bolts, and automotive drivetrain components where machining cycle time is critical.

High-strength quenched and tempered Cr-Ni-Mo steel. Excellent hardenability and toughness, suitable for large cross-sections. Used for heavy-duty shafts, gears, turbine parts, and aerospace components.

Free-cutting variant of 34Cr4 (1.7033) — sulfur addition (0.020-0.040%) for improved machinability on CNC automatics. Same QT properties as 34Cr4. Used for shafts, spindles, bolts, studs, and automotive components in high volume on automatic lathes.