Stainless Steel 301 · supply condition
Stainless Steel 301 Extra Hard
Properties of the Extra Hard condition, compared with the other 301 tempers.
Thin-gauge strip for flat springs and constant-force parts where the highest strength is required.
What is 301 Extra Hard?
301 Extra Hard is 301 supplied in the Extra Hard condition — thin-gauge strip for flat springs and constant-force parts where the highest strength is required. 301 Extra Hard has a yield strength of 1,350 MPa (196 ksi) and a tensile strength of 1,550 MPa (225 ksi) — stronger than 99% of stainless steel grades. Elongation at break is 6% and the elastic modulus is 193 GPa (28 Msi). 301 Extra Hard has a density of 7.88 g/cm³ (0.285 lb/in³), heavier than 59% of stainless steel grades. It melts at 1,395°C (2,543 °F). Cold Rolled is the default condition FabDigit quotes; Extra Hard is available on request or by drawing note.
Advantages
- High strength — 1,350 MPa (196 ksi), better than 99% of stainless steel grades
- Polishes to a fine finish — 80/100, better than 89% of stainless steel grades
Limitations
- Limited ductility — 6%, worse than 99% of stainless steel grades
- Limited formability — 12/100, worse than 93% of stainless steel grades
- Limited service temperature — 300°C (572 °F), worse than 90% of stainless steel grades
- High embodied carbon — 5.8 kg CO₂/kg, worse than 85% of stainless steel grades
301 Extra Hard properties
Typical room-temperature values for 301 Extra Hard — 9 properties are specific to this condition; the rest are grade-level values shared by every 301 temper. Each bar shows where the value sits among the stainless steel grades in FabDigit's library — further right is higher.
Physical3
301 Extra Hard has a density of 7.88 g/cm³ (0.285 lb/in³), heavier than 59% of stainless steel grades. It melts at 1,395°C (2,543 °F).
Mechanical17
301 Extra Hard has a yield strength of 1,350 MPa (196 ksi) and a tensile strength of 1,550 MPa (225 ksi) — stronger than 99% of stainless steel grades. Elongation at break is 6% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
301 Extra Hard is rated for continuous service to 300°C (572 °F). It conducts heat at 16.2 W/m·K (9.36 BTU/hr·ft·°F), better than 64% of stainless steel grades. Thermal expansion is 16.9 µm/m·K (9.39 µin/in·°F).
Electrical3
301 Extra Hard conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (60/100), worse than 58% of stainless steel grades.
Sustainability4
Producing a kilogram of 301 Extra Hard takes about 53 MJ of energy and emits 5.8 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 55%.
Manufacturability7
301 Extra Hard's machinability is fair (35/100, better than 51% of stainless steel grades); weldability good (65/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 301 tempers and conditions
301 is also supplied in 9 other conditions. The full side-by-side table is on the 301 overview.
- Cold RolledDefaultMost commonly stocked strip/sheet condition: good strength with usable bendability.570 MPa yield · 27 HRC
- Spring Temper WireCold-drawn round wire for corrosion-resistant compression/extension springs; strength rises as diameter falls.1,450 MPa yield · 48 HRC
- Extra HardThin-gauge strip for flat springs and constant-force parts where the highest strength is required.1,350 MPa yield · 46 HRC
- Full HardMaximum standard strength for spring clips, shims and wear strip; bend only along grain with generous radii.1,100 MPa yield · 42 HRC
- Three-Quarter HardChoose for flat springs and high-strength panels needing only mild forming.1,000 MPa yield · 39 HRC
- Half HardCommon structural/clip temper: high strength with limited 90° bend capability.830 MPa yield · 35 HRC
- Quarter HardUse where moderate bending is still needed but 304-level strength is not enough.620 MPa yield · 28 HRC
- eighth_hardLightly cold-rolled 301 strip/sheet to ASTM A666 1/8-Hard temper — modest strength increase with still-generous bending and forming ductility.500 MPa yield · 225 HB
- sixteenth_hardVery lightly temper-rolled 301 strip/sheet (ASTM A666 1/16-Hard) — small strength gain over annealed while keeping near-annealed formability.400 MPa yield · 200 HB
- AnnealedPick for deep drawing, severe forming or welding; softest and least magnetic condition.280 MPa yield · 165 HB
Working with 301 Extra Hard
Is 301 easy to machine?
Gummy and strongly work-hardening: use rigid setups, positive-rake sharp carbide, heavy feed, low-to-moderate speed and flood coolant; never let the tool dwell or the surface will harden.
Can 301 be welded?
Readily GTAW/GMAW/resistance welded with 308L/309L filler; keep heat input low, no preheat, avoid slow cooling in 425–870 °C to limit carbide precipitation, and expect loss of cold-worked strength in the HAZ.
Can 301 be formed, bent or molded?
Excellent stretch formability in the annealed temper thanks to the very high work-hardening rate (n ≈ 0.4), but forces and springback are high and interstage annealing is often needed; bend hard tempers transverse to the rolling direction only.
What surface finishes work on 301?
Not anodizable — passivate per ASTM A967 after machining/welding; takes bright-anneal, No.4 brush and No.8 mirror polish well and accepts PVD colour or electropolishing.
301 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C≤0.15 % (higher than 304 — drives work hardening) | ≤ 0.15 | 0.1 |
| Si | ≤ 1 | 0.5 |
| Mn | ≤ 2 | 1.2 |
| P | ≤ 0.05 | — |
| SEN 1.4310 allows ≤0.015 | ≤ 0.03 | — |
| Cr | 16 – 18 | 17 |
| Nilow Ni keeps austenite metastable | 6 – 8 | 7 |
| N | ≤ 0.1 | — |
| Fe | balance | — |
301 Extra Hard — frequently asked
What is 301 Extra Hard used for?
301 Extra Hard is typically used for flat springs and spring clips, subway and rail car body panels, hose and band clamps, structural formed panels, retaining clips and brackets and spring-temper wire forms. In short: highest strength stainless spring.
What is the yield strength of 301 Extra Hard?
301 Extra Hard has a typical yield strength of 1,350 MPa (196 ksi) and a tensile strength of 1,550 MPa (225 ksi) — stronger than 99% of stainless steel grades. Strength varies by condition: see the 10 listed tempers.
Is 301 Extra Hard easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of stainless steel grades). Gummy and strongly work-hardening: use rigid setups, positive-rake sharp carbide, heavy feed, low-to-moderate speed and flood coolant; never let the tool dwell or the surface will harden.
Can 301 Extra Hard be welded?
Yes — weldability is rated good (65/100). Readily GTAW/GMAW/resistance welded with 308L/309L filler; keep heat input low, no preheat, avoid slow cooling in 425–870 °C to limit carbide precipitation, and expect loss of cold-worked strength in the HAZ.
What surface finishes work on 301 Extra Hard?
Not anodizable — passivate per ASTM A967 after machining/welding; takes bright-anneal, No.4 brush and No.8 mirror polish well and accepts PVD colour or electropolishing.
Can 301 Extra Hard be formed, bent or molded?
Excellent stretch formability in the annealed temper thanks to the very high work-hardening rate (n ≈ 0.4), but forces and springback are high and interstage annealing is often needed; bend hard tempers transverse to the rolling direction only.
What is the maximum service temperature of 301 Extra Hard?
301 Extra Hard is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 301 Extra Hard?
Yes — 301 Extra Hard is available for sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A666 — Annealed or Cold-Worked Austenitic Stainless Steel Sheet, Strip, Plate and Flat Bar — ASTM International (2015)
- EN 10088-2 / EN 10151 — Stainless steels: flat products and spring strip (1.4310) — CEN (2014)
- EN 10270-3 — Steel wire for mechanical springs, stainless spring steel wire — CEN (2011)
- GB/T 3280 / GB/T 20878 (1Cr17Ni7, 12Cr17Ni7) — SAC (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Outokumpu / Sandvik stainless strip and spring wire datasheets (301, 1.4310) — Outokumpu, Sandvik (2023)
- SMM / Mysteel — SMM / Mysteel (2026)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.