Stainless Steel 301LN 3/4H
Supply condition
AISI/SAE 301LN · UNS S30153 · EN 1.4318
3/4H = three-quarter hard
Choose for flat springs, shims and very high-strength strip with minimal forming.
Values for the 3/4H condition
Other 301LN tempers and conditions
301LN is listed in 7 conditions; see the grade overview at 301LN.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Pick for maximum formability and weldability — deep-drawn, stretch-formed or welded parts that still need ~400 MPa yield. | 400 | 750 | 50 | 88 HRB | — |
1/16-Hard | Use when a modest strength gain over annealed is needed while keeping good bending and roll-forming behaviour. | 530 | 870 | 38 | 95 HRB | — |
1/8-Hard | Intermediate strength strip for brackets and roll-formed profiles that still require moderate bend radii. | 640 | 950 | 30 | 22 HRC | — |
Quarter hard | Common structural strength level for rail-car skins and load-bearing sheet where some bending is still required. | 750 | 1,050 | 25 | 27 HRC | — |
Half hard | High strength-to-weight sheet for structures, springs and clamps where only gentle forming is done. | 950 | 1,200 | 16 | 33 HRC | — |
3/4HThis page Three-quarter hard | Choose for flat springs, shims and very high-strength strip with minimal forming. | 1,100 | 1,330 | 11 | 38 HRC | 2.4 % IACS |
Full hard | Maximum strength strip for spring clips, straps and flat springs; essentially no forming beyond simple bends across the rolling direction. | 1,250 | 1,450 | 8 | 42 HRC | — |
What is 301LN 3/4H?
301LN 3/4H is 301LN supplied in the 3/4H condition — choose for flat springs, shims and very high-strength strip with minimal forming. 301LN 3/4H has a yield strength of 1,100 MPa (160 ksi) and a tensile strength of 1,330 MPa (193 ksi) — stronger than 98% of stainless steel grades. Elongation at break is 11% and the elastic modulus is 195 GPa (28.3 Msi). 301LN 3/4H has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,400°C (2,552 °F). ANN is the default condition FabDigit quotes; 3/4H is available on request or by drawing note.
Advantages
- High strength — 1,100 MPa (160 ksi), better than 98% of stainless steel grades
- Polishes to a fine finish — 80/100, better than 89% of stainless steel grades
Limitations
- Limited ductility — 11%, worse than 96% of stainless steel grades
- Limited service temperature — 280°C (536 °F), worse than 96% of stainless steel grades
- Difficult to machine — 25/100, worse than 88% of stainless steel grades
- Low fracture toughness — 85 MPa·√m (77.4 ksi·√in), worse than 77% of stainless steel grades
- Needs corrosion protection — 52/100, worse than 76% of stainless steel grades
301LN 3/4H properties
Typical room-temperature values for 301LN 3/4H; 23 are specific to this condition. Other listed values are 301LN reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
301LN 3/4H has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical15
301LN 3/4H has a yield strength of 1,100 MPa (160 ksi) and a tensile strength of 1,330 MPa (193 ksi) — stronger than 98% of stainless steel grades. Elongation at break is 11% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
301LN 3/4H is rated for continuous service to 280°C (536 °F). It conducts heat at 15 W/m·K (8.67 BTU/hr·ft·°F), worse than 59% of stainless steel grades. Thermal expansion is 16 µm/m·K (8.89 µin/in·°F).
Electrical3
301LN 3/4H conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (52/100), worse than 76% of stainless steel grades.
Sustainability4
Producing a kilogram of 301LN 3/4H takes about 53 MJ of energy and emits 4.3 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 60%.
Manufacturability7
301LN 3/4H's machinability is poor (25/100, worse than 88% of stainless steel grades); weldability good (60/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 301LN 3/4H
Is 301LN easy to machine?
Gummy and strongly work-hardening — use rigid setups, sharp positive-rake carbide, heavy positive feed, ~40 % of 1212 speeds and flood coolant; avoid dwelling to prevent a hardened skin.
Can 301LN be welded?
Very good with GTAW/GMAW/laser/resistance welding using 308L/307-type or matching filler; low C + N avoids sensitization, but cold-worked strength is lost in the HAZ and heat input should be kept low to limit distortion.
Can 301LN be formed, bent or molded?
Excellent stretch- and deep-drawability in the annealed state (high n-value, strong work hardening with martensite formation); allow generous springback compensation and inter-stage annealing for severe draws, and increase bend radii sharply in 1/2-hard and above.
What surface finishes work on 301LN?
Supplied 2B/BA/No.4; passivate or electropolish after fabrication for best corrosion behaviour, and pickle/blast off weld heat tint — no anodizing (electrolytic colouring or PVD if colour is needed).
301LN 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 |
|---|---|---|
| Clow-carbon for weld corrosion resistance | ≤ 0.03 | 0.02 |
| Si | ≤ 1 | 0.5 |
| Mn | ≤ 2 | 1.3 |
| P | ≤ 0.05 | — |
| S≤0.015 typical for good weldability | ≤ 0.03 | — |
| Cr | 16 – 18 | 17 |
| Nilow Ni gives metastable austenite | 6 – 8 | 6.7 |
| Nsolid-solution strengthening | 0.07 – 0.2 | 0.14 |
| Fe | balance | — |
301LN 3/4H — frequently asked
What is 301LN 3/4H used for?
301LN 3/4H is typically used for rail vehicle bodies, structural sheet panels and tanks. In short: nitrogen-strengthened weldable 301; high strength-to-weight sheet; excellent stretch formability.
What is the yield strength of 301LN 3/4H?
301LN 3/4H has a typical yield strength of 1,100 MPa (160 ksi) and a tensile strength of 1,330 MPa (193 ksi) — stronger than 98% of stainless steel grades. Strength varies by condition: see the 7 listed tempers.
Is 301LN 3/4H easy to machine?
Not especially — machinability is rated poor (25/100, worse than 88% of stainless steel grades). Gummy and strongly work-hardening — use rigid setups, sharp positive-rake carbide, heavy positive feed, ~40 % of 1212 speeds and flood coolant; avoid dwelling to prevent a hardened skin.
Can 301LN 3/4H be welded?
Yes — weldability is rated good (60/100). Very good with GTAW/GMAW/laser/resistance welding using 308L/307-type or matching filler; low C + N avoids sensitization, but cold-worked strength is lost in the HAZ and heat input should be kept low to limit distortion.
What surface finishes work on 301LN 3/4H?
Supplied 2B/BA/No.4; passivate or electropolish after fabrication for best corrosion behaviour, and pickle/blast off weld heat tint — no anodizing (electrolytic colouring or PVD if colour is needed).
Can 301LN 3/4H be formed, bent or molded?
Excellent stretch- and deep-drawability in the annealed state (high n-value, strong work hardening with martensite formation); allow generous springback compensation and inter-stage annealing for severe draws, and increase bend radii sharply in 1/2-hard and above.
What is the maximum service temperature of 301LN 3/4H?
301LN 3/4H is rated for continuous use to about 280°C (536 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 301LN-ANN and 301LN-FH?
ANN is the default condition — pick for maximum formability and weldability — deep-drawn, stretch-formed or welded parts that still need ~400 MPa yield. FH: maximum strength strip for spring clips, straps and flat springs; essentially no forming beyond simple bends across the rolling direction. Yield strength is 400 MPa in ANN versus 1,250 MPa in FH.
Sources
- ASTM A666 – Standard Specification for Annealed or Cold-Worked Austenitic Stainless Steel Sheet, Strip, Plate, and Flat Bar — ASTM International (2015)
- EN 10088-1/-2 (X2CrNiN18-7, 1.4318) — CEN (2014)
- Outokumpu Forta 301LN / 4318 datasheet — Outokumpu (2021)
- ASM Handbook Vol.1 – Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.13B – Corrosion: Materials — ASM International (2005)
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.