Stainless Steel 302 · supply condition
Stainless Steel 302-3/4 Hard
Properties of the 3/4 Hard condition, compared with the other 302 tempers.
Near-spring temper strip for flat springs and retaining parts formed with generous radii.
What is 302-3/4 Hard?
302-3/4 Hard is 302 supplied in the 3/4 Hard condition — near-spring temper strip for flat springs and retaining parts formed with generous radii. 302-3/4 Hard has a yield strength of 965 MPa (140 ksi) and a tensile strength of 1,240 MPa (180 ksi) — stronger than 98% of stainless steel grades. Elongation at break is 5% and the elastic modulus is 193 GPa (28 Msi). 302-3/4 Hard has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 67% of stainless steel grades. It melts at 1,400°C (2,552 °F). Annealed is the default condition FabDigit quotes; 3/4 Hard is available on request or by drawing note.
Advantages
- High strength — 965 MPa (140 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 — 5%, worse than 100% of stainless steel grades
302-3/4 Hard properties
Typical room-temperature values for 302-3/4 Hard — 8 properties are specific to this condition; the rest are grade-level values shared by every 302 temper. Each bar shows where the value sits among the stainless steel grades in FabDigit's library — further right is higher.
Physical3
302-3/4 Hard has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 67% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
302-3/4 Hard has a yield strength of 965 MPa (140 ksi) and a tensile strength of 1,240 MPa (180 ksi) — stronger than 98% of stainless steel grades. Elongation at break is 5% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
302-3/4 Hard is rated for continuous service to 760°C (1,400 °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 17.3 µm/m·K (9.61 µin/in·°F).
Electrical3
302-3/4 Hard conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (66/100), better than 58% of stainless steel grades.
Sustainability4
Producing a kilogram of 302-3/4 Hard takes about 53 MJ of energy and emits 5.2 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 60%.
Manufacturability7
302-3/4 Hard's machinability is fair (42/100, better than 79% of stainless steel grades); weldability good (55/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 302 tempers and conditions
302 is also supplied in 10 other conditions. The full side-by-side table is on the 302 overview.
- AnnealedDefaultDefault stocked condition for sheet, strip, bar and wire that will be deep drawn, bent or coiled.275 MPa yield · 150 HB
- Spring Temper WireThe classic 302 product form: compression/extension springs, snap rings and formed wire; strength rises sharply as wire diameter falls.1,400 MPa yield · 45 HRC
- Full HardMaximum cold-rolled strength for flat springs, blades and shims used essentially flat.1,030 MPa yield · 41 HRC
- 3/4 HardNear-spring temper strip for flat springs and retaining parts formed with generous radii.965 MPa yield · 37 HRC
- 1_2_hardCold-rolled 302 half-hard temper per ASTM A666 (Rp0.2 ≥760 MPa, Rm ≥1035 MPa) — high-strength springy strip with limited bend ductility.830 MPa yield · 32 HRC
- 1/2 HardHigher strength stamping temper for flat springs, shims and structural clips with gentle bend radii only.800 MPa yield · 32 HRC
- Cold DrawnPick for shafts, pins and machined parts needing better straightness, surface finish and roughly double the annealed yield strength.690 MPa yield · 24 HRC
- 1_4_hardCold-rolled 302 quarter-hard temper per ASTM A666 (Rp0.2 ≥515 MPa, Rm ≥860 MPa) for moderately formed springy parts, clips and brackets.585 MPa yield · 25 HRC
- 1/4 HardCommon temper for stamped brackets, clips and washers that still need moderate bending.550 MPa yield · 27 HRC
- 1_16_hardLightly cold-rolled 302 strip/sheet temper per ASTM A666 (Rp0.2 ≥310 MPa) that keeps most of the annealed ductility for bending and forming.380 MPa yield · 190 HB
Working with 302-3/4 Hard
Is 302 easy to machine?
Gummy and work-hardening like 304 — use rigid setups, sharp positive-rake carbide, heavy constant feed, 20–35 % lower surface speed than mild steel and flood coolant to avoid glazing.
Can 302 be welded?
GTAW/GMAW/resistance welding are all practical with 308L/347 filler, but the ≤0.15 % C makes the HAZ sensitization-prone: keep heat input low and post-weld solution anneal for corrosive or high-temperature service.
Can 302 be formed, bent or molded?
Excellent deep-draw and spring-coiling behaviour with high work hardening; allow springback and interstage annealing on severe draws, and stress-relieve coiled springs at 260–400 °C.
What surface finishes work on 302?
Not anodizable — passivate per ASTM A967 or electropolish; takes a high mechanical polish (No.4 to mirror) and accepts electroplating with proper Woods-nickel strike.
302 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 |
|---|---|---|
| Chigher than 304 — gives the extra cold-work strength | ≤ 0.15 | 0.1 |
| Cr | 17 – 19 | 18 |
| Ni | 8 – 10 | 9 |
| Mn | ≤ 2 | 1 |
| Si1.00 max in some product specs | ≤ 0.75 | 0.5 |
| N | ≤ 0.1 | 0.05 |
| P | ≤ 0.05 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
302-3/4 Hard — frequently asked
What is 302-3/4 Hard used for?
302-3/4 Hard is typically used for springs, kitchen sinks and cookware. In short: general-purpose austenitic bar.
What is the yield strength of 302-3/4 Hard?
302-3/4 Hard has a typical yield strength of 965 MPa (140 ksi) and a tensile strength of 1,240 MPa (180 ksi) — stronger than 98% of stainless steel grades. Strength varies by condition: see the 11 listed tempers.
Is 302-3/4 Hard easy to machine?
Not especially — machinability is rated fair (42/100, better than 79% of stainless steel grades). Gummy and work-hardening like 304 — use rigid setups, sharp positive-rake carbide, heavy constant feed, 20–35 % lower surface speed than mild steel and flood coolant to avoid glazing.
Can 302-3/4 Hard be welded?
Yes — weldability is rated good (55/100). GTAW/GMAW/resistance welding are all practical with 308L/347 filler, but the ≤0.15 % C makes the HAZ sensitization-prone: keep heat input low and post-weld solution anneal for corrosive or high-temperature service.
What surface finishes work on 302-3/4 Hard?
Not anodizable — passivate per ASTM A967 or electropolish; takes a high mechanical polish (No.4 to mirror) and accepts electroplating with proper Woods-nickel strike.
Can 302-3/4 Hard be formed, bent or molded?
Excellent deep-draw and spring-coiling behaviour with high work hardening; allow springback and interstage annealing on severe draws, and stress-relieve coiled springs at 260–400 °C.
What is the maximum service temperature of 302-3/4 Hard?
302-3/4 Hard is rated for continuous use to about 760°C (1,400 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 302-3/4 Hard?
Yes — 302-3/4 Hard is available for CNC machining and 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)
- ASTM A276/A276M — Stainless Steel Bars and Shapes — ASTM International (2023)
- ASTM A313/A313M — Stainless Steel Spring Wire — ASTM International (2018)
- EN 10088-3 (X10CrNi18-8, 1.4319) — CEN (2014)
- JIS G 4313 / G 4303 (SUS302) — JSA (2011)
- GB/T 1220 (12Cr18Ni9) — SAC (2007)
- 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)
- Machinery's Handbook, 31st ed. (machinability ratings) — Industrial Press (2020)
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.