Stainless Steel 303 · supply condition
Stainless Steel 303 Cold Worked 1/4 Hard
Properties of the Cold Worked 1/4 Hard condition, compared with the other 303 tempers.
Higher-strength small-diameter bar and wire for fasteners where extra proof strength is required.
What is 303 Cold Worked 1/4 Hard?
303 Cold Worked 1/4 Hard is 303 supplied in the Cold Worked 1/4 Hard condition — higher-strength small-diameter bar and wire for fasteners where extra proof strength is required. 303 Cold Worked 1/4 Hard has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 88% of stainless steel grades. Elongation at break is 15% and the elastic modulus is 193 GPa (28 Msi). 303 Cold Worked 1/4 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). Cold Drawn is the default condition FabDigit quotes; Cold Worked 1/4 Hard is available on request or by drawing note.
Advantages
- Easy to machine — 72/100, better than 99% of stainless steel grades
- High strength — 620 MPa (89.9 ksi), better than 88% of stainless steel grades
Limitations
- Hard to polish — 40/100, worse than 99% of stainless steel grades
- Difficult to weld — 25/100, worse than 92% of stainless steel grades
- Limited ductility — 15%, worse than 89% of stainless steel grades
- High embodied carbon — 5.5 kg CO₂/kg, worse than 77% of stainless steel grades
303 Cold Worked 1/4 Hard properties
Typical room-temperature values for 303 Cold Worked 1/4 Hard — 9 properties are specific to this condition; the rest are grade-level values shared by every 303 temper. Each bar shows where the value sits among the stainless steel grades in FabDigit's library — further right is higher.
Physical3
303 Cold Worked 1/4 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
303 Cold Worked 1/4 Hard has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 88% of stainless steel grades. Elongation at break is 15% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
303 Cold Worked 1/4 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
303 Cold Worked 1/4 Hard conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 63% of stainless steel grades.
Sustainability4
Producing a kilogram of 303 Cold Worked 1/4 Hard takes about 53 MJ of energy and emits 5.5 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 65%.
Manufacturability7
303 Cold Worked 1/4 Hard's machinability is very good (72/100, better than 99% of stainless steel grades); weldability poor (25/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 303 tempers and conditions
303 is also supplied in 4 other conditions. The full side-by-side table is on the 303 overview.
- Cold DrawnDefaultStandard stocked condition for screw-machine bar: higher strength, tight size tolerance and the best chip control.450 MPa yield · 240 HB
- Cold Worked 1/4 HardHigher-strength small-diameter bar and wire for fasteners where extra proof strength is required.620 MPa yield · 29 HRC
- CD Ground & PolishedPick when a precise diameter and a smooth shaft surface are needed straight from stock (pins, spindles, shafts).450 MPa yield · 240 HB
- AnnealedSoftest, most ductile and most corrosion-resistant condition; choose for cold heading, bending or when maximum ductility is needed.260 MPa yield · 165 HB
Working with 303 Cold Worked 1/4 Hard
Is 303 easy to machine?
The best-machining austenitic stainless: run 30–50 % faster than 304 with sharp positive-rake tools, rigid setups and generous coolant; chips break cleanly thanks to MnS.
Can 303 be welded?
Not recommended — high sulfur promotes hot cracking and porosity; if unavoidable use 308L/312 filler, low heat input and no restraint, and expect reduced corrosion resistance.
Can 303 be formed, bent or molded?
Only light cold forming (thread rolling, mild bending); transverse ductility is poor and sulfide stringers open into cracks on tight bends — use 304 for deep drawing.
What surface finishes work on 303?
Passivate per ASTM A967 (nitric or citric) after machining; electropolish improves pitting resistance, but a mirror polish is hard to achieve because sulfides pull out.
303 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 | 0.08 |
| Mncombines with S to form free-machining MnS | ≤ 2 | 1.5 |
| Si | ≤ 1 | 0.5 |
| P | ≤ 0.2 | 0.03 |
| Sdeliberate free-machining addition | 0.15 – 0.35 | 0.25 |
| Cr | 17 – 19 | 18 |
| Ni | 8 – 10 | 9 |
| Mooptional at producer's discretion (ASTM A582) | ≤ 0.6 | — |
| Fe | balance | — |
303 Cold Worked 1/4 Hard — frequently asked
What is 303 Cold Worked 1/4 Hard used for?
303 Cold Worked 1/4 Hard is typically used for CNC turned shafts, valve bodies and stems, nuts and threaded fittings, bushings and spacers, shaft couplings and instrument and connector bodies. In short: easiest machining stainless.
What is the yield strength of 303 Cold Worked 1/4 Hard?
303 Cold Worked 1/4 Hard has a typical yield strength of 620 MPa (89.9 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 88% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is 303 Cold Worked 1/4 Hard easy to machine?
Yes — machinability is rated very good (72/100, better than 99% of stainless steel grades). The best-machining austenitic stainless: run 30–50 % faster than 304 with sharp positive-rake tools, rigid setups and generous coolant; chips break cleanly thanks to MnS.
Can 303 Cold Worked 1/4 Hard be welded?
Not readily — weldability is rated poor (25/100). Not recommended — high sulfur promotes hot cracking and porosity; if unavoidable use 308L/312 filler, low heat input and no restraint, and expect reduced corrosion resistance.
What surface finishes work on 303 Cold Worked 1/4 Hard?
Passivate per ASTM A967 (nitric or citric) after machining; electropolish improves pitting resistance, but a mirror polish is hard to achieve because sulfides pull out.
Can 303 Cold Worked 1/4 Hard be formed, bent or molded?
Only light cold forming (thread rolling, mild bending); transverse ductility is poor and sulfide stringers open into cracks on tight bends — use 304 for deep drawing.
What is the maximum service temperature of 303 Cold Worked 1/4 Hard?
303 Cold Worked 1/4 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 303 Cold Worked 1/4 Hard?
Yes — 303 Cold Worked 1/4 Hard is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A582/A582M Free-Machining Stainless Steel Bars — ASTM International (2021)
- EN 10088-3 Stainless steels — Semi-finished products, bars, rods (1.4305) — CEN (2014)
- GB/T 1220 (Y1Cr18Ni9) — SAC (2007)
- JIS G 4303 Stainless steel bars (SUS303) — JSA (2012)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
- Sandvik / Outokumpu free-machining austenitic grade datasheets — Sandvik, Outokumpu (2022)
- SMM / Mysteel — SMM, Mysteel (2025)
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.