Stainless Steel 303Se · temper
Stainless Steel 303Se Annealed
Properties of the Annealed condition, compared with the other 303Se tempers.
Pick when maximum ductility, lowest hardness for secondary cold forming/heading, or fully non-magnetic behaviour is required.
What is 303Se Annealed?
303Se Annealed is 303Se in the Annealed temper — pick when maximum ductility, lowest hardness for secondary cold forming/heading, or fully non-magnetic behaviour is required. 303Se Annealed has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 96% of stainless steel grades. Elongation at break is 50% and the elastic modulus is 193 GPa (28 Msi). 303Se Annealed 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; Annealed is available on request or by drawing note.
Advantages
- Easy to machine — 82/100, better than 100% of stainless steel grades
- Ductile — tolerates forming and impact — 50%, better than 90% of stainless steel grades
Limitations
- Low strength — 240 MPa (34.8 ksi), worse than 96% of stainless steel grades
- Difficult to weld — 22/100, worse than 94% of stainless steel grades
303Se Annealed properties
Typical room-temperature values for 303Se Annealed — 16 properties are specific to this condition; the rest are grade-level values shared by every 303Se temper. Each bar shows where the value sits among the stainless steel grades in FabDigit's library — further right is higher.
Physical3
303Se Annealed 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
303Se Annealed has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 96% of stainless steel grades. Elongation at break is 50% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
303Se Annealed 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
303Se Annealed conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (57/100), worse than 66% of stainless steel grades.
Sustainability4
Producing a kilogram of 303Se Annealed takes about 54 MJ of energy and emits 4.8 kg of CO₂ — less than 59% of stainless steel grades. Typical recycled content is 55%.
Manufacturability7
303Se Annealed's machinability is very good (82/100, better than 100% of stainless steel grades); weldability poor (22/100); formability good (55/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 303Se tempers and conditions
303Se is also supplied in 2 other conditions. The full side-by-side table is on the 303Se overview.
- Cold DrawnDefaultStandard commercial screw-machine stock: straight, close-tolerance bar with higher strength and better chip control than annealed.415 MPa yield · 228 HB
- Cold Drawn High TensileChoose when higher yield strength and wear resistance are needed in small diameters and forming/welding is not required.620 MPa yield · 27 HRC
- AnnealedPick when maximum ductility, lowest hardness for secondary cold forming/heading, or fully non-magnetic behaviour is required.240 MPa yield · 160 HB
Working with 303Se Annealed
Is 303Se easy to machine?
Best-in-class austenitic machining — run 20–30% faster than 304, keep positive rake and sharp tools, coolant-rich; selenides give smoother finish and better threads/knurls than sulphide 303.
Can 303Se be welded?
Not recommended: selenium promotes severe hot cracking and porosity; if unavoidable, use 308L/309 filler, minimum heat input, no filler-free autogenous welds, and expect reduced joint corrosion resistance.
Can 303Se be formed, bent or molded?
Cold heading, thread rolling and knurling are acceptable (better than 303-S), but avoid severe bending or deep transverse forming because inclusions cause directional ductility loss; hot work 1150–1260 °C then anneal ~1040 °C and quench.
What surface finishes work on 303Se?
Passivate per ASTM A967 (nitric or citric) after machining to remove smeared inclusions; takes a good mechanical polish, but electroplating/electropolishing gives patchy results around selenide stringers; no anodizing.
303Se 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 |
| Cr | 17 – 19 | 18 |
| Ni | 8 – 10 | 9 |
| Mn | ≤ 2 | 1.5 |
| Si | ≤ 1 | 0.6 |
| Semin; free-machining addition | ≥ 0.15 | 0.2 |
| P | ≤ 0.2 | 0.04 |
| S | ≤ 0.06 | 0.02 |
| Fe | balance | — |
303Se Annealed — frequently asked
What is 303Se Annealed used for?
303Se Annealed is typically used for machined fittings, threaded shafts, cold-headed screws and studs, valve stems, instrument spindles and electrical connector bodies. In short: selenium machining stainless.
What is the yield strength of 303Se Annealed?
303Se Annealed has a typical yield strength of 240 MPa (34.8 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 96% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is 303Se Annealed easy to machine?
Yes — machinability is rated very good (82/100, better than 100% of stainless steel grades). Best-in-class austenitic machining — run 20–30% faster than 304, keep positive rake and sharp tools, coolant-rich; selenides give smoother finish and better threads/knurls than sulphide 303.
Can 303Se Annealed be welded?
Not readily — weldability is rated poor (22/100). Not recommended: selenium promotes severe hot cracking and porosity; if unavoidable, use 308L/309 filler, minimum heat input, no filler-free autogenous welds, and expect reduced joint corrosion resistance.
What surface finishes work on 303Se Annealed?
Passivate per ASTM A967 (nitric or citric) after machining to remove smeared inclusions; takes a good mechanical polish, but electroplating/electropolishing gives patchy results around selenide stringers; no anodizing.
Can 303Se Annealed be formed, bent or molded?
Cold heading, thread rolling and knurling are acceptable (better than 303-S), but avoid severe bending or deep transverse forming because inclusions cause directional ductility loss; hot work 1150–1260 °C then anneal ~1040 °C and quench.
What is the maximum service temperature of 303Se Annealed?
303Se Annealed 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 303Se Annealed?
Yes — 303Se Annealed 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)
- SAE J405 / UNS S30323 chemical composition — SAE International (2013)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Machinery's Handbook — machinability ratings of stainless steels — Industrial Press (2020)
- GB/T 1220 (Y1Cr18Ni9Se) — SAC (2007)
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.