Stainless Steel 302B
AISI/SAE 302B · UNS S30215
302B (S30215) is a silicon-enhanced 18-8 austenitic stainless, with 2–3 % Si added to 302 to improve resistance to scaling at elevated temperature.
Reference datasheet — 302B is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the Annealed condition
302B tempers and conditions
302B is supplied in 7 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault solution annealed 1010–1120 °C, rapid cooled | Standard stocked condition for furnace parts, fixtures and formed heat-resisting components. | 275 | 655 | 55 | 165 HB | — |
Hot Rolled (mill finish, not solution treated) | Cheapest plate/bar form for rough furnace hardware where scale and looser properties are acceptable. | 290 | 620 | 45 | 180 HB | — |
Quarter hard | Choose when moderate extra strength is needed and some bending/forming is still required. | 550 | 895 | 25 | 25 HRC | — |
cold-finished bar/wire (annealed then drawn) | Cold-finished bar for machined furnace fasteners and fixtures needing tighter tolerance and higher strength. | 620 | 860 | 25 | 25 HRC | — |
Half hard | For flat springy parts and brackets where strength matters more than bendability. | 790 | 1,070 | 15 | 32 HRC | — |
Three-quarter hard | High-strength strip for clips and light spring parts; only gentle forming possible. | 965 | 1,240 | 10 | 37 HRC | — |
cold rolled to full-hard temper | Maximum as-rolled strength for flat springs and shim stock; essentially not formable. | 1,000 | 1,310 | 7 | 41 HRC | — |
What is 302B?
302B (S30215) is a silicon-enhanced 18-8 austenitic stainless, with 2–3 % Si added to 302 to improve resistance to scaling at elevated temperature. Annealed bar and sheet are rated at 275 MPa yield, 655 MPa tensile, 55 % elongation and 165 HB (85 HRB), with a maximum service temperature of 1090 °C, and the grade is stocked annealed, cold drawn, hot rolled and in quarter- through full-hard tempers. The silicon makes it abrasive to machine and raises hot-cracking risk in welding, and aqueous corrosion resistance is no better than 302; 309 or 310 are the alternatives when higher creep strength is needed. 302B has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F). 302B has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 655 MPa (95 ksi) — weaker than 77% of stainless steel grades. Elongation at break is 55% and the elastic modulus is 193 GPa (28 Msi).
What is 302B used for?
- furnace parts
- heat-resistant fixtures
- high-temperature springs
Advantages
- Ductile — tolerates forming and impact — 55%, better than 97% of stainless steel grades
- High service temperature — 1,090°C (1,994 °F), better than 93% of stainless steel grades
- Forms and bends easily — 70/100, better than 79% of stainless steel grades
Limitations
- Low strength — 275 MPa (39.9 ksi), worse than 77% of stainless steel grades
302B properties
Typical room-temperature values for 302B-Annealed; bars are the position among stainless steel grades.
Physical3
302B has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical14
302B has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 655 MPa (95 ksi) — weaker than 77% of stainless steel grades. Elongation at break is 55% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
302B is rated for continuous service to 1,090°C (1,994 °F). It conducts heat at 15.9 W/m·K (9.19 BTU/hr·ft·°F), better than 55% of stainless steel grades. Thermal expansion is 16.2 µm/m·K (9 µin/in·°F).
Electrical3
302B conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 52% of stainless steel grades.
Sustainability4
Producing a kilogram of 302B takes about 53 MJ of energy and emits 5 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 60%.
Manufacturability7
302B's machinability is poor (34/100, worse than 55% of stainless steel grades); weldability good (55/100); formability very good (70/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. 302B is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 302B
Is 302B easy to machine?
Machines like a gummy 18-8 but the 2–3 % Si is abrasive and work-hardens fast — use rigid setups, sharp coated carbide, positive rake, heavy positive feed and flood coolant; ~40 % of AISI 1212.
Can 302B be welded?
GTAW/GMAW with 309/310-type filler; high Si plus high C raise hot-cracking and sensitization risk, so keep heat input low, avoid restraint and solution anneal afterwards if aqueous corrosion service is intended.
Can 302B be formed, bent or molded?
Cold forms and deep draws reasonably well in the annealed condition but work-hardens faster than 304; hot work at 1150–1200 °C and cool rapidly through 870–425 °C to avoid carbide precipitation.
302B 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 |
|---|---|---|
| Chigh carbon — sensitization prone | ≤ 0.15 | 0.1 |
| Mn | ≤ 2 | 1.2 |
| Sikey addition for scaling resistance | 2 – 3 | 2.5 |
| P | ≤ 0.05 | 0.03 |
| S | ≤ 0.03 | 0.02 |
| Cr | 17 – 19 | 18 |
| Ni | 8 – 10 | 9 |
| Nwhere specified | ≤ 0.1 | 0.05 |
| Fe | balance |
What surface finishes work on 302B?
Pickle and passivate after hot work — the silicon-rich scale is tenacious and needs longer HF/HNO₃ pickling or grit blasting; takes a good mechanical polish but slightly below 304 due to silicate inclusions.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Organic Coating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel 302B in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- S30215
How much does 302B cost?
302B is a premium-cost stainless steel ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
302B — frequently asked
What is 302B used for?
302B is typically used for furnace parts, heat-resistant fixtures and high-temperature springs. In short: scaling-resistant 18-8 variant; 1090 °C maximum service; abrasive silicon-bearing grade.
What is the yield strength of 302B?
302B has a typical yield strength of 275 MPa (39.9 ksi) and a tensile strength of 655 MPa (95 ksi) — weaker than 77% of stainless steel grades. Strength varies by condition: see the 7 listed tempers.
Is 302B easy to machine?
Not especially — machinability is rated poor (34/100, worse than 55% of stainless steel grades). Machines like a gummy 18-8 but the 2–3 % Si is abrasive and work-hardens fast — use rigid setups, sharp coated carbide, positive rake, heavy positive feed and flood coolant; ~40 % of AISI 1212.
Can 302B be welded?
Yes — weldability is rated good (55/100). GTAW/GMAW with 309/310-type filler; high Si plus high C raise hot-cracking and sensitization risk, so keep heat input low, avoid restraint and solution anneal afterwards if aqueous corrosion service is intended.
What surface finishes work on 302B?
Pickle and passivate after hot work — the silicon-rich scale is tenacious and needs longer HF/HNO₃ pickling or grit blasting; takes a good mechanical polish but slightly below 304 due to silicate inclusions.
Can 302B be formed, bent or molded?
Cold forms and deep draws reasonably well in the annealed condition but work-hardens faster than 304; hot work at 1150–1200 °C and cool rapidly through 870–425 °C to avoid carbide precipitation.
What is the maximum service temperature of 302B?
302B is rated for continuous use to about 1,090°C (1,994 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 302B cost?
302B is a premium-cost stainless steel ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM A276/A276M — Stainless Steel Bars and Shapes — ASTM International (2023)
- ASTM A240/A240M — Chromium and Chromium-Nickel Stainless Steel Plate, Sheet and Strip — ASTM International (2023)
- ASTM A666 — Annealed or Cold-Worked Austenitic Stainless Steel Sheet, Strip, Plate and Flat Bar — ASTM International (2015)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- SAE/ASTM Unified Numbering System (UNS) S30215 listing — SAE International / ASTM (2019)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.