Stainless Steel S40975
UNS S40975
S40975 is a 409-family stabilized ferritic stainless tuned for catalytic-converter shells, combining good formability with moderate high-temperature oxidation resistance.
Reference datasheet — S40975 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 ANN condition
S40975 tempers and conditions
S40975 is supplied in 2 conditions, soft to hard. ANN is the default FabDigit quotes; the values on this page are for it.
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Standard stocked condition for converter shells, exhaust tubing and stampings — maximum formability and weldability. | 250 | 440 | 30 | 145 HB | — |
Temper Rolled | Slight cold work for improved flatness, stiffness and stretcher-strain suppression in roll-formed shells. | 350 | 490 | 22 | 178 HB | 2.9 % IACS |
Supply forms, finishes and certifications
Ways S40975 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
CD-BAR | Cold Drawn bar/wire | Supply form |
WLD-TUBE | Welded tube, as-welded | Supply form |
2B | Cold rolled, annealed, pickled and lightly skin-passed | Surface finish |
2D | Cold rolled, annealed and pickled | Surface finish |
BA | Bright annealed | Surface finish |
HRAP | HRAP | Surface finish |
What is S40975?
S40975 is a 409-family stabilized ferritic stainless tuned for catalytic-converter shells, combining good formability with moderate high-temperature oxidation resistance. Typical forms are sheet and coil (ANN, 2B, 2D, HRAP, BA, temper-rolled), welded tube and cold-drawn bar, with 250 MPa yield, 440 MPa tensile, 30 % elongation and 145 HB (78 HRB); weldability scores 78 and formability 80, the highest in this 409 group. Service is capped near 675 °C and the surface stains in salt exposure, so coating or passivation is needed on visible parts. S40930 or S40977 are the nearest substitutes when supplier chemistry differs. S40975 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,450°C (2,642 °F). S40975 has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 91% of stainless steel grades. Elongation at break is 30% and the elastic modulus is 200 GPa (29 Msi).
What is S40975 used for?
- Catalytic converter shells
- Exhaust heat shields
- Welded exhaust tube and pipe
- Muffler shells
- Exhaust flanges and brackets
- Deep-drawn exhaust end caps
Advantages
- Easy to machine — 55/100, better than 94% of stainless steel grades
- Forms and bends easily — 80/100, better than 93% of stainless steel grades
- Low embodied carbon — 3.4 kg CO₂/kg, better than 91% of stainless steel grades
- Conducts heat well — 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 87% of stainless steel grades
- High electrical conductivity — 2.9 % IACS, better than 87% of stainless steel grades
Limitations
- Low strength — 250 MPa (36.3 ksi), worse than 91% of stainless steel grades
- Needs corrosion protection — 42/100, worse than 90% of stainless steel grades
- Hard to polish — 55/100, worse than 89% of stainless steel grades
S40975 properties
Typical room-temperature values for S40975-ANN; bars are the position among stainless steel grades.
Physical3
S40975 has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,450°C (2,642 °F).
Mechanical15
S40975 has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 91% of stainless steel grades. Elongation at break is 30% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
S40975 is rated for continuous service to 675°C (1,247 °F). It conducts heat at 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 87% of stainless steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
S40975 conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (42/100), worse than 90% of stainless steel grades.
Sustainability4
Producing a kilogram of S40975 takes about 42 MJ of energy and emits 3.4 kg of CO₂ — less than 95% of stainless steel grades. Typical recycled content is 70%.
Manufacturability6
S40975's machinability is good (55/100, better than 94% of stainless steel grades); weldability very good (78/100); formability very good (80/100).
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. S40975 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S40975
Is S40975 easy to machine?
Machines like a soft low-alloy steel but is somewhat gummy — use sharp, positive-rake carbide, rigid setups, 0.1–0.3 mm/rev feeds and flood coolant to avoid built-up edge.
Can S40975 be welded?
Readily GTAW/GMAW/resistance/laser welded without post-weld anneal thanks to Ti stabilization; keep heat input low to limit HAZ grain growth, use 409Cb/430Ti or 308L/309L filler, and back-purge to avoid oxidation.
Can S40975 be formed, bent or molded?
Excellent roll-forming, deep-drawing and tube-bending behaviour with r-value typical of stabilized ferritics; watch springback and roping/ridging on heavily drawn panels.
S40975 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 stabilized ferritic | ≤ 0.03 | 0.02 |
| Mn | ≤ 1 | 0.4 |
| Siaids high-temperature oxidation resistance | ≤ 1 | 0.5 |
| P | ≤ 0.04 | 0.03 |
| S | ≤ 0.02 | 0 |
| Cr | 10.5 – 11.75 | 11.2 |
| Nideliberate Ni addition for toughness / HAZ ductility (distinguishes S40975 from S40910/S40920) | 0.5 – 1 | 0.75 |
| TiTi ≥ 6×(C+N) for stabilization | 0.1 – 1 | 0.25 |
| N | ≤ 0.03 | 0.02 |
| Fe | balance |
What surface finishes work on S40975?
Normally used as-pickled or aluminized/painted; can be bead-blasted or brushed, but it stains in salt exposure — passivation or coating is recommended for cosmetic outer parts.
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
How much does S40975 cost?
S40975 is a standard-cost stainless steel ($$), cheaper than about 71% 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.
S40975 — frequently asked
What is S40975 used for?
S40975 is typically used for catalytic converter shells, exhaust heat shields, welded exhaust tube and pipe, muffler shells, exhaust flanges and brackets and deep-drawn exhaust end caps. In short: most formable 409 variant; converter-shell workhorse; good weldability, no PWHT.
What is the yield strength of S40975?
S40975 has a typical yield strength of 250 MPa (36.3 ksi) and a tensile strength of 440 MPa (63.8 ksi) — weaker than 91% of stainless steel grades. Strength varies by condition: see the 2 listed tempers.
Is S40975 easy to machine?
Reasonably — machinability is rated good (55/100, better than 94% of stainless steel grades). Machines like a soft low-alloy steel but is somewhat gummy — use sharp, positive-rake carbide, rigid setups, 0.1–0.3 mm/rev feeds and flood coolant to avoid built-up edge.
Can S40975 be welded?
Yes — weldability is rated very good (78/100). Readily GTAW/GMAW/resistance/laser welded without post-weld anneal thanks to Ti stabilization; keep heat input low to limit HAZ grain growth, use 409Cb/430Ti or 308L/309L filler, and back-purge to avoid oxidation.
What surface finishes work on S40975?
Normally used as-pickled or aluminized/painted; can be bead-blasted or brushed, but it stains in salt exposure — passivation or coating is recommended for cosmetic outer parts.
Can S40975 be formed, bent or molded?
Excellent roll-forming, deep-drawing and tube-bending behaviour with r-value typical of stabilized ferritics; watch springback and roping/ridging on heavily drawn panels.
What is the maximum service temperature of S40975?
S40975 is rated for continuous use to about 675°C (1,247 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between S40975-ANN and S40975-TR?
ANN is the default condition — standard stocked condition for converter shells, exhaust tubing and stampings — maximum formability and weldability. TR: slight cold work for improved flatness, stiffness and stretcher-strain suppression in roll-formed shells. Yield strength is 250 MPa in ANN versus 350 MPa in TR.
How much does S40975 cost?
S40975 is a standard-cost stainless steel ($$), cheaper than about 71% 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 A240/A240M — Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip — ASTM International (2023)
- ASTM A268/A268M — Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing — ASTM International (2022)
- ASTM A1010 / SAE J405 UNS designations for stainless steels — ASTM / SAE (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Type 409 / 409 Ni ferritic stainless steel product data — AK Steel / Cleveland-Cliffs (2020)
- Stainless steel grade datasheets (ferritic 4xx series) — Outokumpu / worldstainless (2022)
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.