Stainless Steel S40977
UNS S40977
S40977 is a stabilized 409-family ferritic stainless used interchangeably with other 409 variants in automotive exhaust manufacturing, with the exact Ti/Nb balance set by supplier chemistry.
Reference datasheet — S40977 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-2B condition
S40977 tempers and conditions
S40977 is supplied in 4 conditions, soft to hard. ANN-2B is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed 2D | Choose for severe deep drawing where the dull matte surface holds lubricant better than 2B. | 240 | 415 | 32 | 140 HB | 2.9 % IACS |
ANN-2BDefault Annealed 2B | Default exhaust-industry supply condition for roll-formed tube, stamped shells and heat shields. | 250 | 420 | 30 | 145 HB | 2.9 % IACS |
No.1 | Heavier gauge (>3 mm) plate for manifolds, mufflers baffles and fabricated ducting. | 255 | 430 | 28 | 150 HB | 2.9 % IACS |
Temper rolled / skin passed | Slightly stiffer strip for flat heat shields and clamps where springback and flatness matter more than draw depth. | 340 | 470 | 20 | 175 HB | 2.9 % IACS |
Supply forms, finishes and certifications
Ways S40977 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 | Supply form |
WLD-TUBE | Welded tube, as-welded and bright/annealed | Supply form |
BA | Bright annealed | Surface finish |
What is S40977?
S40977 is a stabilized 409-family ferritic stainless used interchangeably with other 409 variants in automotive exhaust manufacturing, with the exact Ti/Nb balance set by supplier chemistry. It is stocked as annealed 2B/2D sheet, BA, HRAP No. 1, skin-passed temper-rolled coil, welded tube and cold-drawn bar, with 250 MPa yield, 420 MPa tensile, 30 % elongation, 145 HB (78 HRB) and a formability score of 75. Maximum service temperature is about 675 °C and the grade will surface-rust in road-salt or humid exposure. Use S40975 where deeper draws are required. S40977 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,450°C (2,642 °F). S40977 has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 91% of stainless steel grades. Elongation at break is 30% and the elastic modulus is 200 GPa (29 Msi).
What is S40977 used for?
- exhaust systems
- mufflers
- resonators
Advantages
- Low embodied carbon — 2.8 kg CO₂/kg, better than 99% of stainless steel grades
- Easy to machine — 55/100, better than 94% 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
- Readily welded — 85/100, better than 87% of stainless steel grades
Limitations
- Hard to polish — 45/100, worse than 96% of stainless steel grades
- Needs corrosion protection — 38/100, worse than 95% of stainless steel grades
- Low strength — 250 MPa (36.3 ksi), worse than 91% of stainless steel grades
- Low fracture toughness — 70 MPa·√m (63.7 ksi·√in), worse than 83% of stainless steel grades
S40977 properties
Typical room-temperature values for S40977-ANN-2B; bars are the position among stainless steel grades.
Physical3
S40977 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,450°C (2,642 °F).
Mechanical16
S40977 has a yield strength of 250 MPa (36.3 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 91% of stainless steel grades. Elongation at break is 30% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
S40977 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
S40977 conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (38/100), worse than 95% of stainless steel grades.
Sustainability4
Producing a kilogram of S40977 takes about 42 MJ of energy and emits 2.8 kg of CO₂ — less than 95% of stainless steel grades. Typical recycled content is 70%.
Manufacturability7
S40977's machinability is good (55/100, better than 94% of stainless steel grades); weldability excellent (85/100); formability very good (75/100).
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. S40977 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S40977
Is S40977 easy to machine?
Machines like a soft low-alloy steel but is stringy — use sharp positive-rake carbide, rigid setups, 15–25 % lower speed than 1018 and flood coolant to avoid built-up edge.
Can S40977 be welded?
Excellent: Ti/Nb stabilization prevents HAZ sensitization, so GTAW/laser/HF autogenous tube welds need no post-weld anneal; use 409Cb/430Ti/309L filler, keep heat input low and interpass < 150 °C to limit grain coarsening.
Can S40977 be formed, bent or molded?
Good roll-forming, mandrel bending and moderate deep drawing (r̄ ≈ 1.3); watch ridging/roping on drawn faces and allow more springback than mild steel.
S40977 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 |
| Si | ≤ 1 | 0.5 |
| P | ≤ 0.04 | 0.03 |
| S | ≤ 0.02 | 0 |
| Cr | 10.5 – 11.7 | 11.2 |
| Ni | ≤ 0.5 | 0.2 |
| N | ≤ 0.03 | 0.02 |
| Tiprimary stabilizer; Ti+Nb ≥ 0.08 + 8(C+N), total ≤ 0.75 per A240 note | ≤ 0.75 | 0.2 |
| Nbsupplementary stabilizer; supplier chemistry varies within the Ti+Nb envelope | ≤ 0.4 | 0.1 |
| Fe | balance |
What surface finishes work on S40977?
Normally supplied 2B/2D and left bare or coated with high-temperature silicone/aluminized paint; passivate after grinding, avoid carbon-steel tooling contamination, and expect only a matte polish.
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 S40977 cost?
S40977 is a budget-cost stainless steel ($), cheaper than about 90% 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.
S40977 — frequently asked
What is S40977 used for?
S40977 is typically used for exhaust systems, mufflers and resonators. In short: interchangeable 409 exhaust grade; stabilized, no post-weld anneal; wide product-form availability.
What is the yield strength of S40977?
S40977 has a typical yield strength of 250 MPa (36.3 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 91% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is S40977 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 stringy — use sharp positive-rake carbide, rigid setups, 15–25 % lower speed than 1018 and flood coolant to avoid built-up edge.
Can S40977 be welded?
Yes — weldability is rated excellent (85/100). Excellent: Ti/Nb stabilization prevents HAZ sensitization, so GTAW/laser/HF autogenous tube welds need no post-weld anneal; use 409Cb/430Ti/309L filler, keep heat input low and interpass < 150 °C to limit grain coarsening.
What surface finishes work on S40977?
Normally supplied 2B/2D and left bare or coated with high-temperature silicone/aluminized paint; passivate after grinding, avoid carbon-steel tooling contamination, and expect only a matte polish.
Can S40977 be formed, bent or molded?
Good roll-forming, mandrel bending and moderate deep drawing (r̄ ≈ 1.3); watch ridging/roping on drawn faces and allow more springback than mild steel.
What is the maximum service temperature of S40977?
S40977 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 S40977 ANN-2B and S40977 TR-SKIN?
ANN-2B is the default condition — default exhaust-industry supply condition for roll-formed tube, stamped shells and heat shields. TR-SKIN: slightly stiffer strip for flat heat shields and clamps where springback and flatness matter more than draw depth. Yield strength is 250 MPa in ANN-2B versus 340 MPa in TR-SKIN.
How much does S40977 cost?
S40977 is a budget-cost stainless steel ($), cheaper than about 90% 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/Martensitic Stainless Steel Tubing — ASTM International (2022)
- ASTM A554 — Welded Stainless Steel Mechanical Tubing — ASTM International (2021)
- GB/T 3280 / 022Cr11Ti (S11163 ) — SAC (2015)
- Type 409 / 409 Ultra Form ferritic stainless product data — Cleveland-Cliffs (AK Steel) (2021)
- 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)
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.