Stainless Steel S40977 HRAP-No1
Heat-treated state
UNS S40977
HRAP-No1 = no.1
Heavier gauge (>3 mm) plate for manifolds, mufflers baffles and fabricated ducting.
Values for the HRAP-No1 condition
Other S40977 tempers and conditions
S40977 is listed in 4 conditions; see the grade overview at S40977.
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 |
HRAP-No1This page 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 |
What is S40977 HRAP-No1?
S40977 HRAP-No1 is S40977 heat treated to HRAP-No1 — heavier gauge (>3 mm) plate for manifolds, mufflers baffles and fabricated ducting. S40977 HRAP-No1 has a yield strength of 255 MPa (37 ksi) and a tensile strength of 430 MPa (62.4 ksi) — weaker than 87% of stainless steel grades. Elongation at break is 28% and the elastic modulus is 200 GPa (29 Msi). S40977 HRAP-No1 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). ANN-2B is the default condition FabDigit quotes; HRAP-No1 is available on request or by drawing note.
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
- Needs corrosion protection — 35/100, worse than 97% of stainless steel grades
- Hard to polish — 45/100, worse than 96% of stainless steel grades
- Low strength — 255 MPa (37 ksi), worse than 87% of stainless steel grades
- Low fracture toughness — 68 MPa·√m (61.9 ksi·√in), worse than 85% of stainless steel grades
S40977 HRAP-No1 properties
Typical room-temperature values for S40977 HRAP-No1; 22 are specific to this condition. Other listed values are S40977 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
S40977 HRAP-No1 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 HRAP-No1 has a yield strength of 255 MPa (37 ksi) and a tensile strength of 430 MPa (62.4 ksi) — weaker than 87% of stainless steel grades. Elongation at break is 28% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
S40977 HRAP-No1 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 HRAP-No1 conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (35/100), worse than 97% of stainless steel grades.
Sustainability4
Producing a kilogram of S40977 HRAP-No1 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 HRAP-No1's machinability is good (55/100, better than 94% of stainless steel grades); weldability excellent (85/100); formability good (68/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S40977 HRAP-No1
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.
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.
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 | — |
S40977 HRAP-No1 — frequently asked
What is S40977 HRAP-No1 used for?
S40977 HRAP-No1 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 HRAP-No1?
S40977 HRAP-No1 has a typical yield strength of 255 MPa (37 ksi) and a tensile strength of 430 MPa (62.4 ksi) — weaker than 87% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is S40977 HRAP-No1 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 HRAP-No1 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 HRAP-No1?
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 HRAP-No1 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 HRAP-No1?
S40977 HRAP-No1 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.