Steel AHSS · grade
Steel AHSS TWIP940
Properties of the TWIP940 condition, compared with the other AHSS tempers.
Use when extreme elongation and crash-energy absorption are needed; austenitic and non-magnetic, but costly and delayed-cracking sensitive.
What is AHSS TWIP940?
AHSS TWIP940 is AHSS in the TWIP940 grade — use when extreme elongation and crash-energy absorption are needed; austenitic and non-magnetic, but costly and delayed-cracking sensitive. AHSS TWIP940 has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 63% of steel grades. Elongation at break is 55% and the elastic modulus is 180 GPa (26.1 Msi). AHSS TWIP940 has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,500°C (2,732 °F). HR is the default condition FabDigit quotes; TWIP940 is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 55%, better than 100% of steel grades
- Forms and bends easily — 85/100, better than 96% of steel grades
Limitations
- Difficult to machine — 20/100, worse than 97% of steel grades
- Low stiffness — 180 GPa (26.1 Msi), worse than 96% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 79% of steel grades
AHSS TWIP940 properties
Typical room-temperature values for AHSS TWIP940 — 11 properties are specific to this condition; the rest are grade-level values shared by every AHSS temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
AHSS TWIP940 has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,500°C (2,732 °F).
Mechanical14
AHSS TWIP940 has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 63% of steel grades. Elongation at break is 55% and the elastic modulus is 180 GPa (26.1 Msi).
Thermal6
AHSS TWIP940 is rated for continuous service to 200°C (392 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 18 µm/m·K (10 µin/in·°F).
Electrical3
AHSS TWIP940 conducts electricity at 8.6 % IACS, better than 66% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of AHSS TWIP940 takes about 27 MJ of energy and emits 2.2 kg of CO₂ — less than 59% of steel grades. Typical recycled content is 25%.
Manufacturability7
AHSS TWIP940's machinability is poor (20/100, worse than 97% of steel grades); weldability fair (45/100); formability excellent (85/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other AHSS tempers and conditions
AHSS is also supplied in 14 other conditions. The full side-by-side table is on the AHSS overview.
- HRDefaultCheapest AHSS form for thicker structural parts (2–8 mm): chassis arms, wheels, seat and suspension brackets.400 MPa yield · 185 HB
- PHS1500Hot-stamped in-die quenched martensite for A/B-pillars, roof rails and tunnels: near-zero springback and highest strength, but no cold formability and needs laser trimming.1,150 MPa yield · 47 HRC
- MS1300Roll-formed only: bumper beams, door impact bars and side-intrusion tubes needing maximum strength per mass.1,100 MPa yield · 42 HRC
- DP1180Top cold-formable DP class for near-hot-stamping strength in roll-formed or mild-draw parts.950 MPa yield · 38 HRC
- Q&P980Third-generation AHSS: DP980 strength with roughly double the elongation for complex cold-stamped safety parts.720 MPa yield · 31 HRC
- DP980High-strength cold stamping grade for anti-intrusion beams and pillar reinforcements; needs springback compensation.700 MPa yield · 31 HRC
- CP800High yield-to-tensile ratio with good edge-stretch and hole expansion: chassis, roll-formed sections and bumper beams.700 MPa yield · 255 HB
- DP780Workhorse crash-energy grade for B-pillar reinforcements, rockers and longitudinal members.510 MPa yield · 23 HRC
- TWIP940Use when extreme elongation and crash-energy absorption are needed; austenitic and non-magnetic, but costly and delayed-cracking sensitive.500 MPa yield · 250 HB
- TRIP780Pick when a deep-drawn or stretch-formed part needs 780 MPa strength with DP590-level elongation and high energy absorption.470 MPa yield · 240 HB
- TMCPControlled-rolled/accelerated-cooled hot band giving fine bainitic-ferritic structure: high yield with good low-temperature toughness and weldability for structural/plate use.460 MPa yield · 195 HB
- CRStandard body-in-white gauge (0.6–2.5 mm) with tight thickness tolerance and best surface for exposed/structural stampings.380 MPa yield · 190 HB
- GalvanizedChoose for corrosion-critical automotive body panels and closures where zinc coating plus paintability is required.380 MPa yield · 185 HB
- DP590Entry AHSS: best stretch-formability of the DP family for reinforcements, rails and seat structures.380 MPa yield · 190 HB
Working with AHSS TWIP940
Is AHSS easy to machine?
Abrasive multiphase/martensitic structure — use rigid setups, coated carbide or CBN, low feed per tooth; laser or waterjet cutting is preferred over shearing above ~1000 MPa to avoid edge damage.
Can AHSS be welded?
Resistance spot weldable with adjusted (often multi-pulse) schedules and higher electrode force; watch HAZ softening in DP/MS, liquid-metal embrittlement on Zn coatings, and use low-hydrogen practice or laser welding for high-strength classes.
Can AHSS be formed, bent or molded?
Higher press loads and 2–3× the springback of mild steel; compensate die geometry, allow generous bend radii, and roll-form rather than draw grades above ~1000 MPa; press-hardening grades are formed hot at 900–950 °C and quenched in the die.
What surface finishes work on AHSS?
Not anodizable; supplied bare, hot-dip galvanized (GI/GA), Zn-Mg or Al-Si coated, then phosphated and e-coated/painted — avoid electroplating on ≥1200 MPa parts due to hydrogen embrittlement risk.
AHSS 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 |
|---|---|---|
| C0.06–0.15 for DP/TRIP/CP; up to ~0.25 for MS and 22MnB5 | 0.06 – 0.23 | 0.12 |
| Mnhigh-Mn TWIP grades contain 15–25 % Mn | 0.8 – 2.6 | 1.8 |
| Si1.0–2.0 % in TRIP/Q&P to stabilise retained austenite | 0.05 – 2 | 0.3 |
| Crhardenability | 0 – 0.6 | 0.25 |
| Moretards ferrite/pearlite | 0 – 0.5 | 0.15 |
| Aldeoxidation; up to 1.5 % in Al-alloyed TRIP | 0.02 – 1.5 | 0.05 |
| Nbgrain refinement (microalloying) | 0 – 0.06 | 0.03 |
| TiN fixing, B protection | 0 – 0.05 | 0.02 |
| Voptional precipitation strengthening | 0 – 0.1 | — |
| Bessential in press-hardening 22MnB5 | 0 – 0.01 | 0 |
| P | ≤ 0.03 | 0.01 |
| S | ≤ 0.02 | 0.01 |
| N | ≤ 0.01 | 0.01 |
| Fe | balance | — |
AHSS TWIP940 — frequently asked
What is AHSS TWIP940 used for?
AHSS TWIP940 is typically used for automotive crash and bumper beams, A- and B-pillar reinforcements, door impact beams, rocker panels and roof rails, seat structures and frames and chassis and suspension arms. In short: lightweight; high-strength.
What is the yield strength of AHSS TWIP940?
AHSS TWIP940 has a typical yield strength of 500 MPa (72.5 ksi) and a tensile strength of 980 MPa (142 ksi) — stronger than 63% of steel grades. Strength varies by condition: see the 15 listed tempers.
Is AHSS TWIP940 easy to machine?
Not especially — machinability is rated poor (20/100, worse than 97% of steel grades). Abrasive multiphase/martensitic structure — use rigid setups, coated carbide or CBN, low feed per tooth; laser or waterjet cutting is preferred over shearing above ~1000 MPa to avoid edge damage.
Can AHSS TWIP940 be welded?
With care — weldability is rated fair (45/100). Resistance spot weldable with adjusted (often multi-pulse) schedules and higher electrode force; watch HAZ softening in DP/MS, liquid-metal embrittlement on Zn coatings, and use low-hydrogen practice or laser welding for high-strength classes.
What surface finishes work on AHSS TWIP940?
Not anodizable; supplied bare, hot-dip galvanized (GI/GA), Zn-Mg or Al-Si coated, then phosphated and e-coated/painted — avoid electroplating on ≥1200 MPa parts due to hydrogen embrittlement risk.
Can AHSS TWIP940 be formed, bent or molded?
Higher press loads and 2–3× the springback of mild steel; compensate die geometry, allow generous bend radii, and roll-form rather than draw grades above ~1000 MPa; press-hardening grades are formed hot at 900–950 °C and quenched in the die.
What is the maximum service temperature of AHSS TWIP940?
AHSS TWIP940 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between AHSS-HR and AHSS PHS1500?
HR is the default condition — cheapest AHSS form for thicker structural parts (2–8 mm): chassis arms, wheels, seat and suspension brackets. PHS1500: hot-stamped in-die quenched martensite for A/B-pillars, roof rails and tunnels: near-zero springback and highest strength, but no cold formability and needs laser trimming. Yield strength is 400 MPa in HR versus 1,150 MPa in PHS1500.
Can FabDigit make parts in AHSS TWIP940?
Yes — AHSS TWIP940 is available for sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- Advanced High-Strength Steels Application Guidelines v7 — WorldAutoSteel (2021)
- SAE J2745 — Advanced High Strength Steel Sheet — SAE International (2019)
- VDA 239-100 — Sheet Steel for Cold Forming — VDA (2016)
- EN 10338 / EN 10346 — hot & cold rolled multiphase and coated steels — CEN (2015)
- Dual Phase, Complex Phase and Usibor product data — ArcelorMittal (2023)
- Automotive high-strength steel catalogue — Baosteel (2023)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
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.