Steel A709 HPS100W QT-HEAVY
Heat-treated state
ASTM A709 HPS100W
Heavy-gauge Q&T plate; ASTM A709 permits reduced 620 MPa minimum yield above 65 mm thickness.
Values for the QT-HEAVY condition
Other A709 HPS100W tempers and conditions
A709 HPS100W is listed in 3 conditions; see the grade overview at A709 HPS100W.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
QT-HEAVYThis page over 65 mm to 100 mm (2-1/2 to 4 in) | Heavy-gauge Q&T plate; ASTM A709 permits reduced 620 MPa minimum yield above 65 mm thickness. | 680 | 780 | 20 | 22 HRC | 6.6 % IACS |
QTDefault Quenched and tempered | Standard supply condition for HPS 100W bridge girder flange and web plates up to 65 mm. | 740 | 830 | 20 | 24 HRC | — |
Cooled from hot working, cold worked and naturally aged | Order with the T (non-fracture-critical) Charpy supplement when the member is redundant but low-temperature service applies. | 740 | 830 | 20 | 24 HRC | 6.6 % IACS |
What is A709 HPS100W QT-HEAVY?
A709 HPS100W QT-HEAVY is A709 HPS100W heat treated to QT-HEAVY — heavy-gauge Q&T plate; ASTM A709 permits reduced 620 MPa minimum yield above 65 mm thickness. A709 HPS100W QT-HEAVY has a yield strength of 680 MPa (98.6 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 80% of steel grades. Elongation at break is 20% and the elastic modulus is 200 GPa (29 Msi). A709 HPS100W QT-HEAVY has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). QT is the default condition FabDigit quotes; QT-HEAVY is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 190 MPa·√m (172.9 ksi·√in), better than 99% of steel grades
- Good corrosion resistance — 26/100, better than 93% of steel grades
- High strength — 680 MPa (98.6 ksi), better than 80% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
- Low electrical conductivity — 6.6 % IACS, worse than 76% of steel grades
A709 HPS100W QT-HEAVY properties
Typical room-temperature values for A709 HPS100W QT-HEAVY; 22 are specific to this condition. Other listed values are A709 HPS100W reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A709 HPS100W QT-HEAVY has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
A709 HPS100W QT-HEAVY has a yield strength of 680 MPa (98.6 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 80% of steel grades. Elongation at break is 20% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
A709 HPS100W QT-HEAVY is rated for continuous service to 400°C (752 °F). It conducts heat at 38 W/m·K (22 BTU/hr·ft·°F), worse than 69% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
A709 HPS100W QT-HEAVY conducts electricity at 6.6 % IACS, worse than 76% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (26/100), better than 93% of steel grades.
Sustainability4
Producing a kilogram of A709 HPS100W QT-HEAVY takes about 31 MJ of energy and emits 2.3 kg of CO₂ — more than 64% of steel grades. Typical recycled content is 30%.
Manufacturability5
A709 HPS100W QT-HEAVY's machinability is fair (41/100, worse than 74% of steel grades); weldability good (68/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A709 HPS100W QT-HEAVY
Is A709 HPS100W easy to machine?
Machine as a ~250 HB Q&T plate: rigid setups, carbide inserts at 60–110 m/min, generous feed, plenty of coolant; drill and ream holes rather than punch in fracture-critical members.
Can A709 HPS100W be welded?
Excellent weldability for its strength class — use AWS D1.5 low-hydrogen 100 ksi consumables, control heat input (typically 1.2–2.4 kJ/mm) and preheat/interpass per plate thickness to avoid HAZ softening and hydrogen cracking.
Can A709 HPS100W be formed, bent or molded?
Hot-rolled Q&T plate: cold-form only with large bend radii (≥3–4t transverse to rolling) or press-brake hot; avoid flame straightening above the tempering temperature.
What surface finishes work on A709 HPS100W?
Normally used uncoated so a stable weathering patina develops (detail for drainage and avoid chloride splash); where coated, blast to SSPC-SP10 and apply a zinc-rich/epoxy/urethane bridge system.
A709 HPS100W 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 for weldability | ≤ 0.08 | 0.06 |
| Mn | 0.95 – 1.5 | 1.2 |
| P | ≤ 0.02 | 0.01 |
| Sultra-low S for through-thickness toughness | ≤ 0.01 | 0 |
| Si | 0.15 – 0.35 | 0.25 |
| Cuweathering + precipitation strengthening | 0.9 – 1.2 | 1.05 |
| Ni | 0.65 – 0.9 | 0.8 |
| Cr | 0.45 – 0.7 | 0.6 |
| Mo | 0.4 – 0.65 | 0.5 |
| V | 0.04 – 0.08 | 0.06 |
| Al | 0.02 – 0.05 | 0.03 |
| N | ≤ 0.02 | 0.01 |
| Fe | balance | — |
A709 HPS100W QT-HEAVY — frequently asked
What is A709 HPS100W QT-HEAVY used for?
A709 HPS100W QT-HEAVY is typically used for bridge girders, structural weldments and highway infrastructure. In short: weathering 100 ksi bridge plate; best weldability at 100 ksi; bridge toughness classes.
What is the yield strength of A709 HPS100W QT-HEAVY?
A709 HPS100W QT-HEAVY has a typical yield strength of 680 MPa (98.6 ksi) and a tensile strength of 780 MPa (113 ksi) — stronger than 80% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is A709 HPS100W QT-HEAVY easy to machine?
Not especially — machinability is rated fair (41/100, worse than 74% of steel grades). Machine as a ~250 HB Q&T plate: rigid setups, carbide inserts at 60–110 m/min, generous feed, plenty of coolant; drill and ream holes rather than punch in fracture-critical members.
Can A709 HPS100W QT-HEAVY be welded?
Yes — weldability is rated good (68/100). Excellent weldability for its strength class — use AWS D1.5 low-hydrogen 100 ksi consumables, control heat input (typically 1.2–2.4 kJ/mm) and preheat/interpass per plate thickness to avoid HAZ softening and hydrogen cracking.
What surface finishes work on A709 HPS100W QT-HEAVY?
Normally used uncoated so a stable weathering patina develops (detail for drainage and avoid chloride splash); where coated, blast to SSPC-SP10 and apply a zinc-rich/epoxy/urethane bridge system.
Can A709 HPS100W QT-HEAVY be formed, bent or molded?
Hot-rolled Q&T plate: cold-form only with large bend radii (≥3–4t transverse to rolling) or press-brake hot; avoid flame straightening above the tempering temperature.
What is the maximum service temperature of A709 HPS100W QT-HEAVY?
A709 HPS100W QT-HEAVY is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A709 HPS100W-QT and A709 HPS100W-T2?
QT is the default condition — standard supply condition for HPS 100W bridge girder flange and web plates up to 65 mm. T2: order with the T (non-fracture-critical) Charpy supplement when the member is redundant but low-temperature service applies. Yield strength is 740 MPa in QT versus 740 MPa in T2.
Sources
- ASTM A709/A709M — Standard Specification for Structural Steel for Bridges — ASTM International (2021)
- AASHTO M 270M/M 270 — Structural Steel for Bridges — AASHTO (2020)
- AWS D1.5/D1.5M Bridge Welding Code — AWS/AASHTO (2020)
- High Performance Steel Designers' Guide (HPS 70W / HPS 100W) — FHWA / AISI (2002)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- AASHTO LRFD Bridge Design Specifications (material constants) — AASHTO (2020)
- Mysteel / SMM — Mysteel (2026)
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.