Steel Q460-Q (Bridge structural steel)
Heat-treated state
GB Q460
Pick for welded steel bridges needing certified −40 °C impact energy, fine-grain practice and tight flatness/ultrasonic quality.
Values for the Q condition
Other Q460 tempers and conditions
Q460 is listed in 6 conditions; see the grade overview at Q460.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
HRDefault Hot rolled | Standard stocked condition for plate, sections and coil where service temperature stays at or above 0 °C. | 500 | 620 | 21 | 185 HB | 8.2 % IACS |
Weathering (atmospheric corrosion resistant) steel Q460NH, GB/T 4171 | Pick for unpainted or long-maintenance-interval exposed structures where the Cu-Cr-Ni patina roughly doubles-to-quadruples paint-free life. | 500 | 620 | 20 | 190 HB | 7.6 % IACS |
Normalized | Pick when guaranteed low-temperature notch toughness down to −40/−60 °C and uniform through-thickness properties are required. | 505 | 630 | 22 | 185 HB | 8.2 % IACS |
Building structural steel plate | Pick for seismic building frames: capped yield range and yield/tensile ratio ≤0.83 plus through-thickness (Z-direction) options. | 505 | 630 | 22 | 188 HB | 8.2 % IACS |
QThis page Bridge structural steel | Pick for welded steel bridges needing certified −40 °C impact energy, fine-grain practice and tight flatness/ultrasonic quality. | 505 | 630 | 22 | 187 HB | 8.2 % IACS |
Thermomechanically controlled processed | Pick for the leanest carbon equivalent and best field weldability with low-temperature toughness, typically in thick plate. | 510 | 610 | 23 | 180 HB | — |
What is Q460-Q?
Q460-Q is Q460 heat treated to Q — pick for welded steel bridges needing certified −40 °C impact energy, fine-grain practice and tight flatness/ultrasonic quality. Q460-Q has a yield strength of 505 MPa (73.2 ksi) and a tensile strength of 630 MPa (91.4 ksi) — stronger than 64% of steel grades. Elongation at break is 22% and the elastic modulus is 206 GPa (29.9 Msi). Q460-Q has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). HR is the default condition FabDigit quotes; Q is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 125 MPa·√m (113.8 ksi·√in), better than 85% of steel grades
- Readily welded — 80/100, better than 79% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
Q460-Q properties
Typical room-temperature values for Q460-Q; 23 are specific to this condition. Other listed values are Q460 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
Q460-Q has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
Q460-Q has a yield strength of 505 MPa (73.2 ksi) and a tensile strength of 630 MPa (91.4 ksi) — stronger than 64% of steel grades. Elongation at break is 22% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
Q460-Q is rated for continuous service to 350°C (662 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
Q460-Q conducts electricity at 8.2 % IACS, better than 61% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of Q460-Q takes about 26 MJ of energy and emits 2.1 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 25%.
Manufacturability8
Q460-Q's machinability is fair (52/100, better than 52% of steel grades); weldability very good (80/100); formability good (57/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Q460-Q
Is Q460 easy to machine?
Cuts like a tough 500 MPa-yield HSLA steel — use rigid setups, coated carbide at ~120–180 m/min and positive feeds to avoid work hardening; drilling and tapping are noticeably harder than Q235.
Can Q460 be welded?
Readily welded by SMAW/GMAW/SAW with 550–620 MPa class consumables; keep heat input moderate, preheat ~100–150 °C above 25–30 mm or with high CEV, and avoid over-welding TMCP plate to prevent HAZ softening.
Can Q460 be formed, bent or molded?
Cold bends to the GB/T 1591 mandrel with generous radii (≥2.5–3 t) and springback allowance; hot forming should stay below the normalizing/TMCP temperature or properties must be re-established by heat treatment.
What surface finishes work on Q460?
No anodizing; shot-blast to Sa 2.5 then zinc-rich epoxy, hot-dip galvanize (watch Si/P for coating appearance) or use the NH weathering variant for bare exposure.
Q460 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 |
|---|---|---|
| C≤0.20 for as-rolled Q460C; ≤0.16 for Q460M | ≤ 0.2 | 0.16 |
| Si | ≤ 0.6 | 0.3 |
| Mn | 1 – 1.8 | 1.55 |
| P≤0.025 for D, ≤0.020 for E/F class | ≤ 0.03 | 0.02 |
| S≤0.020 for D, ≤0.010 for E/F class | ≤ 0.03 | 0.01 |
| Nbmicro-alloying | ≤ 0.11 | 0.04 |
| Vmicro-alloying | ≤ 0.2 | 0.06 |
| Timicro-alloying | ≤ 0.2 | 0.02 |
| Cr | ≤ 0.3 | 0.1 |
| Ni | ≤ 0.8 | 0.15 |
| Cu | ≤ 0.4 | 0.15 |
| Mo | ≤ 0.2 | 0.05 |
| Altotal Al, fine-grain practice | ≥ 0.02 | 0.03 |
| N | ≤ 0.02 | 0.01 |
| Fe | balance | — |
Q460-Q — frequently asked
What is Q460-Q used for?
Q460-Q is typically used for bridges, crane structures and industrial frames. In short: high-strength structural plate.
What is the yield strength of Q460-Q?
Q460-Q has a typical yield strength of 505 MPa (73.2 ksi) and a tensile strength of 630 MPa (91.4 ksi) — stronger than 64% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is Q460-Q easy to machine?
Reasonably — machinability is rated fair (52/100, better than 52% of steel grades). Cuts like a tough 500 MPa-yield HSLA steel — use rigid setups, coated carbide at ~120–180 m/min and positive feeds to avoid work hardening; drilling and tapping are noticeably harder than Q235.
Can Q460-Q be welded?
Yes — weldability is rated very good (80/100). Readily welded by SMAW/GMAW/SAW with 550–620 MPa class consumables; keep heat input moderate, preheat ~100–150 °C above 25–30 mm or with high CEV, and avoid over-welding TMCP plate to prevent HAZ softening.
What surface finishes work on Q460-Q?
No anodizing; shot-blast to Sa 2.5 then zinc-rich epoxy, hot-dip galvanize (watch Si/P for coating appearance) or use the NH weathering variant for bare exposure.
Can Q460-Q be formed, bent or molded?
Cold bends to the GB/T 1591 mandrel with generous radii (≥2.5–3 t) and springback allowance; hot forming should stay below the normalizing/TMCP temperature or properties must be re-established by heat treatment.
What is the maximum service temperature of Q460-Q?
Q460-Q is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Q460-HR and Q460-M?
HR is the default condition — standard stocked condition for plate, sections and coil where service temperature stays at or above 0 °C. M: pick for the leanest carbon equivalent and best field weldability with low-temperature toughness, typically in thick plate. Yield strength is 500 MPa in HR versus 510 MPa in M.
Can FabDigit make parts in Q460-Q?
Yes — Q460-Q is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- GB/T 1591 High strength low alloy structural steels (2018)
- GB/T 19879 Steel plates for building structure — SAC (2015)
- GB/T 714 Structural steel for bridge — SAC (2015)
- GB/T 4171 Atmospheric corrosion resisting structural steel — SAC (2008)
- GB 50017 Standard for design of steel structures — MOHURD (2017)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- Mysteel / SMM (Q460C) (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.