Steel S690QL · heat-treated state · default condition
Steel S690QL Q&T
Properties of the Q&T condition, compared with the other S690QL tempers.
Standard as-delivered plate condition; full 690 MPa minimum yield — pick for normal boom, chassis and lifting-structure plate.
What is S690QL Q&T?
S690QL Q&T is S690QL heat treated to Q&T — standard as-delivered plate condition; full 690 MPa minimum yield — pick for normal boom, chassis and lifting-structure plate. S690QL Q&T has a yield strength of 760 MPa (110 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 85% of steel grades. Elongation at break is 16% and the elastic modulus is 210 GPa (30.5 Msi). S690QL Q&T has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,440°C (2,624 °F).
Advantages
- High strength — 760 MPa (110 ksi), better than 85% of steel grades
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 80% of steel grades
Limitations
- High embodied carbon — 2.5 kg CO₂/kg, worse than 82% of steel grades
- Difficult to machine — 40/100, worse than 76% of steel grades
S690QL Q&T properties
Typical room-temperature values for S690QL Q&T — 9 properties are specific to this condition; the rest are grade-level values shared by every S690QL temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
S690QL Q&T has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,440°C (2,624 °F).
Mechanical16
S690QL Q&T has a yield strength of 760 MPa (110 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 85% of steel grades. Elongation at break is 16% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
S690QL Q&T is rated for continuous service to 350°C (662 °F). It conducts heat at 35 W/m·K (20.2 BTU/hr·ft·°F), worse than 74% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical2
S690QL Q&T has an electrical resistivity of 2.4×10⁻⁷ Ω·m.
Chemical & Environmental3
Corrosion resistance is not recommended (14/100), better than 70% of steel grades.
Sustainability4
Producing a kilogram of S690QL Q&T takes about 32 MJ of energy and emits 2.5 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 30%.
Manufacturability6
S690QL Q&T's machinability is fair (40/100, worse than 76% of steel grades); weldability good (65/100); formability fair (45/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other S690QL tempers and conditions
S690QL is also supplied in 3 other conditions. The full side-by-side table is on the S690QL overview.
- Q&TDefaultStandard as-delivered plate condition; full 690 MPa minimum yield — pick for normal boom, chassis and lifting-structure plate.760 MPa yield · 27 HRC
Working with S690QL Q&T
Is S690QL easy to machine?
Machines like a ~270 HB Q&T alloy steel: rigid setups, coated carbide, moderate speeds and positive feeds; expect springback-free but tool-wearing chips and relieve stresses before finish machining thick sections.
Can S690QL be welded?
Good weldability with low-hydrogen consumables matching ~690 MPa; control preheat/interpass (typically 100–150 °C for thick or restrained joints), limit heat input to protect HAZ toughness, and keep hydrogen out to avoid cold cracking.
Can S690QL be formed, bent or molded?
Cold bendable with inner radius roughly 3–4× thickness transverse to rolling direction; grind-smooth burr-free edges before bending and avoid hot forming above the tempering temperature.
What surface finishes work on S690QL?
No self-protection — blast, then paint, zinc-rich primer or metallize; hot-dip galvanizing is possible but assess liquid-metal-assisted cracking risk at this strength level.
S690QL 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 |
|---|---|---|
| Cmax for t ≤ 50 mm | ≤ 0.2 | 0.16 |
| Si | ≤ 0.8 | 0.3 |
| Mn | ≤ 1.7 | 1.3 |
| P | ≤ 0.03 | 0.01 |
| S | ≤ 0.01 | 0 |
| N | ≤ 0.02 | 0.01 |
| Cr | ≤ 1.5 | 0.5 |
| Ni | ≤ 2 | 0.6 |
| Mo | ≤ 0.7 | 0.4 |
| Cu | ≤ 0.5 | 0.15 |
| V | ≤ 0.12 | 0.05 |
| Nb | ≤ 0.06 | 0.02 |
| Ti | ≤ 0.05 | 0.02 |
| Zr | ≤ 0.05 | — |
| B | ≤ 0.01 | 0 |
| Altotal Al, minimum | ≥ 0.02 | 0.03 |
| Fe | balance | — |
S690QL Q&T — frequently asked
What is S690QL Q&T used for?
S690QL Q&T is typically used for mobile crane booms, tipper and dump bodies, concrete pump booms, mining equipment structures, excavator arms and buckets and trailer and chassis frames. In short: high-strength Q&T plate.
What is the yield strength of S690QL Q&T?
S690QL Q&T has a typical yield strength of 760 MPa (110 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 85% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is S690QL Q&T easy to machine?
Not especially — machinability is rated fair (40/100, worse than 76% of steel grades). Machines like a ~270 HB Q&T alloy steel: rigid setups, coated carbide, moderate speeds and positive feeds; expect springback-free but tool-wearing chips and relieve stresses before finish machining thick sections.
Can S690QL Q&T be welded?
Yes — weldability is rated good (65/100). Good weldability with low-hydrogen consumables matching ~690 MPa; control preheat/interpass (typically 100–150 °C for thick or restrained joints), limit heat input to protect HAZ toughness, and keep hydrogen out to avoid cold cracking.
What surface finishes work on S690QL Q&T?
No self-protection — blast, then paint, zinc-rich primer or metallize; hot-dip galvanizing is possible but assess liquid-metal-assisted cracking risk at this strength level.
Can S690QL Q&T be formed, bent or molded?
Cold bendable with inner radius roughly 3–4× thickness transverse to rolling direction; grind-smooth burr-free edges before bending and avoid hot forming above the tempering temperature.
What is the maximum service temperature of S690QL Q&T?
S690QL Q&T 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.
Can FabDigit make parts in S690QL Q&T?
Yes — S690QL Q&T is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- EN 10025-6 Hot rolled products of structural steels — Part 6: flat products of high yield strength structural steels in the quenched and tempered condition — CEN (2019)
- Strenx 700 / Weldox 700 structural plate data — SSAB (2023)
- DILLIMAX 690 high-strength quenched and tempered steel plate — Dillinger (2022)
- 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)
- GB/T 16270 (Q690D/E equivalent) — SAC (2009)
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.