Steel P690QL1-QT (Quenched and tempered)
Heat-treated state · default condition
EN 1.8881
Standard delivery condition of P690QL1 plate; full 690 MPa minimum yield with -40 °C impact guarantee.
Values for the QT condition
Other P690QL1 tempers and conditions
P690QL1 is listed in 4 conditions; see the grade overview at P690QL1.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
QT | Maximum thickness range; lowest guaranteed strength due to reduced quench severity in the core. | 670 | 790 | 17 | 23 HRC | 6.9 % IACS |
QT | Heavy-wall plate; thickness-derated proof strength for vessel shells and forged-like sections. | 690 | 800 | 17 | 24 HRC | 6.9 % IACS |
Quenched, tempered and stress relieved / PWHT simulated | Choose when the fabricated vessel receives PWHT; properties must be verified on simulated-heat-treated coupons because strength drops. | 700 | 800 | 18 | 24 HRC | 6.9 % IACS |
QTDefaultThis page Quenched and tempered | Standard delivery condition of P690QL1 plate; full 690 MPa minimum yield with -40 °C impact guarantee. | 730 | 830 | 17 | 26 HRC | 6.9 % IACS |
What is P690QL1-QT?
P690QL1-QT is P690QL1 heat treated to QT — standard delivery condition of P690QL1 plate; full 690 MPa minimum yield with -40 °C impact guarantee. P690QL1-QT has a yield strength of 730 MPa (106 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 83% of steel grades. Elongation at break is 17% and the elastic modulus is 210 GPa (30.5 Msi). P690QL1-QT 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
- Tough — resists crack growth — 130 MPa·√m (118.3 ksi·√in), better than 89% of steel grades
- High strength — 730 MPa (106 ksi), better than 83% of steel grades
Limitations
- Difficult to machine — 40/100, worse than 77% of steel grades
P690QL1-QT properties
Typical room-temperature values for P690QL1-QT; 23 are specific to this condition. Other listed values are P690QL1 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
P690QL1-QT 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
P690QL1-QT has a yield strength of 730 MPa (106 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 83% of steel grades. Elongation at break is 17% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
P690QL1-QT is rated for continuous service to 400°C (752 °F). It conducts heat at 36 W/m·K (20.8 BTU/hr·ft·°F), worse than 73% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
P690QL1-QT conducts electricity at 6.9 % IACS, worse than 76% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of P690QL1-QT takes about 30 MJ of energy and emits 2.3 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 25%.
Manufacturability7
P690QL1-QT's machinability is fair (40/100, worse than 77% of steel grades); weldability good (65/100); formability fair (45/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with P690QL1-QT
Is P690QL1 easy to machine?
Machine as ~260 HB alloy steel: rigid setup, coated carbide, moderate speeds and positive rake; avoid rubbing that work-hardens the surface.
Can P690QL1 be welded?
Weldable with low-hydrogen consumables; preheat typically 100–150 °C (thickness/CEV dependent), control interpass ≤ 200 °C and heat input to protect HAZ toughness, PWHT below the tempering temperature only.
Can P690QL1 be formed, bent or molded?
Cold bend with generous inside radii (≈3–5 t transverse) and dies aligned to rolling direction; hot forming above the tempering temperature destroys the Q&T properties and requires re-heat-treatment.
What surface finishes work on P690QL1?
Not anodizable — shot-blast to Sa 2½ then zinc-rich epoxy primer or metallize; hot-dip galvanizing needs caution at this strength level (LME/hydrogen risk).
P690QL1 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 |
|---|---|---|
| Cladle analysis | ≤ 0.2 | 0.16 |
| Si | ≤ 0.8 | 0.3 |
| Mn | 0.8 – 1.7 | 1.3 |
| P | ≤ 0.02 | 0.01 |
| S | ≤ 0.01 | 0 |
| Altotal Al, grain refining | ≥ 0.02 | 0.04 |
| Cr | ≤ 1.5 | 0.5 |
| Cu | ≤ 0.5 | 0.2 |
| Mo | ≤ 0.7 | 0.45 |
| Ni | ≤ 2.5 | 1.5 |
| Nb | ≤ 0.06 | 0.03 |
| Ti | ≤ 0.05 | 0.02 |
| V | ≤ 0.12 | 0.05 |
| Zr | ≤ 0.05 | — |
| B | ≤ 0.01 | 0 |
| N | ≤ 0.02 | 0.01 |
| Fe | balance | — |
P690QL1-QT — frequently asked
What is P690QL1-QT used for?
P690QL1-QT is typically used for pressure vessels, mobile crane booms, heavy structural frames, earthmoving equipment and offshore structures. In short: 690 MPa weldable plate; low-temperature impact qualified; weight-saving structural grade.
What is the yield strength of P690QL1-QT?
P690QL1-QT has a typical yield strength of 730 MPa (106 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 83% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is P690QL1-QT easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% of steel grades). Machine as ~260 HB alloy steel: rigid setup, coated carbide, moderate speeds and positive rake; avoid rubbing that work-hardens the surface.
Can P690QL1-QT be welded?
Yes — weldability is rated good (65/100). Weldable with low-hydrogen consumables; preheat typically 100–150 °C (thickness/CEV dependent), control interpass ≤ 200 °C and heat input to protect HAZ toughness, PWHT below the tempering temperature only.
What surface finishes work on P690QL1-QT?
Not anodizable — shot-blast to Sa 2½ then zinc-rich epoxy primer or metallize; hot-dip galvanizing needs caution at this strength level (LME/hydrogen risk).
Can P690QL1-QT be formed, bent or molded?
Cold bend with generous inside radii (≈3–5 t transverse) and dies aligned to rolling direction; hot forming above the tempering temperature destroys the Q&T properties and requires re-heat-treatment.
What is the maximum service temperature of P690QL1-QT?
P690QL1-QT 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.
Sources
- EN 10028-6 Flat products made of steels for pressure purposes — Weldable fine grain steels, quenched and tempered — CEN (2017)
- EN 10025-6 Hot rolled products of structural steels — Flat products of high yield strength structural steels in the quenched and tempered condition — CEN (2019)
- 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)
- Quenched and tempered 690 MPa pressure vessel plate datasheets (Dillinger / SSAB / Voestalpine class products) — various mills (2023)
- Mysteel / SMM (2025)
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.