Steel E590-QT (Quenched and tempered)
Heat-treated state · default condition
EN E590
Standard route for heavier plate: gives the most reliable 590 MPa yield plus good -20 °C impact energy.
Values for the QT condition
Other E590 tempers and conditions
E590 is listed in 5 conditions; see the grade overview at E590.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Stress relieved | Applied to welded or heavily cold-formed fabrications to cut residual stress and distortion, at a small loss of yield strength. | 600 | 770 | 19 | 19 HRC | 9.5 % IACS |
as-rolled (hot rolled, no subsequent heat treatment) | Cheapest supply route for thin plate and sections where the rolling schedule alone meets the 590 MPa minimum. | 610 | 780 | 17 | 21 HRC | 9.5 % IACS |
Normalized | Pick when uniform fine-grain structure and reliable low-temperature (K2) toughness through the thickness are needed. | 615 | 780 | 19 | 20 HRC | 9.5 % IACS |
QTDefaultThis page Quenched and tempered | Standard route for heavier plate: gives the most reliable 590 MPa yield plus good -20 °C impact energy. | 620 | 800 | 18 | 22 HRC | — |
Thermomechanically controlled processed | Choose for the lowest carbon equivalent and best field weldability at equal strength; not re-normalizable after hot forming. | 630 | 790 | 20 | 21 HRC | 9.5 % IACS |
What is E590-QT?
E590-QT is E590 heat treated to QT — standard route for heavier plate: gives the most reliable 590 MPa yield plus good -20 °C impact energy. E590-QT has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 78% of steel grades. Elongation at break is 18% and the elastic modulus is 210 GPa (30.5 Msi). E590-QT 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).
Advantages
- High strength — 620 MPa (89.9 ksi), better than 78% of steel grades
- High electrical conductivity — 9.5 % IACS, better than 75% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
E590-QT properties
Typical room-temperature values for E590-QT; 12 are specific to this condition. Other listed values are E590 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
E590-QT 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).
Mechanical17
E590-QT has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 78% of steel grades. Elongation at break is 18% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
E590-QT 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
E590-QT conducts electricity at 9.5 % IACS, better than 75% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of E590-QT takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability6
E590-QT's machinability is fair (45/100, worse than 65% of steel grades); weldability good (55/100); formability fair (40/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with E590-QT
Is E590 easy to machine?
Machines like a 700–800 MPa HSLA steel: rigid setups, coated carbide, moderate speeds (~50–80 m/min) and positive rake; expect ~50 % of 1212 throughput.
Can E590 be welded?
Weldable with low-hydrogen SMAW/GMAW/SAW using matching 590 MPa-class consumables; preheat 100–150 °C on thicker plate and control heat input to protect HAZ toughness.
Can E590 be formed, bent or molded?
Cold-bendable but needs generous radii (≈3t transverse, 4t longitudinal) and press-brake capacity sized for ~2× mild-steel force; hot forming above 580 °C requires re-heat-treatment for +N/+QT deliveries.
What surface finishes work on E590?
No native corrosion resistance — shot blast to Sa 2½ then prime/paint, metallize or hot-dip galvanize (watch Si content for coating thickness); no anodizing applies.
E590 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, thin product; higher C allowed on heavy plate | ≤ 0.2 | 0.17 |
| Si | ≤ 0.6 | 0.35 |
| Mn | ≤ 1.7 | 1.45 |
| PK2 quality | ≤ 0.03 | 0.02 |
| SK2 quality | ≤ 0.03 | 0.01 |
| Nunless bound by Al/Ti | ≤ 0.02 | 0.01 |
| Altotal Al, grain refining | ≥ 0.02 | 0.03 |
| Nboptional micro-alloying | ≤ 0.05 | 0.03 |
| Voptional micro-alloying | ≤ 0.1 | 0.05 |
| Tioptional micro-alloying | ≤ 0.05 | 0.02 |
| Fe | balance | — |
E590-QT — frequently asked
What is E590-QT used for?
E590-QT is typically used for heavy equipment structural members, cranes, load-bearing brackets and high-strength fabrications. In short: 590 MPa yield structural steel; weight-saving over S355; demands weld heat-input control.
What is the yield strength of E590-QT?
E590-QT has a typical yield strength of 620 MPa (89.9 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 78% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is E590-QT easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machines like a 700–800 MPa HSLA steel: rigid setups, coated carbide, moderate speeds (~50–80 m/min) and positive rake; expect ~50 % of 1212 throughput.
Can E590-QT be welded?
Yes — weldability is rated good (55/100). Weldable with low-hydrogen SMAW/GMAW/SAW using matching 590 MPa-class consumables; preheat 100–150 °C on thicker plate and control heat input to protect HAZ toughness.
What surface finishes work on E590-QT?
No native corrosion resistance — shot blast to Sa 2½ then prime/paint, metallize or hot-dip galvanize (watch Si content for coating thickness); no anodizing applies.
Can E590-QT be formed, bent or molded?
Cold-bendable but needs generous radii (≈3t transverse, 4t longitudinal) and press-brake capacity sized for ~2× mild-steel force; hot forming above 580 °C requires re-heat-treatment for +N/+QT deliveries.
What is the maximum service temperature of E590-QT?
E590-QT 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 E590-QT and E590-SR?
QT is the default condition — standard route for heavier plate: gives the most reliable 590 MPa yield plus good -20 °C impact energy. SR: applied to welded or heavily cold-formed fabrications to cut residual stress and distortion, at a small loss of yield strength. Yield strength is 620 MPa in QT versus 600 MPa in SR.
Sources
- ISO 630 — Structural steels: plates, wide flats, bars, sections and profiles — ISO (2021)
- EN 10027-2 steel numbering (material No. 1.0644) — CEN (2015)
- 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)
- ASTM A370 — Mechanical Testing of Steel Products (hardness conversions) — ASTM (2022)
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.