Steel E590-M vs E590-QT
Steel · E590 temper comparison
E590-M and E590-QT are two conditions of the same steel grade, E590: M (thermomechanically controlled processed) versus QT (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. Both yield at about 630 MPa — the mechanical properties are the same, and the difference is in how the stock is processed and what it is certified to (thermomechanically controlled processed versus quenched and tempered). E590-M is the more ductile: elongation 20% versus 18% for E590-QT. E590-QT runs hotter in service (350°C vs 300°C continuous). On the shop floor, E590-M welds better (very good vs good).
E590-MChoose it when the part is bent, formed or impact-loaded, or when it will be welded.
E590-QTChoose it when the part sees heat.
E590-M vs E590-QT: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Shear Modulus 81 GPa11.7 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,425°C2,597 °F · Liquidus Temperature 1,510°C2,750 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 45 W/m·K26 BTU/hr·ft·°F · Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12 µm/m·K6.7 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 9.5 % IACS · Electrical Resistivity 1.8×10⁻⁷ Ω·m7.09 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V · Corrosion Resistance 10 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Same in both: Machinability Rating (AISI 1212 = 100 %) 50% · Brazeability / Solderability 40 / 100 · Polishability 45 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 25 MJ/kg10,748 BTU/lb · Embodied Carbon (primary production) 2 kg CO₂/kg · Embodied Water 40 L/kg4.8 gal/lb · Typical Recycled Content 25%
Strength versus weight
Yield strength against density for every steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
E590-M vs E590-QT — frequently asked
What is the difference between E590-M and E590-QT?
E590-M and E590-QT are two conditions of the same steel grade, E590: M (thermomechanically controlled processed) versus QT (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. Both yield at about 630 MPa — the mechanical properties are the same, and the difference is in how the stock is processed and what it is certified to (thermomechanically controlled processed versus quenched and tempered).
Which condition does FabDigit quote by default, M or QT?
QT is the default E590 condition in the FabDigit quote flow. The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.
Which welds better, E590-M or E590-QT?
E590-M. Its weldability rates very good (70/100) against good (55/100) for E590-QT.
Ready to make it?
Upload a CAD file and FabDigit prices the part in E590-M and E590-QT side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.