Steel HSLA-QT vs HSLA TMCP
Steel · HSLA temper comparison
HSLA-QT and HSLA TMCP are two conditions of the same steel grade, HSLA: QT (quenched and tempered) versus TMCP (thermomechanically controlled processed). The chemistry is identical, so every difference below comes from the condition. HSLA-QT is the stronger of the two: yield strength 620 MPa (89.9 ksi) against 430 MPa (62.4 ksi) for HSLA TMCP, about 44% more; tensile strength follows at 720 MPa (104 ksi) vs 550 MPa (79.8 ksi). In exchange, HSLA TMCP is the more ductile: elongation 22% versus 18% for HSLA-QT, and HSLA-QT is harder (235 HB vs 175 HB). HSLA TMCP runs hotter in service (400°C vs 350°C continuous). On the shop floor, HSLA TMCP welds better (excellent vs good).
HSLA-QTChoose it when strength drives the design.
HSLA TMCPChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
HSLA-QT vs HSLA TMCP: 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
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Reduction in Area 50% · Compressive Strength 345 MPa50 ksi · Shear Strength 300 MPa43.5 ksi · Hardness, Rockwell B 80 HRB · Hardness, Vickers 158 HV
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 270 J/g116 BTU/lb · Min Service Temperature -60°C-76 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 9 % IACS · Electrical Resistivity 1.9×10⁻⁷ Ω·m7.48 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V · Corrosion Resistance 16 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Same in both: Machinability 58 / 100 · Castability 30 / 100 · Brazeability / Solderability 60 / 100 · Polishability 50 / 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 45 L/kg5.4 gal/lb · Typical Recycled Content 30%
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.
HSLA-QT vs HSLA TMCP — frequently asked
Is HSLA-QT stronger than HSLA TMCP?
Yes. HSLA-QT has a typical yield strength of 620 MPa (89.9 ksi) against 430 MPa (62.4 ksi) for HSLA TMCP — about 44% more. Tensile strength is 720 MPa (104 ksi) vs 550 MPa (79.8 ksi).
Which condition does FabDigit quote by default, QT or TMCP?
HR is the default HSLA condition in the FabDigit quote flow (neither QT nor TMCP). 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, HSLA-QT or HSLA TMCP?
HSLA TMCP. Its weldability rates excellent (85/100) against good (65/100) for HSLA-QT.
Ready to make it?
Upload a CAD file and FabDigit prices the part in HSLA-QT and HSLA TMCP 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.