Steel A656 Grade 80-QT vs A656 Grade 80 TMCP
Steel · A656 Grade 80 temper comparison
A656 Grade 80-QT and A656 Grade 80 TMCP are two conditions of the same steel grade, A656 Grade 80: QT (quenched and tempered) versus TMCP (thermomechanically controlled processed). 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 (quenched and tempered versus thermomechanically controlled processed). A656 Grade 80-QT is harder — 21 HRC against 18 HRC for A656 Grade 80 TMCP — which matters for wear surfaces and threads.
A656 Grade 80-QTChoose it when surface hardness matters.
A656 Grade 80-QT vs A656 Grade 80 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.
A656 Grade 80-QTA656 Grade 80 TMCP
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
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 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Elongation at Break 20%
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,450°C2,642 °F · Liquidus Temperature 1,510°C2,750 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Same in both: 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 · Max Service Temperature (continuous) 350°C662 °F · Min Service Temperature -50°C-58 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.62 V · Corrosion Resistance 12 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Same in both: Brazeability / Solderability 55 / 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) 2.1 kg CO₂/kg · Embodied Water 35 L/kg4.2 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.
A656 Grade 80-QT vs A656 Grade 80 TMCP — frequently asked
What is the difference between A656 Grade 80-QT and A656 Grade 80 TMCP?
A656 Grade 80-QT and A656 Grade 80 TMCP are two conditions of the same steel grade, A656 Grade 80: QT (quenched and tempered) versus TMCP (thermomechanically controlled processed). 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 (quenched and tempered versus thermomechanically controlled processed).
Which condition does FabDigit quote by default, QT or TMCP?
HR is the default A656 Grade 80 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, A656 Grade 80-QT or A656 Grade 80 TMCP?
A656 Grade 80 TMCP. Its weldability rates very good (78/100) against very good (70/100) for A656 Grade 80-QT.
Ready to make it?
Upload a CAD file and FabDigit prices the part in A656 Grade 80-QT and A656 Grade 80 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.