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Steel M1 vs T8

Steel · grade comparison

Steel M1 and T8 are both steel grades. T8 is the stronger of the two: tensile strength 900 MPa (131 ksi) against 830 MPa (120 ksi) for M1, about 8% more. In exchange, M1 is the more ductile: elongation 18% versus 15% for T8. M1 is lighter (7.89 g/cm³ vs 8.6 g/cm³ for T8) and T8 runs hotter in service (400°C vs 300°C continuous). On the shop floor, M1 welds better (25 vs 15 out of 100).

M1Choose it when the part is bent, formed or impact-loaded, or when weight is the constraint.

T8Choose it when strength drives the design, or when the part sees heat.

M1 vs T8: properties

M1T8

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

217 GPa31.5 Msi
220 GPa31.9 Msi

Shear Modulus

83 GPa12 Msi
85 GPa12.3 Msi

Bulk Modulus

160 GPa23.2 Msi
170 GPa24.7 Msi

Poisson's Ratio

0.28
0.29

Tensile Strength (Ultimate)

830 MPa120 ksi
900 MPa131 ksi

Yield Strength (0.2% offset)

550 MPa79.8 ksi
570 MPa82.7 ksi

Elongation at Break

18%
15%

Reduction in Area

32%
25%

Compressive Strength

800 MPa116 ksi
1,200 MPa174 ksi

Shear Strength

550 MPa79.8 ksi
—

Fatigue Strength (Endurance Limit)

380 MPa55.1 ksi
—

Hardness, Brinell

235 HB
240 HB

Hardness, Rockwell C

22 HRC
—

Hardness, Vickers

248 HV
250 HV

Same in both: Charpy V-Notch Impact (RT) 25 J18.4 ft·lbf · Hardness, Rockwell B 99 HRB

Physical

Density and transition temperatures.

Density

7.89 g/cm³0.29 lb/in³
8.6 g/cm³0.31 lb/in³

Melting Point (Solidus)

1,290°C2,354 °F
1,400°C2,552 °F

Liquidus Temperature

1,430°C2,606 °F
1,460°C2,660 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Expansion (CTE, 20–100 °C)

10.5 µm/m·K5.8 µin/in·°F
11.2 µm/m·K6.2 µin/in·°F

Max Service Temperature (continuous)

300°C572 °F
400°C752 °F

Min Service Temperature

-100°C-148 °F
-40°C-40 °F

Same in both: Thermal Conductivity 22 W/m·K12.7 BTU/hr·ft·°F · Specific Heat Capacity 420 J/kg·K0.1 BTU/lb·°F · Latent Heat of Fusion 250 J/g107 BTU/lb

Electrical

Conductivity and insulation.

Same in both: Electrical Conductivity 3.1 % IACS · Electrical Resistivity 5.5×10⁻⁷ Ω·m21.7 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.5 V
-0.6 V

Corrosion Resistance

12 / 100
18 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability Rating (AISI 1212 = 100 %)

30%
40%

Weldability

25 / 100
15 / 100

Formability (cold)

25 / 100
12 / 100

Castability

30 / 100
—

Brazeability / Solderability

45 / 100
55 / 100

Polishability

65 / 100
70 / 100

Same in both: Machinability 35 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

55 MJ/kg23,646 BTU/lb
60 MJ/kg25,795 BTU/lb

Embodied Carbon (primary production)

3.6 kg CO₂/kg
4.2 kg CO₂/kg

Embodied Water

95 L/kg11.4 gal/lb
90 L/kg10.8 gal/lb

Typical Recycled Content

40%
35%

Common Calculations

Ratios derived from the values above.

Specific Stiffness (E / density)

27.5 MN·m/kg
25.6 MN·m/kg

Modulus of Resilience

697 kJ/m³
738 kJ/m³

Thermal Diffusivity

6.6 mm²/s
6.1 mm²/s

Same in both: Specific Strength (UTS / density) 105 kN·m/kg · Thermal Shock Resistance Index 8

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.

2005001,0002,0007.588.5Density (g/cm³)Yield strength (MPa) — log scaleT8M1

Manufacturing and finishing

CapabilityM1T8
CNC machining—Yes
Default condition—Annealed
Relative cost$$$ Premium$$$ Premium
Min. machined wall—0.8 mm
Best machined surface—Ra 1.6 µm
AlCrN—Yes
AlTiN—Yes
Black Oxide—Yes
CVD Al2O3—Yes
CVD TiCN—Yes
CVD TiN—Yes
Cerakote—Yes
Chrome Plating—Yes
CrN—Yes
DLC—Yes
E-Coating—Yes
HVOF Coating—Yes
Hot-Dip Galvanizing—Yes
MoS2—Yes
Multilayer CVD—Yes
Nickel Plating—Yes
PTFE Coating—Yes
Painting—Yes

They share 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

M1 vs T8 — frequently asked

Is T8 stronger than M1?

Yes. T8 has a typical tensile strength of 900 MPa (131 ksi) against 830 MPa (120 ksi) for M1 — about 8% more.

Which is cheaper, M1 or T8?

Both sit in the same relative cost tier ($$$, premium); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which welds better, M1 or T8?

M1. Its weldability rates poor (25/100) against poor (15/100) for T8.

Ready to make it?

Upload a CAD file and FabDigit prices the part in M1 and T8 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.