Steel M4 Hardened & Tempered vs M4 Stress Relieved
Steel · M4 temper comparison
M4 Hardened & Tempered and M4 Stress Relieved are two conditions of the same steel grade, M4: Hardened & Tempered (quenched and tempered) versus Stress Relieved. The chemistry is identical, so every difference below comes from the condition. M4 Hardened & Tempered is the stronger of the two: tensile strength 2,200 MPa (319 ksi) against 890 MPa (129 ksi) for M4 Stress Relieved, about 147% more. M4 Hardened & Tempered is harder — 63 HRC against 25 HRC for M4 Stress Relieved — which matters for wear surfaces and threads. On the shop floor, M4 Stress Relieved machines more easily (poor vs not recommended).
M4 Hardened & TemperedChoose it when strength drives the design, or when surface hardness matters.
M4 Stress RelievedChoose it when the part is machined in volume.
M4 Hardened & Tempered vs M4 Stress Relieved: 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.
M4 Hardened & TemperedM4 Stress Relieved
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
Fracture Toughness (K_IC)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 217 GPa31.5 Msi · Shear Modulus 84 GPa12.2 Msi · Bulk Modulus 165 GPa23.9 Msi · Poisson's Ratio 0.28
Physical
Density and transition temperatures.
Same in both: Density 7.97 g/cm³0.29 lb/in³ · Melting Point (Solidus) 1,250°C2,282 °F · Liquidus Temperature 1,420°C2,588 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
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 · Thermal Expansion (CTE, 20–100 °C) 11 µm/m·K6.1 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -60°C-76 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.9 % IACS · Electrical Resistivity 6×10⁻⁷ Ω·m23.6 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.58 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Same in both: Weldability 15 / 100 · Formability (cold) 12 / 100 · Castability 20 / 100 · Brazeability / Solderability 45 / 100 · Polishability 50 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 58 MJ/kg24,936 BTU/lb · Embodied Carbon (primary production) 4.2 kg CO₂/kg · Embodied Water 110 L/kg13.2 gal/lb · Typical Recycled Content 35%
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.
M4 Hardened & Tempered vs M4 Stress Relieved — frequently asked
Is M4 Hardened & Tempered stronger than M4 Stress Relieved?
Yes. M4 Hardened & Tempered has a typical tensile strength of 2,200 MPa (319 ksi) against 890 MPa (129 ksi) for M4 Stress Relieved — about 147% more.
Which condition does FabDigit quote by default, Hardened & Tempered or Stress Relieved?
Annealed is the default M4 condition in the FabDigit quote flow (neither Hardened & Tempered nor Stress Relieved). 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 is easier to machine, M4 Hardened & Tempered or M4 Stress Relieved?
M4 Stress Relieved. Its machinability rates poor (24/100) against not recommended (5/100) for M4 Hardened & Tempered.
Ready to make it?
Upload a CAD file and FabDigit prices the part in M4 Hardened & Tempered and M4 Stress Relieved 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.