Steel M45 Annealed vs M45 H&T+Nitrided
Steel · M45 temper comparison
M45 Annealed and M45 H&T+Nitrided are two conditions of the same steel grade, M45: Annealed versus H&T+Nitrided (H&T + Plasma/Salt-bath Nitrided surface). The chemistry is identical, so every difference below comes from the condition. M45 H&T+Nitrided is the stronger of the two: yield strength 2,000 MPa (290 ksi) against 620 MPa (89.9 ksi) for M45 Annealed, about 3.2 times as much; tensile strength follows at 2,250 MPa (326 ksi) vs 950 MPa (138 ksi). In exchange, M45 Annealed is the more ductile: elongation 12% versus 0.5% for M45 H&T+Nitrided, and M45 H&T+Nitrided is harder (68 HRC vs 26 HRC). M45 H&T+Nitrided runs hotter in service (600°C vs 200°C continuous). On the shop floor, M45 Annealed machines more easily (poor vs not recommended) and M45 Annealed welds better (poor vs not recommended).
M45 AnnealedChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
M45 H&T+NitridedChoose it when strength drives the design, or when the part sees heat.
M45 Annealed vs M45 H&T+Nitrided: 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.
Elastic (Young's) Modulus
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, Rockwell C
Hardness, Vickers
Same in both: Shear Modulus 84 GPa12.2 Msi · Bulk Modulus 165 GPa23.9 Msi · Poisson's Ratio 0.29 · Hardness, Brinell 269 HB
Physical
Density and transition temperatures.
Same in both: Density 8.1 g/cm³0.29 lb/in³ · Melting Point (Solidus) 1,260°C2,300 °F · Liquidus Temperature 1,420°C2,588 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 420 J/kg·K0.1 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.8 µm/m·K6 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -60°C-76 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V
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: Castability 25 / 100 · Brazeability / Solderability 60 / 100 · Polishability 75 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 55 MJ/kg23,646 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.
M45 Annealed vs M45 H&T+Nitrided — frequently asked
Is M45 H&T+Nitrided stronger than M45 Annealed?
Yes. M45 H&T+Nitrided has a typical yield strength of 2,000 MPa (290 ksi) against 620 MPa (89.9 ksi) for M45 Annealed — about 3.2 times as much. Tensile strength is 2,250 MPa (326 ksi) vs 950 MPa (138 ksi).
Which condition does FabDigit quote by default, Annealed or H&T+Nitrided?
Annealed is the default M45 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 is easier to machine, M45 Annealed or M45 H&T+Nitrided?
M45 Annealed. Its machinability rates poor (25/100) against not recommended (3/100) for M45 H&T+Nitrided; for welding the order is M45 Annealed first (poor, 15/100) then M45 H&T+Nitrided (not recommended, 3/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in M45 Annealed and M45 H&T+Nitrided 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.