Steel 4340M Annealed vs 4340M-HR
Steel · 4340M temper comparison
4340M Annealed and 4340M-HR are two conditions of the same steel grade, 4340M: Annealed versus HR (hot rolled). The chemistry is identical, so every difference below comes from the condition. 4340M-HR is the stronger of the two: yield strength 1,150 MPa (167 ksi) against 690 MPa (100 ksi) for 4340M Annealed, about 67% more; tensile strength follows at 1,550 MPa (225 ksi) vs 930 MPa (135 ksi). In exchange, 4340M Annealed is the more ductile: elongation 15% versus 6% for 4340M-HR, and 4340M-HR is harder (444 HB vs 262 HB). 4340M Annealed runs hotter in service (400°C vs 290°C continuous). On the shop floor, 4340M Annealed machines more easily (fair vs poor).
4340M AnnealedChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
4340M-HRChoose it when strength drives the design.
4340M Annealed vs 4340M-HR: 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
Reduction in Area
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Shear Modulus 78 GPa11.3 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 1,200 MPa174 ksi · Shear Strength 930 MPa135 ksi · Fracture Toughness (K_IC) 40 MPa·√m36.4 ksi·√in · Hardness, Vickers 470 HV
Physical
Density and transition temperatures.
Same in both: Density 7.83 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,480°C2,696 °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 475 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.7 µm/m·K6.5 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -73°C-99 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 7 % IACS · Electrical Resistivity 2.4×10⁻⁷ Ω·m9.45 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 14 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Formability (cold)
Same in both: Weldability 12 / 100 · Castability 25 / 100 · Brazeability / Solderability 20 / 100 · Polishability 75 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 36 MJ/kg15,477 BTU/lb · Embodied Carbon (primary production) 2.6 kg CO₂/kg · Embodied Water 60 L/kg7.2 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.
4340M Annealed vs 4340M-HR — frequently asked
Is 4340M-HR stronger than 4340M Annealed?
Yes. 4340M-HR has a typical yield strength of 1,150 MPa (167 ksi) against 690 MPa (100 ksi) for 4340M Annealed — about 67% more. Tensile strength is 1,550 MPa (225 ksi) vs 930 MPa (135 ksi).
Which condition does FabDigit quote by default, Annealed or HR?
HR is the default 4340M 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, 4340M Annealed or 4340M-HR?
4340M Annealed. Its machinability rates fair (42/100) against poor (15/100) for 4340M-HR.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 4340M Annealed and 4340M-HR 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.