Steel 1.2343 vs 4340
Steel · grade comparison
Steel 1.2343 and 4340 are both steel grades. 4340 is the stronger of the two: yield strength 620 MPa (89.9 ksi) against 500 MPa (72.5 ksi) for 1.2343, about 24% more; tensile strength follows at 950 MPa (138 ksi) vs 800 MPa (116 ksi). 4340 is the more ductile: elongation 18% versus 16% for 1.2343, and 4340 is harder (285 HB vs 205 HB). 4340 conducts heat better (44.5 W/m·K vs 24.5 W/m·K). On the shop floor, 1.2343 welds better (fair vs poor) and 1.2343 sits in a lower cost tier (standard, $$) than 4340 (premium, $$$).
1.2343Choose it when it will be welded, or when cost is the deciding factor.
4340Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.
1.2343 vs 4340: 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
Shear Modulus
Bulk Modulus
Poisson's Ratio
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, Brinell
Hardness, Rockwell B
Hardness, Rockwell C
Hardness, Vickers
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Min Service Temperature
Latent Heat of Fusion
Same in both: Max Service Temperature (continuous) 400°C752 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Castability
Brazeability / Solderability
Same in both: Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Typical Recycled Content
Same in both: Embodied Water 60 L/kg7.2 gal/lb
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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.
Manufacturing and finishing
| Capability | 1.2343 | 4340 |
|---|---|---|
| Sheet metal | — | Yes |
| Default condition | Annealed | HR |
| Relative cost | $$ Standard | $$$ Premium |
| Min. machined wall | 0.8 mm | 0.8 mm |
| Best machined surface | Ra 1.6 µm | Ra 1.6 µm |
Both are offered for CNC machining. Both take the same 38 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, Copper Plating, CrN, DLC, E-Coating and 26 more.
1.2343 vs 4340 — frequently asked
Is 4340 stronger than 1.2343?
Yes. 4340 has a typical yield strength of 620 MPa (89.9 ksi) against 500 MPa (72.5 ksi) for 1.2343 — about 24% more. Tensile strength is 950 MPa (138 ksi) vs 800 MPa (116 ksi).
Which is cheaper, 1.2343 or 4340?
1.2343 is the lower-cost material: it sits in the standard tier ($$) while 4340 is premium ($$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which welds better, 1.2343 or 4340?
1.2343. Its weldability rates fair (45/100) against poor (33/100) for 4340.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 1.2343 and 4340 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.