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Steel 340X vs A242

Steel · grade comparison

Steel 340X and A242 are both steel grades. A242 is the stronger of the two: tensile strength 510 MPa (74 ksi) against 450 MPa (65.3 ksi) for 340X, about 13% more. A242 is harder — 155 HB against 140 HB for 340X — which matters for wear surfaces and threads. 340X conducts electricity better (9.5 % IACS vs 8.5 % IACS).

A242Choose it when strength drives the design, or when surface hardness matters.

340X vs A242: properties

340XA242

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

207 GPa30 Msi
200 GPa29 Msi

Shear Modulus

80 GPa11.6 Msi
79 GPa11.5 Msi

Tensile Strength (Ultimate)

450 MPa65.3 ksi
510 MPa74 ksi

Elongation at Break

26%
24%

Reduction in Area

65%
50%

Shear Strength

300 MPa43.5 ksi
320 MPa46.4 ksi

Fatigue Strength (Endurance Limit)

225 MPa32.6 ksi
245 MPa35.5 ksi

Fracture Toughness (K_IC)

100 MPa·√m91 ksi·√in
120 MPa·√m109 ksi·√in

Charpy V-Notch Impact (RT)

50 J36.9 ft·lbf
55 J40.6 ft·lbf

Hardness, Brinell

140 HB
155 HB

Hardness, Rockwell B

76 HRB
82 HRB

Hardness, Vickers

148 HV
163 HV

Same in both: Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Yield Strength (0.2% offset) 370 MPa53.7 ksi · Compressive Strength 370 MPa53.7 ksi

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,500°C2,732 °F
1,450°C2,642 °F

Liquidus Temperature

1,525°C2,777 °F
1,510°C2,750 °F

Same in both: Density 7.85 g/cm³0.28 lb/in³

Thermal

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

Thermal Expansion (CTE, 20–100 °C)

12 µm/m·K6.7 µin/in·°F
11.7 µm/m·K6.5 µin/in·°F

Latent Heat of Fusion

270 J/g116 BTU/lb
247 J/g106 BTU/lb

Min Service Temperature

-40°C-40 °F
-30°C-22 °F

Same in both: Thermal Conductivity 48 W/m·K27.7 BTU/hr·ft·°F · Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Max Service Temperature (continuous) 350°C662 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

9.5 % IACS
8.5 % IACS

Electrical Resistivity

1.8×10⁻⁷ Ω·m7.09 µΩ·in
2×10⁻⁷ Ω·m7.87 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.62 V
-0.6 V

Corrosion Resistance

12 / 100
35 / 100

Manufacturability

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

Machinability

55 / 100
58 / 100

Machinability Rating (AISI 1212 = 100 %)

58%
60%

Weldability

89 / 100
80 / 100

Formability (cold)

74 / 100
65 / 100

Brazeability / Solderability

60 / 100
40 / 100

Polishability

55 / 100
40 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Carbon (primary production)

2.1 kg CO₂/kg
1.9 kg CO₂/kg

Typical Recycled Content

25%
30%

Same in both: Embodied Energy (primary production) 25 MJ/kg10,748 BTU/lb · Embodied Water 40 L/kg4.8 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

57 kN·m/kg
65 kN·m/kg

Specific Stiffness (E / density)

26.4 MN·m/kg
25.5 MN·m/kg

Modulus of Resilience

331 kJ/m³
342 kJ/m³

Thermal Shock Resistance Index

9
10

Same in both: Thermal Diffusivity 13 mm²/s

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 scaleA242340X

Manufacturing and finishing

Capability340XA242
Default condition——
Relative cost$ Budget$ Budget
Min. machined wall——
Best machined surface——

Both take the same 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

340X vs A242 — frequently asked

Is A242 stronger than 340X?

Yes. A242 has a typical tensile strength of 510 MPa (74 ksi) against 450 MPa (65.3 ksi) for 340X — about 13% more.

Which is cheaper, 340X or A242?

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

Which welds better, 340X or A242?

340X. Its weldability rates excellent (89/100) against very good (80/100) for A242.

Ready to make it?

Upload a CAD file and FabDigit prices the part in 340X and A242 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.