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Steel A242 vs SPA-H

Steel · grade comparison

Steel A242 and SPA-H are both steel grades. SPA-H is the stronger of the two: yield strength 390 MPa (56.6 ksi) against 370 MPa (53.7 ksi) for A242, about 5% more. SPA-H is the more ductile: elongation 28% versus 24% for A242.

SPA-HChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.

A242 vs SPA-H: properties

A242SPA-H

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

200 GPa29 Msi
205 GPa29.7 Msi

Shear Modulus

79 GPa11.5 Msi
80 GPa11.6 Msi

Tensile Strength (Ultimate)

510 MPa74 ksi
520 MPa75.4 ksi

Yield Strength (0.2% offset)

370 MPa53.7 ksi
390 MPa56.6 ksi

Elongation at Break

24%
28%

Reduction in Area

50%
55%

Compressive Strength

370 MPa53.7 ksi
390 MPa56.6 ksi

Shear Strength

320 MPa46.4 ksi
350 MPa50.8 ksi

Fatigue Strength (Endurance Limit)

245 MPa35.5 ksi
250 MPa36.3 ksi

Fracture Toughness (K_IC)

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

Charpy V-Notch Impact (RT)

55 J40.6 ft·lbf
50 J36.9 ft·lbf

Hardness, Brinell

155 HB
160 HB

Hardness, Rockwell B

82 HRB
84 HRB

Hardness, Vickers

163 HV
168 HV

Same in both: Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,450°C2,642 °F
1,480°C2,696 °F

Liquidus Temperature

1,510°C2,750 °F
1,520°C2,768 °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 Conductivity

48 W/m·K27.7 BTU/hr·ft·°F
50 W/m·K28.9 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

11.7 µm/m·K6.5 µin/in·°F
12.2 µm/m·K6.8 µin/in·°F

Latent Heat of Fusion

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

Min Service Temperature

-30°C-22 °F
-20°C-4 °F

Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Max Service Temperature (continuous) 350°C662 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

8.5 % IACS
7.8 % IACS

Electrical Resistivity

2×10⁻⁷ Ω·m7.87 µΩ·in
2.2×10⁻⁷ Ω·m8.66 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.6 V
-0.62 V

Corrosion Resistance

35 / 100
32 / 100

Manufacturability

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

Machinability

58 / 100
60 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
62%

Formability (cold)

65 / 100
68 / 100

Brazeability / Solderability

40 / 100
60 / 100

Polishability

40 / 100
45 / 100

Same in both: Weldability 80 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Carbon (primary production)

1.9 kg CO₂/kg
2.1 kg CO₂/kg

Embodied Water

40 L/kg4.8 gal/lb
45 L/kg5.4 gal/lb

Typical Recycled Content

30%
25%

Same in both: Embodied Energy (primary production) 25 MJ/kg10,748 BTU/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

65 kN·m/kg
66 kN·m/kg

Specific Stiffness (E / density)

25.5 MN·m/kg
26.1 MN·m/kg

Modulus of Resilience

342 kJ/m³
371 kJ/m³

Thermal Diffusivity

13 mm²/s
13.6 mm²/s

Same in both: Thermal Shock Resistance Index 10

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 scaleA242SPA-H

Manufacturing and finishing

CapabilityA242SPA-H
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.

A242 vs SPA-H — frequently asked

Is SPA-H stronger than A242?

Yes. SPA-H has a typical yield strength of 390 MPa (56.6 ksi) against 370 MPa (53.7 ksi) for A242 — about 5% more. Tensile strength is 520 MPa (75.4 ksi) vs 510 MPa (74 ksi).

Which is cheaper, A242 or SPA-H?

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.

When should I choose A242 over SPA-H?

Pick SPA-H when strength drives the design, or when the part is bent, formed or impact-loaded.

Ready to make it?

Upload a CAD file and FabDigit prices the part in A242 and SPA-H 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.