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Steel A656 vs SPHC

Steel · grade comparison

Steel A656 and SPHC are both steel grades, both structural steel. A656 is the stronger of the two: yield strength 580 MPa (84.1 ksi) against 240 MPa (34.8 ksi) for SPHC, about 142% more; tensile strength follows at 660 MPa (95.7 ksi) vs 310 MPa (45 ksi). In exchange, SPHC is the more ductile: elongation 38% versus 16% for A656, and A656 is harder (215 HB vs 110 HB). SPHC runs hotter in service (400°C vs 350°C continuous) and SPHC conducts heat better (52 W/m·K vs 46 W/m·K). On the shop floor, SPHC machines more easily (good vs fair) and SPHC welds better (excellent vs very good).

A656Choose it when strength drives the design.

SPHCChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.

A656 vs SPHC: properties

A656SPHC

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

200 GPa29 Msi
205 GPa29.7 Msi

Tensile Strength (Ultimate)

660 MPa95.7 ksi
310 MPa45 ksi

Yield Strength (0.2% offset)

580 MPa84.1 ksi
240 MPa34.8 ksi

Elongation at Break

16%
38%

Reduction in Area

50%
60%

Compressive Strength

580 MPa84.1 ksi
—

Shear Strength

420 MPa60.9 ksi
210 MPa30.5 ksi

Fatigue Strength (Endurance Limit)

290 MPa42.1 ksi
155 MPa22.5 ksi

Fracture Toughness (K_IC)

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

Charpy V-Notch Impact (RT)

80 J59 ft·lbf
45 J33.2 ft·lbf

Hardness, Brinell

215 HB
110 HB

Hardness, Rockwell B

96 HRB
64 HRB

Hardness, Rockwell C

18 HRC
—

Hardness, Vickers

225 HV
115 HV

Same in both: Shear Modulus 79 GPa11.5 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,425°C2,597 °F
1,495°C2,723 °F

Liquidus Temperature

1,510°C2,750 °F
1,530°C2,786 °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

46 W/m·K26.6 BTU/hr·ft·°F
52 W/m·K30 BTU/hr·ft·°F

Latent Heat of Fusion

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

Max Service Temperature (continuous)

350°C662 °F
400°C752 °F

Min Service Temperature

-40°C-40 °F
-20°C-4 °F

Same in both: Specific Heat Capacity 480 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12 µm/m·K6.7 µin/in·°F

Electrical

Conductivity and insulation.

Electrical Conductivity

9 % IACS
10.5 % IACS

Electrical Resistivity

1.9×10⁻⁷ Ω·m7.48 µΩ·in
1.65×10⁻⁷ Ω·m6.5 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

12 / 100
10 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -0.62 V

Manufacturability

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

Machinability

50 / 100
68 / 100

Machinability Rating (AISI 1212 = 100 %)

50%
68%

Weldability

75 / 100
95 / 100

Formability (cold)

65 / 100
80 / 100

Brazeability / Solderability

45 / 100
70 / 100

Polishability

45 / 100
40 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

25 MJ/kg10,748 BTU/lb
26 MJ/kg11,178 BTU/lb

Embodied Carbon (primary production)

2 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%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

84 kN·m/kg
39 kN·m/kg

Specific Stiffness (E / density)

25.5 MN·m/kg
26.1 MN·m/kg

Modulus of Resilience

841 kJ/m³
140 kJ/m³

Thermal Diffusivity

12.2 mm²/s
13.8 mm²/s

Thermal Shock Resistance Index

13
7

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 scaleA656SPHC

Manufacturing and finishing

CapabilityA656SPHC
CNC machiningYes—
Default conditionHRHR
Relative cost$ Budget$ Budget
Min. machined wall0.8 mm—
Best machined surfaceRa 1.6 µm—
AlCrNYes—
AlTiNYes—
CVD Al2O3Yes—
CVD TiCNYes—
CVD TiNYes—
CrNYes—
DLCYes—
HVOF CoatingYes—
MoS2Yes—
Multilayer CVDYes—
TiAlNYes—
TiB2Yes—
TiCNYes—
TiNYes—
WC/CYes—
ZrNYes—

Both are offered for Sheet metal. They share 22 finishes: Black Oxide, Cerakote, Chrome Plating, Copper Plating, E-Coating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Hot-Dip Galvanizing, Manganese Phosphate, Nickel Plating and 10 more.

A656 vs SPHC — frequently asked

Is A656 stronger than SPHC?

Yes. A656 has a typical yield strength of 580 MPa (84.1 ksi) against 240 MPa (34.8 ksi) for SPHC — about 142% more. Tensile strength is 660 MPa (95.7 ksi) vs 310 MPa (45 ksi).

Which is cheaper, A656 or SPHC?

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 is easier to machine, A656 or SPHC?

SPHC. Its machinability rates good (68/100) against fair (50/100) for A656; for welding the order is SPHC first (excellent, 95/100) then A656 (very good, 75/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in A656 and SPHC 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.