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Steel A242 vs S550MC

Steel · grade comparison

Steel A242 and S550MC are both steel grades. S550MC is the stronger of the two: yield strength 595 MPa (86.3 ksi) against 370 MPa (53.7 ksi) for A242, about 61% more; tensile strength follows at 680 MPa (98.6 ksi) vs 510 MPa (74 ksi). In exchange, A242 is the more ductile: elongation 24% versus 16% for S550MC, and S550MC is harder (200 HB vs 155 HB). On the shop floor, A242 machines more easily (good vs fair).

A242Choose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.

S550MCChoose it when strength drives the design.

A242 vs S550MC: properties

A242S550MC

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

200 GPa29 Msi
210 GPa30.5 Msi

Shear Modulus

79 GPa11.5 Msi
81 GPa11.7 Msi

Tensile Strength (Ultimate)

510 MPa74 ksi
680 MPa98.6 ksi

Yield Strength (0.2% offset)

370 MPa53.7 ksi
595 MPa86.3 ksi

Elongation at Break

24%
16%

Reduction in Area

50%
55%

Compressive Strength

370 MPa53.7 ksi
595 MPa86.3 ksi

Shear Strength

320 MPa46.4 ksi
420 MPa60.9 ksi

Fatigue Strength (Endurance Limit)

245 MPa35.5 ksi
320 MPa46.4 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
60 J44.3 ft·lbf

Hardness, Brinell

155 HB
200 HB

Hardness, Rockwell B

82 HRB
95 HRB

Hardness, Vickers

163 HV
210 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
1,500°C2,732 °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
45 W/m·K26 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

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

Latent Heat of Fusion

247 J/g106 BTU/lb
250 J/g107 BTU/lb

Min Service Temperature

-30°C-22 °F
-40°C-40 °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
9 % IACS

Electrical Resistivity

2×10⁻⁷ Ω·m7.87 µΩ·in
1.9×10⁻⁷ Ω·m7.48 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
12 / 100

Manufacturability

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

Machinability

58 / 100
45 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
55%

Formability (cold)

65 / 100
62 / 100

Brazeability / Solderability

40 / 100
50 / 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

Typical Recycled Content

30%
25%

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)

65 kN·m/kg
87 kN·m/kg

Specific Stiffness (E / density)

25.5 MN·m/kg
26.8 MN·m/kg

Modulus of Resilience

342 kJ/m³
843 kJ/m³

Thermal Diffusivity

13 mm²/s
12.2 mm²/s

Thermal Shock Resistance Index

10
12

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 scaleA242S550MC

Manufacturing and finishing

CapabilityA242S550MC
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 S550MC — frequently asked

Is S550MC stronger than A242?

Yes. S550MC has a typical yield strength of 595 MPa (86.3 ksi) against 370 MPa (53.7 ksi) for A242 — about 61% more. Tensile strength is 680 MPa (98.6 ksi) vs 510 MPa (74 ksi).

Which is cheaper, A242 or S550MC?

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, A242 or S550MC?

A242. Its machinability rates good (58/100) against fair (45/100) for S550MC.

Ready to make it?

Upload a CAD file and FabDigit prices the part in A242 and S550MC 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.