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Steel 5160 vs 8642

Steel · grade comparison

Steel 5160 and 8642 are both steel grades. 8642 is the stronger of the two: yield strength 1,020 MPa (148 ksi) against 275 MPa (39.9 ksi) for 5160, about 3.7 times as much; tensile strength follows at 1,130 MPa (164 ksi) vs 725 MPa (105 ksi). In exchange, 5160 is the more ductile: elongation 17% versus 15% for 8642, and 8642 is harder (320 HB vs 197 HB). 8642 runs hotter in service (400°C vs 250°C continuous). On the shop floor, 8642 welds better (fair vs poor) and 8642 sits in a lower cost tier (budget, $) than 5160 (premium, $$$).

5160Choose it when the part is bent, formed or impact-loaded.

8642Choose it when strength drives the design, or when the part sees heat.

5160 vs 8642: properties

51608642

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

725 MPa105 ksi
1,130 MPa164 ksi

Yield Strength (0.2% offset)

275 MPa39.9 ksi
1,020 MPa148 ksi

Elongation at Break

17%
15%

Reduction in Area

31%
52%

Shear Strength

450 MPa65.3 ksi
680 MPa98.6 ksi

Fatigue Strength (Endurance Limit)

330 MPa47.9 ksi
500 MPa72.5 ksi

Charpy V-Notch Impact (RT)

25 J18.4 ft·lbf
40 J29.5 ft·lbf

Hardness, Brinell

197 HB
320 HB

Hardness, Rockwell B

92 HRB
—

Compressive Strength

—
1,030 MPa149 ksi

Fracture Toughness (K_IC)

—
80 MPa·√m72.8 ksi·√in

Hardness, Rockwell C

—
34 HRC

Hardness, Vickers

—
335 HV

Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 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
1,420°C2,588 °F

Same in both: Density 7.85 g/cm³0.28 lb/in³ · Liquidus Temperature 1,490°C2,714 °F

Thermal

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

Thermal Conductivity

46 W/m·K26.6 BTU/hr·ft·°F
44 W/m·K25.4 BTU/hr·ft·°F

Specific Heat Capacity

490 J/kg·K0.12 BTU/lb·°F
475 J/kg·K0.11 BTU/lb·°F

Max Service Temperature (continuous)

250°C482 °F
400°C752 °F

Same in both: Thermal Expansion (CTE, 20–100 °C) 12.3 µm/m·K6.8 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -40°C-40 °F

Electrical

Conductivity and insulation.

Same in both: Electrical Conductivity 7.8 % IACS · Electrical Resistivity 2.2×10⁻⁷ Ω·m8.66 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

10 / 100
12 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V

Manufacturability

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

Machinability

55 / 100
50 / 100

Machinability Rating (AISI 1212 = 100 %)

56%
55%

Weldability

25 / 100
35 / 100

Formability (cold)

45 / 100
25 / 100

Castability

40 / 100
—

Brazeability / Solderability

55 / 100
50 / 100

Polishability

70 / 100
65 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

30 MJ/kg12,898 BTU/lb
34 MJ/kg14,617 BTU/lb

Embodied Carbon (primary production)

2.2 kg CO₂/kg
2.4 kg CO₂/kg

Typical Recycled Content

35%
30%

Same in both: Embodied Water 60 L/kg7.2 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

92 kN·m/kg
144 kN·m/kg

Modulus of Resilience

184 kJ/m³
2,538 kJ/m³

Thermal Diffusivity

12 mm²/s
11.8 mm²/s

Thermal Shock Resistance Index

13
20

Same in both: Specific Stiffness (E / density) 26.1 MN·m/kg

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 scale51608642

Manufacturing and finishing

Capability51608642
CNC machiningYes—
Sheet metalYes—
Default conditionAnnealed—
Relative cost$$$ Premium$ Budget
Min. machined wall0.8 mm—
Best machined surfaceRa 1.6 µm—
AlCrNYes—
AlTiNYes—
Black OxideYes—
CVD Al2O3Yes—
CVD TiCNYes—
CVD TiNYes—
CerakoteYes—
Chrome PlatingYes—
CrNYes—
DLCYes—
E-CoatingYes—
HVOF CoatingYes—
Hot-Dip GalvanizingYes—
MoS2Yes—
Multilayer CVDYes—
Nickel PlatingYes—
PTFE CoatingYes—
PaintingYes—

They share 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

5160 vs 8642 — frequently asked

Is 8642 stronger than 5160?

Yes. 8642 has a typical yield strength of 1,020 MPa (148 ksi) against 275 MPa (39.9 ksi) for 5160 — about 3.7 times as much. Tensile strength is 1,130 MPa (164 ksi) vs 725 MPa (105 ksi).

Which is cheaper, 5160 or 8642?

8642 is the lower-cost material: it sits in the budget tier ($) while 5160 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 is easier to machine, 5160 or 8642?

5160. Its machinability rates good (55/100) against fair (50/100) for 8642; for welding the order is 8642 first (fair, 35/100) then 5160 (poor, 25/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 5160 and 8642 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.