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Steel 4620 vs S15CK

Steel · grade comparison

Steel 4620 and S15CK are both steel grades. 4620 is the stronger of the two: yield strength 360 MPa (52.2 ksi) against 255 MPa (37 ksi) for S15CK, about 41% more; tensile strength follows at 570 MPa (82.7 ksi) vs 420 MPa (60.9 ksi). In exchange, S15CK is the more ductile: elongation 32% versus 26% for 4620, and 4620 is harder (163 HB vs 121 HB). S15CK conducts electricity better (10.8 % IACS vs 8 % IACS). On the shop floor, S15CK welds better (excellent vs good) and S15CK sits in a lower cost tier (budget, $) than 4620 (standard, $$).

4620Choose it when strength drives the design.

S15CKChoose it when the part is bent, formed or impact-loaded, or when it will be welded.

4620 vs S15CK: properties

4620S15CK

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

570 MPa82.7 ksi
420 MPa60.9 ksi

Yield Strength (0.2% offset)

360 MPa52.2 ksi
255 MPa37 ksi

Elongation at Break

26%
32%

Reduction in Area

55%
60%

Shear Strength

380 MPa55.1 ksi
270 MPa39.2 ksi

Fatigue Strength (Endurance Limit)

260 MPa37.7 ksi
200 MPa29 ksi

Charpy V-Notch Impact (RT)

85 J62.7 ft·lbf
90 J66.4 ft·lbf

Hardness, Brinell

163 HB
121 HB

Hardness, Rockwell B

84 HRB
68 HRB

Compressive Strength

—
255 MPa37 ksi

Fracture Toughness (K_IC)

—
100 MPa·√m91 ksi·√in

Hardness, Vickers

—
127 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.

Density

7.85 g/cm³0.28 lb/in³
7.86 g/cm³0.28 lb/in³

Melting Point (Solidus)

1,420°C2,588 °F
1,495°C2,723 °F

Liquidus Temperature

1,500°C2,732 °F
1,520°C2,768 °F

Thermal

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

Thermal Conductivity

46 W/m·K26.6 BTU/hr·ft·°F
51 W/m·K29.5 BTU/hr·ft·°F

Specific Heat Capacity

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

Min Service Temperature

-50°C-58 °F
-20°C-4 °F

Same in both: Thermal Expansion (CTE, 20–100 °C) 11.9 µm/m·K6.6 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Max Service Temperature (continuous) 400°C752 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

8 % IACS
10.8 % IACS

Electrical Resistivity

2.2×10⁻⁷ Ω·m8.66 µΩ·in
1.6×10⁻⁷ Ω·m6.3 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.61 V
-0.62 V

Corrosion Resistance

12 / 100
10 / 100

Manufacturability

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

Machinability

57 / 100
50 / 100

Machinability Rating (AISI 1212 = 100 %)

65%
60%

Weldability

65 / 100
95 / 100

Formability (cold)

58 / 100
85 / 100

Brazeability / Solderability

70 / 100
85 / 100

Polishability

55 / 100
45 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

29 MJ/kg12,468 BTU/lb
25 MJ/kg10,748 BTU/lb

Embodied Carbon (primary production)

2.2 kg CO₂/kg
1.9 kg CO₂/kg

Embodied Water

55 L/kg6.6 gal/lb
40 L/kg4.8 gal/lb

Same in both: Typical Recycled Content 30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

73 kN·m/kg
53 kN·m/kg

Modulus of Resilience

316 kJ/m³
159 kJ/m³

Thermal Diffusivity

12.3 mm²/s
13.8 mm²/s

Thermal Shock Resistance Index

11
9

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 scale4620S15CK

Manufacturing and finishing

Capability4620S15CK
CNC machiningYes—
Sheet metalYes—
Default conditionHR—
Relative cost$$ Standard$ 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.

4620 vs S15CK — frequently asked

Is 4620 stronger than S15CK?

Yes. 4620 has a typical yield strength of 360 MPa (52.2 ksi) against 255 MPa (37 ksi) for S15CK — about 41% more. Tensile strength is 570 MPa (82.7 ksi) vs 420 MPa (60.9 ksi).

Which is cheaper, 4620 or S15CK?

S15CK is the lower-cost material: it sits in the budget tier ($) while 4620 is standard ($$). 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, 4620 or S15CK?

4620. Its machinability rates good (57/100) against fair (50/100) for S15CK; for welding the order is S15CK first (excellent, 95/100) then 4620 (good, 65/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 4620 and S15CK 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.