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Steel Hardox 500 vs S690Q

Steel · grade comparison

Steel Hardox 500 and S690Q are both steel grades. Hardox 500 is the stronger of the two: yield strength 1,300 MPa (189 ksi) against 750 MPa (109 ksi) for S690Q, about 73% more; tensile strength follows at 1,600 MPa (232 ksi) vs 840 MPa (122 ksi). In exchange, S690Q is the more ductile: elongation 16% versus 8% for Hardox 500, and Hardox 500 is harder (500 HB vs 260 HB). S690Q runs hotter in service (400°C vs 250°C continuous) and S690Q conducts heat better (40 W/m·K vs 30 W/m·K). On the shop floor, S690Q machines more easily (fair vs poor), S690Q welds better (65 vs 55 out of 100), and S690Q sits in a lower cost tier (budget, $) than Hardox 500 (standard, $$).

Hardox 500Choose it when strength drives the design.

S690QChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.

Hardox 500 vs S690Q: properties

Hardox 500S690Q

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

80 GPa11.6 Msi
81 GPa11.7 Msi

Bulk Modulus

160 GPa23.2 Msi
165 GPa23.9 Msi

Tensile Strength (Ultimate)

1,600 MPa232 ksi
840 MPa122 ksi

Yield Strength (0.2% offset)

1,300 MPa189 ksi
750 MPa109 ksi

Elongation at Break

8%
16%

Compressive Strength

1,300 MPa189 ksi
750 MPa109 ksi

Shear Strength

960 MPa139 ksi
500 MPa72.5 ksi

Fatigue Strength (Endurance Limit)

650 MPa94.3 ksi
380 MPa55.1 ksi

Fracture Toughness (K_IC)

60 MPa·√m54.6 ksi·√in
130 MPa·√m118 ksi·√in

Charpy V-Notch Impact (RT)

40 J29.5 ft·lbf
110 J81.1 ft·lbf

Hardness, Brinell

500 HB
260 HB

Hardness, Rockwell C

50 HRC
25 HRC

Hardness, Vickers

530 HV
273 HV

Reduction in Area

—
55%

Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Poisson's Ratio 0.3

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,420°C2,588 °F
1,425°C2,597 °F

Same in both: Density 7.85 g/cm³0.28 lb/in³ · Liquidus Temperature 1,500°C2,732 °F

Thermal

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

Thermal Conductivity

30 W/m·K17.3 BTU/hr·ft·°F
40 W/m·K23.1 BTU/hr·ft·°F

Specific Heat Capacity

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

Max Service Temperature (continuous)

250°C482 °F
400°C752 °F

Min Service Temperature

-40°C-40 °F
-20°C-4 °F

Same in both: Thermal Expansion (CTE, 20–100 °C) 12 µm/m·K6.7 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb

Electrical

Conductivity and insulation.

Electrical Conductivity

6 % IACS
7.5 % IACS

Electrical Resistivity

3×10⁻⁷ Ω·m11.8 µΩ·in
2.3×10⁻⁷ Ω·m9.06 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.62 V
-0.61 V

Corrosion Resistance

12 / 100
14 / 100

Manufacturability

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

Machinability

22 / 100
38 / 100

Machinability Rating (AISI 1212 = 100 %)

18%
45%

Weldability

55 / 100
65 / 100

Formability (cold)

25 / 100
40 / 100

Polishability

60 / 100
50 / 100

Brazeability / Solderability

—
40 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

30 MJ/kg12,898 BTU/lb
29 MJ/kg12,468 BTU/lb

Embodied Carbon (primary production)

2.2 kg CO₂/kg
2.3 kg CO₂/kg

Embodied Water

40 L/kg4.8 gal/lb
60 L/kg7.2 gal/lb

Same in both: Typical Recycled Content 25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

204 kN·m/kg
107 kN·m/kg

Modulus of Resilience

4,024 kJ/m³
1,339 kJ/m³

Thermal Diffusivity

8.1 mm²/s
11.1 mm²/s

Thermal Shock Resistance Index

19
13

Same in both: Specific Stiffness (E / density) 26.8 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 scaleHardox 500S690Q

Manufacturing and finishing

CapabilityHardox 500S690Q
CNC machiningYes—
Sheet metalYes—
Default conditionQ&T—
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.

Hardox 500 vs S690Q — frequently asked

Is Hardox 500 stronger than S690Q?

Yes. Hardox 500 has a typical yield strength of 1,300 MPa (189 ksi) against 750 MPa (109 ksi) for S690Q — about 73% more. Tensile strength is 1,600 MPa (232 ksi) vs 840 MPa (122 ksi).

Which is cheaper, Hardox 500 or S690Q?

S690Q is the lower-cost material: it sits in the budget tier ($) while Hardox 500 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, Hardox 500 or S690Q?

S690Q. Its machinability rates fair (38/100) against poor (22/100) for Hardox 500; for welding the order is S690Q first (good, 65/100) then Hardox 500 (good, 55/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in Hardox 500 and S690Q 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.