Steel Hardox 600 vs S690Q
Steel · grade comparison
Steel Hardox 600 and S690Q are both steel grades. Hardox 600 is the stronger of the two: yield strength 1,650 MPa (239 ksi) against 750 MPa (109 ksi) for S690Q, about 120% more; tensile strength follows at 2,000 MPa (290 ksi) vs 840 MPa (122 ksi). In exchange, S690Q is the more ductile: elongation 16% versus 7% for Hardox 600, and Hardox 600 is harder (600 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 not recommended), S690Q welds better (good vs poor), and S690Q sits in a lower cost tier (budget, $) than Hardox 600 (standard, $$).
Hardox 600Choose it when strength drives the design.
S690QChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
Hardox 600 vs S690Q: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Bulk Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Shear Modulus 81 GPa11.7 Msi · Poisson's Ratio 0.3
Physical
Density and transition temperatures.
Melting Point (Solidus)
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
Specific Heat Capacity
Max Service Temperature (continuous)
Min Service Temperature
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 Resistivity
Electrical Conductivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Polishability
Brazeability / Solderability
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Water
Same in both: Embodied Carbon (primary production) 2.3 kg CO₂/kg · Typical Recycled Content 25%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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.
Manufacturing and finishing
| Capability | Hardox 600 | S690Q |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$ Standard | $ 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.
Hardox 600 vs S690Q — frequently asked
Is Hardox 600 stronger than S690Q?
Yes. Hardox 600 has a typical yield strength of 1,650 MPa (239 ksi) against 750 MPa (109 ksi) for S690Q — about 120% more. Tensile strength is 2,000 MPa (290 ksi) vs 840 MPa (122 ksi).
Which is cheaper, Hardox 600 or S690Q?
S690Q is the lower-cost material: it sits in the budget tier ($) while Hardox 600 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 600 or S690Q?
S690Q. Its machinability rates fair (38/100) against not recommended (8/100) for Hardox 600; for welding the order is S690Q first (good, 65/100) then Hardox 600 (poor, 30/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in Hardox 600 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.