Steel 4150 vs S690QL
Steel · grade comparison
Steel 4150 and S690QL are both steel grades, both high strength steel. S690QL is the stronger of the two: yield strength 760 MPa (110 ksi) against 520 MPa (75.4 ksi) for 4150, about 46% more. S690QL is harder — 265 HB against 235 HB for 4150 — which matters for wear surfaces and threads. 4150 runs hotter in service (400°C vs 350°C continuous) and 4150 conducts heat better (42.6 W/m·K vs 35 W/m·K). On the shop floor, S690QL welds better (good vs poor), S690QL forms better (fair vs poor), and S690QL sits in a lower cost tier (standard, $$) than 4150 (premium, $$$).
4150Choose it when the part sees heat.
S690QLChoose it when strength drives the design, or when surface hardness matters.
4150 vs S690QL: 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.
Elastic (Young's) Modulus
Shear Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Reduction in Area
Shear Strength
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Compressive Strength
Fracture Toughness (K_IC)
Same in both: Bulk Modulus 160 GPa23.2 Msi · Elongation at Break 16% · Fatigue Strength (Endurance Limit) 390 MPa56.6 ksi
Physical
Density and transition temperatures.
Melting Point (Solidus)
Liquidus Temperature
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
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Max Service Temperature (continuous)
Same in both: Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
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)
Castability
Brazeability / Solderability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Same in both: Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 30%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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 | 4150 | S690QL |
|---|---|---|
| Default condition | HR | Q&T |
| Relative cost | $$$ Premium | $$ Standard |
| Min. machined wall | 0.8 mm | 0.8 mm |
| Best machined surface | Ra 1.6 µm | Ra 1.6 µm |
Both are offered for CNC machining and Sheet metal. Both take the same 38 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, Copper Plating, CrN, DLC, E-Coating and 26 more.
4150 vs S690QL — frequently asked
Is S690QL stronger than 4150?
Yes. S690QL has a typical yield strength of 760 MPa (110 ksi) against 520 MPa (75.4 ksi) for 4150 — about 46% more. Tensile strength is 830 MPa (120 ksi) vs 860 MPa (125 ksi).
Which is cheaper, 4150 or S690QL?
S690QL is the lower-cost material: it sits in the standard tier ($$) while 4150 is premium ($$$). 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, 4150 or S690QL?
4150, by a small margin. Both rate fair for machinability — 45/100 against 40/100 for S690QL; for welding the order is S690QL first (good, 65/100) then 4150 (poor, 25/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 4150 and S690QL 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.