Steel Q355D vs SPHC
Steel · grade comparison
Steel Q355D and SPHC are both steel grades, both structural steel. Q355D is the stronger of the two: yield strength 380 MPa (55.1 ksi) against 240 MPa (34.8 ksi) for SPHC, about 58% more; tensile strength follows at 530 MPa (76.9 ksi) vs 310 MPa (45 ksi). In exchange, SPHC is the more ductile: elongation 38% versus 25% for Q355D, and Q355D is harder (155 HB vs 110 HB). SPHC conducts heat better (52 W/m·K vs 46 W/m·K). On the shop floor, SPHC machines more easily (68 vs 55 out of 100).
Q355DChoose it when strength drives the design.
SPHCChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
Q355D vs SPHC: 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)
Elongation at Break
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Bulk Modulus 160 GPa23.2 Msi · Fracture Toughness (K_IC) 120 MPa·√m109 ksi·√in
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
Latent Heat of Fusion
Same in both: Thermal Expansion (CTE, 20–100 °C) 12 µm/m·K6.7 µin/in·°F · Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.62 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Brazeability / Solderability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 25%
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 | Q355D | SPHC |
|---|---|---|
| CNC machining | Yes | — |
| Default condition | HR | HR |
| Relative cost | $ Budget | $ Budget |
| Min. machined wall | 0.8 mm | — |
| Best machined surface | Ra 1.6 µm | — |
| AlCrN | Yes | — |
| AlTiN | Yes | — |
| CVD Al2O3 | Yes | — |
| CVD TiCN | Yes | — |
| CVD TiN | Yes | — |
| CrN | Yes | — |
| DLC | Yes | — |
| HVOF Coating | Yes | — |
| MoS2 | Yes | — |
| Multilayer CVD | Yes | — |
| TiAlN | Yes | — |
| TiB2 | Yes | — |
| TiCN | Yes | — |
| TiN | Yes | — |
| WC/C | Yes | — |
| ZrN | Yes | — |
Both are offered for Sheet metal. They share 22 finishes: Black Oxide, Cerakote, Chrome Plating, Copper Plating, E-Coating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Hot-Dip Galvanizing, Manganese Phosphate, Nickel Plating and 10 more.
Q355D vs SPHC — frequently asked
Is Q355D stronger than SPHC?
Yes. Q355D has a typical yield strength of 380 MPa (55.1 ksi) against 240 MPa (34.8 ksi) for SPHC — about 58% more. Tensile strength is 530 MPa (76.9 ksi) vs 310 MPa (45 ksi).
Which is cheaper, Q355D or SPHC?
Both sit in the same relative cost tier ($, budget); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, Q355D or SPHC?
SPHC, by a small margin. Both rate good for machinability — 68/100 against 55/100 for Q355D; for welding the order is SPHC first (excellent, 95/100) then Q355D (excellent, 88/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in Q355D and SPHC 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.