Steel 38MnVS6 vs SACM645
Steel · grade comparison
Steel 38MnVS6 and SACM645 are both steel grades, both specialty steel. SACM645 is the stronger of the two: yield strength 780 MPa (113 ksi) against 600 MPa (87 ksi) for 38MnVS6, about 30% more; tensile strength follows at 950 MPa (138 ksi) vs 900 MPa (131 ksi). SACM645 is the more ductile: elongation 17% versus 14% for 38MnVS6. SACM645 runs hotter in service (450°C vs 350°C continuous) and 38MnVS6 conducts heat better (44 W/m·K vs 36 W/m·K). On the shop floor, 38MnVS6 machines more easily (good vs fair) and 38MnVS6 welds better (30 vs 18 out of 100).
38MnVS6Choose it when the part is machined in volume, or when it will be welded.
SACM645Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.
38MnVS6 vs SACM645: 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
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, Rockwell C
Same in both: Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Hardness, Brinell 270 HB · Hardness, Vickers 285 HV
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Same in both: Liquidus Temperature 1,490°C2,714 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Latent Heat of Fusion 250 J/g107 BTU/lb
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Galvanic Potential (seawater, vs SCE)
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Polishability
Brazeability / Solderability
Same in both: Formability (cold) 25 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
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 | 38MnVS6 | SACM645 |
|---|---|---|
| Default condition | As Forged | Q&T |
| Relative cost | $$ Standard | $$ 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.
38MnVS6 vs SACM645 — frequently asked
Is SACM645 stronger than 38MnVS6?
Yes. SACM645 has a typical yield strength of 780 MPa (113 ksi) against 600 MPa (87 ksi) for 38MnVS6 — about 30% more. Tensile strength is 950 MPa (138 ksi) vs 900 MPa (131 ksi).
Which is cheaper, 38MnVS6 or SACM645?
Both sit in the same relative cost tier ($$, standard); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, 38MnVS6 or SACM645?
38MnVS6. Its machinability rates good (58/100) against fair (42/100) for SACM645; for welding the order is 38MnVS6 first (poor, 30/100) then SACM645 (poor, 18/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 38MnVS6 and SACM645 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.