Steel 300M vs 4330
Steel · grade comparison
Steel 300M and 4330 are both steel grades, both aerospace steel. 300M is the stronger of the two: yield strength 760 MPa (110 ksi) against 600 MPa (87 ksi) for 4330, about 27% more; tensile strength follows at 1,100 MPa (160 ksi) vs 900 MPa (131 ksi). In exchange, 4330 is the more ductile: elongation 18% versus 12% for 300M, and 300M is harder (320 HB vs 262 HB). On the shop floor, 4330 machines more easily (52 vs 38 out of 100), 4330 welds better (fair vs poor), and 4330 sits in a lower cost tier (standard, $$) than 300M (specialty, $$$$$).
300MChoose it when strength drives the design.
4330Choose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
300M vs 4330: 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
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
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: Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Reduction in Area 45%
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
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
Min Service Temperature
Same in both: Max Service Temperature (continuous) 400°C752 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Same in both: Electrical Conductivity 8 % IACS
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V
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)
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 | 300M | 4330 |
|---|---|---|
| Default condition | HR | HR |
| Relative cost | $$$$$ Specialty | $$ 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.
300M vs 4330 — frequently asked
Is 300M stronger than 4330?
Yes. 300M has a typical yield strength of 760 MPa (110 ksi) against 600 MPa (87 ksi) for 4330 — about 27% more. Tensile strength is 1,100 MPa (160 ksi) vs 900 MPa (131 ksi).
Which is cheaper, 300M or 4330?
4330 is the lower-cost material: it sits in the standard tier ($$) while 300M is specialty ($$$$$). 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, 300M or 4330?
4330, by a small margin. Both rate fair for machinability — 52/100 against 38/100 for 300M; for welding the order is 4330 first (fair, 45/100) then 300M (poor, 25/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 300M and 4330 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.