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Steel HPM38 vs P2

Steel · grade comparison

Steel HPM38 and P2 are both steel grades. HPM38 is the stronger of the two: yield strength 520 MPa (75.4 ksi) against 330 MPa (47.9 ksi) for P2, about 58% more; tensile strength follows at 760 MPa (110 ksi) vs 510 MPa (74 ksi). In exchange, P2 is the more ductile: elongation 27% versus 18% for HPM38, and HPM38 is harder (215 HB vs 110 HB). P2 conducts heat better (40 W/m·K vs 20 W/m·K). On the shop floor, P2 machines more easily (very good vs fair) and P2 welds better (good vs poor).

HPM38Choose it when strength drives the design.

P2Choose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.

HPM38 vs P2: properties

HPM38P2

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

79 GPa11.5 Msi
80 GPa11.6 Msi

Tensile Strength (Ultimate)

760 MPa110 ksi
510 MPa74 ksi

Yield Strength (0.2% offset)

520 MPa75.4 ksi
330 MPa47.9 ksi

Elongation at Break

18%
27%

Reduction in Area

45%
58%

Compressive Strength

560 MPa81.2 ksi
340 MPa49.3 ksi

Shear Strength

460 MPa66.7 ksi
330 MPa47.9 ksi

Fatigue Strength (Endurance Limit)

370 MPa53.7 ksi
230 MPa33.4 ksi

Fracture Toughness (K_IC)

70 MPa·√m63.7 ksi·√in
100 MPa·√m91 ksi·√in

Charpy V-Notch Impact (RT)

22 J16.2 ft·lbf
110 J81.1 ft·lbf

Hardness, Brinell

215 HB
110 HB

Hardness, Rockwell C

18 HRC
—

Hardness, Vickers

225 HV
115 HV

Hardness, Rockwell B

—
63 HRB

Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29

Physical

Density and transition temperatures.

Density

7.8 g/cm³0.28 lb/in³
7.85 g/cm³0.28 lb/in³

Liquidus Temperature

1,480°C2,696 °F
1,500°C2,732 °F

Same in both: Melting Point (Solidus) 1,420°C2,588 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

20 W/m·K11.6 BTU/hr·ft·°F
40 W/m·K23.1 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

10.8 µm/m·K6 µin/in·°F
12.4 µm/m·K6.9 µin/in·°F

Min Service Temperature

-40°C-40 °F
-20°C-4 °F

Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Max Service Temperature (continuous) 400°C752 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

2.9 % IACS
8.5 % IACS

Electrical Resistivity

6×10⁻⁷ Ω·m23.6 µΩ·in
2×10⁻⁷ Ω·m7.87 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.35 V
-0.61 V

Corrosion Resistance

48 / 100
12 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

45 / 100
70 / 100

Machinability Rating (AISI 1212 = 100 %)

45%
65%

Weldability

25 / 100
60 / 100

Formability (cold)

25 / 100
70 / 100

Castability

20 / 100
35 / 100

Brazeability / Solderability

30 / 100
55 / 100

Polishability

85 / 100
75 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

52 MJ/kg22,356 BTU/lb
34 MJ/kg14,617 BTU/lb

Embodied Carbon (primary production)

3.6 kg CO₂/kg
2.4 kg CO₂/kg

Embodied Water

90 L/kg10.8 gal/lb
60 L/kg7.2 gal/lb

Typical Recycled Content

40%
35%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

97 kN·m/kg
65 kN·m/kg

Specific Stiffness (E / density)

26.3 MN·m/kg
26.1 MN·m/kg

Modulus of Resilience

660 kJ/m³
266 kJ/m³

Thermal Diffusivity

5.6 mm²/s
11.1 mm²/s

Thermal Shock Resistance Index

7
8

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.

2005001,0002,0007.588.5Density (g/cm³)Yield strength (MPa) — log scaleP2HPM38

Manufacturing and finishing

CapabilityHPM38P2
Default condition——
Relative cost$$$ Premium$$$ Premium
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.

HPM38 vs P2 — frequently asked

Is HPM38 stronger than P2?

Yes. HPM38 has a typical yield strength of 520 MPa (75.4 ksi) against 330 MPa (47.9 ksi) for P2 — about 58% more. Tensile strength is 760 MPa (110 ksi) vs 510 MPa (74 ksi).

Which is cheaper, HPM38 or P2?

Both sit in the same relative cost tier ($$$, premium); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which is easier to machine, HPM38 or P2?

P2. Its machinability rates very good (70/100) against fair (45/100) for HPM38; for welding the order is P2 first (good, 60/100) then HPM38 (poor, 25/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in HPM38 and P2 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.