FabDigit

Steel HPM38 vs P1 vs P2 vs P21

Benchmark · 4 materials

Side-by-side benchmark of 4 steel grades.

HPM38 vs P1 and 2 more: properties

HPM38P1P2P21

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

79 GPa11.5 Msi
80 GPa11.6 Msi
80 GPa11.6 Msi
80 GPa11.6 Msi

Bulk Modulus

160 GPa23.2 Msi
160 GPa23.2 Msi
160 GPa23.2 Msi
163 GPa23.6 Msi

Tensile Strength (Ultimate)

760 MPa110 ksi
380 MPa55.1 ksi
510 MPa74 ksi
1,300 MPa189 ksi

Yield Strength (0.2% offset)

520 MPa75.4 ksi
240 MPa34.8 ksi
330 MPa47.9 ksi
1,150 MPa167 ksi

Elongation at Break

18%
35%
27%
14%

Reduction in Area

45%
62%
58%
50%

Compressive Strength

560 MPa81.2 ksi
250 MPa36.3 ksi
340 MPa49.3 ksi
1,250 MPa181 ksi

Shear Strength

460 MPa66.7 ksi
260 MPa37.7 ksi
330 MPa47.9 ksi
790 MPa115 ksi

Fatigue Strength (Endurance Limit)

370 MPa53.7 ksi
180 MPa26.1 ksi
230 MPa33.4 ksi
570 MPa82.7 ksi

Fracture Toughness (K_IC)

70 MPa·√m63.7 ksi·√in
120 MPa·√m109 ksi·√in
100 MPa·√m91 ksi·√in
80 MPa·√m72.8 ksi·√in

Charpy V-Notch Impact (RT)

22 J16.2 ft·lbf
120 J88.5 ft·lbf
110 J81.1 ft·lbf
25 J18.4 ft·lbf

Hardness, Brinell

215 HB
120 HB
110 HB
375 HB

Hardness, Rockwell C

18 HRC
40 HRC

Hardness, Vickers

225 HV
125 HV
115 HV
400 HV

Hardness, Rockwell B

68 HRB
63 HRB

Same in both: Elastic (Young's) Modulus 205 GPa29.7 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
7.85 g/cm³0.28 lb/in³
7.83 g/cm³0.28 lb/in³

Melting Point (Solidus)

1,420°C2,588 °F
1,425°C2,597 °F
1,420°C2,588 °F
1,420°C2,588 °F

Liquidus Temperature

1,480°C2,696 °F
1,510°C2,750 °F
1,500°C2,732 °F
1,490°C2,714 °F

Thermal

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

Thermal Conductivity

20 W/m·K11.6 BTU/hr·ft·°F
50 W/m·K28.9 BTU/hr·ft·°F
40 W/m·K23.1 BTU/hr·ft·°F
33 W/m·K19.1 BTU/hr·ft·°F

Specific Heat Capacity

460 J/kg·K0.11 BTU/lb·°F
470 J/kg·K0.11 BTU/lb·°F
460 J/kg·K0.11 BTU/lb·°F
460 J/kg·K0.11 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

10.8 µm/m·K6 µin/in·°F
12 µm/m·K6.7 µin/in·°F
12.4 µm/m·K6.9 µin/in·°F
12.4 µm/m·K6.9 µin/in·°F

Latent Heat of Fusion

250 J/g107 BTU/lb
270 J/g116 BTU/lb
250 J/g107 BTU/lb
270 J/g116 BTU/lb

Max Service Temperature (continuous)

400°C752 °F
350°C662 °F
400°C752 °F
450°C842 °F

Min Service Temperature

-40°C-40 °F
-20°C-4 °F
-20°C-4 °F
-30°C-22 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

2.9 % IACS
11 % IACS
8.5 % IACS
4.9 % IACS

Electrical Resistivity

6×10⁻⁷ Ω·m23.6 µΩ·in
1.6×10⁻⁷ Ω·m6.3 µΩ·in
2×10⁻⁷ Ω·m7.87 µΩ·in
3.5×10⁻⁷ Ω·m13.8 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.35 V
-0.61 V
-0.61 V
-0.6 V

Corrosion Resistance

48 / 100
10 / 100
12 / 100
16 / 100

Manufacturability

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

Machinability

45 / 100
60 / 100
70 / 100
45 / 100

Machinability Rating (AISI 1212 = 100 %)

45%
65%
65%
45%

Weldability

25 / 100
85 / 100
60 / 100
55 / 100

Formability (cold)

25 / 100
90 / 100
70 / 100
15 / 100

Castability

20 / 100
40 / 100
35 / 100
35 / 100

Brazeability / Solderability

30 / 100
75 / 100
55 / 100
40 / 100

Polishability

85 / 100
55 / 100
75 / 100
90 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

52 MJ/kg22,356 BTU/lb
25 MJ/kg10,748 BTU/lb
34 MJ/kg14,617 BTU/lb
34 MJ/kg14,617 BTU/lb

Embodied Carbon (primary production)

3.6 kg CO₂/kg
1.9 kg CO₂/kg
2.4 kg CO₂/kg
2.4 kg CO₂/kg

Embodied Water

90 L/kg10.8 gal/lb
45 L/kg5.4 gal/lb
60 L/kg7.2 gal/lb
60 L/kg7.2 gal/lb

Typical Recycled Content

40%
30%
35%
30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

97 kN·m/kg
48 kN·m/kg
65 kN·m/kg
166 kN·m/kg

Specific Stiffness (E / density)

26.3 MN·m/kg
26.1 MN·m/kg
26.1 MN·m/kg
26.2 MN·m/kg

Modulus of Resilience

660 kJ/m³
140 kJ/m³
266 kJ/m³
3,226 kJ/m³

Thermal Diffusivity

5.6 mm²/s
13.6 mm²/s
11.1 mm²/s
9.2 mm²/s

Thermal Shock Resistance Index

7
8
8
17

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 scaleP1P2P21HPM38

Manufacturing and finishing

CapabilityHPM38P1P2P21
Default condition
Relative cost$$$ Premium$$ Standard$$$ Premium$$$ 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.

Ready to make it?

Upload a CAD file and FabDigit prices the part in HPM38 and P1 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.