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Stainless Steel 15-5 PH vs AM-355

Stainless Steel · grade comparison

Stainless Steel 15-5 PH and AM-355 are both stainless steel grades. AM-355 is the stronger of the two: yield strength 1,070 MPa (155 ksi) against 795 MPa (115 ksi) for 15-5 PH, about 35% more; tensile strength follows at 1,275 MPa (185 ksi) vs 1,030 MPa (149 ksi). AM-355 is the more ductile: elongation 17% versus 14% for 15-5 PH, and AM-355 is harder (375 HB vs 311 HB). AM-355 runs hotter in service (425°C vs 300°C continuous). On the shop floor, 15-5 PH machines more easily (fair vs poor), 15-5 PH welds better (very good vs fair), and AM-355 sits in a lower cost tier (high, $$$$) than 15-5 PH (specialty, $$$$$).

15-5 PHChoose it when the part is machined in volume, or when it will be welded.

AM-355Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.

15-5 PH vs AM-355: properties

15-5 PHAM-355

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

196 GPa28.4 Msi
200 GPa29 Msi

Bulk Modulus

148 GPa21.5 Msi
160 GPa23.2 Msi

Poisson's Ratio

0.27
0.29

Tensile Strength (Ultimate)

1,030 MPa149 ksi
1,275 MPa185 ksi

Yield Strength (0.2% offset)

795 MPa115 ksi
1,070 MPa155 ksi

Elongation at Break

14%
17%

Reduction in Area

55%
50%

Compressive Strength

810 MPa117 ksi
1,100 MPa160 ksi

Shear Strength

640 MPa92.8 ksi
790 MPa115 ksi

Fatigue Strength (Endurance Limit)

480 MPa69.6 ksi
620 MPa89.9 ksi

Fracture Toughness (K_IC)

110 MPa·√m100 ksi·√in
55 MPa·√m50.1 ksi·√in

Charpy V-Notch Impact (RT)

30 J22.1 ft·lbf
22 J16.2 ft·lbf

Hardness, Brinell

311 HB
375 HB

Hardness, Rockwell C

33 HRC
40 HRC

Hardness, Vickers

330 HV
395 HV

Same in both: Shear Modulus 77 GPa11.2 Msi

Physical

Density and transition temperatures.

Density

7.8 g/cm³0.28 lb/in³
7.91 g/cm³0.29 lb/in³

Liquidus Temperature

1,440°C2,624 °F
1,450°C2,642 °F

Same in both: Melting Point (Solidus) 1,400°C2,552 °F

Thermal

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

Thermal Conductivity

17.9 W/m·K10.3 BTU/hr·ft·°F
16.3 W/m·K9.4 BTU/hr·ft·°F

Specific Heat Capacity

420 J/kg·K0.1 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
11.6 µm/m·K6.4 µin/in·°F

Max Service Temperature (continuous)

300°C572 °F
425°C797 °F

Min Service Temperature

-73°C-99 °F
-196°C-321 °F

Same in both: Latent Heat of Fusion 270 J/g116 BTU/lb

Electrical

Conductivity and insulation.

Same in both: Electrical Conductivity 2.2 % IACS · Electrical Resistivity 8×10⁻⁷ Ω·m31.5 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.28 V
-0.15 V

Corrosion Resistance

57 / 100
55 / 100

Manufacturability

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

Machinability

42 / 100
22 / 100

Machinability Rating (AISI 1212 = 100 %)

45%
20%

Weldability

70 / 100
35 / 100

Formability (cold)

45 / 100
10 / 100

Castability

55 / 100
25 / 100

Brazeability / Solderability

45 / 100
40 / 100

Polishability

80 / 100
70 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

55 MJ/kg23,646 BTU/lb
57 MJ/kg24,506 BTU/lb

Embodied Carbon (primary production)

5.5 kg CO₂/kg
4.6 kg CO₂/kg

Embodied Water

190 L/kg22.8 gal/lb
150 L/kg18 gal/lb

Typical Recycled Content

35%
40%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

132 kN·m/kg
161 kN·m/kg

Specific Stiffness (E / density)

25.1 MN·m/kg
25.3 MN·m/kg

Modulus of Resilience

1,612 kJ/m³
2,862 kJ/m³

Thermal Diffusivity

5.5 mm²/s
4.5 mm²/s

Same in both: Thermal Shock Resistance Index 9

Strength versus weight

Yield strength against density for every stainless steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

3005007001,0001,5002,0007.27.47.67.888.2Density (g/cm³)Yield strength (MPa) — log scale15-5 PHAM-355

Manufacturing and finishing

Capability15-5 PHAM-355
CNC machiningYes—
Sheet metalYes—
3D printingYes—
Default conditionCondition A—
Relative cost$$$$$ Specialty$$$$ High
Min. machined wall0.8 mm—
Best machined surfaceRa 1.6 µm—
AlCrNYes—
AlTiNYes—
Black OxideYes—
CVD Al2O3Yes—
CVD TiCNYes—
CVD TiNYes—
CerakoteYes—
Chrome PlatingYes—
CrNYes—
DLCYes—
Electropolished (Metal AM)Yes—
ElectropolishingYes—
HVOF CoatingYes—
MoS2Yes—
Multilayer CVDYes—
Nickel PlatingYes—
PTFE CoatingYes—
PaintingYes—

They share 7 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Pickling, Plasma Spray, Silver Plating.

15-5 PH vs AM-355 — frequently asked

Is AM-355 stronger than 15-5 PH?

Yes. AM-355 has a typical yield strength of 1,070 MPa (155 ksi) against 795 MPa (115 ksi) for 15-5 PH — about 35% more. Tensile strength is 1,275 MPa (185 ksi) vs 1,030 MPa (149 ksi).

Which is cheaper, 15-5 PH or AM-355?

AM-355 is the lower-cost material: it sits in the high tier ($$$$) while 15-5 PH is specialty ($$$$$). 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, 15-5 PH or AM-355?

15-5 PH. Its machinability rates fair (42/100) against poor (22/100) for AM-355; for welding the order is 15-5 PH first (very good, 70/100) then AM-355 (fair, 35/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 15-5 PH and AM-355 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.