ACI-ASTM CA15M (J91151) Cast Stainless Steel
ACI-ASTM CA15M steel is a martensitic stainless steel formulated for casting. Cited properties are appropriate for the heat treated (HT) condition. CA15M is the designation in both the ACI and ASTM systems for this material. J91151 is the UNS number. Additionally, the common industry name is 12 Chromium.
It has a fairly high thermal conductivity among cast martensitic stainless steels. In addition, it has a moderately low base cost and a moderately high electrical conductivity.
The graph bars on the material properties cards below compare ACI-ASTM CA15M steel to: cast martensitic stainless steels (top), all iron alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Brinell Hardness
210
Elastic (Young's, Tensile) Modulus
200 GPa 28 x 106 psi
Elongation at Break
20 %
Fatigue Strength
330 MPa 48 x 103 psi
Poisson's Ratio
0.28
Reduction in Area
34 %
Shear Modulus
76 GPa 11 x 106 psi
Tensile Strength: Ultimate (UTS)
690 MPa 100 x 103 psi
Tensile Strength: Yield (Proof)
510 MPa 74 x 103 psi
Thermal Properties
Latent Heat of Fusion
270 J/g
Maximum Temperature: Corrosion
390 °C 730 °F
Maximum Temperature: Mechanical
760 °C 1400 °F
Melting Completion (Liquidus)
1450 °C 2640 °F
Melting Onset (Solidus)
1410 °C 2570 °F
Specific Heat Capacity
480 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
27 W/m-K 15 BTU/h-ft-°F
Thermal Expansion
10 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
3.0 % IACS
Electrical Conductivity: Equal Weight (Specific)
3.5 % IACS
Otherwise Unclassified Properties
Base Metal Price
7.5 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
2.1 kg CO2/kg material
Embodied Energy
29 MJ/kg 12 x 103 BTU/lb
Embodied Water
100 L/kg 12 gal/lb
Common Calculations
PREN (Pitting Resistance)
15
Resilience: Ultimate (Unit Rupture Work)
130 MJ/m3
Resilience: Unit (Modulus of Resilience)
670 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
25 points
Strength to Weight: Axial
25 points
Strength to Weight: Bending
22 points
Thermal Diffusivity
7.2 mm2/s
Thermal Shock Resistance
25 points
Alloy Composition
Among cast stainless steels, the composition of ACI-ASTM CA15M steel is notable for containing comparatively high amounts of chromium (Cr) and molybdenum (Mo). Chromium is the defining alloying element of stainless steel. Higher chromium content imparts additional corrosion resistance. Molybdenum is used to facilitate tempering. In addition, it offers modest bonuses to a wide range of material properties.
| Fe | 82.1 to 88.4 | |
| Cr | 11.5 to 14 | |
| Mo | 0.15 to 1.0 | |
| Mn | 0 to 1.0 | |
| Ni | 0 to 1.0 | |
| Si | 0 to 0.65 | |
| C | 0 to 0.15 | |
| P | 0 to 0.040 | |
| S | 0 to 0.040 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM A743: Standard Specification for Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion Resistant, for General Application
Machining of Stainless Steels and Super Alloys: Traditional and Nontraditional Techniques, Helmi A. Youssef, 2016
Corrosion of Stainless Steels, A. John Sedriks, 1996
ASM Specialty Handbook: Stainless Steels, J. R. Davis (editor), 1994
Advances in Stainless Steels, Baldev Raj et al. (editors), 2010