ASTM Grade HT (15Cr-35Ni, N08605) Cast Stainless Steel
ASTM grade HT steel is an austenitic stainless steel formulated for casting. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. HT is the ASTM designation for this material. N08605 is the UNS number. And 15Cr-35Ni is the common industry name.
It has a moderately low thermal conductivity among cast austenitic stainless steels. In addition, it has a fairly low ductility and a moderately high base cost.
The graph bars on the material properties cards below compare ASTM grade HT steel to: cast austenitic 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
150
Elastic (Young's, Tensile) Modulus
190 GPa 28 x 106 psi
Elongation at Break
4.6 %
Fatigue Strength
130 MPa 18 x 103 psi
Poisson's Ratio
0.28
Shear Modulus
76 GPa 11 x 106 psi
Tensile Strength: Ultimate (UTS)
500 MPa 73 x 103 psi
Tensile Strength: Yield (Proof)
270 MPa 38 x 103 psi
Thermal Properties
Latent Heat of Fusion
310 J/g
Maximum Temperature: Corrosion
400 °C 750 °F
Maximum Temperature: Mechanical
1010 °C 1850 °F
Melting Completion (Liquidus)
1390 °C 2530 °F
Melting Onset (Solidus)
1340 °C 2440 °F
Specific Heat Capacity
480 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
12 W/m-K 7.0 BTU/h-ft-°F
Thermal Expansion
15 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
1.7 % IACS
Electrical Conductivity: Equal Weight (Specific)
1.9 % IACS
Otherwise Unclassified Properties
Base Metal Price
31 % relative
Density
8.0 g/cm3 500 lb/ft3
Embodied Carbon
5.4 kg CO2/kg material
Embodied Energy
76 MJ/kg 33 x 103 BTU/lb
Embodied Water
190 L/kg 22 gal/lb
Common Calculations
PREN (Pitting Resistance)
18
Resilience: Ultimate (Unit Rupture Work)
19 MJ/m3
Resilience: Unit (Modulus of Resilience)
180 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
18 points
Strength to Weight: Bending
18 points
Thermal Diffusivity
3.2 mm2/s
Thermal Shock Resistance
12 points
Alloy Composition
Among cast stainless steels, the composition of ASTM grade HT steel is notable for containing comparatively high amounts of nickel (Ni) and silicon (Si). Nickel is primarily used to achieve a specific microstructure. In addition, it has a beneficial effect on mechanical properties and certain types of corrosion. Silicon content is typically governed by metallurgical processing concerns, but it can also be added for the purpose of improving oxidation resistance.
| Fe | 38.2 to 51.7 | |
| Ni | 33 to 37 | |
| Cr | 15 to 19 | |
| Si | 0 to 2.5 | |
| Mn | 0 to 2.0 | |
| C | 0.35 to 0.75 | |
| Mo | 0 to 0.5 | |
| 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 A297: Standard Specification for Steel Castings, Iron-Chromium and Iron-Chromium-Nickel, Heat Resistant, for General Application
Corrosion of Austenitic Stainless Steels: Mechanism, Mitigation and Monitoring, H. S. Khatak and B. Raj (editors), 2002
Austenitic Stainless Steels: Microstructure and Mechanical Properties, P. Marshall, 1984
ASM Specialty Handbook: Stainless Steels, J. R. Davis (editor), 1994