317LMN Stainless Steel (UNS S31726) – Composition, Properties and Uses
If you’re looking for a metal that can handle extreme temperatures and caustic chemicals, consider 317LMN stainless steel. This type of stainless steel is extremely resistant to corrosion and oxidation, so it’s often used in applications where the metal might be exposed to harsh conditions. This blog post will discuss the composition, physical properties, mechanical properties, and uses of 317LMN stainless steel.
317LMN Stainless Steel Composition
UNS S31726 is an austenitic alloy composed of iron (Fe), chromium (Cr), nickel (Ni), molybdenum (Mo) and nitrogen (N). The chemical composition of this alloy is typically expressed as follows: Fe 25.5-28%, Cr 18-20%, Ni 10-14%, Mo 3-4% and N 0.13-0.38%. The higher levels of chromium, molybdenum and nitrogen make this alloy so resistant to corrosion and oxidation.
| Element | Content (%) |
|---|---|
| Iron, Fe | Balance |
| Chromium, Cr | 17 – 20 |
| Nickel, Ni | 13.5 – 17.5 |
| Molybdenum, Mo | 4-5 |
| Manganese, Mn | 2 |
| Silicon, Si | 0.75 |
| Nitrogen, N | 0.10 – 0.20 |
| Phosphorus, P | 0.045 |
| Sulfur, S | 0.03 |
| Carbon, C | 0.03 |
317LMN Stainless Steel Physical Properties
| Density LBM/in^3 |
Coefficient of Thermal Expansion (min/in)-°F |
Thermal Conductivity BTU/ft^2-hr-°F-in | Specific Heat BTU/lbm -°F | Modules of Elasticity (annealed)^2-psi | |
|---|---|---|---|---|---|
| at 68 °F | at 77 – 212°F | at 77 – 1832°F | 68-212°F | at 32 – 212°F | in tension (E) |
| 0.29 | 9.2 | 10.8 | 100.8 | 0.11 | 28 x 10^6 |
317LMN Stainless Steel Mechanical Properties
The tensile strength of 317LMN ss ranges from 70 to 95 ksi. It has a yield strength ranging from 40 to 60 ksi and an elongation range from 15-45%. Its hardness ranges between 150 to 200 HBW on the Rockwell scale. This type of stainless steel also has good fatigue strength with an endurance limit ranging between 11 – 12 ksi.
| Properties | Metric | Imperial |
|---|---|---|
| Ultimate tensile strength | 614 MPa | 89 ksi |
| Yield strength | 317 MPa | 46 ksi |
| Elongation at break | 53% | 53% |
| Reduction in area | 69% | 69% |
| Hardness, Rockwell | 80 | 80 |
317LMN Stainless Steel Equivalent
- X2CrNiMoN17-13-5 (1.4439)
- S31726
- Z3CND18-14-05Az
317LMN Stainless Steel Uses
Because it’s highly resistant to corrosion and oxidation, this type of stainless steel can be used in applications where exposure to extreme temperatures or caustic chemicals is common such as chemical processing plants, paper mills or refineries. It’s also commonly used in power plant scrubber systems since it can withstand high temperatures without succumbing to corrosion or oxidation over time. It’s also used in oil production equipment since it can withstand high pressure without deforming or losing any properties due to its high tensile strength rating.
Conclusion
317LMN stainless steel offers superior resistance against corrosion and oxidation, making it ideal for use in extreme temperatures or applications with caustic chemicals. Its composition includes iron, chromium, nickel, molybdenum and nitrogen, which give it excellent mechanical properties, including a modulus of elasticity of 30 x 106 psi at 68˚F(20˚C) as well as good fatigue strength with an endurance limit ranging between 11 – 12 ksi. Common uses include chemical processing plants, paper mills, refineries, power plant scrubber systems, oil production equipment, etc. All these factors make 317LMN a great choice when your application calls for strong resistance against environmental elements such as high temperatures or corrosive materials.
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