UNS N08367 (NAS 254NM) is a highly corrosion-resistant stainless steel containing high chromium and high molybdenum. Even in the harsh environment of high temperature, sea water or flue gas desulfurization, it still maintains good corrosion resistance. In some environments, it can be comparable to Hastelloy and titanium plates, and is a highly economical stainless steel with high corrosion resistance. The following briefly introduces the relevant performance of UNS N08367.
1. The chemical composition:
Table 1 Chemical composition (ASTM B688-96)
| Element | C | Si | Mn | P | S | Ni | Cr | M0 | Cu | N |
|---|---|---|---|---|---|---|---|---|---|---|
| Specifications | ≤0.030 | ≤1.00 | ≤2.00 | ≤0.040 | ≤0.030 | 23.5~25.5 | 20.00~22.00 | 6.00~7.00 | ≤0.75 | 0.18~0.25 |
| Actual | 0.010 | 0.11 | 1.1 | 0.19 | 0.001 | 24.29 | 21.89 | 6.18 | 0.10 | 0.20 |
2. The mechanical properties (ASTM B688-96)
| Distinguish | Yield Strength（MPa） | Tensile Strength（MPa） | EL（%） | Hardness（HBN） |
| Specifications | ≥310 | ≥650 | ≥30 | ≤100 |
| Actual | 422 | 770 | 45 | 88 |
3. Corrosion resistance
Because UNS N08367 contains high concentrations of chromium, molybdenum and nitrogen, it can also show excellent pitting corrosion resistance and crevice corrosion resistance in a chloride environment. The figure on the right shows the relationship between the pitting index PRE in the aqueous solution of ferrous chloride and the critical temperature CCT (Critical Crevice Corrosion Temperature). UNS N08367 can give full play to its excellent corrosion resistance in the corrosion environment where it is difficult to maintain the corrosion resistance of duplex stainless steel.
4. Heat treatment
Because UNS N08367 is austenitic stainless steel, its heat treatment meets the standard of austenitic stainless steel. Usually there are the following heat treatment processes:
1) Solution heat treatment conditions: 1105~1175℃ water cooling
2) Stress heat treatment: 450~550℃ atmospheric cooling
5. Workability
Cold rolling and hot rolling are almost the same as ordinary 304, 316 standard austenitic The body is consistent with stainless steel.
6. Uses:
Seawater desalination device, flue gas desulfurization environment, drug reflection container and piping.