1.4539 plate, good oxidation resistance. However, the structural stability of this grade breaks down at high temperatures, especially above 400¡ãC. ASTM A240 UNS N08904 material can be solution heat treated at 1090-1175¡ãC followed by quenching. Heat treatment is suitable for hardening it. 1.4539 sheet is mainly used in oil refining equipment, pulp and paper processing industry, gas scrubbing plants, etc.