The maximum operating temperature of stainless steels will vary, dependent upon the grade and microstructure. Many stainless steels will form the deleterious sigma phase, with a loss of impact toughness and corrosion resistance, when exposed to elevated temperature over time.
Therefore, duplex and super duplex grades should not be used at temperatures above 250degC unless for very short periods only. Other grades, particularly ferritic stainless steels, can embrittle above 475degC, with a catastrophic loss of mechanical properties. In addition, most grades will soften and their strength will fall with rising temperatures. However, more highly alloyed austenitic grades can be used at temperatures beyond 500degC. If in doubt, consult Langley Alloys for guidance from our experienced team, which includes several metallurgists.
If you have any questions about the use of stainless steel at high temperatures, please contact us today.