Heat Resistance Of 304 Stainless Steel

Generally, the upper limit temperature that can be safely used as a mechanical part is about 450℃~600℃. 

The strength decreases with the increase of temperature, and it is about 1/3 of the normal temperature at 750℃. Not that it can't be used even at higher temperatures, but creep is also an issue. For example, SUS304 was used as a jig for brazing in a furnace at 1050°C, but it gradually deformed and became unusable. 

Also, if heated at a temperature of 600°C to 800°C for about 10 minutes or more, it will become sensitive (*) and corrosion resistance will be reduced, so do not use it if there is a problem with corrosion resistance within this temperature range. 

Plasticly worked materials (forging, high rate draw, sheet, etc.) can be sensitized in about 1 hour even at 450°C. 

As for low temperature, it can be used even at liquid nitrogen temperature: -196℃, without worrying about low temperature embrittlement.  

*: Due to the precipitation of chromium carbide, the phenomenon of insufficient chromium (less than 13%) in the base metal is likely to cause intergranular corrosion and intergranular stress corrosion cracking.