The two most commonly used types of stainless steel nowadays are
304316 (or 1.4308 and 1.4408 corresponding to German/European
standards). The main difference in chemical composition between 316
and 304 is that 316 contains Mo, and it is generally recognized
that 316 has better corrosion resistance and is more resistant to
corrosion than 304 in high-temperature environments. So in
high-temperature environments, engineers generally choose 316
material components. But there is no absolute thing. In a
concentrated sulfuric acid environment, no matter how high the
temperature is, do not use 316! Otherwise, this matter would be a
big deal. People who study mechanics have all learned about
threads. Remember the black solid lubricant that needs to be
applied to prevent thread bite under high temperatures: molybdenum
disulfide (MoS2). From it, two conclusions can be drawn: [1] Mo is
indeed a high-temperature resistant substance (do you use a
crucible to melt Zhidao Huangjin? Molybdenum crucible!). [2]
Molybdenum easily reacts with high valent sulfur ions to form
sulfides. So no type of stainless steel is super invincible and
corrosion-resistant. After all, stainless steel is a piece of steel
with more impurities (although these impurities may be more
corrosion-resistant than steel), which can react with other
substances.