What exactly are "steel" and "iron", what are their characteristics, and what is their relationship? How did the 304, 304L, 316, and 316L we usually call come from, and what are the differences between them?
Steel: A material with iron as the main element, carbon content generally below 2%, and other elements. ——GB/T 13304-91 "Steel Classification"
Iron: A metallic element with atomic number 26. Iron materials have strong ferromagnetism, good plasticity and thermal conductivity.
Stainless steel: resistant to weak corrosive media such as air, steam, and water, or stainless steel. The commonly used steel grades are 304, 304L, 316, 316L, which are 300 series steels of austenitic stainless steel.
