Carbon steel and stainless steel can be identified with the naked eye. The specific material must be tested with a material detector to detect the label and the content of various elements.

In the steel industry, materials include: Q235, Q345, 16Mn, 16MnR, 20G, 15CrMoR, Q550, 10CrMoAl, S355JR, A537CL2, etc.