Q235 ordinary carbon structural steel-ordinary steel plate is a kind of steel. Q represents the yield limit of this material, and the latter 235 refers to the yield value of this material, which is about 235MPa. The yield value will decrease with the increase of material thickness. Because of moderate carbon content, good comprehensive properties and good matching of strength, plasticity and weldability, it is the most widely used.
Hardness is a technical term in physics, which refers to the local resistance of materials to hard objects pressed into their surfaces. The local resistance of solids to foreign invasion is an index to compare the hardness of various materials. There are different hardness standards because different test methods are specified. Various hardness standards have different mechanical meanings and cannot be directly converted, but they can be compared through experiments.