I believe that everyone will encounter such a situation when purchasing ASTM 304 304L 316 316L stainless steel sheet. It is obviously a 6mm thick sheet, but the actual thickness cannot be reached. This is the tolerance of stainless steel sheet. Tolerance is the recognized allowable thickness deviation, and it is also a "hidden rule" in the stainless steel industry, because the rolling process of the steel mill machinery is slightly deformed by heat, resulting in a deviation in the thickness of the rolled ASTM 304 304L 316 316L stainless steel sheet. Thick in the middle and thin on both sides. Therefore, the actual thickness is often not up to the theoretical thickness. For example, a board with a standard thickness of 5mm has an actual thickness of only 4.7mm.
In domestic tolerances are often negative tolerances, of course, there are positive tolerances, but very few. When buying and selling stainless steel plates, it is usually calculated according to the theoretical thickness, which is why the theoretical price is lower than the weighing price. The tolerance is also divided into size, and the price is also different. The price of the large tolerance is cheaper. For example, for ASTM 304 304L 316 316L stainless steel sheet with a standard thickness of 6mm, if the actual thickness is less than 5.5mm, it is a large tolerance.