"Mirror" is not polished (BA surface):

Cold knowledge: The "mirror" effect (Bright Annealed Finish, BA surface) of stainless steel that we often talk about is not achieved by post-mechanical polishing. It is formed during the final annealing process by heating the coil in a protective atmosphere furnace filled with hydrogen or hydrogen-nitrogen mixed gas, and then bright annealing and cooling between very smooth mirror polishing rollers. The surface is as bright as a mirror and almost free of oxidation, which is the product of "natural beauty".

One roll may weigh more than two adult African elephants:

Cold knowledge: Although a roll of stainless steel seems not to be huge (1-2 meters in diameter), its weight is amazing. A roll of 304 stainless steel with a thickness of 1mm, a width of 1.5 meters, and a length of 2000 meters (typical specifications) weighs nearly 24 tons! This is equivalent to the total weight of two adult African elephants.

The thickness unit "micrometer" is the norm, and the precision is comparable to that of a hair:

Cold knowledge: The thickness of stainless steel coils is usually expressed in millimeters (mm), but in production and precision applications, micrometers (μm, 1mm = 1000μm) are more commonly used. The thickness tolerance control is extremely strict. For example, for a 0.4mm thick coil, the tolerance may be required to be controlled at ±10μm or even smaller (±0.01mm). The diameter of a human hair is about 70μm, which shows its high precision.

Edge treatment: burrs vs. burrs, the difference is huge:

Cold knowledge: The edge treatment of stainless steel coils is very important. We often say "deburring", but "burrs" and "burrs" are two different things.

Burrs: It is a sharp, tiny metal protrusion produced on the edge during shearing or striping. It is very easy to cut people and must be removed through a special deburring process (such as scraping, grinding, electrolysis, etc.).

Burrs: Sometimes refers to the area of the edge that is slightly thickened or not straight enough (also called "edge waves") formed naturally during the rolling process. It is part of the rolling process characteristics and is not a sharp protrusion. Whether to remove the "burrs" depends on the use requirements of the final product (if a very neat edge is required, trimming is required).

Embossed rolls are not just for beauty:

Cold knowledge: Stainless steel rolls with patterns (such as diamonds, squares, hairlines, etc.) on the surface, in addition to improving aesthetics and anti-slip properties, have an important function: increasing rigidity. The tiny concave and convex structures formed by embossing, like origami, can significantly improve the bending resistance of the plate, making it less likely to deform at the same thickness. It is particularly suitable for occasions that require a certain degree of rigidity, such as building decoration and elevator cars.