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What is the difference between cold rolled sheet and hot rolled sheet?

2021-03-31 11:05:28

1. Different brightness

The cold-rolled steel plate is very bright, flat, good in appearance and standard in thickness. When it is not rusted, it looks a bit as bright as stainless steel; the hot-rolled surface is rough, the shape is not cold-rolled, and it is iron gray when it is not rusted. of.

2. Different smoothness

The cold plate is processed by cold rolling, and the surface has no oxide skin, and the quality is good. The hot plate is processed by hot rolling, and the surface has oxide scale, and the thickness of the plate is lower. After electroplating, it can be distinguished from the smoothness of the surface. The smoothness of cold-rolled board is higher than that of hot-rolled board.


3. Different materials

Cold-rolled sheets are made from hot-rolled coils, which are rolled below the recrystallization temperature at room temperature, including plates and coils, which can be produced by many domestic steel plants such as Baosteel, Wuhan Iron and Steel, Anshan Iron and Steel, etc. Among them, the ones delivered in pieces are called steel plates, also called box plates or flat plates; the ones that are long in length and delivered in coils are called steel strips, also called coiled plates.

The hot plate uses continuous casting slab or blooming slab as raw material, heated by a walking heating furnace, high-pressure water descaling, and then enters the rough rolling mill. The rough rolling material is cut head, tail, and then enters the finishing rolling mill for computer-controlled rolling. After finishing rolling, it undergoes laminar cooling (computer-controlled cooling rate) and coiled by a coiler to become a straight hair coil.

4. Different specifications and thickness

Cold-rolled sheets are generally thin gauges with a thickness of less than 3.0mm. Silver-white is galvanized sheet, and color is color-coated sheet. The surface is absolutely oil-free. The whiter is also cold-rolled sheet, which is very clean and flat, with strong reflection, and is made of steel. Harder.

The hot-rolled sheet is generally 1.5mm or more, and the thinnest is not less than 1.0. If it is less than 0.8, it is definitely a cold-rolled sheet. The surface is iron gray, brown and earthy, with temperature-changing oxidation patterns, and the surface is rougher than the cold-rolled sheet (flattened Except) The surface process is obviously not as fine as the cold-rolled plate.