Difference Between Hot Rolled Steel Coil & Cold Rolled Steel Coil

Hot rolled steel tends to have rough edges and surfaces that require decarburization or other treatments to prepare it for subsequent production operations. In contrast, cold-rolled steel typically has a glossy and smooth surface that allows it to be used as-is in production operations. Steel produced by the cold rolling process has higher strength and hardness than steel produced by the hot rolling process. The higher material strength and hardness brought about by the cold rolling process are accompanied by greater internal stress. These stresses must be relieved before the material can be machined; otherwise, the final part or product may warp.

Difinitions:

The hot rolling is relative to cold rolling. Cold rolling is rolled below the crystallization temperature, and the hot rolling is rolled above the crystallization temperature. Simply put, a piece of billet passes through several rolled rolling after heating, and then cuts edges to correct it into a hot rolled steel plate.
Hot rolled steel sheets and coils are basic carbon steel products with the oxide film stripped off mechanically, chemically or a combination of both methods. Hot rolled steel is most commonly used when dimensional tolerances and surface finish quality are not critical.

Cold Rolling Steel use hot-rolled steel rolls as raw materials. After washing and removing oxidation skin, cold rolling. The cold and hardening caused by continuous cold deformation increases the intensity, hardness, toughness, toughness Plastic indicators are

Features:

Hot Rolling:

1. Low energy consumption, good plastic processing, low deformation resistance, not obvious processing hardening, easy rolling, reducing the energy consumption required for metal deformation.
2. Hot rolling usually uses large -cast ingots, large pressure rolled under pressure, fast production rhythm and large output, which creates conditions for large -scale production.
3. The casting tissue is transformed into a processing organization through hot rolling, and the plasticity of the material is greatly improved through the transformation of the tissue.
4. The characteristics of the rolling method determine that the performance of the plates has various opposite sex. One is the vertical, horizontal and height of the material, and there is a significant performance difference. There are obvious directionalism in system.

Cold Rolling:

Because it has not undergone annealing treatment, the hardness of cold rolling (HRB is greater than 90), and the mechanical processing performance is extremely poor. It can only be simply directed with bending process with less than 90 degrees (vertically in the rolling direction).

Advantages:

Hot Rolled Steel:

(1) Hot rolling can significantly reduce energy consumption and reduce costs. During hot rolling, the metal plasticity and low deformation resistance have greatly reduced the energy consumption of metal deformation.
(2) Hot rolling can improve the processing process of metal and alloy. The large grains that are about to cast are broken, significantly cracking healing, reducing or eliminating casting defects, transforming the cast state tissue into a deformation tissue to improve the processing performance of alloy.
(3) Hot rolling usually uses large -cast ingots, which not only improves production efficiency, but also creates conditions for improving rolling speed and achieving continuous and automation of rolling process.

Cold Rolled Steel:

Fast speed of molding, high yield, and no damage coating, can be made into a variety of section forms to meet the needs of the use conditions; cold rolling can cause large plastic deformation of steel, thereby increasing the yield of steel point.

Usages:

Malleable at high temperatures, hot rolled steel is easy to weld, form and drill, which makes hot rolled steel sheets and hot rolled steel coils ideal for a wide variety of uses including but not limited to the following: Automotive panels, Tool boxes, Hoppers, Drip pans, Fuel tanks, Trailer siding & roofing, Building & construction, Shipping containers, Appliances, Heavy equipment, Stampings, Construction, etc.

Cold Rolled Steel coils and sheets wildly used for general structural parts and stamping parts of construction machinery, transportation machinery, construction machinery, lifting machinery, agricultural machinery and light industry civilian industries.