The difference between cold rolling and hot rolling of punching net

- Dec 04, 2018-

The cold-rolled plate punching net and the hot-rolled plate punching net material are two different rolling technologies. As the name suggests, cold rolling is to make the steel at normal temperature, and the hardness of the steel is large. Hot rolling is the steel that is made at high temperatures.


First, the introduction of hot rolled sheet

Continuous casting slab or slab slab is used as raw material, heated by step heating furnace, dewatered by high pressure water and then into rough rolling mill. The rough rolling material is cut into the tail and tail, and then enters the finishing mill to carry out computer controlled rolling. After the final rolling, it is subjected to laminar cooling (computer controlled cooling rate) and the coiler is taken up to become a straight hair roll. The head and tail of the straight hair roll tend to be tongue-shaped and fish-tail-shaped, and the thickness and width are poorly accurate. The edge often has defects such as a wave shape, a folded edge, and a tower shape. The weight of the coil is heavier and the inner diameter of the coil is 760 mm. (Generally, the tube industry likes to use it.) After the straight hair is wound through the cutting, cutting, trimming and multi-pass straightening, leveling and other finishing lines, then cutting or rewinding, it becomes: hot rolling Steel plates, flat hot rolled steel coils, slitting belts and other products. If the hot-rolled finishing rolls are pickled to remove scale and oiled, they are hot-rolled pickled rolls. This product has a tendency to partially replace cold-rolled sheets, and the price is moderate, which is very popular among users.


Second, the introduction of cold rolled sheet

The hot-rolled steel coil is used as raw material, and the scale is removed by pickling, and then cold-rolled, and the finished product is rolled hard roll. The cold work hardening caused by continuous cold deformation causes the strength and hardness of the rolled hard roll to rise, and the toughness index decreases. Therefore, the punching performance will deteriorate and can only be used for parts that are simply deformed. Rolled hard rolls can be used as raw materials for hot-dip galvanizing plants because the hot-dip galvanizing units are equipped with an annealing line. The hard roll weight is generally 6~13.5 tons, and the inner diameter of the steel coil is 610mm.


Generally, cold-rolled rolled sheets and coils should be subjected to continuous annealing (CAPL unit) or hood furnace annealing to eliminate cold work hardening and rolling stress, and achieve the mechanical properties specified in the corresponding standards.


The surface quality, appearance and dimensional accuracy of the cold-rolled sheet punching net are superior to those of the hot-rolled sheet, and the thickness of the product is thinly rolled to about 0.18 mm, which is favored by the majority of users. Deep processing of products with cold-rolled steel coils as a substrate has become a high value-added product. Such as electro-galvanizing, hot-dip galvanizing, fingerprint-resistant electro-galvanizing, color-coated steel coils and vibration-damping composite steel sheets, PVC laminated steel sheets, etc., so that these products have excellent quality, high corrosion resistance and other excellent quality, have been widely used. Cold rolled steel coils must be finished after annealing, including cutting, tailing, trimming, leveling, leveling, rewinding, or longitudinal shearing. Cold-rolled sheet punching nets are widely used in automobile manufacturing, home appliances, instrument switches, construction, office furniture and other industries.