Stainless Steel Sheet Coil Cooling technology
Plate is mainly used for ships, bridges, boilers, containers, petrochemicals, engineering machinery and national defense construction, etc., its variety, the use of a wide temperature range (-200 ~ 600 ℃), the use of complex environment (weather resistance, Corrosion resistance, etc.), the use of high requirements (toughness, weldability, etc.). Therefore, the plate is the national economy in the strategic significance of the steel varieties. In the plate rolling, the control of the microstructure is one of the keys to improve the steel sheet yield. In this respect, the new technology which is being developed at home and abroad in recent years mainly has the following.
Intermediate cooling technology. From the current domestic control of the rolling process applications, the ultra-widely used controlled rolling is a two-stage rolling, that is, recrystallization zone rolling and non-recrystallization zone rolling. In these two stages, it is necessary to avoid the partial recrystallization zone. The roughing of the intermediate blank is the measures taken to meet this requirement. The intermediate cooling device is used to increase the cooling capacity of the intermediate billet on the roller bed before or after the machine or the machine of the single-stand rolling mill between the rough rolling mill and the finishing mill of the double-stand production line to improve the production capacity of the rolling mill. With this device, the waiting time of the middle blank can be reduced by 35% to 80%. The device combined with intermediate cooling control rolling and rolling control cooling, can also be used to produce superfine grain steel, or sandwich steel, this steel because there is a certain thickness (4mm) ultra-fine grain layer, so Has a high crack performance. China's Tangshan Iron and Steel, Nanjing Iron and Steel added a middle blank cooling equipment, not only improve the production capacity of rolling mill, but also strengthen the control of steel properties, and expand the scope of steel varieties.
Second, pre - straightening technology. The pre-straightening machine can be installed between the finishing mill and the steel plate cooling device, which is intended to reduce the head or tail warpage of the steel plate and to correct the flatness defects in the middle section of the steel plate. Straightening operations avoids the accumulation of harmful water on the steel plate and improves the cooling uniformity, resulting in a well-finished product. The pre-straightening machine is to be synchronized with the roller table and has a speed accuracy combined with the cooling technology.
3. Ultra-high density laminar flow cooling technology. Beijing University of Science and Technology has developed ultra-high density laminar flow cooling system, which can not only greatly improve the cooling rate of steel plate, improve the performance of steel, and can reduce the cost of alloy without increasing the running cost. Its cooling rate than the Japanese JFE development of the super cooling system increased by 50%, 20mm thickness of the steel plate of its cooling rate can reach 45 ℃ / s. At present, the use of the equipment system, has successfully developed a high-strength steel Q550-Q800 and high-strength container board N610E.