Steel plates are hot rolled products that have a relatively high thickness. Products having a thickness of over 4.5 mm are classified as steel plates, and those having a thickness of over 100 mm are called thick steel plates. Slabs of steel plates made through continuous casting are tailored to the dimensions specified by the customer through rolling and cooling before being cut into their final sizes.
Powered by state-of-the-art facility and technology, POSCO operates a totally computerized, end-to-end full automatic production system. This allows us to deliver high-quality and high-performance products fit to the needs of customers.
The 4-high reversible finishing mill with the maximum load of 7000 tons minimizes internal defects even in extremely thick plates. Automatic gauge control and shape control systems can reduce not only the thickness deviation of plates but also improve the flatness.
The PILAC (POSCO In-line Accelerated Cooling) system enables the production of high strength steel without heat treatment through rolling and accelerated cooling. Using the mist cooling method with suction type, the PILAC system has a high cooling capacity and is able to maintain a uniform temperature gradient in the widthwise direction. This leads to a reduction of plate quality deviation.
The hot leveler is used to make superior quality flat plates by eliminating residual stress left on rolled plates.
After passing through the cooler, the plates undergo a dimensional accuracy inspection and then cut into appropriate width and length according to plate grade and thickness using either mechanical shearing machine or flame planner. To obtain a higher degree of dimensional accuracy in products, production conditions are determined by such factors as the air knife gap and the nozzle size of the gas torch.
To attain the plate structure demanded by customers, plates undergo heat treatment after having the scale removed by shot blasters. The heat treating facilities are of a non-oxidizing radiation tube type, which produces scale-free heat-treated plates.
The ultrasonic tester checks for blow holes, pipes, and laminations and other internal defects. This test is performed to guarantee the internal quality of plates demanded by customers.