To cater to the market demand for high-strength oil & gas pipeline steel, Bayi Steel decided to produce quality structural steel, duplex steel, X80 and X100 steel. The mass production of these high-value-added products have more stringent requirements on hot strip mill quick cooling capacity, heavy-duty coiling capacity at low temperature. 
 

The heavy-duty coiler for 1,750mm HSM of Bayi Steel is designed, manufactured and commissioned by Chinese companies, with CISDI undertaking the general technical responsibility and supplying EIC & hydraulic equipment. The down coiler is designed with rocker-arm type pinch roll, step-less mandrel expansion and 3 wrapper rollers (with auto stepping function). The coiler is provided with high and low speed, with high speed for thin-gauge strip coiling and low speed for hard & thick strip coiling. To ensure smooth threading of hard and thick strips, holddown roller and chute rollers are installed. Wrapper roller compression function will be activated for coiling strips over 7.5mm thick to ensure good tightness and less telescopicity. The coil stripping car is servo hydraulically driven. Dual loop control by position-pressure is applied at the end of coiling to ensure proper tail coiling and reliable coil connection. So far the coiler has been successfully used for coiling strips of 2mm~15.6mm, 18.4mm thick, with all data meeting the performance test requirements.
 

The proprietary intensive cooling system of CISDI has also been successfully applied in hot strip mill of Bayi Steel, for which CISDI Engineering Co., Ltd. provided equipment design, Chongqing CISDI Heavy Machinery Co., Ltd. provided manufacturing while CISDI Electric Technology Co., Ltd. provided model and electrical control. To implement the cooling system, the existing hot strip mill is modified by replacing the first seven laminar cooling zones with 7 groups of intensive cooling zones. The revamped cooling system can provide cooling rate up to 20~30°C/s (with strip speed at 2.8m/s), and the low-temperature cooling target temperature can reach 500~530°C, allowing the production of duplex steel and X80-X100 pipeline steel.