Research On Cold Roll Control Technology Of Single Stand Direct-Pulling

With high control precision and low running cost, the cold rolling pilot mill can simulate cold rolling processes well, and it can also precisely record and analyze the experimental data, meeting the urgent needs of Chinese iron and steel industry to develop new cold rolled steel grade and optimize new production technology.This thesis is based on the project titled Research and Development of Single Stand Direct-Pulling-High Cold Rolling Pilot Mill, which was built in the Technology Centre of AnSteel by The State Key Laboratory of Rolling and Automation (RAL), Northeastern University. The main research works are as follows:1. The research on the cold-rolling pilot mill and rolling process. In this thesis we analyze the process equipment, the automatic control system and the main functions and characteristics of the single stand direct-pulling hydraulic tension rolling mill. Compared with other pilot mills in and abroad, the design of RAL is much better in rationality and practicability, particularly suitable for the research and development of steel grade and technology.2. The development of the software of the automatic tension control system. According to the principle and characteristic of the automatic tension control system of the pilot mill, new software was developed. It enhances the tension controlling stability for extreme thin strip. By on site rolling experiments, the test for positioning accuracy of the tension control system was carried out, and the stabilization and accuracy of the tension control system was examined.3. The research on the gap control system. The gap control system of the single stand direct-pulling hydraulic tension rolling mill was analyzed. This control system includes two parts, one is electrical gap control (APC) which is mainly used to regulate the rolling line, and the other is hydraulic gap control (AGC) which completes AGC during rolling process. Through the positioning accuracy test of the electrical gap control and hydraulic gap control, the accuracy of the gap control system was proved.4. The development of the method for measuring thickness indirectly. According to the gauge control system of the single stand direct-pulling hydraulic tension rolling mill, the method for measuring thickness indirectly was developed, which is based on the principle that the flow rate per second in the rolling process is equal. The accuracy of the indirect method for thickness measurement was proved through a lot of on site rolling experiments.5. Design the synthetic experimental schemes and rolling process for SPCC and TRIP steel etc. and mass data was collected. The experimental results show that the tension controlling accuracy is0.25%, and the thickness controlling accuracy satisfies the requirements of cold rolled high precision strip.