The process flow of the hot rolling production line roughly includes slab storage, heating, rough rolling, finishing rolling, coiling, transportation chain, finishing and other processes. The main task of the rough rolling process is to roll a heated slab with a thickness of about 230 - 250mm into an intermediate slab with a thickness of about 40mm for rolling into the finished product size by the finishing mill. As the first process of the rolling line, roughing mill shoulders tasks such as plate shape control, temperature control, width control, and surface quality control. As a rough rolling operator, my production assessment indicators mainly include: fault downtime, quality lockdown rate, etc. After I was hired as a senior technician and chief operator, I took on the task of proposing to improve equipment functions from the perspective of production technology. It is necessary to transform some good operating experience and experience into automatic control models or technologies to achieve Baosteel's goal of continuously improving labor efficiency. In the process, I have continued to grow and improve.
In order to roll silicon steel and high-strength steel, 1880 designed and introduced high-pressure high-speed rolling technology and fully automatic rolling technology, which led to a very prominent problem of roughing mill slipping, which ultimately affected normal production and continued scrap accidents. I summarized my experience in controlling slip during operation, combined with the 1880 equipment, and proposed an improvement plan for automatic slip control, and finally formed an automatic slip control method for the rough rolling process.
In the process of producing oriented silicon steel, because the wedge requirements for silicon steel are much higher than those for carbon steel production, the wedge control of rough rolling intermediate slabs once became the bottleneck in the production of oriented silicon steel. To reduce the wedge shape of the intermediate billet, we must first control the plate shape. I summarized my experience in manually adjusting the plate shape during the work in 2050, and proposed to automatically adjust the roll gap deviation of the rolling mill by using the pressure deviation detected by the side guide plates before and after the rolling mill. The control idea of adjusting the plate shape of the intermediate billet was developed in cooperation with electrical technicians, and finally formed the automatic control technology for correcting the deviation of the intermediate billet in rough rolling. In addition, my experience in plate shape adjustment of "straightening the front stand and leveling the rear stand" has been widely promoted and applied among operators, and the production of small wedge shapes of hot rolled strip steel has been realized;
During the width control process of hot rolled strip, due to the influence of temperature, steel grade, and specification, the existing control model is not accurate enough to control the narrowing of the head and tail of strip. After learning the model control theory, I proposed the idea of smoothing over-control, and finally developed a quadratic curve model with technicians, which made the control process more stable; Most strip heads and tails will shrink during the rolling process. However, when the finishing mill pulls severely and the rough rolling has to be widened, because the head and tail of the strip are rolled tension-free during the finish rolling, the strip head and tail will be excessively wide. In order to ensure that the width of the head and tail of the strip is not excessively wide, we often manually close the edge roll gap first. After the strip head passes through the rolling mill, the edge roll gap is manually opened, and when the tail of the strip is about to leave the rolling mill, the edge roll gap is manually closed. Based on this manual control method, I worked with the model technical team to develop a head and tail winding shortening stroke curve control model, which realized automatic control of the roll gap when the head and tail width of the strip is excessively wide.
In order to increase the production capacity of Baosteel's steelmaking plant, Baosteel used online width adjustment technology for continuous casting, which produced many continuous casting slabs with inconsistent widths before and after, which we call conical slabs. This conical billet was first rolled by cutting it offline into a rectangular parallelepiped. However, when it was too late for cutting, the steel mill would send the uncut slab to hot rolling, resulting in an increase in the width of the hot rolled strip. When rolling this kind of strip steel, I would manually open or reduce the roll gap according to the change in the rolling force of the vertical roll, which reduced the width blocking amount. Based on this, I summarized the width control method of the conical billet, and then developed the conical billet width control technology together with the technology.
This achievement has formed a total of 3 invention patents, 14 utility model patents, and more than 50 technical secrets, producing more than 15 million economic benefits every year. Four control methods have been promoted to similar production lines in Baosteel, and all have achieved remarkable results., has wide promotion and application prospects.