Through the unremitting efforts of Shougang Research Institute of Technology, Shougang Cold-Rolled Company, and Jingtang Company, the output of Shougang’s galvanized automobile plate increased by 80% on a year-over-year basis in the first quarter of 2019, and the quality and performance indicators of this product were greatly improved. Shougang’s galvanized automobile outer covering steel has successfully replaced similar imported products and is applied to high-end joint venture auto enterprises, helping Shougang’s auto plate to keep moving to the high end.

Among all kinds of automobile plates, the galvanized plates for cars represent the highest level of automotive steel in terms of variety and quality. The batch and stable supply of galvanized auto plates for high-end users becomes a sign measuring the capacity and level of steel factories. This goal is also the top priority for Shougang's transformation and development and high-end service. In addition to the traditional performance stability and overall surface quality stability of high-end galvanized plate products, high-end automakers have put forward higher standards for indicators related to the surface structure of steel sheets. How to transform the requirements of high-end users into Shougang's suitable and executable production process system to produce products that meet the special needs of users are the problems that the project team must solve.

As a key indicator of the surface structure of steel plate, the surface waviness control of the high-end galvanized plate product is a worldwide problem, affecting the surface quality of the hot-dip galvanized automobile plate. Liu Libin, chief engineer of the Sheet Research Institute of Shougang Research Institute of Technology, led the galvanizing process quality research team to carry out systematic laboratory analysis of surface waviness control, and carried out a large number of production line experiments with technicians from Shougang Cold-Rolled Company and Jingtang Company, studying the influence laws of the process steps on the surface waviness index. In order to shorten the research cycle as much as possible, Liu Libin and team members Hu Yanhui and Li Yan collected and aggregated the test data from the production line during the daytime, and worked overtime to analyze the data and discuss new processes and the feasibility of technical plans. Then they discussed and implemented plans with production line engineers the next day. It was a common practice for them to work successively for a couple of days without a break. Just because of the tenacity of overcoming difficulties, the research team finally found a breakthrough and determined effective process control measures to greatly improve the surface waviness index of galvanized plate, which has successfully passed the certification of high-end users.

Another difficulty in the quality of galvanized automotive plate is the control of the uniformity of the oil film on the strip surface. In order to solve the problem of uneven oil film, the research team led by Dr. Jiang Guangrui traced and observed the oil film during production of coiled strip and during the use of uncoiled strip for ten-odd successive hours in the production lines and user sites. Using the first-hand data tracked, they constantly explored the correspondence between oil film uniformity and process parameters, repeatedly optimized and adjusted and closely monitored the subsequent production and use, and verified the effectiveness of process adjustment. In the end, the surface oil film uniformity index of the galvanized products has been significantly improved, reaching the international advanced level for similar products.

The most difficult part of the galvanized plate is the side plate of the passenger vehicles. This part has high pressure forming difficulty, and zero tolerance to surface quality defects. Before the trial production of side plates for high-end users, the team learned that the company had very strict requirements for the performance indicators and stability of the materials. In order to pass the verification, the team member Zheng Xuebin proposed the best performance control range of the material based on the detailed analysis and simulated calculation of the parts; in order to meet the performance index and accuracy requirements, team member Wei Dong worked hard and confirmed the best production process after a large number of continuous retreat simulator tests and base industrial tests. The final test results of the user trials confirmed that Shougang’s products not only met the requirements in terms of control accuracy of key indicators such as yield strength and roughness, but also were highly recognized by users at a level far above the standard level.

In order to implement the new concept of transformation and upgrading of Shougang's “manufacturing + service”, the project team continued to strengthen service awareness and responded to user requests 24 hours a day. Early one Saturday morning, team member Liu Guoliang received a call from a user who had problems in the production process of the outer plate. Having just returned to Beijing after a business trip the night before, he rushed to the production line immediately. After obtaining the original defective samples, he and his colleagues analyzed the inspection data and key process parameters of the whole process one by one, analyzed the causes, and researched and communicated with staff from the technical quality department of the production line, optimizing and adjusting the key parameters of the continuous casting process, and successfully solving the problems at the fastest speed. The follow-up team promoted this experience and solidified the process optimization of each process in the certified coil production process to ensure stable supply.

The entire galvanized outer plate research team is like a set of closely matched linkage gears, each with its own functions and tacit understanding. It is this kind of efficient and synergistic team spirit that enables continuous improvement and breakthrough in scientific research and innovation. The technological breakthrough and successful application of key process quality research projects for high-end automotive galvanized plates have effectively improved the overall level of Shougang's automotive sheet production line, improved market share and brand competitiveness, which is of great significance for Shougang’s auto sheets to be high-end and to support Shougang Group’s transformation and development.