Efficient Welding Technology for Wheel Steel and Galvanized Sheet

Hegang Group has established a comprehensive technology research and development platform, with 3 national recognized enterprise technology centers, 6 provincial-level recognized enterprise technology centers, 7 CNAS recognized physical and chemical laboratories, as well as 6 provincial-level engineering technology research centers for cold-rolled and coated steel plates, steel structural steel, etc. It also has 3 academician workstations and 3 postdoctoral research workstations. We are equipped with over 10 sets of first-class deep processing and other pilot equipment, as well as over 130 high-end physical and chemical testing equipment in physics, chemistry, mechanics, and other fields. We also have 6 sets of various welding experimental equipment. A joint innovation center has been established with the University of Wollongong, and a project titled "Development of Welding Processes for Wheel Steel and Galvanized Sheet" has been initiated with a supporting funding of AUD 600000 (approximately RMB 2.85 million). We plan to apply for a special funding of 500000 yuan for talent introduction. The breakdown of the expenses is as follows: international travel expenses, petty expenses (or salary subsidies), accommodation expenses, inter city transportation expenses, technical guidance fees, teaching fees, patent technology transfer fees, translation fees, a total of 10555582040 Australian participants from our partner, and 10 participants from Hegang Group. The proposed expert information is Valerie Linton, who is currently a professor and dean of the School of Engineering and Information at the University of Wollongong, Australia. I graduated with a bachelor's degree and a doctoral degree from the University of Sheffield and the University of Cambridge in the UK. After graduation, I served as a senior welding researcher at British Steel and a professor at the University of Adelaide in Australia. I have extensive experience in predicting, analyzing, and simulating the microstructure of welded joints under different welding conditions. Currently, I am a member of WeldingCRC in Australia and CEO of the Energy Pipeline Steel Association. So far, a total of 35 papers have been published, with a total of 328 citations. Dr. Han Jian is currently a researcher at the School of Engineering and Information Technology at the University of Wollongong, Australia. He holds bachelor's and doctoral degrees from Tianjin University and Wollongong University in Australia, respectively. He has successively served as the leading researcher of Baosteel Research Institute, senior manager of International Iron and Steel Association, research assistant of Wollongong University and senior welding expert of Asia Pacific R&D Center of Linde Group in Germany. During my work in China, I was the research backbone of national level projects such as "Development and Weldability Research of National Petroleum Reserve Steel" and "Key Technologies and Application Demonstration of Resource Saving Special Steel". During my time in Australia, I was a member of the "Australian Welding Engineering Center" and "National Defense Steel Material Research and Development Center". More than 30 SCI papers have been published and 6 Chinese invention patents have been granted. The technical difficulties of this project lie in the following two aspects: 1) After flash butt welding of steel wheels, they need to undergo forming processes such as expanding and bulging. Due to the coarse structure and poor toughness of the welded joints, cracking problems often occur during the forming process. 2) When welding galvanized sheet, the arc temperature is much higher than the gasification temperature of the zinc layer, which causes the zinc layer to burn and affect the corrosion resistance of the sheet. More seriously, zinc vapor can be trapped in the molten pool, solidifying in the welding material to form porosity defects, which can lead to welding quality issues such as cracking. Solution and research content: 1) Conduct weldability evaluation on typical wheel steel, optimize the process parameters of flash butt welding, and conduct corresponding numerical simulation research. Establish the relationship between flash butt welding process parameters such as upset force, current and voltage, heating time, and the microstructure of various parts of the welded joint, and further clarify the impact of welding process on mechanical properties, especially service performance. 2) For galvanized sheets with different thicknesses and zinc layers, the design of welding shielding gas and welding current and voltage speed are adjusted, and high-speed photography is used to elucidate the interaction process and mechanism of zinc vapor, arc, and molten pool during typical galvanized sheet welding process, and to accurately optimize welding quality. The expected objectives are (1) to clarify the influence of flash butt welding process parameters on the microstructure of important parts such as the fusion zone and Heat-affected zone of different wheel steel welded joints, and to clarify the change law of their mechanical properties (2) to carry out process parameter optimization research for specific flash butt welding wheel parts, and solve the problem of weld joint forming cracking, Reduce the cracking rate of the welded joint of the wheel steel to within 2%. (3) Optimize the welding process of galvanized sheets with different zinc layer thicknesses and clarify the impact of oxidizing gases in the protective gas on the welding quality of galvanized sheet products. (4) Use high-speed camera method to study the welding process parameters and establish the corresponding relationship between each parameter and the formation of zinc vapor. (5) Train 1-2 high-end welding technology talents, Completed 2-3 related papers (including 2 core and above papers from Peking University) and applied for 2 patents. Han Steel Company of Hegang Group has successively developed low-carbon microalloy series and dual phase series wheel steel, and has produced over 1.6 million tons of wheel steel to date, making it one of the company's flagship products for hot-rolled plates. The hot base galvanizing line of Chenggang Company of Hegang Group was put into operation in 2019. Hangang Company of Hegang Group has successively developed low-carbon microalloy series and dual phase series wheel steel. To date, it has produced over 1.6 million tons of wheel steel, making it one of the company's flagship products for hot-rolled plates. The hot dip galvanizing line of Hegang Group Chenggang Company was put into operation in 2019, with advantages such as high substrate strength and wide range of zinc layer thickness. Its ultra-thick zinc layer products are widely used in fields such as construction and pipe galleries. After flash butt welding of steel for wheels, it is necessary to undergo forming processes such as expanding and bulging. Due to the coarse structure and poor toughness of the welded joint, cracking problems often occur during the forming process. The factors that affect the cracking of steel welded joints for wheels are complex, mainly because the matching between welding and forming processes has not been clarified during the welding and forming composite process of steel. Therefore, it is imperative to conduct systematic simulation and experimental research on the welding forming process of typical wheel steel with different composition systems, in order to clarify its cracking mechanism. Conducting this study is not only conducive to accurate and clear diagnosis of the causes of welded joint cracking, but also directly improves the quality and user satisfaction of wheel steel products of Hegang Group. When welding galvanized sheet, due to the arc temperature being much higher than the gasification temperature of the zinc layer (the zinc layer melts at 787 º C and gasifies at 1663 º C), the zinc vapor generated during the welding process mixes with air to form zinc oxide, resulting in the burning of the zinc layer. In addition, with the transition flow of high-temperature molten steel, zinc vapor will also be drawn into the molten pool and solidify in the weld bead in the form of gas, forming pore defects. At present, galvanized sheets in China are welded after polishing the zinc layer. To ensure their corrosion resistance, they must be repainted, which affects production efficiency and causes environmental pollution. Therefore, welding defect in the welding process of galvanized steel plate can be reduced by carrying out the research on the matching of welding process optimization and welding materials of galvanized steel plate.