Optimization Of Contact Welding Process For High Strength And Toughness Bainite Rail

China Railway after the 20th century 80,90 era heavy and the rapid development in recent years, has basically taken shape both high-speed and heavy-duty situation.In order to meet China's largest railway transport capacity, high-density, heavy-duty needs of the rail line for higher and higher demands.In this context ANGANG first started the "high-strength ductile bainite rail study" project, and successfully produced China's first batch of bainite rail, it will now use the rail from 900 MPa compressive strength increased to 1100 MPa, the rail is more good mechanical properties. Bainite rail will be laid to the line, we must first have good welding performance. For its welding performance,the domestic current still in the exploratory stage.Bainite rail welding performance is good or bad is directly related to the promotion of values such rail. So take advantage of the current used by the contact welding (i.e. flash welding)machine to study bainite rail welding performance is of great significance. According to TB1632-91 requirements, each welded rail of new material should design a new set of welding parameters. Through type test, to test the performance of rail welding and welding parameters set by the pros. So in the welding test, the best approach is conducted in the laboratory welding small specimen testing, to explore new types of steel welding performance, base metal rail that bainite weldability good. In a small specimen tests, we found a set of welding parameters, and based on this, set parameters at GAAS80/700 contact welding machine then test the 60 kg / m bainite welded rail road.GAAS80/700 soldering machine has a total of 27 parameters, including 13 parameters on a greater impact on the quality of welding. In light of the new steel pilot, set of parameters very difficult, after testing thousands of joints, each post-mortem can be explored over a complete set of welding parameters, the reason is the 13 parameters and the interaction between each other constraints. So should deeply analytic welding process as well as the nature of the internal ioint constitution,and based on this understanding of the content and parameters of the joint properties of the need to build a mathematical model to intuitive understanding of the changes in the parameters of the joint quality of laws, and saving time, effort, the provincial materials, thus rapid completed test patterns. Orthogonal test method based on the characteristics of soldering machine, from the mathematical point of view gradually approaching, the test parameter optimization method. The method is time-saving, just over 200 joints to identify a set of high quality parameters, welding parameters set by the joint, through TB/1632-91 required by the test, to the department of frequency standards, and based on this, come up with a normalizing process parameters, thereby successfully end a post-mortem type tasks. Using orthogonal test, very quickly to draw up a set of welding parameters, it marks bainite rail has entered a substantive stage of the practice, bainite rail become the most promising, to satisfy the country's high-speed railway, and the strength and toughness of heavy demand, and become the 21st century's new generation of rail.