Research On The Hot Rolling Process Of Q460E Crisscross Deformed Steel

The thesis is mainly on the process of hot rolling of crisscross deformed steel which is specifically used in the manufacturing of combined type brake beam. On the basis of the characteristics of the section of the steel, the thesis introduces a new type of pass system which is the combination of the trapezoidal pass, bottom cut hat pass, convexity trapezoidal pass and the double-wedge pass. Through this system, the two steps of rough rolling and fine rolling are combined together, and by the means of moving rolling line, the difficulties of being produced on small size rolling mills are solved. In the thesis, there are introductions of the crisscross deformed steel on the followings in detail: design of the pass, disposition of the pass, selection of the roll materials, design of guides and guards and the machining process of the pass, etc.; there are also introduction of the newly design of bottom cut hat pass, convexity trapezoidal pass and the double-wedge pass, etc. and the disposition of the pass is according to the form of 5-2-1-1 on the basis of the features of the rolling mills. In view of the features of the small size rolling mills and also that this is the first time of using this pass system, the selection of the rolling materials are considered both on wear-resisting property and economy. In the process of rough rolling, the alloy semisteel was chosen, and the unlimited chrome and molybdenum chilled iron roll material was used in the process of fine rolling. The design of the guides and guards are mainly on the basis of utility and to simple the design to make it be convenient in machining and adjustment. The structure of the guides and guards are improved according to the reality of the rolled pieces. In order to solve the problems in pass machining, a new machining process is introduced which can machine the closed type pass system on the general old type lathe. There are analyses in the thesis why the Q460E microalloy steel should use the processes of rolling control and cooling control, and also there are arguments on how to realize rolling control and cooling control in assuring the mechanical property of the steel and the quality of the products. The manner of making the deformed steel to satisfy the technical requirements on the condition of un-straightening is introduced to rolling control and cooling control. There are also analysis and arguments in details on the problems of rolling procedure, the features and causes of the general defects and its solutions, and this will have a good effect on the production. By the evidence of production experience and the implementation of the above suggestions, it is obvious that the complicated deformed steel in middle size can be produced on small size rolling mills, and the quality of the products can be assured.