Optimization of molybdenum plate rolling process
The crystal structure of refractory metal molybdenum is body-centered cubic. Because of its high temperature strength, high temperature hardness and stiffness, strong shock resistance and corrosion resistance, good electrical and thermal conductivity, low coefficient of expansion and excellent heat-resistant fatigue performance, it is widely used in boat dishes, heating elements, heat insulation screen and other aspects.
In molybdenum material, plate is most widely used. With the rapid development of aerospace, electronics and other industries, a large number of wide and long high quality molybdenum plates are needed. The molybdenum plate is not only required to have good plasticity, high strength, low anisotropy, but also to have high dimensional accuracy, good shape and good surface quality when used to make various electrical vacuum devices. Therefore, the surface of molybdenum plate is required to have no cracks, peels, burr and other defects, the homogeneity of molybdenum plate and strict control of dimensional tolerance, tensile strength and elongation should be controlled in a certain range in recent years, the thickness of molybdenum plate is less than 0.5 mm after hot rolling, warm rolling, cold rolling and other processes of 12mm thick molybdenum blank. The properties of molybdenum plate produced by this process are uniform, and its chemical composition and mechanical properties can meet the requirements of users. But in the process of production, the sheet rolling waste phenomenon is serious, rolling parts often appear a variety of defects, such as head mouth cracking, lamination, edge crack and so on, and the finished molybdenum plate surface sometimes appear burr, peeling and other defects, resulting in low molybdenum plate yield. For the molybdenum plate with small defects, the quality of the plate can be qualified after alkali washing and surface grinding, but the production process is increased, the loss of molybdenum plate and environmental protection treatment are increased, and the production cost is increased correspondingly.
(1) Hot rolling temperature and initial fire deformation rate have important effects on the comprehensive properties of molybdenum sheet. When the hot rolling temperature is 1250℃ and the initial fire deformation rate is 37.5%, the comprehensive mechanical properties of molybdenum sheet after rolling are better.
(2) The improved rolling technology not only effectively improves the surface quality of molybdenum plate products, but also greatly improves the yield.
