Design of Warm - Forming Process for Open Die Forgings
Taking the spline active forging of a 90 motorcycle in the 90 type motorcycle as an example, according to the principle of the temperature extrusion technology, the mold forging analysis and the temperature forming process of the complex shape Open Die Forgings are analyzed, and the complex shape is discussed. Mold forging temperature extrusion molding process design of the difficulties and key points, combined with the actual production, developed for the actual production of the temperature extrusion process. Designed a set of economical and practical temperature extrusion molding die, and introduced the mold structure and the principle of the workpiece. The mass production test proved that the temperature extrusion molding process for the production of mold forging quality and stability, bumps full, and the mold structure is reasonable, versatility, high production efficiency. Gear is the machinery industry is widely used, the performance requirements of the higher transmission parts, most of the need for forging blanks. Among them, some of the complex shape, the end with a bump and has a part of the non-mating surface can be less without cutting to meet the requirements of the Open Die Forgings, is a mold forging process design a technical difficulty. In general, due to the complex geometrical shape of the mold, the traditional hot forging method is easy to produce forging defects, it is difficult to meet its quality requirements, and the use of temperature extrusion process technology is one of the technical difficulties to solve its technical difficulties. Warm extrusion is hot extrusion, is based on the cold extrusion process developed a few less cutting process, the deformation temperature is generally above room temperature to the hot extrusion temperature below the range. Warm extrusion technology to a certain extent, both the advantages of cold and hot extrusion, but also reduce their respective shortcomings. Since the metal is heated and squeezed in a higher temperature range, it is possible to omit the auxiliary process such as pre-annealing and phosphating in the process, thereby reducing the problem of environmental pollution due to the phosphating treatment. Moreover, because the deformation of the blank than the cold when the small, the mold life can also be higher than the cold extrusion. Compared with the hot extrusion, but also overcome the strong oxidation due to reduce product surface quality problems, so the product size and mechanical properties are better than hot extrusion.
In the process of Open Die Forgings process design process, by the rough selection of unreasonable factors such as the impact of the blank in the cavity often occurs in the reflow or convection phenomenon, and thus produce a more obvious folding. Conventional flange production process, as shown in Figure 2. With punch diameter o1 with blank diameter. The ratio between the gradual increase in the incidence of folding phenomenon will gradually reduce, on the contrary, the incidence of folding phenomenon will be high. Mold cavity size hl / o1 and o1 / o2 ratio of the increase, that is, the cavity gradually deepened, narrowed, can greatly reduce the incidence of folding, on the contrary, the incidence of folding phenomenon will be high. With the punch edge edge radius R gradually increases, the incidence of folding will be reduced, on the contrary, the incidence of folding will be high. However, the radius R only affects the larger diameter of the blank, but its effect on the smaller diameter of the smaller punch.
Under normal circumstances, the use of mold temperature of 250 ℃. In the process of multi-fire production, the temperature of the mold forging between the fire is room temperature. And in the next fire before the production, you need to re-install the mold, heating, removal and other treatment, the last fire with the fire after the treatment of the mold center is usually not completely coincide. The Open Die Forgings in the upper mold cavity can not be fully inserted into the upper mold cavity, which can cause the side of the deviation to collapse. The occurrence of this folding phenomenon is similar to that caused by the deformation of the die forging, but the reason for the two is completely different. The main method is to minimize the fire of the mold forging to achieve the improvement of the technological level The
In the module there are discontinuous, convex shape of the Open Die Forgings, after more fire Open Die Forgings treatment, by the operation of the beat and punching edge and other factors, mold forgings are usually different degrees of deformation phenomenon. In the next fire forging, as the upper hammering center is the same as this fire, the formed bosses can not be all placed in the upper mold cavity, and at the edge of the Open Die Forgings It will produce folding phenomenon, and the more measures, the higher the incidence of folding, the more serious the degree. Therefore, in the process of forging process, should minimize the fire, as far as possible to do a fire molding.