Crawler shoe is the key component of roadheader walking mechanism, which is connected by pin to form crawler shoe chain. When one of the crawler shoes has a problem, it will affect the normal work of the whole crawler shoe chain and roadheader. Therefore, the improvement and optimization of track plate casting technology to improve the product quality and service life is of great significance to improve the comprehensive performance of the equipment. EPC technology is known as “green casting technology” for its less pollution, high dimensional accuracy, small machining allowance and high production efficiency. In actual production, the best casting process plan is usually made according to experience and trial and error, which not only increases the development cost, but also prolongs the manufacturing cycle, which is not conducive to the competition of enterprises in the market. The development and application of numerical simulation technology in the casting field can effectively reduce the number of tests and shorten the product manufacturing cycle, which is a very important auxiliary means in the process of making casting process plan.
The casting solidification process of track shoe was simulated by ProCAST software. The casting defects were predicted through the simulation analysis of the temperature field and stress field of the casting, which provided a reference for the enterprise to formulate the casting process plan in the future production.
(1) the lower the pouring temperature of lost foam casting, the smaller the shrinkage porosity and porosity of the casting. However, the low temperature will reduce the fluidity of molten steel, resulting in incomplete combustion of the foam pattern in the mold, and the casting is prone to defects such as insufficient casting, cold separation and slag inclusion. When the pouring temperature of track shoe is 1610 ℃, the shrinkage cavity (shrinkage porosity) is reduced obviously.
(2) The effective stress of the casting is not obviously affected by the pouring speed. Considering the poor fluidity and easy oxidation of the molten steel, the pouring speed is 14kg / s.
(3) The pouring temperature has a great influence on the effective stress of castings. The effective stress of the casting decreases obviously with the decrease of pouring temperature.
Through the simulation of solidification process of track shoe casting, the location and size of defects were predicted. Through the optimization of process parameters and production test verification, the best casting process was determined. Fig. 1 is the foam pattern and casting after coating the actual production.
Figure 2 shows the actual production of castings after magnetic particle inspection. It can be seen that there are no obvious defects on the surface of the track shoe casting, and the qualified rate has been greatly improved. According to the feedback from customers, the service life of the track shoe has been increased by about 20%.