In 2020, the international and domestic economy went down seriously, the domestic foundry industry was in great depression, and many foundry companies laid off a large number of workers or even closed down. Our company also encountered great business difficulties. The orders for the bolster side frame of the main product shrank significantly, the production of small and medium-sized parts in the domestic market and the national railway freight car almost stopped, and a large number of people stopped working, shunted and faced the edge of bankruptcy. In order to survive, our company has actively expanded the international market and signed the project development contract of B10 motor shell steel castings with foreign well-known company A. the company has gathered all excellent engineering and technical personnel, front-line high skilled personnel and all advantageous resources. After 8 months, it has passed the project certification of the company. This type of motor shell steel castings is used in European and American high-power diesel locomotives. Each vehicle uses 12 motor shell steel castings, and the annual market is about 10000-12000 pieces. However, there are three manufacturers in the world, one in the Czech Republic and one in India. The competition is fierce in China. Whoever has good quality and low price can get about 50% of the share. For example, our company can get an order of 5000-6000 pieces every year, Our company can not only survive in the lowest period of the industry, but also make a profit, which is very helpful to the development of the company.
Although ZHY casting successfully passed the certification of company a in January 2021 and obtained a small batch order of 200 pieces in the early stage, in the small batch production from January to March 2016, due to imperfect process and unskilled personnel, many quality problems occurred in the motor shell steel castings, such as sand inclusion, crack, air hole, casting deformation, inner hole processing deformation, positioning pin hole position out of tolerance, etc., and the scrap rate reached 19%, The quality level is not up to expectations, and the production cost is very high. Even if we grab the market order, we are still in a state of huge loss. Therefore, it is urgent to find out the key quality problems, analyze and study the root causes of the problems and solve them.
Motor shell steel castings are the main products of our company after transformation and upgrading, and they are also the key products related to whether our company can survive the crisis. Through the defect analysis and process optimization research on the motor shell of steel casting, it is analyzed and clarified what the main defects of the motor shell steel casting are and what the reasons are. It is proposed to take corresponding process measures and Countermeasures to fundamentally improve the product quality of the motor shell steel casting, reduce the scrap rate, reduce the production cost and improve the market competitiveness of the company, which is of far-reaching significance to the development of the company: improve the technological level of the company’s process manufacturing; Solve the employment problem of more than 200 people in the company; Create a profit of 2-3 million yuan / year for the company; It has laid a solid foundation for the company to further explore the international market. The research of this subject solves the problems of crack and sand inclusion in the manufacturing process of steel casting motor shell, and greatly improves the product quality. At the same time, the research results of this subject have practical guiding significance and reference value for the research of the same type of products.