In terms of structure, due to the split structure, the steel top of the piston is designed as a self-supporting component, and the "drilling cooling" method is adopted to improve the rigidity and heat dissipation capacity of the piston head. The split piston structure adopts high-strength bolts, and the piston skirt adopts high-quality Grade A heat-resistant alloy steel.
In terms of technology, Jiangsu Yonghang Rail Transit Technology Co., Ltd. has carried out strict quality control from the beginning of steel top forging. We attach great importance to each process, and we strictly control the equipment and parameters in each process. Repeated testing is carried out for each link. Steel top forging and heat treatment are the process elements that need to be controlled in the manufacturing process. Large-scale forging machines are used for steel top forging, and through precise die forging, the blank forging accuracy is guaranteed, the machining allowance is reduced, and good tissue fibers are obtained at the same time.
The entire processing of the steel top is completed by large-scale high-precision CNC, and the life of the steel top after the ring groove is hardened is greatly extended. In order to improve the traditional oscillating piston cooling method, Jiangsu Yonghang Rail Transit Technology Co., Ltd. is a piston steel The top provides a number of blind holes drilled radially obliquely outward from the central cooling surface. The number and arrangement of the holes and their effect on the temperature rise of the piston head are determined by calculation. The numerous blind holes on the piston head and the oil cavity on the thin-walled ductile iron skirt create a very large cooling cavity. With the help of the reciprocating motion of the piston, the exchange process of the cooling oil flowing in and out in the holes is improved, and the plate between the holes is effectively reduced. Compared with the traditional oscillating cooling cavity piston, the structural strength is greatly improved.
Piston skirt Jiangsu Yonghang Rail Transit Technology Co., Ltd. is using hot die forging process. Forging and heat treatment of steel skirt are process elements that need to be controlled in the manufacturing process. Large-scale forging machines are used for steel top forging, and through precise molds, the blank forging accuracy and surface quality are ensured, and at the same time, good tissue fibers are obtained.
The steel skirt should be subjected to heat treatment after rough machining to obtain very high performance indicators (greater than 1000Mpa) to meet the needs of the high explosion pressure of the whole machine. The entire processing is also carried out by large-scale high-precision CNC to ensure the uniformity of wall thickness during processing. and surface quality. The final product skirt is graphitized. For the piston skirt, the surface treatment is graphitized, and the graphite layer can reduce the initial wear of the engine.