Several typical thin-walled engine block sand castings such as ea188 were selected and formed by wet sand casting process. Experimental research was carried out on the surface defects of sand castings and the process control related to surface quality in the process of sand casting. Figure 2-1 shows one of the engine block sand castings with complex structure. The sand castings used in the experiment are sand casting complex thin-walled cylinder blocks, with two pieces of each type. The horizontal horizontal pouring process and triethylamine cold core box sand core are adopted. Taking the cylinder block of ea188 engine as an example, the general wall thickness of the cylinder block is 3.5 ± 0.8mm.
Engine sand castings are made of gray cast iron. At present, green sand casting process is still the most widely used in the production of sand cast iron cylinder block, especially the static pressure and air impact molding line with low energy consumption, low noise, less pollution, high efficiency and reliable operation has become the main process of sand cast iron cylinder block blank production.
The process flow of sand casting used in the study is as follows:
(1) Sand casting and melting process: the microcomputer distributed control hot air dedusting cupola and 45 ton cored power frequency holding furnace are adopted, and the 8 ton 400KW air pressure holding ladle pouring process is adopted.
(2) Sand casting molding process: German kW static pressure molding line and American CPU automatic control Simpson sand treatment system are adopted.
(3) Sand casting process: loramendi, Suzhou programmable control cold box core making machine.
(4) Sand casting cleaning process: German high-efficiency squirrel cage shot blasting machine, special oil channel shot blasting equipment for cylinder block and oil channel inner cavity inspection endoscope are adopted.