Dalian castings are generally made of uniform A-type graphite gray cast iron. In some cases, cr0.5% ～ 1.0%, Mo (0.6 ± 0.1)%; Hypereutectic or low sulfur gray cast iron can resist thermal shock and improve the service life of metal mold. Gray cast iron metal mold is used for medium and small parts, with a general mold life of 2000 ~ 5000 times. In the casting cost, the metal mold cost generally accounts for 10%. In addition, the water cooling system for external welding of thin steel metal profile can be used, which can have a long service life. Including D-type graphite gray cast iron and fine ductile iron, the matrix is ferrite. It can also adopt normalizing, annealing or isothermal quenching processes to obtain different substrates. The painting should not be completed at one time. Because the painting is very thick, the paint is easy to crack, so two to three layers should be applied. The overall thickness of the coating should be controlled at about 1mm. In the manufacturing of castings in Dalian, the physical and mechanical properties of materials have a great impact on the selection of process parameters, the setting of gating and riser and chill, the heat treatment technology, and the post-treatment technology of castings.
