With the implementation of the “Three Guarantees” responsibility system in the international automobile industry, the quality requirements of automobile parts are becoming higher and higher. For the cylinder head of the key parts of the automobile engine, the product quality requirements are to keep improving, and the quality control...
The main defects in the trial production of hook body and hook tongue parts are crack, air hole, sand inclusion and mechanical sand sticking. Cracks are mainly thermal cracks, that is, the cracks caused by the obstruction of solid-state shrinkage of steel castings when the steel castings are still...
Although the wet mold clay sand has good concession and refrigeration, crack defects still appear from time to time in the production of Wet Mold clay sand steel castings. The wet mold clay sand has high moisture content, rapid cooling of steel castings, complex part structure and large difference...
The cracks of the motor shell are typical thermal cracks. There are more than 40 cracks and more than 80 cracks in each motor shell. Among them, the number of cracks at the fillet of the inner cylinder accounts for 50%, the cracks at the part with excessive wall...
The total number of cracks in the motor shell produced by furan resin sand casting process is about 70, while the total number of cracks in the motor shell produced by alkaline phenolic resin sand casting process is 30 on average, and the number of crack defects is reduced...
The larger the hot brittle zone of the alloy, the greater the shrinkage of the casting in this temperature range, and the greater the tendency of forming hot tears casting defects. Any element that enlarges the hot brittle zone can promote the formation of hot cracking. The effects of...
The formation mechanism of hot tears casting defects mainly includes liquid film theory and strength theory. According to the liquid film theory, when the casting is cooled near the solidus, there is still a small amount of non solidified liquid around the grain to form a liquid film. When...
The appearance characteristics of hot tears casting defects are that the tears propagates along the grain boundary, the appearance is tortuous, the surface has oxidation color, is not smooth, the surface is wide and the interior is narrow. It usually occurs in the hot spot where the section thickness...
The causes of cracks and sand inclusion defects in motor shell steel castings are studied from the perspective of process optimization. The research on process optimization mainly includes four aspects. ① Optimization of molding sand process in sand casting. The addition amount of alkaline phenolic resin is 1.5% ~...
The formation reason and process of tensile crack casting defect are different from that of shrinkage crack casting defect. 1) When the molten steel is poured into the casting cavity, the surface of the steel casting near the sand mold begins to solidify first and forms a solidification layer....