1. Location and shape of crack defects in cylinder block castings During the trial production process, cracks were found between the cylinder barrel after the sand falling of the cylinder block casting. The location and shape of crack defects are shown in Figure 1. It can be seen that...
According to fracture mechanics, once the position of a certain point in the area near the top of the casting crack is determined, the stress intensity factor ki is the only control parameter of the stress, displacement and strain at that point, and the stress state at the tip...
1. Cold cracking casting defect Cold cracking casting defect refers to the crack caused by the casting stress greater than the alloy strength limit when the casting solidifies and cools to the elastic state. Therefore, cold cracking casting defects usually appear in the tensile part of the casting, especially...
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...