Inherent defect of casting, when used in the equipment, the production will bring unpredictable risks, not only will shorten the service life, there will be accidents. Production of castings business, its business goal is to maximize profits. For this reason, in the production process as much as possible to improve the yield of the casting. Casting the total weight of the finished product was qualified and investment casting metal charge a percentage of the total weight. According to the casting material, the size, the yield of normal in the following ranges: Small pieces of iron castings 60% to 64%, with 64% to 70%, large 70%. 80% Steel Castings 50% to 55% 45% ductile iron and alloy iron castings. 50% Malleable Iron Castings 38% to 45% Steel Castings 50% to 55% Aluminum casting about 50% In order to reduce casting defects and improve yield casting, casting defects must be effectively controlled. And accurately determine the defect is a precondition to solve the casting defects. Thus, workers need to understand the casting defects analytical tools, including the general and specific analytical tools to determine the type of defect, analyze its causes, and then propose preventive measures and implement them from a technology and management. Casting defect analysis and research, it is one of the key technologies to improve casting yield. However, the difficulty is not small. Mainly in: ① it involves a wide range of knowledge, such as alloys, casting, molding materials, casting detection equipment and other aspects of the production process knowledge. ② diversity causes of casting defects, a defect can be caused by a variety of reasons, but one reason they may cause some defects. Conditionality ③ technical measures, such as the use of certain measures. -1- To prevent certain types of defects, but may lead to another kind of defect. ④ factors difficult to control, such as raw material quality, air temperature and humidity and so on. It is noteworthy that the same type although flawed, but for different casting alloy castings, its causes and preventive measures there is a difference. For example, the same iron-carbon alloy, with the emergence of larvae L defect reduction, for the purposes of steel castings, should riser, cold iron to prevent shrinkage defects; and for large thick-walled ductile iron pieces, you can use expansion of graphite during solidification produce, while the use of non-riser casting to eliminate shrinkage defects. Therefore, concrete analysis of concrete conditions. In order to deepen the understanding of the casting defects, some casting defects typical cases analyzed, might be helpful. http://www.cnwxyszj.com
.gif)
.gif)