Analysis of the poor quality of Wear-resistant Castings
Wear-resistant Castings are an important part of the mechanical products, the mechanical products have a great impact on the performance of Wear-resistant Castings wear and dimensional stability, directly affect the accuracy of the machine and the service life, but the current airport wear Casting there are still many problems, these problems arising from what factors related to it? Here is a simple analysis.
1. The quality of raw materials for casting, metal charge, refractory materials, fuel, flux and other materials substandard quality, will make Wear-resistant Castings produce pores, pinholes, slag, sticky sand and other defects, affecting the appearance of Wear-resistant Castings and Internal quality, serious Wear-resistant Castings will be scrapped.
2. Process operation, to develop a reasonable process operating procedures, that is, according to Wear-resistant Castings structure, weight and size, casting alloy characteristics and production conditions, select the appropriate sub-surface and shape, core method, Cold iron, riser and pouring system, to improve the technical level of workers, so that the correct implementation of the rules.
3. Reasonable design of Wear-resistant Castings, the design, in addition to working conditions and metal materials to determine the performance of Wear-resistant Castings geometric shapes, size, but also from the casting alloy and casting process characteristics to consider the rationality of the design , That is, the size effect and solidification, shrinkage, stress and other issues, in order to avoid or reduce the composition of copper parts segregation, deformation, cracking and other defects.
At present, China's Wear-resistant Castings low prices, but the overall poor quality, poor economic efficiency, why the domestic Wear-resistant Castings will appear such a situation? Mainly because the domestic casting business competition still remain in the simple price competition, with the price to seize the market, resulting in poor quality Wear-resistant Castings. In addition, the domestic casting enterprise equipment mainly from abroad, there is no independent development of technology and innovation; China's foundry technical personnel and senior technical workers are relatively lacking, and wear-resistant casting standard system and the integration of international standards And inspection and certification work has not yet further strengthened; compared with other industries, casting industry in scientific research, training, although established, but also difficult to adapt to the rapid development of the foundry market.
Resulting in poor quality of domestic Wear-resistant Castings, in addition to the technical aspects of the factors, some external factors can not be ignored, China's Wear-resistant Castings want to be recognized in the domestic and international markets, the need is to improve the quality of Wear-resistant Castings, the formation of good competition Environment, independent development, closely follow the trend of the international market development, not behind closed doors.
For Wear-resistant Castings we do not feel strange, wear-resistant casting applications have a long history. In ancient times, people use Wear-resistant Castings to do coins, weapons, tools and some living utensils. However, in modern times, Wear-resistant Castings are mainly used for rough parts of machine parts or directly used as machine parts. Mechanical products, Wear-resistant Castings began to account for more and more, the amount is increased year by year, Wear-resistant Castings shape, variety is also changing. Wear-resistant Castings gradually become an indispensable part of our daily life, all kinds of door handles, door locks, small water pipes and other occasions can see the use of Wear-resistant Castings.
Wear-resistant Castings have excellent mechanical and physical properties, it can have a variety of different strength, hardness, toughness with the comprehensive performance, but also both one or more special properties, such as wear, high temperature and low temperature Corrosion and so on.
Wear-resistant Castings of the weight and size range is very wide, the lightest weight only a few grams, the most important can reach 400 tons, the thinnest wall only 0.5 mm, the thickest can be more than 1 meter, the length can be from a few millimeters to ten A few meters, to meet the requirements of different industrial sectors.
Comparison between Wear-resistant Castings and stainless steel forgings:
1. Wear-resistant Castings have good wear resistance and shock absorption function, because the cast iron graphite is conducive to lubrication and oil storage, so good wear resistance. Similarly, due to the presence of graphite, gray cast iron shock resistance is better than steel The
2. Wear-resistant casting process performance is good, because the gray cast iron with high carbon content, close to the eutectic composition, so the melting point is relatively low, good fluidity, shrinkage is small, so suitable for complex casting or thin-walled Wear-resistant Castings.In addition, Since graphite is easy to form chips during cutting, the machinability of gray cast iron is better than that of steel.