Metal Castings in China
Nowadays, the outputs of all kinds of metal castings reach to more than 5 million tons in China, these metal castings widely used in every field of national economy, according to the statistics, the metal castings occupied 30-85% of the whole machine weight in machine equipments. At the same time, because the materials, technology and detective methods improve fast, the inner quality of castings, size accuracy and the surface finish reach to a high level, so among the machine products, the work of metal casting design is very large.
Metal castings produced depend on the casting methods.
1. The metal casting methods of machine tool castings can produce any kind of blanks and parts with complex shapes, such as the bodies of the internal-combustion engines, air cylinders, screw propellers and all kinds of pumps and so on. Because the limit of casting methods to the metal castings is small, so the metal castings can use reasonable section shapes base on the situation of force.
2. Use special casting, inlay casting and double-metal metal casting can make the structures of parts more reasonable and these methods can solve some problems which other metal casting methods can not solve, so they can acquire more economic effects. To some small and complex parts, we can use melted module precise casting and ceramic core methods to produce; they not only solve process problems but also increase the passing rate and save the materials.
3. The some iron parts only can be produced by casting methods.
The characteristics of the metal castings
General speaking, the cost of metal castings is low because the row materials are low and can be get easily, besides, some wasting metals can be melted again, the cost of the equipments of metal casting is low and so on.
The problems of metal castings produced in casting methods.
The mechanical properties of metal castings is not better than forgings which both have the same metal materials, the quality of metal castings is not stable and easily produce flaw products, so we do not use these metal castings to make some important parts.
In short, in order to produce good metals castings, we not only need to know about the methods of casting, but also need to consider what metal castings we desire.