Centrifugal cast copper castings have a long history of […]
Centrifugal cast copper castings have a long history of application. Ancient people used castings and some living utensils. In modern times, castings are mainly used as blanks for machine parts, and some precision castings can also be directly used as parts of machines. Castings account for a large proportion of mechanical products. For example, in tractors, the weight of castings accounts for 50~70% of the weight of the whole machine, 40~70% of agricultural machinery, and 70~90% of machine tools and internal combustion engines. Among all kinds of castings, the most suitable castings for machinery use, the most complex shape, and the largest amount, accounting for about 60% of the total output of castings. This is followed by steel ingot molds for metallurgy and pipes for engineering, as well as some tools in life. Castings are also closely related to daily life. For example, door handles, door locks, radiators, water pipes, iron pans, gas hobs, irons, etc., which are often used, are castings. There are many classification methods for castings: according to the different metal materials used, they are divided into steel castings, cast iron parts, cast copper parts, cast aluminum parts, cast magnesium parts, cast zinc parts, and cast titanium parts. Each type of casting can be further divided into different types according to its chemical composition or metallographic structure. For example, cast iron parts can be divided into gray iron castings, ductile iron castings, vermicular graphite iron castings, malleable iron castings, alloy cast iron fittings, etc.; according to different molding methods, castings can be divided into ordinary sand castings, metal castings, and die castings. , centrifugal castings, continuous castings, investment castings, ceramic castings, electroslag remelting castings, bimetal castings, etc. Among them, ordinary sand castings are the most widely used, accounting for about 80% of all castings. Non-ferrous metal castings such as aluminum, magnesium and zinc are mostly die-casting parts.
The proportion of liquid molded parts in machinery and equipment is very large. In machine tools, internal combustion engines, mining machinery, heavy machinery, liquid molded parts account for 70%~90% of the total weight; in automobiles and tractors, 50%~70%; Agricultural machinery accounts for 40% to 70%. The liquid molding process can be used in such a wide range of applications because it has the following advantages:
(1) It is possible to manufacture a blank having a complicated inner cavity and a complicated shape. Such as various cabinets, machine bed, cylinder block, cylinder head and so on.
(2) The process flexibility is large and the adaptability is wide. The size of the liquid molded part is almost unlimited, and the weight thereof may be several grams to several hundred tons, and the wall thickness may be from about 0.5 mm to about 1 m. Any metal material that can be dissolved into a liquid state in the industry can be used for liquid molding. For cast iron with poor plasticity, liquid forming is the only way to produce its blanks or parts.
(3) The cost of liquid molded parts is low. Liquid forming allows direct use of waste parts and chips, resulting in lower equipment costs. At the same time, the liquid molded parts have a small processing margin and save metal.