Cast Iron itself has the hard points: one is the cast iron material after heat processing, organizational structure change, the composition of hard small, hard points to the cutting surface density changes occur, the hard point for cutting has certain influence. But when this small changes in the cutting process encountered outside of knife edge sharp and passivation in the shearing process appears directly difference; two is better than that of high hardness particle or lump in iron castings, the casting defects called inclusion”. The reasons are mixed with the precipitate or alloy than the base metal hard metal or non metal compound particles, such as three two aluminum oxide, three aluminum, titanium etc.. Cast iron material according to the different grades of Aluminum Alloy, the differences of tissue components caused by differences in surface density, decrease the adhesion of hard points and the matrix, thus the density difference of cast iron point often in sharp edge processing under the condition of hard point is “empty pound” and formed “small shrinkage”.
In the process of nonferrous metal casting. The metal casting is widely used by many enterprises because of its many advantages, because of its high mechanical properties than the sand casting. The same alloy cast iron, the average tensile strength can be increased by about 25%, the yield strength increased about 20%, the corrosion resistance and hardness also increased significantly; secondly the accuracy and surface finish of the aluminum casting sand casting is high, and the quality and size stability; also the casting process yield from. Liquid metal consumption is reduced, can save 15 to 30% more or less; no sand sand, can save the other materials from 80 to 100%; in addition, the metal mold casting production and high efficiency: the reason of reducing casting defects; the process is simple, easy to realize mechanization and automation. Although many advantages but has its shortcomings, the thick section Aluminum Alloy casting precision or to reach the ideal level, so users are required to set aside some processing capacity of processing procedure, if mass production, the economic loss is enormous. Over the years, I have been determined to improve the accuracy of the metal casting to do some articles, how to make the thick broken blood aluminum alloy casting accuracy and improve the level of improvement.
First I in tooling, equipment gradually increase investment, it is a good article, manufacturing technology of casting model is also gradually upgrade, there are hundreds of sets: size model and equipment model corresponding to only a very simple mold machine to have a number of automatic and tiltable casting die casting machine. With a good horse, with a good saddle, the operator of the quality of training and the use of scientific and rational operation of the process, will eventually enable me to achieve the dream of improving the accuracy of large-scale non-ferrous metal castings.