Gray iron castings adopt lost foam, resin sand casting process, equipped with large gas tempering kiln, artificial aging, quenching and tempering to release internal stress, etc., to improve the accuracy of castings after processing. In the finishing process of the bed, the machine tool will cause thermal deformation of the spindle due to long-term cutting, which will affect the final machining accuracy. For high-precision machine tools and large-scale machine tools, the machining error caused by thermal deformation accounts for about 40~70%. Because thermal deformation can only be improved but cannot be eliminated, when the machine tool is determined, it is generally only possible to control the cutting conditions of the machine tool. To achieve the purpose of stabilizing the temperature of the machine tool, so as to avoid the influence of temperature changes on the machining accuracy.
When the foundry manufactures bed casting products, as a large-scale casting, it must undergo heat treatment to improve its performance and improve the inherent quality of cast iron castings. Metal heat treatment is one of the important processes in mechanical manufacturing. Compared with other processing processes, heat treatment generally does not change the shape and overall chemical composition of the workpiece, but by changing the internal microstructure of the workpiece or changing the chemical composition of the surface of the workpiece. , To give or improve the performance of the workpiece.
The graphite of gray iron is flat and flake, and the graphite of ductile iron is spherical. If the spheroidal graphite cast iron is hit with a sound similar to that of carbon steel, it indicates that the spheroidal graphite cast iron is well spheroidized. But the sound of gray iron percussion sounds dull.
First, after the pressure is maintained, the mold must be opened to take out the precision casting product, so the time from the end of injection to the opening of the die-casting mold is called the mold opening time. Opening the mold in sufficient time can make the precision casting have a certain strength in the mold. If the opening time and the ejection time are inconsistent, the product will deform and crack. If the opening time is too short, the casting will be demoulded when the strength is relatively low, which will also cause the casting to deform.
Stainless steel casting is a technology in the foundry industry, but it is different from the traditional foundry industry because of the high added value of precision casting products. According to relevant statistics, the added value of European and American precision casting products in aerospace equipment and engines accounted for nearly 70% of the total added value, while in China this proportion is less than 35%.