Casting is a process in which a metal is smelted into a liquid that meets certain requirements and poured into a mold, which is cooled and solidified and subjected to a treatment to obtain a casting having a predetermined shape, size and performance. Casting is one of the basic processes of the modern machinery manufacturing industry.
Casting is a metal thermal processing technology that has been mastered by humans for a long time. It has a history of about 6,000 years. China has entered the heyday of bronze castings between about 1700 and 1000 BC, and the process has reached a fairly high level. The Shang dynasty of China’s Shang dynasty, weighing 875 kilograms, was founded by Zeng Houyi, the Zeng Houyi of the Warring States period, and the translucent mirror of the Western Han Dynasty.
Most of the early castings were tools or tools for agricultural production, religion, and life, and the art was strong. The casting process at that time was developed in parallel with the ceramics process and was greatly influenced by pottery.
In 513 BC, China cast the first cast iron piece in the world, which was written in Jinju, with a weight of about 270 kg. Europe also began producing cast iron parts around the eighth century. The emergence of cast iron parts has expanded the range of applications for castings. For example, in the 15th and 17th centuries, Germany, France and other countries have laid a number of cast iron pipes that supply drinking water to residents. After the industrial revolution of the 18th century, industries such as steam engines, textile machines and railways rose, castings entered a new era of service for large industries, and casting technology began to develop.
In the 20th century, the development speed of casting is very fast. One of the important factors is the advancement of product technology, which requires various mechanical and physical properties of castings to be better, while still having good mechanical processing performance. Another reason is the mechanical industry itself and others. The development of industries such as chemicals and instruments has created favorable material conditions for the foundry industry. Such as the development of testing methods, to ensure the improvement and stability of casting quality, and to provide conditions for the development of casting theory; the invention of electron microscopy, etc., to help people penetrate into the microscopic world of metal, explore the mystery of metal crystallization, study the theory of metal solidification To guide casting production.
During this period, a large number of new cast metal materials with superior performance and rich variety, such as ductile iron, weldable malleable cast iron, ultra-low carbon stainless steel, aluminum-copper, aluminum-silicon, aluminum-magnesium alloy, titanium-based, nickel-based alloy, etc. And invented a new process for the inoculation of gray cast iron, making the casting more adaptable.
After the 1950s, there were new technologies such as wet sand high pressure molding, chemical hardening sand molding and core making, negative pressure molding and other special casting and shot blasting, which made the castings have high shape, dimensional accuracy and good surface finish. The working conditions and environmental sanitation of the foundry were also greatly improved.
In the significant progress of the foundry industry since the 20th century, the two new processes of gray cast iron gestation treatment and chemical hardening sand molding have special significance. These two inventions have broken through the traditional methods that have lasted for thousands of years, opening up new fields for the casting process and having a major impact on improving the competitiveness of castings.
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