In the 20th century, the development of casting is very fast. One of the important factors is the progress of product technology, which requires the castings to have better mechanical and physical properties, and still have good machining properties.Another reason is that the development of the mechanical industry itself and other industries such as chemical industry and instrumentation has created favorable material conditions for the foundry industry.For example, the development of detection means ensures the improvement and stability of casting quality and provides conditions for the development of casting theory.The invention of electron microscope and so on, help people go deep into the microscopic world of metal, probe the mystery of metal crystallization, study the theory of metal solidification, guide casting production.Developed a large number of superior performance in this period, a variety of new casting metal materials, such as nodular cast iron, the welding of malleable cast iron, ultra-low carbon stainless steel, aluminum, copper, aluminum, silicon, aluminum and magnesium alloys, titanium, nickel base alloy, etc., and the new process of grey cast iron inoculation treatment, the adaptability of castings is more extensive.Since the 1950s, high pressure wet sand molding, chemically hardened sand molding and core-making, negative pressure molding and other special casting, shot blasting cleaning and other new technologies have emerged, making the casting with high shape and size accuracy and good surface finish, and greatly improving the working conditions and environmental sanitation of the casting workshop.In the great progress of casting industry since the 20th century, the inoculation and treatment of gray cast iron and the chemical hardening sand molding are of special significance.These two inventions break through the traditional method which has lasted for thousands of years, and open up a new field of casting technology.

Precision foundry casting is generally classified according to molding method, which is conventionally divided into ordinary sand mold casting and special casting.Common sand mold casting includes wet sand mold, dry sand mold and chemically hardened sand mold.According to the different molding materials, special casting can be divided into two categories: one with natural mineral sand as the main molding materials, such as investment casting, shell casting, negative pressure casting, mud casting, solid casting, ceramic casting, etc.A class of metal as the main casting material, such as metal mold casting, centrifugal casting, continuous casting, pressure casting, low pressure casting, casting process can be divided into three basic parts, namely, casting metal preparation, casting preparation and casting treatment.Casting metal is used in casting production for casting metal materials, it is a kind of metal element as the main component, and join other metal or non-metallic elements and composition of alloy, customary called casting alloy, mainly cast iron, cast steel and cast non-ferrous alloy.Metal smelting is not only a simple melting, but also includes smelting process, so that the cast metal, in terms of temperature, chemical composition and purity are in line with the expected requirements.For this reason, various inspection tests should be carried out in the smelting process for the purpose of quality control, and the liquid metal can be allowed to be poured after reaching the specified indexes.Sometimes, in order to meet the higher requirements, the metal liquid in the furnace after the process, such as desulfurization, vacuum degassing, outside the furnace refining, inoculation or deterioration treatment.Common equipment for smelting metal includes cupola, electric arc furnace, induction furnace, resistance furnace, and reflection furnace.

Different casting methods have different preparation contents.Taking the most widely used sand mold casting as an example, mold preparation includes two major tasks: molding material preparation and molding core making.In sand casting is used to model core making all kinds of raw materials, such as casting sand, sand binder, and other accessories, and a mixture of them, core sand, coating etc are collectively referred to as moulding material molding materials prepared by the nature of the task is in accordance with the requirements of the castings, metal, choose appropriate raw sand, binder and accessories, and then according to certain proportion mixed them into certain properties of the sand and core sand.The commonly used sand mixing equipment includes roller sand mixing machine, counterflow sand mixing machine and blade groove sand mixing machine.The latter is designed for mixing chemical self-hardening sand, continuous mixing, fast speed.In the 20th century, the development of casting is very fast. One of the important factors is the progress of product technology, which requires the castings to have better mechanical and physical properties, and still have good machining properties.Another reason is that the development of the mechanical industry itself and other industries such as chemical industry and instrumentation has created favorable material conditions for the foundry industry.For example, the development of detection means ensures the improvement and stability of casting quality and provides conditions for the development of casting theory.The invention of electron microscope and so on, help people go deep into the microscopic world of metal, probe the mystery of metal crystallization, study the theory of metal solidification, guide casting production.Developed a large number of superior performance in this period, a variety of new casting metal materials, such as nodular cast iron, the welding of malleable cast iron, ultra-low carbon stainless steel, aluminum, copper, aluminum, silicon, aluminum and magnesium alloys, titanium, nickel base alloy, etc., and the new process of grey cast iron inoculation treatment, the adaptability of castings is more extensive.Since the 1950s, high pressure wet sand molding, chemically hardened sand molding and core-making, negative pressure molding and other special casting, shot blasting cleaning and other new technologies have emerged, making the casting with high shape and size accuracy and good surface finish, and greatly improving the working conditions and environmental sanitation of the casting workshop.In the great progress of casting industry since the 20th century, the inoculation and treatment of gray cast iron and the chemical hardening sand molding are of special significance.These two inventions break through the traditional method which has lasted for thousands of years, and open up a new field of casting technology.

Casting generally according to the molding method to classification, custom is divided into ordinary sand casting and special casting.Common sand mold casting includes wet sand mold, dry sand mold and chemically hardened sand mold.According to the different molding materials, special casting can be divided into two categories: one with natural mineral sand as the main molding materials, such as investment casting, shell casting, negative pressure casting, mud casting, solid casting, ceramic casting, etc.A class of metal as the main casting materials, such as metal mold casting, centrifugal casting, continuous casting, pressure casting, low pressure casting.

Casting process can be divided into three basic parts, namely, casting metal preparation, mold preparation and casting treatment.Casting metal is used in casting production for casting metal materials, it is a kind of metal element as the main component, and join other metal or non-metallic elements and composition of alloy, customary called casting alloy, mainly cast iron, cast steel and cast non-ferrous alloy.

Metal smelting is not only a simple melting, but also includes smelting process, so that the cast metal, in terms of temperature, chemical composition and purity are in line with the expected requirements.For this reason, various inspection tests should be carried out in the smelting process for the purpose of quality control, and the liquid metal can be allowed to be poured after reaching the specified indexes.Sometimes, in order to meet the higher requirements, the metal liquid in the furnace after the process, such as desulfurization, vacuum degassing, outside the furnace refining, inoculation or deterioration treatment.Common equipment for smelting metal includes cupola, electric arc furnace, induction furnace, resistance furnace, and reflection furnace.

Different casting methods have different preparation contents.Taking the most widely used sand mold casting as an example, mold preparation includes two major tasks: molding material preparation and molding core making.In sand casting is used to model core making all kinds of raw materials, such as casting sand, sand binder, and other accessories, and a mixture of them, core sand, coating etc are collectively referred to as moulding material molding materials prepared by the nature of the task is in accordance with the requirements of the castings, metal, choose appropriate raw sand, binder and accessories, and then according to certain proportion mixed them into certain properties of the sand and core sand.The commonly used sand mixing equipment includes roller sand mixing machine, counterflow sand mixing machine and blade groove sand mixing machine.The latter is designed for mixing chemical self-hardening sand, continuous mixing, fast speed.