Brief Introduction of Casting

Casting is the process of melting the metal into a required liquid and pouring it into the mold. After cooling, solidifying and cleaning, a casting (part or blank) with a predetermined shape, size and properties can be obtained It is the basic technology of modern machinery manufacturing industry. The cost of casting blank is low, especially for the parts with complex shape, especially with a complex cavity, it can show its economy, at the same time, its adaptability is wide, and has better comprehensive mechanical properties. However, there are more materials (such as metal, wood, fuel, molding materials) and equipment (such as metallurgical furnace, sand mixer, molding machine, core making machine, sand falling machine, shot blasting machine, etc.) needed for casting production And will produce dust, harmful gases and noise and pollution of the environment.

Casting is the process of melting the metal into a required liquid and pouring it into the mold. After cooling, solidifying and cleaning, a casting (part or blank) with a predetermined shape, size and properties can be obtained It is the basic technology of modern machinery manufacturing industry. The cost of casting blank is low, especially for the parts with complex shape, especially with a complex cavity, it can show its economy, at the same time, its adaptability is wide, and has better comprehensive mechanical properties. However, there are more materials (such as metal, wood, fuel, molding materials) and equipment (such as metallurgical furnace, sand mixer, molding machine, core making machine, sand falling machine, shot blasting machine, etc.) needed for casting production And will produce dust, harmful gases and noise and pollution of the environment.

Casting is a kind of metal hot-working technology which has a history of about 6000 years. In 3200 BC, bronze frog castings appeared in Mesopotamia. Between the 13th and 10th centuries BC, China has entered the golden age of bronze casting, and its technology has reached a fairly high level Such as the Shang Dynasty’s 875 kg of Simuwu Ding, the Warring States of the Zhengzhou Yi Zun Pan and the Western Han Dynasty, such as the Lens are representative of ancient casting products. The first casting was greatly influenced by pottery. Most of the castings were tools or tools for agricultural production, religion, life and so on. AD 513 BC, China cast the world’s earliest cast iron found in the written record-casting Jin Ding (about 270 kg weight). Around the 8th century, iron castings began to be produced in Europe. After the industrial revolution in the 18th century, casting entered a new period of serving the big industry. In the 20th century, the development of casting is very fast. Ductile Iron, Malleable Iron, ultra-low carbon stainless steel, aluminum copper, aluminum-silicon, aluminum-magnesium alloys, titanium-based, nickel-based alloys, and other cast metal materials have been developed successively. A new inoculation process for grey cast iron was also developed. Since the 1950s, new techniques such as wet sand high-pressure molding, chemical hardened sand molding, core making, negative pressure molding, and other special casting and shot blasting have appeared.

There are many kinds of casting. According to the molding method, the casting can be divided into 1) The common sand molding.  It includes wet sand mold, dry sand mold, and chemical hardening sand mold.  2)Special castings. Based on the different molding materials, it can be divided into two types.  One type, the main molding material is  the natural mineral sand, such as investment casting, mud casting, shell casting in casting workshop, negative pressure casting, solid casting, ceramic casting, etc..  And another type the primary molding material is the metal, such as metal mold casting, pressure casting, continuous casting, low-pressure casting, centrifugal casting, etc.) .

The casting process includes (1) Preparation of the casting mold, the part that makes the liquid metal into the solid casting.  The casting mold can be divided into the sand mold, metal mold, ceramic mold, mud mold, graphite mold, etc.. According to the times of using, it can be divided into one-time type, half-long type, and long-time type, and the quality of mold preparation is the main factor affecting the quality of Castings. (2) Melting and pouring.  Casting metal (casting alloy) mainly has cast iron, cast steel and cast non-ferrous alloy; (3) Castings’ treatment and inspection.  Castings’ treatment including removal of core and casting surface foreign matter, removal of gating and riser, relieving burr and casting joint, heat treatment, shaping, anti-rust treatment and roughing, etc.