Centrifugal Casting Characteristics (Dongguan Foundry)
Centrifugal casting: Molten metal is poured into the casting which revolves around the horizontal, inclined or vertical axis. Under the effect of centrifugal force, the axis of the casting formed by condensation coincides with the axis of the revolving casting. Most castings are simple cylindrical, so it is unnecessary for the core to form the inner hole of the cylinder.
A casting method in which liquid metal is poured into a rotating mould and filled and condensed into a casting under centrifugal force. Centrifugal casting machine is called centrifugal casting machine. The centrifugal casting machine can be divided into three types according to the direction of the rotating axis of the casting mould: horizontal vertical casting machine and inclined casting machine. Horizontal centrifugal casting machine is mainly used for casting various tubular castings, such as water and gas pipes of gray cast iron nodular cast iron. The diameter of the pipe is the smallest 75 mm and the maximum is 3000 mm. In addition, it can pour large-caliber copper rollers for papermaking machine, various carbon steel, alloy steel pipes and double-layer raw steel rollers requiring different compositions in inner and outer layers. Vertical centrifugal casting machine is mainly used to produce various annular castings and smaller non-circular castings.
For centrifugal casting, according to the casting shape, size and batch production, non-metallic mould (such as sand mould, shell mould or molten mould shell mould), metal mould or casting with coating layer or resin sand layer in metal mould can be selected. Mold rotation is an important parameter of centrifugal casting. Satisfactory centrifugal force is needed to increase the fineness of the casting metal, and centrifugal force can not be too large to prevent metal from shortening. Especially for lead bronze, excessive centrifugal force will cause component segregation between the inner and outer walls of the castings. The general speed changes from tens to 1500 revolutions per minute.
Centrifugal casting is characterized by filling and condensation of liquid metal under the effect of centrifugal force, good metal feeding effect, fine arrangement of outer layer of castings, less non-metallic inclusions and good mechanical properties; it does not need moulding and core-making, and saves the investment of related materials and equipment. No riser is needed for casting hollow castings, and the utilization rate of metal can be greatly improved. Therefore, centrifugal casting is a material-saving, energy-saving and high-benefit process for some special shaped castings, but special attention should be paid to the adoption of useful safety measures.
Centrifugal casting can obtain castings without shrinkage, porosity and slag inclusion, with fine arrangement and good mechanical properties. When casting round hollow parts, the core can be omitted. In addition, centrifugal casting does not require a casting system and reduces metal consumption. However, centrifugally cast cylindrical parts have inaccurate inner pore size, more air holes and slag inclusions, so it is necessary to increase processing allowance, and it is not suitable for casting alloys with simple specific gravity segregation.