Mechanical parts are non-detachable basic units that make up the machine, such as bolts, screws, keys, belts, gears, shafts, springs, pins, and so on. China Mechanical Parts are divided into general parts and special parts. A general-purpose part is a part that can be widely used in various machines, and a dedicated part is a part that can be used only in a specific type of machine.
Common materials for mechanical parts
Mechanical parts are made of metallic materials, non-metallic materials and composite materials.
Metal materials are classified into ferrous materials and non-ferrous materials. The ferrous materials include various steels, cast steels and cast irons, which have good mechanical properties (such as strength, ductility, toughness, etc.), are relatively inexpensive and readily available, and can meet a variety of performance and application requirements. Among all kinds of ferrous metals, alloy steels are often used to make important parts because of their excellent properties. Non-ferrous metal materials, including copper alloys, aluminum alloys, bearing alloys, etc., have the advantages of low density, good thermal conductivity and good electrical conductivity, and are usually used in applications where friction, wear and corrosion resistance are required.
Non-metallic materials refer to polymer materials such as plastics, rubber, synthetic fibers, and ceramics. Polymer materials have many advantages, such as abundant raw materials, low density, good elasticity in a suitable temperature range, and good corrosion resistance. The main disadvantage is that it is easy to age, and many of them have poor flame retardancy. In general, heat resistance is not good. The main characteristics of ceramic materials are extremely high hardness, wear resistance, corrosion resistance, high melting point, high stiffness and low density than steel. At present, ceramic materials have been used in structures such as seals, rolling bearings and cutting tools. Its main disadvantages are relatively brittle, low fracture toughness, high price, and poor processing technology.
Composite material refers to a new type of material that is treated by a composite process using two or more materials having significantly different physical and mechanical properties to obtain the desired properties. For example, non-metallic materials such as glass, graphite (carbon), boron, plastic, etc. can be composited into various fiber reinforced composite materials. The plastic composite steel plate with high strength and corrosion resistance can be obtained by attaching plastic to the surface of ordinary carbon steel plate. The main advantage is that it has high strength and elastic modulus, but the quality is extremely small, but also has poor heat resistance and heat conduction. The disadvantage of poor electrical conductivity. In addition, the price of composite materials is relatively expensive. Therefore, composite materials are mainly used in high-tech fields such as aviation and aerospace. In civil products, composite materials also have some applications.