Basic Knowledge of Metal Parts in Manufacture

Metal Parts refer to various accessories made with metallic materials. They are often made from steel, iron and nonferrous metals.  

Iron alloys with 2%-4.3% carbon are cast irons. Iron alloys with 0.03%-2% carbon are steel. Adding various alloying elements into the Fe-C alloys will produce iron or steels with different features. This method is often used to improve their intensity, rigidity, wear-resistance, corrosion resistance and other properties. The general used alloying elements are Si, Mn, Cr, Ni, Mo, W, V, Ti, Nb, B, etc. Varied alloy cast iron and alloy steels are made from them. 

 

Nonferrous alloys generally contain the following categories: light alloys (aluminum alloys, titanium alloys, magnesium alloys, beryllium alloys, etc), heavy nonferrous alloy (copper alloy, zinc alloy, manganese alloy, nickel alloy, etc), low melting point alloys (lead, tin, mercury, cadmium, bismuth, indium, gallium and their alloys), refractory alloys (tungsten, molybdenum, tantalum, niobium alloy alloy alloy, etc), precious metals (gold, silver, platinum, palladium, etc) and rare earth metals. Aluminum alloys are the most commonly used materials among nonferrous alloys. 

 

(1) Preservative treatment and rust-proof treatment. Parkerizing can make the metal parts corrosion resistant and rust proof. 

(2) Hardening treatment. There are three methods to achieve this goal. The first method is to adopt surface carburizating. However, with this method, the surface of products will be darker than the original colors. The second method is to do quenching treatment. The third one is to use vacuum heat treatment. 

 

The processing technologies of metal parts include machining, stamping, precision casting, powder metallurgy, metal injection molding, laser machining, electrical discharge machining, ultrasonic machining, electrolytic machining, beam processing and ultra-high speed machining, etc. Lathing, milling, forging, casting, grinding, CNC machining, CNC numerical control center all belong to the conventional machining. 

 

Metal accessories are used in wide ranges of production and life. According to statistics, 71% of a supersonic Concorde are made from special aluminum alloys. Manufacture of high-speed trains, cars and other vehicles lead to an increasing demand on aluminum. Being beautiful and corrosion resistant, aluminum is also used in architectural ornament. As to the electric system and household appliances, the amount of aluminum conductor used in them surpass that of copper conductors. Aluminum foils can be also applied to package of food and cigarettes. Aluminum alloys can also serve as capacitors. The rotating parts of compressors, turbines, pumps and other equipment in petrochemical industry are required to be wear-resistant and corrosion resistant. That is because media get through them are usually corrosive, with impurities in them. While at the same time, the media rub against rotating parts. Therefore, metal accessories used in these parts need to be wear-resistant and corrosion resistant. It is the same to propellers in ocean transportation facilities.