Throttle body, engine, engine assembly, oil pump, nozzle, tension wheel, cylinder block, bearing bush, water pump, fuel injection, gasket, camshaft, valve, crankshaft, connecting rod assembly, piston, belt, muffler, carburetor, fuel tank, water tank, fan, oil seal, radiator, filter

Metal products are indispensable products in modern industry and life. How to distinguish their quality is the problem we need to pay attention to when we buy and use them. This paper will discuss the quality discrimination method of metal products from the aspects of metal material quality, production process, surface treatment, structure design, function and so on.

Metal products refer to all kinds of practical or decorative products made from metal materials. Metal products can be used in various fields, such as construction, aviation, automobile, industrial manufacturing, medical, metallurgy, electronics and other industries, widely used in a variety of production and daily life.

Window and door hardware refers to the metal parts used for Windows and doors, including locks, handles, hinges, door hinges, etc. As one of the important accessories in home decoration and construction industry, the quality control of window and door hardware accessories is particularly important.