Testing of Materials

the determination of the technological and operational properties of materials, primarily by the use of machines and instruments.

Materials are tested for diverse purposes: to determine the properties of the raw material, to check quality at intermediate stages in production processes, to check finished products, and to aid research. Mechanical, physical, and chemical methods are used to study the properties of materials. Destructive methods damage or completely destroy the object of the tests; nondestructive ones permit further use of the object.

Broadly, there are four types of tests. Mechanical methods test the material’s ability to resist tension, compression, impact, bending, twisting, and shearing and its hardness and fatigue level (that is, its ability to withstand alternating mechanical loads without breaking). Physical tests determine electrical conductivity, heat conductivity, cold resistance, and magnetic and other properties. Chemical tests determine chemical composition and ability to withstand chemical action, especially oxidation. Structural tests (called metalomicrographic tests) determine the mac-rostructure, or structure visible to the naked eye; the microstructure, visible through a microscope; and the crystalline structure, determined primarily by X rays.

Various technological samplings used to check the ability of a material to resist deformation and the actions of temperature and chemicals or its machinability may also be considered testing of materials.