The inspection of appearance quality is generally a non-destructive inspection, usually with the naked eye or a low magnification magnifying glass, and if necessary, non-destructive testing is also used. Due to the requirements of the inspection content, some of the internal quality inspections must use destructive inspections, which are commonly referred to as anatomical tests, such as low magnification inspection, fracture inspection, high magnification tissue inspection, chemical composition analysis, and mechanical performance testing Some can also use non-destructive testing methods, and in order to more accurately evaluate the quality of forgings, destructive testing methods and non-destructive testing methods should be used in combination with each other. In order to analyze the quality problems of forgings at a deep level, the mechanism of research work must also be aided by transmission or scanning electron microscopes and electron probes.
Generally, the inspection methods of internal quality of forgings can be summarized as: macrostructure inspection method, microstructure inspection method, mechanical property inspection, chemical composition analysis method and nondestructive testing method.
Macrostructure inspection is a kind of inspection that uses visual or low magnification magnifiers (generally multiples of 30× or less) to observe and analyze the characteristics of low magnification structures in forging. The commonly used methods for macrostructure inspection of forgings are low-power corrosion method (including thermal corrosion method, cold corrosion method and electrolytic corrosion method), fracture test method and sulfur printing method.