The existence of forging defects, some will affect the quality of subsequent processes or processing quality, some seriously affect the performance and use of forgings, and even greatly reduce the service life of manufactured parts, endangering safety. Therefore, in order to ensure or improve the quality of forgings, in addition to strengthening quality control in the process, to take appropriate measures to eliminate the generation of forging defects, should also carry out the necessary quality inspection, to prevent with the subsequent process (such as heat treatment, surface treatment, cold machining) and the use of performance defects have a bad impact on the forging into the subsequent process. After quality inspection, but also according to the nature of the defects and the degree of impact on the use of forging has been made to take remedial measures to make it meet the technical standards or use of the requirements. Therefore, the forging quality inspection in a sense, on the one hand, the quality of the forging has been made gatekeeper, on the other hand, it is to the forging process to point out the direction of improvement, so as to ensure that the quality of forgings in line with the requirements of the forging technical standards, and to meet the design, processing, use of the requirements.

Inspection of the quality of forgings includes the appearance of quality and internal quality inspection. Appearance quality inspection mainly refers to the geometry of the forgings, shape, surface condition and other items of inspection; internal quality inspection mainly refers to the chemical composition of forgings, macro-organisation, microstructure and mechanical properties and other items of inspection. Specifically, the appearance of the forging quality inspection is to check the shape of the forging, geometric dimensions in line with the provisions of the drawings, the surface of the forging whether there are defects, what is the nature of the defects, and what are their morphological characteristics. Surface condition inspection is generally to check whether the surface of the forging surface surface cracks, folding, wrinkles, pressure pits, orange peel, blistering, scars, corrosion pits, bruises, foreign objects, unfilled, pits, missing meat, scratches and other defects.

The internal quality inspection is to check the inner quality of the forging itself, which is the quality condition that cannot be found by the external quality inspection, and it includes checking the internal defects of the forging as well as the mechanical properties of the forging, and chemical composition analysis should also be carried out on the important parts, key parts or large forgings. For internal defects, we will use low magnification inspection, fracture inspection and high magnification inspection to check whether there are any defects such as internal cracks, shrinkage holes, looseness, coarse crystals, white spots, dendritic crystals, non-conformity of flow lines, flow line disorders, flow-throughs, coarse crystals, oxide films, delaminations, overheating, and overcooking organisations. Mechanical properties are mainly checked for normal temperature tensile strength, plasticity, toughness, hardness, fatigue strength, high-temperature instantaneous breaking strength, high-temperature endurance strength, endurance plasticity and high-temperature creep strength.

Because of the forging made of parts, in the process of its use, the force, the importance of different working conditions, the materials used and metallurgical process is also different, so different departments based on the above and in accordance with the department's requirements will be divided into categories of forgings, different departments, different standards for the classification of forgings is also different.