The existence of forging defects, some will affect the processing quality or processing quality of subsequent processes, and some will seriously affect the performance and use of forgings, or even greatly reduce the service life of the finished parts and endanger safety. Therefore, in order to ensure or improve the quality of custom metal forgings, in addition to strengthening quality control in the process and taking corresponding measures to prevent the occurrence of forging defects, necessary quality inspections should also be carried out to prevent problems with subsequent processes (such as heat treatment, surface treatment, cold working) Forgings with defects that have a negative impact on performance will flow into subsequent processes. After quality inspection, remedial measures can also be taken on the finished forgings according to the nature of the defects and the extent of their impact on use, so that they meet technical standards or usage requirements. Therefore, in a sense, forging quality inspection is, on the one hand, to check the quality of the produced forgings, and on the other hand, it is to point out the direction for improvement of the forging process, thereby ensuring that the quality of forgings meets the requirements of forging technical standards and meets the design, Processing and use requirements.
The inspection of forging quality includes inspection of appearance quality and internal quality. The appearance quality inspection mainly refers to the inspection of the geometric dimensions, shape, surface condition and other items of the forgings; the internal quality inspection mainly refers to the inspection of the chemical composition, macrostructure, microstructure and mechanical properties of the forgings. Specifically, the appearance quality inspection of forgings is to check whether the shape and geometric dimensions of forgings comply with the requirements of the drawing, whether there are defects on the surface of forgings, what nature the defects are, and what their morphological characteristics are. The inspection content of the surface condition is generally to check whether there are surface cracks, folds, wrinkles, pits, orange peels, blisters, scars, corrosion pits, bruises, foreign objects, underfill, pits, lack of flesh, etc. Scratches and other defects.
The internal quality inspection by metal parts manufacturer is to check the inherent quality of the forging itself, which is a quality condition that cannot be discovered by the appearance quality inspection. It includes not only checking the internal defects of the forging, but also checking the mechanical properties of the forging, and for important parts and key parts. Parts or large forgings should also undergo chemical composition analysis. For internal defects, we will use low-magnification inspection, fracture inspection, and high-magnification inspection to check whether the forgings have internal cracks, shrinkage cavities, looseness, coarse grains, white spots, dendrites, streamlines that do not conform to the shape, Defects such as turbulent streamlines, cross-flow, coarse crystal rings, oxide films, delamination, overheating, and overburned structures. As for the mechanical properties, it mainly checks the normal temperature tensile strength, plasticity, toughness, hardness, fatigue strength, high temperature instantaneous fracture strength, high temperature lasting strength, lasting plasticity and high temperature creep strength, etc.
Since forgings are made into forging spare parts, their stress, importance, and working conditions are different during use, and the materials and metallurgical processes used are also different. Therefore, different departments divide forgings into categories based on the above conditions and in accordance with the requirements of the department., different departments and different standards classify forgings differently.
This is the last one.
