The existence of defects in titanium forgings may affect the processing quality or processing quality of subsequent processes, and some will seriously affect the performance and use of forgings, and even greatly reduce the service life of the manufactured parts, endangering safety. Therefore, in order to ensure or improve the quality of forgings, in addition to strengthening quality control in the process and taking corresponding measures to prevent the occurrence of defects in forgings, necessary quality inspections should also be carried out to prevent the subsequent processes (such as heat treatment, surface treatment, cold processing) And the forgings with defects that have bad influence on the use performance are flowed into the subsequent process. After quality inspection, remedial measures can be taken on the manufactured forgings according to the nature of the defect and the degree of impact on the use, so that it can meet the technical standards or requirements of use.
Therefore, in a sense, the quality inspection of forgings, on the one hand, is to check the quality of the manufactured forgings, on the other hand, it points out the direction of improvement for the forging process, so as to ensure that the quality of the forgings meet the requirements of the forging technical standards, and meet Processing and use requirements. The inspection of forging quality includes the 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 forging; the internal quality inspection mainly refers to the inspection of the chemical composition, macrostructure, microstructure and mechanical properties of the forging.
Specifically, the appearance quality inspection of forgings is to check whether the shape and geometric dimensions of the forgings meet the requirements of the drawings, whether the surface of the forgings are defective, what kind of defects are, and their morphological characteristics. The inspection content of the surface condition is generally to check whether there are surface cracks, folds, wrinkles, pits, orange peel, blisters, scars, corrosion pits, bruises, foreign objects, underfill, pits, lack of meat, scratches Marks and other defects. The internal quality inspection is to check the internal quality of the forging itself, which is a quality condition that cannot be found by the appearance quality inspection. It includes not only checking the internal defects of the forgings, but also checking the mechanical properties of the forgings. For important parts, critical parts or large forgings Chemical composition analysis should also be carried out. For internal defects, we will use low-magnification inspection, fracture inspection, and high-magnification inspection to check forgings such as internal cracks, shrinkage holes, looseness, coarse crystals, white spots, dendrites, streamlines that do not conform to the shape, and streamline disorder , Flow through, coarse crystal ring, oxide film, delamination, overheating, overfire tissue and other defects. The mechanical properties are mainly to check the tensile strength at normal temperature, plasticity, toughness, hardness, fatigue strength, high-temperature instantaneous fracture strength, high-temperature endurance strength, endurance plasticity and high-temperature creep strength.
After the forged parts are made into parts, the stress, importance and working conditions are different during use, and the materials and metallurgical processes used are also different. Therefore, different parts are classified into categories according to the above conditions and in accordance with the requirements of this department. Different departments and different standards also classify forgings differently. But no matter what, for the overall quality inspection of forgings, there are two types of inspections, namely the inspection of appearance quality and internal quality, but the types of forgings are different, and the specific inspection items, inspection quantities and inspection requirements are different. . For example, some industrial departments classify structural steel, stainless steel, and heat-resistant steel forgings into category IV for inspection, some departments divide aluminum alloy forgings and die forgings into category III for inspection according to their usage, and some departments divide aluminum alloy, Copper alloy forgings are classified into category IV for inspection.