Standard and method for quality inspection of TC4 titanium forgings and TC4 titanium alloy forgings

The existence of titanium forging defects, some will affect the subsequent process treatment quality or processing quality, and some will seriously affect the performance and use of forgings, and even greatly reduce the service life of the finished product, 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 eliminate the occurrence of forging defects, necessary quality inspection should also be carried out to prevent the flow of forgings with defects that have adverse effects on subsequent processes (such as heat treatment, surface treatment, cold working) and performance. After quality inspection, remedial measures can also be taken according to the nature of the defect and the degree of influence on the use of the forged forging, so that it meets the technical standards or the requirements of use. Therefore, forging quality inspection in a sense, on the one hand is the quality control of the forged forging, on the other hand is to point out the improvement direction of the forging process, so as to ensure that the quality of the forging meets the requirements of the forging technical standards, and meet the requirements of design, processing and use. 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 size, shape, surface condition and other items of forging; The inspection of internal quality mainly refers to the inspection of chemical composition, macroscopic structure, microstructure and mechanical properties of forgings. Specifically, the appearance quality inspection of forgings is to check whether the shape and geometric size of the forgings meet the requirements of the pattern, whether the surface of the forgings has defects, what are the nature of the defects, and what are their morphological characteristics. The inspection content of the surface state is generally to check whether the surface of the forging has surface cracks, folds, creases, pits, orange peel, bubbles, scars, corrosion pits, bumps, foreign objects, not filled, pits, missing meat, scratches and other defects. The inspection of internal quality is to check the internal quality of the forging itself, is the quality of the appearance of the quality inspection can not be found, it includes the inspection of the internal defects of the forging, but also includes the inspection of the mechanical properties of the forging, and the important parts, key parts or large forgings should also be chemical composition analysis. For internal defects, we will check whether there are defects such as internal cracking, shrinkage hole, loose, coarse crystal, white spot, dendritic crystal, flow line does not conform to the shape, flow line disorder, flow through, coarse crystal ring, oxide film, delamination, overheating, overburned tissue through low inspection, fracture inspection and high inspection methods. As for the mechanical properties, it mainly checks the tensile strength, plasticity, toughness, hardness, fatigue strength, high temperature instantaneous breaking strength, high temperature lasting strength, lasting plasticity and high temperature creep strength. Because the forgings are made of parts, in the use of the process of its stress, importance, working conditions are different, the material and metallurgical process is different, so different parts according to the above situation and in accordance with the requirements of the department will be forgings into categories, different departments, different standards of the classification of forgings is also different. But anyway, for the forging quality inspection as a whole can not be separated from two categories of inspection, that is, the appearance of quality and internal quality inspection, but the category of forging is different, its specific inspection items, inspection quantity and inspection requirements are different. For example, some industrial departments will be structural steel, stainless steel, heat-resistant steel forgings are divided into class IV for inspection, some departments will be aluminum alloy forgings and die forgings according to their use into class III for inspection, and some departments will be aluminum alloy, copper alloy forgings into class IV for inspection.