The purpose of forging is to improve the structure, improve the comprehensive properties of metals, forge products with certain shapes, and provide billets or finished products for extrusion, rolling and other processing.

Forging can be divided into: free forging, die forging and precision forging.

Free forging can be used to forge products of various specifications and shapes to meet the specified performance and organization requirements, but with large dimensional deviation and low yield, it is suitable for single piece and small batch production.

Die forging can obtain products with accurate size and consistent shape, with high yield and easy to mass production, but the variety is limited by the model and the manufacturing cycle of the die is long.

Precision forging can only produce shaft forgings, such as bar, step shaft and tube, with accurate size, good surface quality and automatic operation.

Some of the defects of titanium forgings will affect the quality of subsequent processing or processing, some will seriously affect the performance and use of titanium forgings, and even greatly reduce the service life of the finished parts, endangering the safety. Therefore, in order to ensure or improve the quality of titanium forgings, in addition to strengthening the quality control in the process and taking corresponding measures to eliminate the occurrence of titanium forging defects, necessary quality inspection should also be carried out to prevent titanium forgings with defects that have a bad impact on the subsequent processes (such as heat treatment, surface treatment, cold processing) and service performance from flowing into the subsequent processes. After quality inspection, remedial measures can also be taken for the made titanium forgings according to the nature of defects and the degree of influence on use, so as to make them conform to the technical standards or the requirements of use.

Therefore, the quality inspection of titanium forgings in a sense, on the one hand, is to check the quality of the made titanium forgings, on the other hand, to point out the improvement direction of the forging process, so as to ensure that the quality of titanium forgings meets the requirements of the technical standards of titanium forgings, and meets the requirements of design, processing and use.

The quality inspection of titanium forgings includes the inspection of appearance quality and internal quality. Appearance quality inspection mainly refers to the inspection of the geometric dimension, shape, surface condition and other items of titanium forgings; internal quality inspection mainly refers to the inspection of the chemical composition, macro structure, microstructure and mechanical properties of titanium forgings.

Specifically speaking, the appearance quality inspection of titanium forgings is to check whether the shape and geometric dimension of titanium forgings meet the requirements of drawings, whether there are defects on the surface of titanium forgings, what are the defects of what nature, and what are their morphological characteristics. The inspection content of surface condition is generally to check whether there are surface cracks, folds, wrinkles, indentation, orange peel, blisters, scars, corrosion pits, bumps, foreign matters, not filled, pits, lack of meat, scratches and other defects on the surface of titanium forgings.

The inspection of internal quality is to check the internal quality of titanium forging itself, which is a quality condition that can not be found in appearance quality inspection. It includes not only the inspection of internal defects of titanium forging, but also the inspection of mechanical properties of titanium forging, and the chemical composition analysis of important parts, key parts or large titanium forging should also be carried out. For internal defects, we will check whether there are defects such as internal crack, shrinkage cavity, looseness, coarse crystal, white spot, dendrite crystal, flow line does not conform to the shape, flow line disorder, through flow, coarse crystal ring, oxide film, stratification, overheating, overburning structure and so on in titanium forgings by low-power inspection, fracture inspection and high-power inspection. The mechanical properties mainly include tensile strength at room temperature, plasticity, toughness, hardness, fatigue strength, high-temperature instantaneous fracture strength, high-temperature permanent strength, permanent plasticity and high-temperature creep strength.

After titanium forgings are made into parts, the stress, importance and working conditions are different in the use process, and the materials and metallurgical processes used are also different. Therefore, according to the above conditions and the requirements of the Department, titanium forgings are divided into different categories according to different departments and standards. However, no matter what, the overall quality inspection of titanium forgings can not be separated from two major types of inspection, that is, the inspection of appearance quality and internal quality, but the specific inspection items, inspection quantity and inspection requirements are different for different types of titanium forgings.