Quality Inspection Methods for Titanium Alloy Forgings

The presence of defects in TC4 titanium forgings can affect the quality of subsequent processing or machining, while others can severely impact the performance and use of titanium forgings and titanium alloy forgings, even significantly reducing the service life of finished parts and endangering safety. Therefore, to improve the quality of titanium forgings, in addition to strengthening quality control in the process and taking corresponding measures to eliminate defects, necessary quality inspections should be conducted to prevent titanium forgings with defects that adversely affect subsequent processes (such as heat treatment, surface treatment, and cold working) and performance from entering later stages. After quality inspection, remedial measures can be taken for the manufactured titanium forgings based on the nature of the defects and their impact on use, ensuring they meet technical standards or usage requirements. titanium 6al4v foil / titanium forged block / Gr23 Ti-6Al-4V ELI Titanium Sheet

Therefore, titanium forging quality inspection, in a sense, serves two purposes: firstly, it controls the quality of manufactured titanium forgings; secondly, it provides direction for improving the forging process, ensuring that the quality of titanium forgings meets the requirements of titanium forging technical standards and satisfies design, processing, and usage requirements. The inspection of titanium forging quality includes both appearance and internal quality inspection. Visual quality inspection mainly refers to the inspection of the geometric dimensions, shape, and surface condition of titanium forgings; internal quality inspection mainly refers to the inspection of the chemical composition, macrostructure, microstructure, and mechanical properties of titanium forgings.

Specifically, visual quality inspection of titanium forgings involves checking whether the shape and geometric dimensions of the titanium forgings conform to the specifications in the drawings, and whether there are defects on the surface of the titanium forgings, what kind of defects they are, and what their morphological characteristics are. Surface condition inspection generally involves checking for defects such as surface cracks, folds, wrinkles, dents, orange peel, blistering, blemishes, corrosion pits, dents, foreign matter, incomplete filling, pits, missing material, and scratches. Internal quality inspection, on the other hand, examines the inherent quality of the titanium forgings themselves, addressing quality conditions that cannot be detected by visual quality inspection. It includes checking for internal defects and mechanical properties of the titanium forgings, and for important, critical, or large titanium forgings, chemical composition analysis should also be performed. For internal defects, we will use low-magnification inspection, fracture surface inspection, and high-magnification inspection to check for defects in titanium forgings such as internal cracks, shrinkage cavities, porosity, coarse grains, white spots, dendritic crystals, flow lines not conforming to the shape, disordered flow lines, flow penetration, coarse grain rings, oxide films, delamination, overheating, and burnt structures. For mechanical properties, we mainly check room temperature tensile strength, plasticity, toughness, hardness, fatigue strength, high-temperature instantaneous fracture strength, high-temperature creep strength, creep ductility, and high-temperature creep strength.

Because titanium forgings are subjected to different stresses, importance, and working conditions during use, and the materials and metallurgical processes used also vary, different departments classify titanium forgings according to the above conditions and departmental requirements. Different departments and different standards will have different classifications of titanium forgings. However, the overall quality inspection of titanium forgings cannot be separated from two main categories of inspection: appearance quality inspection and internal quality inspection. The only difference is that the specific inspection items, quantities, and requirements differ depending on the category of the titanium forging.