The presence of defects in TC4 titanium forgings can affect the quality of subsequent processing or machining,and in some cases,severely impact the performance and usage of titanium forgings and titanium alloy forgings.These defects may even significantly reduce the service life of the finished products,posing safety hazards.Therefore,to ensure or enhance the quality of titanium forgings,it is essential to strengthen quality control in the manufacturing process and take corresponding measures to eliminate the occurrence of defects.Additionally,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 usage performance from entering subsequent stages.After quality inspection,remedial measures can be taken on the manufactured titanium forgings based on the nature of the defects and their impact on usage,to ensure they meet technical standards or usage requirements.

Therefore,in a sense,the quality inspection of titanium forgings serves as a quality control measure for the already produced titanium forgings on the one hand,and points out directions for improvement in the forging process on the other,thereby ensuring that the quality of titanium forgings meets the requirements of technical standards for titanium forgings and satisfies the demands of design,processing,and use.The quality inspection of titanium forgings includes inspection of both appearance quality and internal quality.Appearance quality inspection mainly refers to the inspection of geometric dimensions,shape,surface condition,and other items of titanium forgings;internal quality inspection mainly refers to the inspection of chemical composition,macrostructure,microstructure,and mechanical properties of titanium forgings.

Specifically,the appearance quality inspection of titanium forgings involves checking whether the shape and geometric dimensions of the titanium forgings comply with the specifications in the drawings,whether there are defects on the surface of the titanium forgings,what kind of defects they are,and what their morphological characteristics are.The inspection of surface conditions generally includes checking whether there are defects such as surface cracks,folds,wrinkles,indentations,orange peel,blisters,scars,corrosion pits,bumps,foreign objects,underfills,pits,undercuts,and scratches on the surface of the titanium forgings.The inspection of internal quality involves checking the inherent quality of the titanium forgings,which cannot be detected by appearance quality inspection.It includes checking both the internal defects and the mechanical properties of the titanium forgings.For important,critical,or large titanium forgings,chemical composition analysis should also be conducted.For internal defects,we will use macro examination,fracture examination,and micro examination to inspect whether the titanium forgings have defects such as internal cracks,shrinkage cavities,porosity,coarse grains,white spots,dendritic crystals,flow lines not conforming to the shape,disordered flow lines,flow crossing,coarse grain rings,oxide films,delamination,overheating,and overburned structures.For mechanical properties,the main inspection items include room temperature tensile strength,plasticity,toughness,hardness,fatigue strength,high-temperature instantaneous fracture strength,high-temperature endurance strength,endurance plasticity,and high-temperature creep strength.

Due to the different stress conditions,importance,and working conditions of titanium forgings after being made into parts during use,the materials and metallurgical processes used vary accordingly.Therefore,different parts of titanium forgings are categorized based on the above conditions and in accordance with the requirements of the department.Different departments and standards also have different classifications for titanium forgings.However,regardless of the situation,the overall quality inspection of titanium forgings cannot be separated into two major categories:appearance quality and internal quality inspection.It is just that the specific inspection items,quantity,and requirements vary depending on the category of titanium forgings.