Study On Quality Control Of Surface Treatment Of Titanium Alloy Fastener For Aviation In T Company

This paper studies surface treatment quality control problems for aerospace titanium alloy fasteners,taking the T company’s fastener surface phosphating processing as an example,through analyzing the problem,solving the problem and evaluating the quality,which can achieve the quality control of phosphating.This paper first analyzes the T company’s phosphating process at the present stage of production.The method of statistical analysis and permutation chart is used to clarify the existing problems:scrap rate and high cost,lack of process capability control,the main reason for the failure of the phosphating is phosphating film is too thin,phosphating film crystallization,phosphating film hanging ash.Then we use WBS decomposition and hierarchical analysis to identify and select the key process,determine the key factors for the titanium alloy matrix,the pretreatment of ultrasonic degreasing,the main ingredient of bath solution concentration and solution temperature,then we can know the key process is titanium alloy matrix material control,ultrasonic oil removal effect control,groove liquid composition fluctuation control.The contents of Al,V,Fe and C in TC4 titanium alloy are taken as experimental factors,the comprehensive evaluation of the film weight,surface resistance,corrosion resistance,and impact resistance of the film in the conversion film performance was considered as the test index,the orthogonal experiment was carried out at three levels.The effects of various alloying elements on the quality of the phosphating film were studied by standard effect analysis and linear analysis of variance,combined with the corresponding surface treatment knowledge,and all of these can determine the corresponding control principles of raw materials.The influence of process parameters of ultrasonic cleaning effect were analyzed,and according to the corresponding process parameters,the historical data of ultrasonic cleaning effect were collected,according to the analysis of multivariate quality control,the new control measures should be taken to the position of the cleaning rack,the amount of the cleaning agent and the treatment time.After the new control measures are taken,the new data is collected to rejudge whether the system is in steady state or not.After the system reaches the steady state,we calculate the multivariate process capability index,and confirm that the system has achieved the control requirements.The contents of HAc,NaF and Na3Po4 in the main components of the bath solution were the experimental factors,the main experimental parameters were the membrane weight in the conversion film performance,the orthogonal experiment is divided into four levels.The experimental results can be used to analyze the effect of Na3Po4 concentration,NaF concentration,pH and other factors on the quality of film forming.On the basis of this,a single factor experiment was conducted to determine the optimum temperature range.In view of the actual production,the control coefficient of the components of each tank liquor was established,and the warning range of the components of each tank liquor was determined.Finally,we use the target decomposition method to decompose the control target into four levels: control layer,test layer,operation layer and interface layer.According to the concrete implementation effect of quality control,the quality control is evaluated.