X-ray Evaluation For Defects In Die-casting Aluminum Parts And Contrast Test Block Fabrication

The X-ray imaging technology is that using the penetration ability of X-ray and the images formed by the difference of X-ray attenuation degree affected by different material density and parts structure during the X-ray penetration process,through the images to evaluate internal characteristics in parts.The way of X-ray inspection mainly include X-ray film and X-ray real-time imagery,but X-ray film exists many disadvantages,such as low efficiency and high check cost;while X-ray real-time imagery has been mature after many years of development.Due to the advantages of-convenient operation,image easy saved and low cost,X-ray real-time imagery can replace the film inspection.The main problems exists to prevent X-ray real-time imagery developing are that if the sensitivity and resolution of X-ray real-time imagery can reach the standard of film inspection;the check of he sensitivity and resolution before machine working and the evaluation of aluminum alloy die-cast parts inspected by X-ray real-time imagery.In this text.The analysis of these three aspects is made to vary the feasibility of X-ray real-time imagery inspection to production practice.This test through using X-ray real-time imagery system and photographic film inspection to inspect the car camshaft cover.Compared with both inspection images,from three aspects including the discovering ability,watching ability and accuracy to study,finding that X-ray real-time imagery system and photographic film inspection have the equal reliability.This particle provided the making method of the sensitivity and resolution block for X-ray real-time imagery and gave validation.The machining standard hole diameter in the blocks are 0.36 mm,0.41 mm,0.52 mm,0.61 mm,0.82 mm,1.02 mm and 1.51 mm.Through the inspection test,the relative sensitivity of X-ray real-time imagery reached 1.52%.Making a series of defects those distance was 0.2mm,and through the test the resolution of X-ray real-time imagery were 0.2mm,the definition of defects images can meet the needs of actual production.In this paper,the evaluation grades for internal defects in the die-cast car parts were studied.The defect images,machining images and line cutting photos had corresponding relationship.The defect images were evaluated according to the corresponding drawings.The internal quality of die cast car parts speed meter table cover was divided into five grades,and then used machining images and line cutting photos to qualify the evaluation results.The test presented the internal defects grade evaluations of die cast car parts were right,which met the need of internal inspection and applied to production practice.