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在小径管透照中,散射线的影响十分严重,对底片的明晰性、反差等透照质量影响比较明显,这主要是由于小径管透照特点所致。而采用低能量,高反差透照,由于管子厚度变化很大,射线到达胶片的强度必然不同,从而在底片上显现的焊缝影响最大黑度和最小黑度的差值也必然很大。这样在底片上缺陷的检出率缩小,焊缝的检出范围也很小。严重影响到检验结果的可靠性。对小径管焊缝透照采用铅箔屏蔽,限制照射场,比普通广野透照对散射比大的试验和应用工艺,对改善透视底片的像质是个有效的方法。换言之,用高能量进行小径管特别是小径较厚壁厚的透照中,采用铅箔屏蔽罩限制
In the small diameter tube through the photos, the impact of scattered lines is very serious, the clarity of the film, contrast and other transparent quality is more obvious, mainly due to the characteristics of small diameter tube through the pass. The use of low-energy, high-contrast transillumination, the tube thickness varies widely, the intensity of radiation must arrive at the film is different, so that the weld appears on the film, the maximum blackness and minimum blackness difference is bound to be large. This film on the defect detection rate reduced, the weld detection range is also small. Seriously affect the reliability of test results. It is an effective method to improve the quality of fluoroscopic film by using lead foil shielding to limit the irradiation field compared with ordinary wide field transillumination test and application process. In other words, the use of high-energy small-diameter pipe, especially thicker diameter thicker transillumination, the use of lead foil shield limit