JIS Z 3105-1984 (methods of radiographic test and classification of radiographs for aluminium welds) and its explanatory note

The method of radiographic test and the classification of radiographs for aluminium welds was included in JIS Z 2341-1955 ''Method of radiographic test for metallic materials'', but with the lapse of many years, many unclear and unreasonable points have become to be observed. The course of deliberation to decide this standard is briefly described. The problems discussed were as follows. In the old standard, the testing method for T-type aluminium welded joints was included, but owing to the institution of JIS Z 3109, it was omitted. As contrast meters, A and B types were excluded, and E 2, 3 and 4 types, F 2, 3 and 4 types and G 2, 3 and 4 types were added besides D 1, 2, 3 and 4 types. In the old standard, the use of contrast meters was limited to the flat plates thinner than 20 mm of butt welding, but they are to be used for all thickness in this standard. The value that the difference of density shown by a contrast meter is divided by density was newly adopted, and stipulated corresponding to thickness. Among the defects to be classified, as to the wrapping-in of oxide, poor penetration and insufficient fusion, the class is to be decided by measuring the defect length. The text of the standard is explained. (Kako, I.)