<\/figure>\n\n\n\nA welder must qualify for each of the processes that he intends to use in production welding. He can take his qualification test for each of these processes in separate test coupons, or in a single test coupon which covers multiple processes. The weld metal thickness for each of these processes must be planned beforehand to obtain qualified weld metal thickness in accordance with QW 452.1 (b).<\/p>\n\n\n\n
If a single coupon is used, the thickness deposited with each of the processes must then be measured and recorded during the preparation of the test coupon (Interpretation IX-92-32 is contextual here).<\/p>\n\n\n\n
Each of the processes is then counted as a separate qualification with its own qualified range for various essential variables. These qualifications can then be used individually or in any combination in production joints (Interpretation with record number 15-35 question 1, and interpretation IX-18-36 are contextual).<\/p>\n\n\n\n
Likewise, multiple welders<\/em> can be qualified on the same test coupon as well, for the same process or different processes. The thickness deposited by each welder should be planned beforehand, and then checked & recorded during preparation of the test coupon. Once the coupon passes the requisite testing of QW 304\/ QW 305, each welder gets qualified for the process with which he deposited.<\/p>\n\n\n\nEach of the qualifications is then counted as a separate qualification with its own qualified ranges for the essential variables. These welders can weld on individual joints, or multiple welders can be deployed on a single production weld as well.<\/p>\n\n\n\n
In a similar way, a single welder can do multiple performance qualifications with the same process, with different essential variables, in a single test coupon.<\/p>\n\n\n\n
For example, he may deposit 10 mm weld thickness in a test coupon with a F-Number 4 electrode, and deposit another 10 mm with a F-Number 43 electrode in the same test coupon. He would then have two qualifications to his name, which would be treated individually.<\/p>\n\n\n\n
The crux of the story is that multiple qualifications can be done on a single test coupon. Each qualification is treated as a standalone qualification which can be used singly or in combination with other qualifications, within the qualified limits of each qualification. Section IX expressly permits this, in QW 306.<\/p>\n\n\n\n
Things To Keep In Mind When Performing Multiple Welder Qualifications Through Single Coupon<\/h2>\n\n\n\n When a combination of qualifications is done in a single test coupon, there are few things that need to be taken note of:<\/p>\n\n\n\n
\nPer QW 306, \u201cfailure of any portion of a combination test in a single test coupon constitutes failure of the entire combination.\u201d<\/li>\n\n\n\n The thickness of test coupon must be minimum 19 mm when three or more welders (using the same or a different welding process) are qualified in a single test coupon.<\/li>\n\n\n\n The weld metal thickness \u2018t\u2019 for each qualification must be determined and used individually in the table of QW 452.1 (b) to determine the qualified weld metal thickness for each qualification.<\/li>\n\n\n\n The thickness of weld metal for determining the type and number of tests in QW 452.1 (a) is to be taken as the total weld metal thickness deposited by all welders and all processes exclusive of the weld reinforcement.<\/li>\n\n\n\n Coupons tested by face and root bends shall be limited to weld deposit made by one welder with one or two processes or two welders with one process each. This is as per Note (2) under Table QW 452.1 (a).<\/li>\n<\/ol>\n\n\n\nNote (1): It is important to bear in mind that at any given time during production welding, only one performance qualification can be considered at a time. That means, the welder\u2019s eligibility to weld on a production joint must be derived from only one qualification at any given instant. The article below explains this in detail.<\/p>\n\n\n\n
Note (2): While preparing a test coupon, if a change occurs in any of the essential variables at any stage, it becomes a different qualification. That is, the portions of the coupon that are deposited with different essential variables must be counted as separate qualifications. The qualified weld deposition range for each such qualification should be reckoned individually, per QW-452.1(b). This has been given at QW-306, as well as in footnotes under QW-452.1(b).<\/p>\n\n\n\n