{"id":740,"date":"2021-12-22T15:27:34","date_gmt":"2021-12-22T15:27:34","guid":{"rendered":"https:\/\/mewelding.com\/?p=740"},"modified":"2023-02-15T01:57:29","modified_gmt":"2023-02-15T01:57:29","slug":"multiple-welder-qualifications-through-single-test-coupon","status":"publish","type":"post","link":"https:\/\/mewelding.com\/multiple-welder-qualifications-through-single-test-coupon\/","title":{"rendered":"Multiple Welder Qualifications Through Single Test Coupon"},"content":{"rendered":"\n

ASME Section IX permits covering multiple welder qualification through single test coupon. In this article, I will discuss various things that must be kept in mind when opting for qualifying multiple welding performance qualifications<\/a> in a single coupon.<\/p>\n\n\n\n

\"multiple<\/figure>\n\n\n\n

A 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\n

Each 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

    \n
  1. Per 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
  2. 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
  3. 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
  4. 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
  5. 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\n

    Note (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

    Welding a Coupon in Multiple Positions to Qualify for All Positions<\/strong><\/h2>\n\n\n\n

    When we talk about why <\/em>a fabricator would try to do multiple qualifications in a single test coupon, the reasons can be many. He may be short on the base metal pieces required to do separate qualifications. Or, the queue in the RT hall may be long, which would make him want to make least number of coupons. These are logistical reasons.<\/p>\n\n\n\n

    Sometimes, the reason may be a more of a technical one. When it is required to qualify a welder for all positions<\/strong>, the ideal way would be to make him take a test coupon in 6G position. However, there are other ways<\/em> as well, to qualify him for all positions.<\/p>\n\n\n\n

    If the requirement is to make a welder ready for welding pipes <\/em>in all positions, the welder can be made to take a pipe coupon (of suitable diameter) in 2G and 5G position. Three quarters of pipe circumference should be welded in 5G position, while one quarter in 2G position. The samples for mechanical testing should then be drawn in accordance with figures in QW-463.2 (f) or QW-463.2 (g).<\/p>\n\n\n\n

    If the requirement is to make a welder ready for welding plates <\/em>in all positions, the welder can be made to take a plate coupon in 2G, 3G and 4G positions. Part of the coupon’s thickness should be filled in 2G position. Then the coupon should be shifted to 3G position, then part of the thickness should be deposited in this position. Then the coupon should be shifted to 4G position, and remaining thickness should be filled in 4G position.<\/p>\n\n\n\n

    The thickness to be deposited in each position should be carefully decided by the welding engineer based on the production requirements.<\/p>\n\n\n\n

    The coupon should be subjected to testing in accordance with QW-304. If it passes, such a coupon qualifies the welder to weld in all <\/strong><\/em>positions.<\/p>\n\n\n\n

    This information is contained in the table under QW-461.9. The interpretation 15-1730 also contains a pertinent query on the subject.<\/p>\n\n\n\n

    Combination of Multiple Performance Qualifications In a Weld<\/h2>\n\n\n\n

    Can A Welder Use A Combination Of His Performance Qualifications In A Single Production Joint?<\/em><\/p>\n\n\n\n

    This is a very interesting question. Many variations of this question have occurred in my mind for many years, as I am sure, must be occurring in the minds of engineers the world over. ASME has issued a good number of Interpretations answering variations of this question.<\/p>\n\n\n\n

    The best way to explain would be to take up a few examples, and explain them individually. Keep reading.<\/p>\n\n\n\n

    OD And F-Number<\/h3>\n\n\n\n