IIW History 1948-1958

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of thi study \ms to complete the code of symbols of electrodes mentioned above. ~fany tests were carried out but the numerous difficulties encountered made it necessary to recommend that small diameter electrodes should be codified in accordance with the general rules of the code without giving symbols relating to the mechanical properties. Sub-Commission C still has on its working programme research on various subjects which, though not yet sufficiently advanced to allow of information about them being gi' en here, will no doubt result in interesting conclusions. D. Sub-Commiss ion D « Deep Penetration Welding » . In 1952, in connexion with the preparation of a code of symbols for elec– trodes, it was necessary to reach agreement on the conventional limit above \vhich an electrode can be considered a « deep penetration electrode ii, both for butt and fi ll et welds. In view of the practical applications, the help of Com– mission V was asked for in finding a non-destructive method, particularly an ultrasonic one, which would make it possible to check the regularity of the penetration along a fillet weld. In 1953. the Commission considered various papers illustrating the possi– bilities offered by deep penetration welding and showing how it should be used. Among these papers may be mentioned : a Japanese contribution dealing particularly with fi llet welding and giving a formula expressing the penetration as a function of the speed and of the welding current; a report on an investigation carried out under the auspices of the Belgian Institute of ·welding, stressing in particular the mechanical characteris– tics of the joints obtained and especially the dynamic strength of fillet welds, \vhich seems higher than that obtained with orclinary electrodes ; a report on an investigation undertaken by the French Institute of Welding \vhich included research work on the many factors likely to influence the penetration and concluding, in the light of experiments for which statistical methods were used, by expressing the penetration by means of a linear function of six terms, in which the coefficients of current, speed, electrode diameter, slope of the plates, distance between the edges, are constants depending upon the t ype of electrode used. I n this paper, stress was placed on the influence of a slope of some de– grees in the plates, welding on the upward slope making it possible to increase the penetration and guarantee its regularity . E . Sub-Commission E « Classification of Electrodes n . Having recognised at Delft, in 1949, the necessity for systematic investiga– tions with a vie\v to designating the various types of electrode, a first draft was considered by the Commission at Oxford in 195I. After some amendments had been made the following year, the Commission adopted a draft entitled Code oj Iutem ation.al ymbols for Covered Electrodes for the W elding oj lvhld and L ow Alloy H1:gh-Tensile S teels and agreed that it was suitable for transmission to the Committee « vVelding n of ISO. For the codification of a given type of electrode, this draft (1) uses six sym– bols for the mechanical characteristics of the metal deposited by fusion , the type of covering, the possibilities of \Velding in different positions and the conditions for electrical supply . Document II-29-53, after having been examined by Sub-Committee 3 of the Technical Committee « Welding i> of ISO, and then by the latter Committee

( r) Document II- 29-53.