IIW History 1948-1958

- 90-

of ISO/TC 44 was proceeding, the views expressed heing taken into considera– tion; the results of the investigations decided upon and mentioned above pro– duced information which enabled the Sub-Conunittee, firstly to adopt a duration of cycle likely to be acceptable to the majority and secondly to lay clown methods for carrying out heating tests on ventilated transformers. The choice of a suitable conventional arc voltage having been raised by I O/TC 44/SC 4, experimental checks were undertaken, as a result of which it was possible to recommend the use of a conventional voltage which is expressed as an increasing linear function of the current. In order to carry out the investigations mentioned above, and also to cleter- 111 ine the fusion constant of electrodes and for the purpose of control in the shops, it was apparent in 1950 that it would be necessary to have available apparatus for the measurement of currents and a rc voltages giving information uninfluenced by fluctuations of short duration. It \Vas therefore decided to investigate the possibilities offered by the use either of an ammeter clamped by the action of a large capacity condenser or of an electronic integrator which functions by count– ing electronic impulses. Various investigations have been undertaken as a result of questions raised by Commission YIII (Hygiene and Safety). Some of these concern the connect– ing devices for cables, recommendations about which have been put fonyarcl; others, which are still in progress, relate , firstly, to no-load voltage reducing devices a nd attempts to reach compromise figures, and , secondly, to the compara– tive study of the various rules dealing with safety in electric arc welding. \~Tith regard to welding cables, two investigations are in hand, one to measure their flexibility, the other with a view to the preparation of recommendation re– garding permissible currents. C. Sub-Commission C « Testing and Measurement of Weld Metal » . In the first place, investigations were carried out with a view to defining the conditions of deposit most suitable for determining the mechanical properties "·hich \vould make it possible to cla sify covered electrodes of diameter of or above 3.15 mm , (0.124 in.), for the arc \Velcling of mild and low-alloy high-ten ile steels. These investigations were necessary to lay clown a range of characteris– tics with a vie\v to the drafting of a code of symbols for electrodes, for which Sub-Commission E « Classification of E lectrodes » was made responsible. Care was taken to find an economical method of testing which would at the same time ensure faithful results and that significant characteristics from the point of vie'v of applications were obtained. Finally, it was agreed to adopt a mould made up of plate bevelled at roo and spaced 16 mm apart at the level of the backing support. The conditions for laying the weld metal, such as the inclination of the electrode, the length depos– ited, the current used, etc., were laid clown as well as the interpass cooling temperature which was fixed at 250° C. A report wa drafted and approved at the Copenhagen meetings (1953), the title being Nfethod of T esting for the Detenninal£o'l1 of the Characterist-ics of IVeld NIetal with a. view to the Syn·ibohsa.t-ion of Covered Electrodes (1). The agreement of Commissions V and VII h aving been obtained, this report was trans– mitted to I SO/TC 44 as a complement to the document II-29-53 of Sub-Com– mis ion E, which is mentioned below. A second investigation was proposed in order to discover a method for deter– mining the characteristics of metal deposited by electrodes for the welding of thin sheets (diameter below 3.15 mm - 0.124 ins), Like the first , the object

( r) Document II-31-53.