IIW History 1948-1958

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it considers a m1111mum impact value sufficient to ensure weldability for these hvo classes of st eel, with all the more safety in that, for the same fracture energy, the t esting temperature is lower. Not withst anding past and future discussions within Sub-Commission C, which is responsible for continuing the study of this question, these t wo principles have been t aken up far beyond the circle of the IIW and have inspired many national and international documents dealing with the same subject. E. Weldability of Steels in relation to their Transformation Character– istics. On its fo undation t he Commission had tackled the problem of hardening in the heat-affected zones of welds in steels and of its consequences as regards the risk of cracking and also, naturally, the effect of hydrogen in t he weld metal. A bibliographical report by Mr. A. ScoRTECCI (Italy) cleared the ground in con– nexion with t his question : B ibliographical and practical experience report on cold cracking in the heat affected zone (r) . L ater, a Sub-Commission,' the Chairman of which was first Mr. T. NOREN (Sweden) and then Mr. H. GRANJON (France) was made responsible fo r studying cracking t ogether \vith the transformation charac– t erist ics of st eel. This investigation, which is at present in progress, began by an interesting comparison between the results obtained by five different labor– atories from the CTS (Controlled Thermal Severity) t est developed by the British ·w elding Research Association and chosen by the Sub-Commission as a common basis of investigation. The resulting report will shortl y be made available. Furthermore, in r957 the Commission adopted t wo important resolutions, which were published in the annual report of the Chairman, dealing with the ext ent to which the concepts « underbead hardness » and « carbon equivalent » are valid, these concepts having been much discussed in welding circles over the last few years. The Commission also asked the Gove.rning Council to approve the publication of the Japanese document C1'acl~ing, dite to welding, in the heat– a//ected zone of afr hardening alloy steels (2) by Messrs H. SEKIGUCHI and T. KOBA Y ASH! ; this document deals with the origin of various t ypes of crack. F. Corrosion Tests. Corrosion problems fall within the terms of reference of the Commission in so far as the resistance to corrosion of a metal may be modified by welding. The Commission has therefore considered the matter a it affects st ainless steels and li ght alloys. As regards stainless steels, the Commission, on the proposal of Mr. F. RAPATZ (Austria), in r952 recommended the Governing Council to approve the publication of a document entitled Corrosion test for ' elded austenitic chromium-nickel corrosion resist-lug steels (3) . In this document two method- a re proposed for accelerated corrosion testing on "'elded specimen without sensibilisation heat treatment. It is true that in many cases such treatment, which t akes a very long time in relation t o the welding operation , appears excessive fo r the selection of weldable stainless st eels. On Dutch initiative, a study has been undertaken on the co rrosion of light a lloys in sea-water : several aluminium alloys from various European countrie. were welded in the Netherlands; the specimens a re still being tested at three stations in Sweden, the Netherlands and Spain respectively.

(1) Document IX-110-54 . (2) Document IX-17 -57. (3) Document IX-27-53.