Cold Cracking and its Prevention in Steel Welding : Report 3 Effects of Heat Input and Restraint

概要

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In the author's previous report, a new cracking parameter P_H was developed so that conditions leading to hydrogen-induced cracking in the welds of high strength steels could be analyzed and predicted using the standard data of the JIS oblique-Y (Tekken-type) cracking test. In this report, it is established that the effects of weld heat input and intensity of restraint on hydrogen-induced cracking can be defined by more generalized P_H formula. The relationships among critical cooling time, critical preheating temperature, cracking parameter P_H, weld heat input, plate thickness, groove shape, eccentricity of weld location, carbon equivalent, diffusible hydrogen content of electrode and cooling condition after welding are discussed in detail in this paper. It is also shown that the effect of diffusible hydrogen content is much smaller under mild restraint than under severe restraint. The intensity of restraint in any case should be converted in the P_H theory into an equivalent intensity in the JIS oblique-Y test, considering heat input, eccentricity and groove shape. The pertinence of P_H analysis and prediction has been verified sufficiently with experimental data obtained from the site-weldability tests of pipeline steels, proposed by Stout for the API, the heel crack tests in tab fillet welding and the H-slit type cracking tests of thick plates with a single-bevel groove.
社団法人溶接学会の論文
1980-10-01