溶接入熱と拘束度を考慮した割れ指数P_H

抄録

In the author's previous report, a new cracking parameter PH was developed so that the 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 a more generalized PH formula.
The pertinence of PH analysis and prediction have been verified sufficiently with expermiental data obtained from the H-slit type cracking tests of thick plates with a single-bevel groove, the site-weldability tests of pipeline steels, proposed by Stout for the API and the heel crack tests in tab fillet welding.
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.