新しい割れ指数P_HAによる冷間割れの解析

抄録

In our previous report IIW IX-1232-82, a new and more generalized formula P_HA for cold cracking parameter has been introduced, considering local accumulation of hydrogen, so that the conditions leading to various types of hydrogen-induced cracking in welded high strength steels can be analyzed and predicted using the data obtained from the standard JIS-y (Tekken type) cracking test. In this report, the formula for the P_HA has been made more accurate with additional JIS-y test data.
The idea of equivalent intensity of restraint R_Fy, which directly concerns the magnitude of local stress concentration near the root of a one-pass weld in a butt-joint, has proven to be very useful in explaining quantitatively the effects of various groove shapes and eccentric weld locations on the values of critical cooling time for the prevention of root cracking.
Moreover, experimental findings on heel cracking (HAZ root cracking in a short fillet weld in a T-joint) of HT50 steels are satisfactorily explained by P_HA analysis.