厚板60kg/mm2高張力鋼溶接部の脆性破壊発生特性(第1報)
切欠角変形付広幅引張試験による検討
1976 年 45 巻 3 号 p. 222-229
詳細
1976 年 45 巻 3 号 p. 222-229
Brittle fracture initiation characteristics of manual arc and submerged arc welded joints of 60 kg/mm2 high strength thick steel plates were investigated by testing wide plate tension specimen with angular distortion and with a surface notch. The test results were analized by fracture mechanics. The results are summarized as follows.:
(1) The lowest V-charpy impact toughness in the weld zone was obtained at the weld fusion line.
(2) At temperatures above 0°C, the fracture initiation stress obtained from the wide plate specimens was not so lower than the yield strength of the steel.
At lower temperatures, however, the fracture initiation stress was greatly lowered. The decrease was particularly remarkable below -10°C in transversely welded W(1) joints and below -5°C in T-type welded W(1)+W(2) joints and also repair welded joints with some residual stress.
(3) The fracture toughness was calculated quantitatively from the fracture initiation stress. The values calculated in the transversely welded W(1) joints, the T-type welded joints and the repair welded joints decrease in a single band as a function of temperature.
(4) The fracture toughness in the weld fusion line of the welded joints for 60 kg/mm2 high strength thick steel is high value above 0°C, but it is remakably lowered in the temperature range of -5-20°C and shows larger dependency on temperature than that for, 80 kg/mm2 high strength thick steel. And this steel does not show the embrittlement by stress relief annealing. Therefore, there is little difference in frecture toughness between as-welded spcimen, stress relieved specimen and repair welded specimen.
(5) The fracture toughness values of the manual arc welded metal and of the submerged arc weld fusion line are almost equal to that of the manual arc weld fusion line.
