熔接々手の脆性破壊(第1報)
母材および熔着鋼の影響
1955 年 24 巻 2-3 号 p. 94-100
詳細
1955 年 24 巻 2-3 号 p. 94-100
Tensile tests were made on welded butt joints with internal defects produced at the root face, left unwelded, of double V grooved joints (Fig. 2). The load was applied perpendicularly to the weld. The sharp transition phenomena reappeard in the presence of such natural defects.
Five charges of structural mild steels, 23 mm thick, and three electrodes with different transition temperatures were used for the test. The dimensions of the root face (G) and reinforcement of weld (δ) were kept constant (G=6 mm, δ=2 mm) and effects of the notch sensitivities of base and deposited metals on the transition temperatures of welded joints were investigated. Of the two transition phenomena, ductility and fracture, only the latter was observable in the temperature range tested. As the result, it was proved that the fracture transition temperature of welded joint (Trs) could be predicted by the equation,
Trs=0.60Trs(B)+0.45Trs(D)-34 (°C),
where Trs(B) and Trs(D) are the 50% shear transition temperatures of base and deposited metals by V-Charpy impact test.
