PURPOSE: To execute a double one layer welding without generating a welding defect, and also with a high efficiency, by butting a steel plate whose plate thickness has been limited, by an X groove which has limited a groove angle and a root face, and welding it by a welding machine of three electrodes or more.
CONSTITUTION: A steel plate 1 of 50W100mm plate thickness is butted by an X groove of 35W60° groove angle 3 and 0.15W0.35t mm root face 2, and a double one layer submerged arc welding is executed by a multi-polar welding machine of three electrodes or more. In this regard, the reason why the plate thickness range has been limited is because when the plate thickness exceeds its upper limit, a welding heat input becomes excessive and a fire resistance of a flux becomes short. Also, the X groove which has limited the groove angle and the root face has been used in order to prevent a pear crack of a weld metal, and a multi-electrode welding machine of three electrodes or more has been used, because in case of two electrodes or less, a sufficient deposited metal cannot be obtained.
MOTOMATSU RYUICHI
SAITO SHIZUKA
MIBU TOSHIYA
