心線中にマンガン及び珪素を特に含有せしめた鋼用熔接棒の研究(第3報)

Abstract

In this report, we manufactured many steel core rods having various manganese, and silicon contents on trial in industrial scale and using them, prepared the arc-welding electrodes whose coating contains no deoxidizes and a small quantity of reducing-gas-producing material. Then, observing the rule of JES 9001-"Arc welding coated electrodes for general steel constructions", we investigated the properties of the above mentioned electrodse in use and measured the properties of weld steel deposited with them. And the following results were obtained.1) In use of the steel core rods containing somewhat much quantities of manganese and silicon, the apparent specific gravities, impact values and elongations of the all weld steels are more excellent than those of the all weld steels deposited with the usual steel core rods whose contents of manganese and silicon are lower. However, the composition-point showing contents of manganese and silicon must exist in the field II-The deoxidation product in this field is the FeO-MnO-SiO2 liquid solution which is unsaturated with silica and has good fluidity.- of the diagram of deoxida-tion with manganese and silicon (Fig.1 ). But, if the manganese and silicon contents are too high, there is a tendency for the above mentioned properties of the all weld steels deposited, with them to become lower.2) The higher the manganese and silicon contents of steel core rods are, the larger the ultimate strengths and hardness of the all weld steels deposited with them become.3) In use of the steel core and having high silicon contents, there is a tendency for the one layer fillet weld of T-joint to contain portions having the so-called striated structures and minute cracks. However, if silicon contents of the core rods are lower than 0.3%, such a tendency of f the fillet weld is not observed.In such a way, it has been made clear that the steel core rods containing suitable large quantities of manganese and silicon are effective for arc-welding of steel.