| 摘要 |
A high-efficiency fillet welding method for conducting, without edge preparation, T-shape fillet welding of thick steel webs having a C content not more than 0.21 wt %. The welding is conducted by using a leading electrode (L) and a trailing electrode (T) composed of wires of about 4.8 to 6.4 mm diameter and containing C in an amount which meets the condition of formula (1), as well as 1.50 to 2.50 wt % of Mn. The welding is executed in such a manner that the ratio IT/IL of the current IT supplied to the trailing electrode (T) to the current IL supplied to the leading electrode (L) ranges from 0.75 to 1.00. The flux used in the welding is a bonded flux containing 60 to 91 wt % in total of SiO2, MgO and CaO, 5 to 30 wt % in total of TiO2, Al2O3 and CaF2, 2 to 8 wt % of metal powder, said flux containing a carbonate gas-forming component in an amount to generate 2 to 10 wt % of gases by thermal decomposition of said carbonate during welding, and the balance incidental impurities, the flux having a bulk specific gravity of 0.80 to 1.20 g/cm3: 0.39CWIRE0.39CWEB+0.22CFLANGE</=0.135 (1) where CWIRE is the C content of the wire (wt %), CWEB is the C content of the web (wt %) and is </=0.21, and CFLANGE is the C content of the flange (wt %) and is </=0.21.
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