The beam-to-column connections of architectural steel structures have conventionally been welded by a semiautomatic multi-layer welding method using a CO2 arc welding process. So, there are the limit of its efficiency and the problem that the welding quality often depends on the welder's workmanship.
By using the electrogas arc welding process which was generally considered difficult to apply to the beam-to-columr connections of architectural steel structures because of the shortage problem in weld toughness due to its conventional high heat input. With the architectural steel plate for large heat input welding newly developed, the reporters, et al. have developed an one pass upward electrogas arc welding process which can produce welds in their deposition rate of two times of the conventional without any program in their toughness and with extremely less weld defects. Moreover, this electrogas arc welding process can be applied to new seismic details such as a non scallop details, etc.. It is the most conspicuous characteristic for this welding process that stable penetration can be secured even for thick steel plates by moving the welding torch as trapezoid within the groove formed by water-cooled copper shoe.
The heat input in this welding process is approximately 7 times as high as that in the conventional process but the charpy impact values in both weld metal and heat-affected zones are not less than 150 J (at 0 degree) in case of the architectural steel plate for large heat input welding newly developed.
So, this new welding process with new developed steel can keep the same degree of toughness in weld zones as those in the conventional steel welded by the conventional CO2 arc welding process.
