Gas Pressure Welding Method for Steel Reinforcing Bars

摘要

In Japan, the majority of steel bars are welded by gas pressure welding. This is because gas pressure welding is superior to other joining methods in its workability. In the Hanshin-Awaji earthquake of January 17, 1995, many gas pressure welds in reinforced concrete were broken at the weld interface. Since then, a reliable quality inspection method has been demanded. A method of flash removal by hot shearing, which makes it possible to easily inspect the weld immediately after welding, has been recently developed. This method is effective in evaluating gas pressure welds in real time, and it possesses high workability and high reliability. The reliability of inspection methods, such as penetrant testing, ultrasonic testing and flash removal by hot shearing, was verified by tensile and bending tests of welded joints. Then the relation between the inspection results and the destructive testing results was investigated. As a result, it was clear that flash removal by the hot shearing method displayed the highest reliability. Thus, flash removal by hot shearing is superior to penetrant testing and ultrasonic testing as a quality inspection method for gas pressure welds.