ข้อมูลผลงานวิจัย

This article presents the results of thermite welding of 100 pounds railway steel grade R260 by studying the effect of pre-heat temperature before thermite welding on the mechanical properties and the soundness of the weld metal. The degree of pre-heat temperature was determined from the point at which the head of railway steel was about to melt. There were two groups of specimens in this study. Each group of specimens consisted of two pieces of thermite welded specimens. For group A specimens, the pre-heat temperature was set to approximately 130-140 degree Celsius at the distance of 6 cm away from the edge to be welded; whereas for group B specimens, the pre-heat temperature was set to higher temperature around 170-180 degree Celsius. Then, all four welded specimens were non-destructive tested and destructive tested. For non-destructive testing, visual test and ultrasonic test were performed to investigate the defects in the weld. For destructive testing, slow bend test was performed to measure the maximum load and maximum deflection up on failure. It was found that the specimens welded with higher pre-heat temperature contained less amount of welding defects and failed at greater load and deflection compared to specimens welded with lower pre-heat temperature.