Development of Innovative Welding for High Performance Bridge Steel

With this research, we would like to provide new materials joining methods to the DOT. This will be achieved with a pulse energy store that has already demonstrated game changing capability in welding a wide variety of metals and alloys. The process we are proposing is known as Homopolar Welding. The weld is created by a solid state fusion welding process whereby high current is passed through the weld interface until the metal reaches forging temperature and then an upset force is applied to the weld interface to complete the process. Some of the steels welded with this process are API 5L Grade X52 X60, and X65. Although they are pipeline steel, they meet the requirements of high performance steel and give confidence that bridge steel will also be welded with good results with this process. Typical test results analyzed from welds of the Nippon X65 series material include tensile yield strengths between 71 and 81 ksi with ductile fracture location predominantly in the parent material. In Charpy V notch testing, a mean value of 91 ft-lb was recorded.