Some aspects regarding ceramic and the welding process with ceramic backing

摘要

The objective of this evaluation was to determine if ceramic tile backing in arc welding applications could provide a back side contour such that gouging and grinding is not required to prepare for subsequent welding or inspection. Ceramic tiles backing was found to provide such a second side contour in all arc applications. Cordierite and cordierite-based ceramics are promising materials for high thermal shock resistance specially compared to alumina or mullite. Mullite-cordierite composites with various mullite contents and microstructures were prepared by a conventional powder processing, i.e. mechanical mixing, forming of green bodies by dry pressing, and sintering at appropriate temperatures. Cordierite and mullite powders were prepared separately and mixed to get the required compositions. All were sintered for 2h at 1350?C, except for the pure cordierite and mullite which were soaked for 3h at 1300?C and 1600?C, respectively. In all welding processes (MAG welding) test assemblies were made by butt welding. Test assemblies with visually acceptable beads were radiographed. The quality control of the weld are verified by a nondestructive evaluation (visual, liquid penetrant, magnetic particles and ultrasonic). Factors such welding technique, base material, thickness and size and/or electrode characteristics may have an important effect and not identified by this work. Ceramic backing evaluation should concentrate on determining the optimum combination of welding parameters and ceramic/weld-joint design. Sintering characteristics, physical and the main thermomechanical properties were also determined. The development of ceramic backing tiles improved the welding result and it's a recognized as a high-quality and reliable welding aid in such heavy industry as shipbuilding and automobiles.