The Study On The Affect Of Ceramic Weld Backing To Weld Bead’s Perfonnance With CO₂One-side Welding

CO2welding with Ceramic weld backing is a high efficiency welding technology, it got double-sided molding with just welded one side. it widely used in ship-building, pressure vessels, bridges and all kinds of steel structures and manufacturing. People all around the world play close attention to one-sided CO2welding. Lots of research and applications is about one-sided CO2. As an important welding materials in one-side welding, Ceramic welding backing’s main function is to hold the liquid metal in weld. But it would have some impaction to the performance of weld bead in high temperature. The current study focused on the different formulations of the ceramic weld backing which have impaction to the performance of weld bead. But it did not form a law now.In this paper, the research is about the affection of ceramic backing’s porosity and alkalinity to the performance of weld bead. Some experiments done to find the tendency between the performance of weld bead and ceramic backing’s porosity and alkalinity. It processed production guiding significance in raw material formulation of. ceramic backing.In the experiment of weld backing’s porosity and weld bead’s performance, the weld backing’s porosity is measured by water absorption experiments.Then moisture absorption rate is measured. And finally the comparison experiments is done to discover the affection of porosity to moisture absorption and diffusible hydrogen in weld bead. In the same parameters,the research try to explain that the affection of alkalinity to crack pattern and toughness.The metallurgy action between weld backing and pool metal was analyzed from the point of welding chemical metallurgy. And influence of alkalinity of weld backing on the distribution of C, Si, Mn, P, S in the weld was discussed. Through a series of experiments showed that:the increasing weld backing’s porosity, diffusible hydrogen in weld bead is also increased, but its content is still to meet national standards; Alkalinity effected the element content distribution of C, Si, Mn, P, S in weld backing, especially greater impact on the content of Si, Mn. In root of weld bead, Mn increases with Alkalinity increases, but Si get a reduction. Alkaline baking is better than acidic baking in toughness because alkaline baking had good component distribution and inclusion. While the toughness of the weld bead with acidic backing also higher than the national standards. Therefore, the rear surface of the acidic backing have beautiful molding appearance in ordinary use, and the mechanical properties can meet the requirements, so a large number of acidic backings were used; alkaline backing is mainly used in high requirements on the mechanical properties.