Welding two different kinds of metals requires heating each of them to increase the strength with the help of a nickel-containing alloy before and after welding. A research team of Institute for Materials Research of Tohoku University developed a new technology to weld two different kinds of metals strong without the extra jobs before and after welding using a high-purity metal whose rate of impurities is as low as one hundredth of the present level.
The team members led by Prof. Kenji Abiko inserted a high-purity stainless steel whose rate of impurity contents, such as carbon and nitrogen, is 100 nanograms per one gram between a stainless steel used for plumbing and an ally used for the container of a boiler, and successfully melted and welded them strong at a high temperature using electric discharge. The welded part does not break even it is folded by 180 degrees. It can be applied widely to power generation plants because it can maintain durability for a long period at a high temperature. Highly efficient thermal power generation requires pipe arrangements resistant to 700 degrees centigrade. A high-purity metal is most suitable for the welding of these pipe arrangements, according to the research team.