Seamless welding procedure tests

According to a different process for seamless pipe production, it is parallel to the longitudinal seam of the steel pipe, welded steel pipe is usually divided into metric, welding thin-walled tube, transformer cooling pipe and so on. Seamless in use with different value and role according to the appropriate method to be used and welding, the welding process used and the type of attention, according to certain production process required for production and processing. Seamless steel pipe with high frequency welding process is relatively simple, fast, continuous production characteristics in the production process is simple and convenient, in accordance with the appropriate production and processing technology. Seamless in civil construction, petrochemical, light industry and other sectors have wide range of applications, used for transporting low-pressure fluid or made into a variety of engineering components and light industrial products, in different industries play an important role and value, to show good properties and performance.

Friction stir welded joints with no pores, fine grain size, fatigue properties, good tensile and flexural properties, welding, no cloud of dust, no splash, energy saving, no wire and shielding gas, welding residual stress and deformation, etc., which is a good applicability soldering method. Cu-Cr alloy has high strength, hardness, good electrical conductivity, thermal conductivity and corrosion resistance, which is the preparation of resistance welding electrodes, metal molds, large high-speed turbine guide bar, power tools, etc. A preferred material for steering. The generator guide bar, electric tools manufacturing process of steering the need for copper-chromium alloys for welding, currently mainly used welding, pressure welding and brazing and other methods. Its physical and chemical properties as well as the copper of impurity elements, which joint prone porosity, strength, corrosion resistance decrease and the welding deformation problems. Currently on friction stir welding of copper -chromium alloy microstructure and properties of welded joints are not many reports, for each pair of solid solution and aging state copper-chromium alloy friction stir welded joint microstructure, hardness and electrical conductivity comparative study of friction stir welding to provide experimental evidence for chromium alloy.

Solid solution of copper -chromium alloy welded joint matrix grain coarse, nugget zone is fine equiaxed grain heat affected zone weld nugget size slightly larger than the area, and there is a certain flow, heat affected zone grain and matrix little difference; weld nugget zone hardness up to 78HB, farther from the weld center lower hardness, hardness until Scientology. Copper-chromium alloy joints aged state matrix structure uneven size equiaxed nugget zone grain refinement, uneven distribution; grain heat affected zone is elongated, with a certain flow resistance; grain heat affected zone than matrix slightly raised; weld nugget zone hardness highest 113HB, the farther away from the center of the weld lower hardness, heat affected zone hardness lowest 91HB, then recovered to the substrate hardness.