Quenching type pulsation welding method

Abstract

The invention discloses a quenching type pulsation welding method, which comprises the following steps: a weldment is horizontally suspended and clamped in a welding fixture, a welder A begins to strike arc and weld with filler wires, after the needed melting quantity is achieved, the welder A stops wire filling, rapidly pulls a welding gun open, and guarantees that the electric arc is not extinguished; when the welder A pulls the welding gun open, a welder B rapidly sprays liquid nitrogen for 1-3s to the center of a molten pool on the front or the back of the weldment, and then moves away a nozzle of the liquid nitrogen; the welder A rapidly operates the welding gun back to the position near the last welding spot to continue performing fusion welding, and the steps are repeated until the welding is finished. As the welding molten pool can be quenched within the shortest period of time instead of being quenched before being about to solidify or is solidified, the refining effect of crystalline grains can be guaranteed, and the normal welding and melting process is not influenced.

Description

technical field [0001] The invention relates to weld grain refinement, and especially designs a pulsating welding method in which the welding torch on the front of the weldment vibrates back and forth, the front or back of the weldment is quenched with liquid nitrogen, and the welding torch and liquid nitrogen nozzle are controlled cooperatively. Background technique [0002] Under normal circumstances, the grains of the weld seam are often coarser than those of the base metal during metal welding, especially for austenitic stainless steel, ferritic stainless steel, and nickel-based alloys. The grains of the weld seam are very coarse, which directly affects the welding process. Mechanical properties and corrosion resistance of joints. [0003] According to the applicant's research on relevant domestic and foreign literature, the grain refinement methods of welds can be divided into two categories: chemical methods and physical methods. Chemical methods include adding refine...

AI Technical Summary

Problems solved by technology

The annealing and recrystallization method after large deformation is not applicable due to the large plastic deformation of the weld after the weldment is formed and the recrystallization equipment and process are complicated.

Although the chemical method of adding refiner, etc. has the advantage of uniform and fine grain refinement in theory, it is difficult to use because of the difficulty in applying the refiner and the phenomenon of floating and agglomeration in the weld pool.

Although the in-situ generation method can avoid adding process complexity to a certain extent, it is also difficult to avoid the disadvantage of "impurity" in the weld, which brings the risk of degradation of mechanical properties and corrosion properties, and is closely related to the welding base metal , it is difficult for a refiner suitable for a certain metal to be suitable for other metal materials

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