Technique for reducing residual stress of motor bed plate in welded structure

Abstract

This invention provides a process for lowering residual stress of welding motor base by using vibrational aging. The process comprises: utilizing three points uniformly distributed on the same circumference as the supporting points, setting rubber gaskets on the supporting points, uniformly fixing the outer wall plates of the welding motor base onto the rubber gaskets, and performing vibrational aging for vibrational aging for 0.5-1 h. The vibrational aging utilizes the crossed point between the perpendicular bisector of two supporting points and the round hole on the outer wall plate as the exciting point, and the point 1/3 hole circumference distant from the exciting point as the detecting point. The exciting force is 1/3 of the working stress. The method utilizes vibrational aging as a substitute for traditional heat aging to lower residual stress of welding motor base. Through selection of appropriate exciting force as well as exciting point position, the method can realize optimal exciting effect. The method has such advantages as flexible operation, good stress-lowering effect, high efficiency, low energy consumption, and no pollution.

Description

technical field [0001] The invention relates to a process method for reducing the residual stress of a motor frame of a welded structure. Background technique [0002] The frame is one of the key components of large electric motors. It is assembled and welded by large steel plates. It has a complex structure, as shown in Figure 1 and Figure 2. It is mainly composed of horizontal outer wall plates A1, outer wall plates B5, inner wall plates A plurality of supporting ribs 4 are welded to form the main frame, and then welded with parts such as side plates 2, and the outer wall plate has a circular hole 6. During the welding process, the weld seam melts at high temperature locally, and solidifies with welding. Near the weld seam, there is tensile and compressive stress between the base metal and the weld seam. Part of the stress is too late to release, and it will remain at the weld seam to form welding residual stress. Due to the interlaced and dense welding seams in the two e...

AI Technical Summary

Problems solved by technology

The disadvantages of adopting thermal aging process to reduce the welding residual stress of machine base are: complex operation, low processing efficiency, generally not less than 24 hours, and limited by environment, site, workpiece size and material, etc., the residual stress elimination rate is not high , waste energy, pollute the environment

[0005] To achieve a good effect of vibration aging, it is mainly to select the support point, excitation point, pick-up point and excitation force of the workpiece. At present, the method of vibration aging has not been applied to the reduction of welding residual stress of large motor bases, and there is no perfect one. a set of craft

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