Relieving Welding Residual Stress by Applying Vibratory Weld Conditioning

Abstract

Heat input of welding causes temperature gradient in the steel structure. After welding and along with temperature cooling down, residual stresses appear around the welding zone, cause the welding deformation. Residual stresses are a result of the temperature gradient, restraint intensity and the dependency of material properties on the temperature, such as yield strength, elasticity modulus, and thermal expansion coefficient. Vibratory weld conditioning is a new technology which vibrates the workpiece while welding by vibrator. Its main purpose is to refine grain, relieve residual stress, minish welding deformation and improve the properties of welded joint. Firstly, electro-slag weld was done in the two kinds of vibration condition: 0.3g and 0.6g. Then, the distribution of welding residual stress was measured with blind hole-drilling method. Results show vibratory weld conditioning may relief welding residual stress greatly and σ max is less than 1/2σ s . From metallograph, vibratory weld conditioning can refine the grain effectively. The grain size of 0.6g was smaller than that of 0.3g. While from the measuring values of residual stress, 0.6g's are higher than that of 0.3g's.And also conclude that after finishing welding continuing vibrating a period to increase the inputting energy is benefit to the relief of welding residual stress. 0.IntroductionElectroslag welding (ESW) firstly developed in the early 1950's by Paton, was developing forward at the steady speed all the time and is especially widely used in heavy manufacturing. ESW has great superiority in thick plate structure, composite structure and thick wall vessel etc [1,2] . However, while welding, the large heat inputting associated with the process results in a coarse-grained cast structure with a wide coarse grained region in the heat affected zone (HAZ) and at the same time it results in the high residual stress [3] .Vibratory weld conditioning (VWC) is also called the process that vibrating the workpiece while welding, which is developed based on the vibratory stress relief (VSR). VWC puts the periodical force on the weld and the whole workpiece in the process of welding to improve the quality of the weld [4] . Serial researches founded that VWC can refine the grain effectively and reduce the magnitude of residual stress and the weld deformation. Comparing to the heat stress relief, VWC has the good qualities of less investment, more convenient operation, no pollution and shorter manufacturing period. Relative to VSR, VWC vibrates the workpiece from the beginning to the end of the welding

A Study on the Microstructure and Fatigue Properties of Welding Joints in Vibration‐Assisted Laser Welding Process

“…In Figure d, the joint is well formed without welding pores, the vibration frequency has no obvious influence on the penetration depth. Zhu et al pointed out that vibration acceleration could be regarded as a good substitute value of the amplitude, which could comprehensively reflect the two parameters of vibration frequency and excitation force. It could be known from the literature that a r is the effective value of vibration acceleration, its expression is shown in Equation where T is the vibration period; a tr is the instantaneous value in one vibration period; and t is time.…”

Corrosion Crack Nucleation Mechanism in the Welded Structures of X65 Steel in Natural Seawater

“…To eliminate the residual stress in specimens of group A1-A4, vibration was imposed by high-speed motor on specimens of group A1-A4 with the VSR method before the corrosion test. e effect of surface residual stress of the welded structure on corroded damaging rates of the weld joint, HAZ, and fusion line was studied through the comparison of differences between surface corrosion morphologies of specimens processed and unprocessed by VSR [36,37]. In order to guarantee the residual stress elimination effect of the VSR method, a three-dimensional stress magnetometer of JH-80 was used to detect the surface residual stress of group A1 before and after VSR.…”

The Influence and Mechanism of Residual Stress on the Corrosion Behavior of Welded Structures

“…However, the welding residual stress has great influence on the corrosion resistance of welded structures while the structures serve in a corrosive environment, thus effecting their security and service life [5][6][7][8] . Methods such as heat treatment and vibratory stress relief (VSR) are usually used to eliminate the residual stress in welded structures to reduce its effects on the structures [9][10][11] . However, it is difficult to eliminate the residual stress completely, especially in large-scale steel structures.…”