Residual stress in high-carbon steel affects the dimensional accuracy, structural stability, and integrity of components. Although the evolution of residual stress under an electric field has received extensive attent...Residual stress in high-carbon steel affects the dimensional accuracy, structural stability, and integrity of components. Although the evolution of residual stress under an electric field has received extensive attention, its elimination mechanism has not been fully clarified. In this study, it was found that the residual stress of high-carbon steel could be effectively relieved within a few minutes through the application of a low density pulse current. The difference between the current pulse treatment and traditional heat treatment in reducing residual stress is that the electric pulse provides additional Gibbs free energy for the system, which promotes dislocation annihilation and carbon atom diffusion to form carbides, thus reducing the free energy of the system. The electroplastic and thermal effects of the pulse current promoted the movement of dislocations under the electric field, thus eliminating the internal stress caused by dislocation entanglement. The precipitation of carbides reduced the carbon content of the steel matrix and lattice shrinkage, thereby reducing the residual tensile stress. Considering that a pulsed current has the advantages of small size, small power requirement, continuous output, and continuously controllable parameters, it has broad application prospects for eliminating residual stress.展开更多
The effect of a pulsed electric current on the residual stress evolution of metal materials has been investigated.It was found that the surface and internal residual stresses in the as-quenched samples were reduced dr...The effect of a pulsed electric current on the residual stress evolution of metal materials has been investigated.It was found that the surface and internal residual stresses in the as-quenched samples were reduced dramatically by electropulsing.A large number of experimental data show that the residual stress reduction is proportional to the initial residual stress and related to the material properties and electropulsing parameters.Under the combined actions of drift electrons,Joule heating,and residual stress,the dislocation mobility was enhanced,resulting in plastic strain and the decrease in residual stress.Drift electrons played a unique role in the electropulsing treatment,acting as an additional force pushing dislocations forward.The dislocations ultimately accumulated at a grain boundary,forming a parallel arrangement.Finally,the phenomenological equation of the residual stress evolution under electropulsing was derived from the experimental data.展开更多
基金The work was financially supported by the Natural Science Foundation of Beijing Municipality(2222065)the National Natural Science Foundation of China(U21B2082)Fundamental Research Funds for the Central Universities(FRF-TP-22-02C2).
文摘Residual stress in high-carbon steel affects the dimensional accuracy, structural stability, and integrity of components. Although the evolution of residual stress under an electric field has received extensive attention, its elimination mechanism has not been fully clarified. In this study, it was found that the residual stress of high-carbon steel could be effectively relieved within a few minutes through the application of a low density pulse current. The difference between the current pulse treatment and traditional heat treatment in reducing residual stress is that the electric pulse provides additional Gibbs free energy for the system, which promotes dislocation annihilation and carbon atom diffusion to form carbides, thus reducing the free energy of the system. The electroplastic and thermal effects of the pulse current promoted the movement of dislocations under the electric field, thus eliminating the internal stress caused by dislocation entanglement. The precipitation of carbides reduced the carbon content of the steel matrix and lattice shrinkage, thereby reducing the residual tensile stress. Considering that a pulsed current has the advantages of small size, small power requirement, continuous output, and continuously controllable parameters, it has broad application prospects for eliminating residual stress.
基金financially supported by the National Natural Science Foundation of China (Nos. 51874023, 51601011 and U1860206)the Fundamental Research Funds for the Central Universities, Recruitment Program of Global Experts.
文摘The effect of a pulsed electric current on the residual stress evolution of metal materials has been investigated.It was found that the surface and internal residual stresses in the as-quenched samples were reduced dramatically by electropulsing.A large number of experimental data show that the residual stress reduction is proportional to the initial residual stress and related to the material properties and electropulsing parameters.Under the combined actions of drift electrons,Joule heating,and residual stress,the dislocation mobility was enhanced,resulting in plastic strain and the decrease in residual stress.Drift electrons played a unique role in the electropulsing treatment,acting as an additional force pushing dislocations forward.The dislocations ultimately accumulated at a grain boundary,forming a parallel arrangement.Finally,the phenomenological equation of the residual stress evolution under electropulsing was derived from the experimental data.