J. Mater. Sci. Technol. ›› 2012, Vol. 28 ›› Issue (9): 803-808.

• Iron and Steel • Previous Articles     Next Articles

Mechanism of Residual Stress Reduction in Low Alloy Steel by a Low Frequency Alternating Magnetic Treatment

Yanli Song, Lin Hua   

  1. School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China
  • Received:2011-07-01 Revised:2011-11-17 Online:2012-09-28 Published:2012-09-28
  • Contact: Yanli SONG
  • Supported by:

    the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of Ministry of Education, China (No. [2002] 383) and the Science and Technology Planning Project of Wuhan City, China (No. 20067003111-05)

Abstract:

Residual stress reduction in low alloy steel by a low frequency alternating magnetic treatment and its mechanism were investigated. Experimental results revealed that average stress reductions of 20%-24% were obtained in the welded samples. Moreover, compared with the zones with lower initial stress levels, more remarkable stress reductions were obtained in the stress concentration zones. The microstructures and magnetic domains were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Based on the analysis of the microstructure and magnetic domain changes, the mechanism of stress reduction by the magnetic treatment has been concluded: (1) the magneto-plastic deformations mainly due to the more uniform redistribution of dislocations are the fundamental cause of stress relaxation; and (2) surface topography is also proved to affect the magnetic treatment results to some degree by influencing magnetic domains.

Key words: Magnetic treatment, Residual stress reduction, Magneto-plastic deformations, Surface topography