Electrically assisted stress relief annealing of automotive springs

• DOI: 10.1007/s12206-017-0740-x
• Publication Date: 2017-08-18T12:19:24Z
• Authors: Gi Dong Park; Van Loi Tran; Sung-Tae Hong; Yong-Ha Jeong; Tae Shik Yeo; Min Jae Nam; Moon-Jo Kim; Sung-Woo Jin; Heung Nam Han
• Keywords: 0205 materials engineering; 02 engineering and technology

In the present study, Electrically assisted (EA) stress relief annealing for automotive springs is experimentally investigated. A concept of EA stress relief annealing is to reduce the process time by superimposing the effect of electroplasticity on that of the elevated temperature. In EA stress relief annealing, the temperature of a cold-coiled spring specimen is rapidly increased to the annealing temperature and held constant by a pulsed electric current. The experimental results show that the performance of EA stress relief annealing clearly surpasses that of a conventional stress relief process, even with a significantly shorter process time and a significantly smaller amount of energy. The result of X-ray diffraction analysis confirms that the annihilation of dislocations during EA stress relief annealing is enhanced, which strongly suggests the occurrence of the electric current induced annealing.