Abstract:In this paper, a thermal treatment apparatus was established to take local heat treatment on zinc鄄coa鄄
ted clinched joints. Then mechanical test was conducted on the specimens under tensile鄄shear condition, and the met鄄
allographic specimens were prepared to observe the metallographic structure of the clinched specimens with heat treat鄄
ment. The micro鄄hardness of metallographic specimens with heat treatment and non鄄heat treatment were also meas鄄
ured. The results exhibited that compared with the clinched specimens with non鄄heat treatment, local heat treatment
largened the degree of joint neck tear and the static strength increased by 16. 7%. The material structure of the
clinched joints has changed from ferrite and pearlite to lath martensite after thermal treatment. In comparison to un鄄
heated treatment, the micro鄄hardness of the new microstructure is increased by 12. 1%.
