THE EFFECT OF PRE-STRAIN ON FATIGUE FOR A HIGH STRENGTH LOW ALLOY (HSLA)STEEL

摘要

The effect of initial plastic strain cycle fatigue lives of HSLA specimens is investigated. Specimens were monotoni-cally, quasi-statically loaded under strain control in tension to produce plastic strains (prestrain conditions s_0 = 0, s_1 = 4,6, s_2 = 35,6 and s_3 = 66,7 % deformation). Surface analysis on the annealed Zn coat on the prestrain surfaces shows that, the higher the deformation the bigger and deeper the cracks on the Zn coat. Results show that the higher prestrain the higher fatigue resistance for all stress applied, specimens with s_3 shows the highest fatigue resistance for these experimental conditions.