Effect of Hydrogen Induced Cracking on the Electromagnetic Properties of API-X80 Steel Sheet

The effect of hydrogen induced cracks (HIC) on nano-mechanical and electromagnetic properties of API-X80 steel sheet was studied. The average grain size of API-X80 were 1.99 mu m with a preferred orientation near < 110 > < 100 >. One day immersion HIC environment resulted in producing the HIC sizes of X-80 in micrometer scale. Diffusible hydrogen is saturated less than 24 hours in this HIC test condition. The diffusible hydrogen contents of the 4 and 6% pre-strained specimens were 4.39 and 4.55, respectively. Micro-cracks more than about 10 in size were clearly observed at the surface after 24 hours of immersion in the standard HIC solution. The average HIC propagating rate was about 0.017 [mu m/sec]. The nano-hardness was increased with increasing the HIC immersion time. The nano-hardness, friction coefficient and fatigue limits were 5.78 [GPa], 0.745 and 0.392 mm for the specimen with 24-hours immersed in HIC environment. The formation of HIC significantly decreased the maximum magnetization.