Formation of Vacancy-type Defects in Cold-drawn Pearlitic Steel during Tensile Deformation with Hydrogen Charging

The effects of hydrogen charge on the formation vacancy-type defects in cold-drawn pearlitic steel were investigated by using positron lifetime spectroscopy, and correlation between susceptibility to embrittlement was discussed. Pearlitic steels aged at 300°C 450°C after cold-drawing used. Both tensile deformed subsequently fractured samples prepared slow strain rate tests (SSRT) with without cathodic charge. Average increased increasing both case 300°C-aged 450°C-aged steels. There is no remarkable effect average results mean applying increases amount lattice such as dislocation or vacancy, although has little effect. On contrary, vacancy cluster component hydrogen-charged SSRT, an increase concentration promoted clustering furthermore. showed more than steel, implying that lamellar structure prevented clustering. Fracture strains SSRT decreased due embrittlement, fracture all tested a strong dependence degree That means big fracturing steels, detrimental attributable promotion