| The effect of hydrogen on tensile strength in dual phase steels, which have different martensite volume fraction and martensite morphology, was studied by load-elongation test. Tensile strength was decreased with increasing hydrogen charging density. If martensite volume fraction and hydrogen charging density was increased, total elongation in step quenched structure was decreased much more than that in intercritical annealed structure. When hydrogen was introduced in intercritical annealed specimen, the void was bigger than non hydrogen-charged specimen during plastic deformation. When hydrogen was introduced in the step quenched specimen and intercritical annealed specimen, the void in the step quenched specimen was bigger than that in the intercritical annealed specimen during plastic deformation. |
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