Korean Institute of Surface Engineering

pISSN : 1225-8024 | eISSN : 3399-8403

공학

한국표면공학회지 (46권3호 126-132)

The Effect of Hydrogen on the Variation of Properties at the Surface Layers of 590 MPa DP Steels Charged with Hydrogen

수소장입시킨 590 MPa DP강의 표면층 물성변화에 관한 수소의 영향

최종운;박재우;강계명;
Choi, Jong-Un;Park, Jae-Woo;Kang, Kae-Myung;

서울과학기술대학교 신소재공학과;서울과학기술대학교 에너지환경대학원 신에너지공학과;
Department of Materials Science & Engineering, Seoul National University of Science and Technology;Department of New Energy Engineering, Graduate School of Energy & Environment, Seoul National University of Science & Technology;

DOI : 10.5695/JKISE.2013.46.3.126

Abstract

It was investigated that the effects of hydrogen charging on the properties of 590 MPa Dual Phase(DP) steels at the surface layers. The hydrogen-charging time was changed from 5 to 50 hours and current densities from 100, 150, and 200 $mA/cm^2$, respectively. It was found that the hydrogen content in the specimen was increased with as the charging time and the current density. The microvickers hardness of the subsurface zone was increased from 215.3 HV to 239.5 HV due to the increase in current density and charging time. The comparison of the absorbed energies tested by a small-punch (SP) test showed that the absorbed energy of the specimen was greatly reduced from 436 to 283 $kgf-mm^2$ because of hydrogen embrittlement. It was confirmed that bulb aspects of fracture surface became more brittle with increasing hydrogen content.

Keywords

Hydrogen content;Charging time and current density;Microvickers hardness;Subsurface zone;Small punch test;Bulb aspects of fracture surface;