Abstract
The effect of hydrogen charging methods on the hydrogen embrittlement characteristics of tempered martensitic steels were discussed in terms of hydrogen diffusion behavior. Two tempered martensitic steels with different Si content were fabricated by quenching and tempering. The steel with high Si content had a lower cementite fraction because the..... More

Abstract
The strain aging and hydrogen embrittlement behavior of two bake hardening (BH) steels with different microstructures were investigated in this study. The single-phase BH steel was composed of fully ferrite, while the dual-phase BH steel consisted of ferrite and 3 % martensite. The BH index and aging index (AI) of..... More

Abstract
The aim of this study was to investigate the effect of precipitates and cold working on the reheat cracking of STS 347 austenitic stainless steel. Three different heat treatments to form NbC and M₂₃C₆ precipitates were applied to the STS 347 austenitic stainless steel and 10% pre-strain was additionally introduced..... More

Abstract
The effect of pre-strain on the hydrogen embrittlement of Nb-free and Nb-added low-carbon steels with ferrite-pearlite structure was investigated in this study. After the steels were electrochemically charged with hydrogen, slow-strain rate tensile (SSRT) tests were conducted on them to examine hydrogen embrittlement behavior. The SSRT test results revealed that..... More

Abstract
In this study the correlation between bainitic microstructure and the low-temperature toughness of high-strength API pipeline steels was discussed in terms of crack initiation and propagation in the microstructure. Three types of API pipeline steels with different bainitic microstructures were fabricated using varying alloying elements and thermo-mechanical processing conditions, and..... More

Abstract
In the present study, the correlation of microstructural factors with yield ratio and uniform elongation was investigated in API X80 linepipe steels with different microstructures by varying thermomechanical control process conditions. The grain size and microstructure fraction of the API X80 linepipe steels were quantitatively measured by EBSD analysis and then..... More

Abstract
In this study the hydrogen embrittlement characteristics of three high-manganese steels were tested using different hydrogen charging methods, and the results were compared with various Mn-containing steels. The results showed that the hydrogen embrittlement susceptibility of the high-manganese steels increased with increasing inherent strength because deformation mechanisms, such as deformation..... More

Abstract
Since reconstruction of old town in Korea requires high-rise and seismic design construction, many attentions have been paid to high strength seismic reinforced steel bar. In the present paper, technical developments and trends are summarized for developing next-generation seismic reinforced steel bar of grade 700 MPa. Steelmaking process requires high..... More

Mechanical Behavior

Abstract
In this study, the effect of microstructural factors on the impact toughness of hypoeutectoid steels with ferrite-pearlite structure was quantitatively investigated using multiple regression analysis. Microstructural analysis results showed that the pearlite fraction increased with increasing austenitizing temperature and decreasing transformation temperature which substantially decreased the pearlite interlamellar spacing and..... More