중탄소강의 페라이트-펄라이트 미세조직과 항복강도에 미치는 Si 첨가의 영향 (Effect of Si on the Yield Strength of Medium-Carbon Steels Consisting of Ferrite and Pearlite)

서지정보

· 발행기관 : 대한금속·재료학회
· 수록지 정보 : 대한금속·재료학회지 / 62권 / 11호 / 897 ~ 910페이지
· 저자명 : 고재현, 김경원, 장재훈, 이기영, 박현, 김정한, 이정원, 김용현, 홍성민, 강전연, 최윤석

초록

To enhance the intrinsic yield strength of the ferrite-pearlite microstructure that inevitably formsin a non-quenched-and-tempered steel for large structural components, this study analyzed the effect ofadding Si. The resulting ferrite-pearlite microstructure in medium-carbon steels was examined, and theresulting increase in yield strength was interpreted based on strengthening mechanisms. Hot-rolled sheetsof 0.3C-1.5Mn steels were fabricated with Si ranging from 0.22 to 2.21 wt. %. Austenitization was conductedat 880°C followed by slow continuous cooling, and ferrite-pearlite microstructures were formed. Withincreasing Si, the yield strength increased from 409.1 to 573.6 MPa. Although there was a negligible changein the austenitic grain size, the mean diameter of the ferritic grains decreased from 8.8 to 5.0 μm, while themean interlamellar spacing of the pearlites decreased from 196.6 to 109.9 nm. Using these quantitative dataabout microstructural features and considering possible strengthening mechanisms, a model to predict yieldstrength was derived via a constrained optimization method. The resulting model indicated that the majormechanisms are the refinement of pearlitic interlamellar spacing and the solid solution strengthening offerrite by Si. Their contribution to the increment in yield strength was over 75 %, while others such as ferriticgrain refinement and increased pearlitic volume fraction have limited influence.

영어초록

To enhance the intrinsic yield strength of the ferrite-pearlite microstructure that inevitably formsin a non-quenched-and-tempered steel for large structural components, this study analyzed the effect ofadding Si. The resulting ferrite-pearlite microstructure in medium-carbon steels was examined, and theresulting increase in yield strength was interpreted based on strengthening mechanisms. Hot-rolled sheetsof 0.3C-1.5Mn steels were fabricated with Si ranging from 0.22 to 2.21 wt. %. Austenitization was conductedat 880°C followed by slow continuous cooling, and ferrite-pearlite microstructures were formed. Withincreasing Si, the yield strength increased from 409.1 to 573.6 MPa. Although there was a negligible changein the austenitic grain size, the mean diameter of the ferritic grains decreased from 8.8 to 5.0 μm, while themean interlamellar spacing of the pearlites decreased from 196.6 to 109.9 nm. Using these quantitative dataabout microstructural features and considering possible strengthening mechanisms, a model to predict yieldstrength was derived via a constrained optimization method. The resulting model indicated that the majormechanisms are the refinement of pearlitic interlamellar spacing and the solid solution strengthening offerrite by Si. Their contribution to the increment in yield strength was over 75 %, while others such as ferriticgrain refinement and increased pearlitic volume fraction have limited influence.

참고자료

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