Effect of thermomechanical treatment and coiling temperature on the strengthening mechanisms of low carbon steels microalloyed with Nb
Abstract One of the options available for coping with current property requirements is to increase microalloying contents. As well as affecting austenite microstructural evolution, this can lead to a larger contribution of precipitation and dislocation density hardening to the mechanical strength. However, it also results in more complex interactions between the strengthening mechanisms, making it difficult to optimize operation parameters. In this work, plane strain compression tests were carried out to produce different austenite microstructures with two low carbon steels microalloyed with different Nb levels (0.04% and 0.11%), followed by coiling simulations in the 500 to 700°C temperature range. The mechanical properties of the transformed microstructures were determined via tensile testing and the specimens were characterized using optical microscopy, EBSD and TEM. Similar austenite grain sizes and strain accumulation levels were obtained for both steels, and as a result, it was observed that increasing Nb content had a small effect on the grain size of the transformed microstructures. On the other hand, the coiling temperature significantly affected the mechanical strength. The lowest strength values are obtained for 700°C; these increase significantly at 600°C (≅90 and 140MPa increase in the Yield Strength (YS) for the low and high Nb steels, respectively) and decrease slightly at 500°C. At the conditions investigated, similar dislocation density levels were determined for both steels, which indicates that the larger YS increase observed for the high Nb steel must be mainly due to the effect of precipitates formed during or after phase transformation.
유료 다운로드의 경우 해당 사이트의 정책에 따라 신규 회원가입, 로그인, 유료 구매 등이 필요할 수 있습니다. 해당 사이트에서 발생하는 귀하의 모든 정보활동은 NDSL의 서비스 정책과 무관합니다.
원문복사신청을 하시면, 일부 해외 인쇄학술지의 경우 외국학술지지원센터(FRIC)에서
무료 원문복사 서비스를 제공합니다.
NDSL에서는 해당 원문을 복사서비스하고 있습니다. 위의 원문복사신청 또는 장바구니 담기를 통하여 원문복사서비스 이용이 가능합니다.
- 이 논문과 함께 출판된 논문 + 더보기