Dynamic transformation during the simulation of strip rolling
- 作者：John J JonasVladimir V BasabeChiradeep GhoshClodualdo Aranas Jr
- 会议时间：2013-06-01
- 关键词：strip mill simulations ; rolling load ; mean flow stress ; dynamic transformation ; interpass time
- 作者单位：Materials Engineering,McGill University,3610 University St.,Montreal,H3A 282,Canada
- 母体文献：第五届宝钢学术年会论文集
- 会议名称：第五届宝钢学术年会
- 会议地点：上海
- 主办单位：中国金属学会
- 语种：chi
摘要
Simulations of hot strip rolling were carried out on the McGill torsion machine at strain rates of 2 and 4 s -1 and cooling rates of 5 - 10℃/s.A 0.09%C-O.036% Nb microalloyed and a 0.79C-0.65 Mn - 0.24Si plain C steel were subjected to pass strains of 0.25 to 0.45 and interpass times of 1 second.By means of double differentiation of the flow curves,it is shown that the dynamic transformation ( DT) of austenite to ferrite takes place during all the passes applied above the respective Ae3 equilibrium transformation temperatures ( 836℃ and 733℃ for the two steels).This type of transformation is initiated at strains of about 0.05,well before the critical strain for the initiation of dynamic recrystallization,and occurs at temperatures as much as 200℃ above the Ae3.The transformation to ferrite reduces the rolling load below the levels expected for single phase austenite and can lead to shape control problems if not taken into account.The DT ferrite formed in this way is Widmanstatten in nature and is converted to polygonal ferrite during further straining.