Characterization and mechanisms of formation of disturbed layer during rolling of aluminium alloys

铝合金轧制过程中扰动层的特征及形成机制

• 批准号: 419620-2011
• 负责人: Riahi, Reza
• 金额: $ 2.91万
• 依托单位: University of Windsor
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=573843
• 关键词: Characterization; mechanisms; formation; disturbed; layer

Aluminum sheets experience high compressive and shear stresses as well as high temperature during hot rolling. These severe conditions alter the local composition and microstructure of the surface by formation of localized layers known as "disturbed layer". The formation of disturbed layer changes the appearance (colour), tribological behaviour, weldability, surface tension, and corrosion resistance of aluminum roll-products. The project aims to improve our understanding of the tribological factors that affect formation of the disturbed surface layer during aluminum rolling using a custom made rolling simulator at the University of Windsor. The disturbed layer is speculated to form mostly during hot rolling process, where the sheet enters to the roll gap at a temperature range of 340C - 550C. Due to sliding friction between the rolls and the sheet surfaces, the speed of the sheet at the exit side of the tandem mills is normally higher than the linear speed of the rolls (forward speed). Due to forward speed, the rolls slide against aluminum sheet surfaces causing localized shear deformation on surface of aluminum sheet mixed with lubricant residues and surface oxides forming the disturbed layer. The proposed research will be conducted by i) in depth microstructural and chemical analyses of surfaces and subsurfaces of the aluminum samples and the steel rolls before and after rolling experiments ii) determining the mechanisms of formation of disturbed layer under various rolling conditions and iii) construction of maps that show the thickness, morphology, composition, and structure of the disturbed layer as functions of rolling parameters. These results will provide significant environmental and economic benefits, including lower energy consumption to produce final products, less re-work, and lower consumption of cleaning chemicals for removal of the layer, and higher quality products.

铝板在热轧过程中承受着较高的压应力、剪应力和高温。这些严重的条件通过形成被称为“扰动层”的局部层来改变表面的局部成分和微观结构。扰动层的形成改变了铝辊产品的外观(颜色)、摩擦学性能、焊接性、表面张力和耐腐蚀性。该项目旨在利用温莎大学定制的轧制模拟器，提高我们对铝轧制过程中影响扰动表面层形成的摩擦学因素的理解。推测扰动层主要在热轧过程中形成，在此过程中，钢板在340℃-550℃的温度范围内进入辊缝。由于轧辊和板材表面之间的滑动摩擦，连轧机组出口侧的板材速度通常高于轧辊的线速度(前进速度)。由于前进速度的影响，轧辊在铝板表面上滑动，在含有润滑剂残留物和表面氧化物的铝板表面产生局部剪切变形，形成扰动层。拟开展的研究包括：1)对轧制试验前后的铝试件和轧辊的表面和亚表面进行深入的显微组织和化学分析；2)确定各种轧制条件下扰动层的形成机理；3)建立扰动层的厚度、形态、成分和结构随轧制参数的变化关系图。这些结果将提供显著的环境和经济效益，包括生产最终产品的能源消耗更低，返工更少，去除涂层的清洁化学品消耗更少，以及更高质量的产品。