6×××系铝合金车体型材粗晶的研究进展

Research on the coarse grain of 6××× series aluminum profile for rail vehicle body

6×××系铝合金作为可热处理强化的中高强度铝合金,具有优良的可焊性和耐蚀性,在轨道交通领域已得到广泛应用。然而,粗晶环的存在严重影响了其作为结构材料的优良性能。介绍了铝型材粗晶产生原因,总结了减小轨道车体用6×××系铝合金型材的晶粒度和粗晶环厚度的措施,包括合金化学成分调整,均匀化退火、挤压工艺和热处理工艺的优化,模具结构调整等。

As a medium high strength aluminum alloy that can be heat treated and strengthened,6 xxx series aluminum alloys have excellent weldability and corrosion resistance,and have been widely used in the field of rail transit.However,the presence of coarse grain rings seriously affects their excellent performance as structural materials.This article introduces the causes of coarse grain formation in aluminum profiles,summarizes the measwres and current research status of reducing the grain size and coarse grain ring thickness of 6×××series aluminum alloy profiles used for rail vehicle body,including alloy chemical composition adjustment,homogenization annealing,optimization of extrusion and heat treatment processes,and mold structure adjustment.