Q460C钢组织特性对表面裂纹成因的影响分析  

Effect of microstructure characteristic of Q460C steel on surface cracks

作　　者：高雅[1] 孙建林[1] 贠冰[1] 赵海兴[1] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083

出　　处：《材料科学与工艺》2011年第5期139-143,共5页Materials Science and Technology

基　　金：国家自然科学基金资助项目(50775051)

摘　　要：通过光学显微组织观察,测定显微组织硬度和能谱分析等方法对Q460C中厚板表面裂纹成因进行了分析研究,分析了热送热装工艺对裂纹形成的影响,分析了轧制过程中裂纹的形成机理.利用热膨胀法结合金相法在Gleeble-1500热模拟实验机上测定了实验钢连续冷却转变曲线,分析了材料组织转变与裂纹形成规律的联系.分析结果表明:热送热装工艺产生了混晶组织,在粗轧阶段未能消除,精轧阶段粗晶区先于细晶区变形,产生不均匀变形,最终导致钢板表面沿粗晶区与细晶区界面开裂.在轧辊摩擦力作用下,多余的变形被向前推压,沿开裂处向钢板表面延伸,随轧制进行,裂纹向内部扩展.热送热装生产中,控制粗轧温度和压下量是控制裂纹产生关键.Metallographic analysis,rigidity test of microstructure and energy spectrum analysis were carried out to study surface crack of Q460C steel plate,the effect of hot delivery and hot charging on surface crack and crack mechanics in rolling process were analyzed.Based on dilatometric test and metallographic analysis,continuous cooling transformation curve of Q460C steel was investigated on gleeble-1500 thermo-mechanical simulator,the relationship between structural transformation and crack mechanics was also studied.The study showed that,mixed crystal was caused by hot delivery and hot charging and retained after rough rolling,in finish rolling process,bulky grains region deformed earlier than fine grains region,and this caused non-uniform deformation.The plate surface cracked at the boundary between bulky and fine grains region.The bulky austenite grains were stretched forward along the grain boundary or the eutectoid ferrite on the boundary and rolled over to the plate surface,the cracks extended in subsequent rolling process.For the rolling production with hot delivery and hot charging process,control of blooming temperature and reduction is the key factor to prevent cracks.

关 键 词：中厚板 表面裂纹 组织转变 混晶 热送热装 

分 类 号：TG335.5[金属学及工艺—金属压力加工]