磁循环处理对珠光体相变的诱发作用  

Influence of magnetic circling treatment on inducing pearlite transformation

作　　者：周晓玲[1] 周荣[1] 蒋业华[1] 史海霞[1] 

机构地区：[1]昆明理工大学机电工程学院,云南昆明650093

出　　处：《金属热处理》2008年第10期68-73,共6页Heat Treatment of Metals

基　　金：云南省自然科学基金(2004E0008Q)

摘　　要：对硅锰铸钢在A1点以上温度进行磁场等温处理诱发珠光体(P)相变的可能性进行了研究,探讨了P形核位置、领先相、核心形态及长大方式。结果表明,①磁场可在A1点以上的温度诱发P,随着磁场作用时间的延长,所诱发的P量的增加主要是P团长大所致,存在一定数量具铁磁性的先共析相、磁场作用时间及其强度的大小是决定在A1以上温度诱发P量的关键因素;②初期形成的P形态并不都呈现出两组成相的平行排列,而是受在晶粒交叉部位、晶界处优先形核的先共析相铁素体(F)形态的限制;③在P形核与长大过程中,P片间距并不是常数,F与渗碳体(Cm)的宽度均下降,降速以Cm为快;④P中Cm可在F片内沉淀析出。Cm的形核与长大速度是制约P形成的主要因素。The possibility of applied magnetic field on inducing pearlite transformation for Si-Mn casting iron at the temperature above the Al point was explored. The nucleation positions, preceding phase, nucleus morphology and growth mode of induced pearlites have been studied. The results show that： （1） Magnetic field can induce the pearlite transformation above the A1 point, the in-sitn growth of induced pearlite colonies contributed to the increasing fraction of pearlite with holding time, two key factors of induced pearlite fraction above A1 lie in the existence of pro-eutectoid phase, the applied period time of magnetic field and its intensity; （2）Two phases of earlier induced pearlites do not have to parallel to each other, the morphology of earlier pearlite is confined by the shapes of pro-eutectoid ferrite which has nucleated at the grain corners and grain boundaries of austenite ; （3）During the processing of nucleating and growing of pearlite, the inter- lamellar spacing does not hold constant, the width of both ferrite and cementite decreases, the decreasing rate of width of ferrite is faster than that of cementite ; （4）Eutectoid cementite can precipitate within eutectoid ferrite. The nucleation and growth of eutectoid cementite are the main factors that constrain the formation of pearlite.

关 键 词：磁诱发相变 等温相变 磁场处理 珠光体 铸钢 

分 类 号：TG142.1[一般工业技术—材料科学与工程] TG156.99[金属学及工艺—金属材料]