Preparation of lead-free free-cutting graphite brasses by graphitization of cementite  

渗碳体石墨化制备无铅易切削石墨黄铜（英文）

作　　者：卓海鸥[1] 唐建成[1] 薛滢妤 叶楠[1] 

机构地区：[1]南昌大学材料科学与工程学院,南昌330031

出　　处：《Transactions of Nonferrous Metals Society of China》2015年第10期3252-3257,共6页中国有色金属学报（英文版）

基　　金：Projects(51271090,51364036,51471083)supported by the National Natural Science Foundation of China;Project(IRT0730)supported by the Program for Changjiang Scholars and Innovative Research Team in University,China;Project(NCET-10-0184)supported by the Program for New Century Excellent Talents in University,China;Project(20103601110001)supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China

摘　　要：Graphite brasses were prepared by graphitizing annealing of cast brasses containing cementite particles,which were in-situ formed during the fasting process.The eutectic cast iron as carbon source was added into common brasses by casting.SEM and EDS were used to analyze the microstructure of graphite brasses,and the relationship between the microstructure and machinability was investigated.The results show that graphite particles are formed by the decomposition of cementite particles in cast brasses.The graphite particles are uniformly dispersed in the brass matrix with the average size of 5.0 μm and the volume fraction of ~1.1%.The machinability in the graphite brass is dramatically increased relative to the common brass,because of the lubricating properties of graphite particles and its role in chip breaking.The workpiece surface of the graphite brasses chips is smooth and burr-free,and the chips of graphite brasses are short（C-shape） and discontinuous,which is much better than that of the long spiral chips of common brasses.通过向黄铜中添加共晶铸铁,在熔铸过程中原位生成渗碳体颗粒,利用石墨化退火工艺使渗碳体分解成石墨从而制得石墨黄铜。利用SEM和EDS分析石墨黄铜的显微组织,探讨显微组织与切削性能的关系。结果表明:铸态黄铜中的渗碳体颗粒经过退火后全部分解为石墨颗粒,石墨颗粒均匀弥散地分布在黄铜基体上,其平均尺寸为5.0μm,体积分数约为1.1%。石墨黄铜的车削表面光滑无毛刺,切屑形貌为短C型,比铅黄铜的粗大,但优于普通黄铜的长螺旋型屑。

关 键 词：lead-free graphite brass graphitization annealing microstructure machinability 

分 类 号：TG291[金属学及工艺—铸造]