环保石墨易切削钢的组织及性能  

Microstructure and properties of environmental graphitized free-cutting steel

作　　者：尹云洋[1] 方芳[1] 严翔[1] 朱丛茂[1] 陈玮[1] 罗国华[1] 官计生[1] 

机构地区：[1]武汉钢铁集团公司研究院,湖北武汉430080

出　　处：《材料热处理学报》2013年第4期133-137,共5页Transactions of Materials and Heat Treatment

摘　　要：石墨易切削钢是顺应易切削无铅、低硫这一发展趋势而产生。具有亚共析成分的钢种其石墨化过程一直较难,因此开发该钢种的关键是促进其石墨化过程。研究表明,通过合理的成分设计和工艺处理,可以在较短的时间内钢中C原子的石墨化。石墨化退火时,C原子除了能在析出相上形成石墨外,还能自发形核及长大形成石墨。经石墨化退火后,试验钢的组织主要由铁素体+石墨+少量渗碳体组成,其中,石墨粒子的尺寸较为细小,分布也较为均匀,渗碳体主要以球状的形式分布铁素体晶粒晶界及晶内。抗拉强度和伸长率分别为595 MPa和33%,表现较高的强度和较好的塑性。Development of low-sulfur and Pb-free free cutting steel is significant because the use of free-cutting steel containing sulfur or lead can result in serious pollution. The hypoeutectoid graphitized free-cutting steel without the addition of sulfur and lead has been dcveloped,and it is found that the graphitization is difficult due to slow graphitizatiun process for this kind of steel, so it is crucial to accelerate the graphitization process for its engineering application. The present study shows that the graphitization process in the free- cutting steel can be shortened by appropriate design of composition and technology. During graphitization, the nucleation of graphite not truly can take place on the second-phase particles, but also spontaneous nucleation and growth in the tested steel. The microstructure of the tested steel consists of ferrite, graphite and little carbide, and the size of graphite particles is fine and the distribution is uniform, the carbide are mainly located at the ferrite grain boundary or in the ferrite. The investigated steel exhibits a good combination of strength and plasticity, its tensile strength and elongation is 595MPa and 33% , respectively.

关 键 词：易切削钢 石墨 组织 性能 

分 类 号：TG157[金属学及工艺—热处理]