石墨形态及金相组织对蠕墨铸铁力学性能的影响  

Effects of Graphite Morphology and Metallographic Structure on Mechanical Properties of Vermicular Graphite Cast Iron

作　　者：林勇传[1] 王凯[1] 黄健友 韦珏宇 

机构地区：[1]广西大学机械工程学院,广西南宁530000

出　　处：《铸造技术》2017年第11期2582-2585,共4页Foundry Technology

基　　金：广西玉林市-广西大学市校科技合作资助项目(玉市校科合201402801)

摘　　要：试验浇铸了5种化学成分基本相同,但蠕化率及金相组织均不同的蠕墨铸铁试样,通过金相、拉伸及硬度等试验,对蠕墨铸铁的蠕化率、石墨形态、金相组织、抗拉强度及布氏硬度进行了测定。研究了蠕化率≥80%的情况下,蠕墨铸铁的蠕化率、石墨形态及金相组织对其抗拉强度和硬度等力学性能的综合影响及机理。结果表明,当蠕化率≥80%的情况下,蠕化率的变化并不能显著影响蠕墨铸铁抗拉强度和硬度等力学性能,降低石墨长宽比可以有效提升蠕墨铸铁抗拉强度和硬度;当蠕化率≥80%且石墨长宽比为5~9的情况下,珠光体体积分数对蠕墨铸铁抗拉强度和硬度等力学性能的影响最显著。珠光体体积分数越高,蠕墨铸铁的抗拉强度和硬度等力学性能越好。Five kinds of vermicular graphite cast iron samples with similar chemical composition but different rate of vermicular cast iron and metallographic structure were prepared. By the means of metallographic, tensile and hardness tests, the rate of vermicular cast iron, graphite morphology, metallographic structure, tensile strength and Brinell hardness of vermicular graphite cast iron were determined. The combined effects of rate of vermicular cast iron, graphite morphology and metallographic structure on mechanical properties such as tensile strength and hardness of vermicular graphite cast iron were investigated at the condition of ≥80% rate of vermicular cast iron. The results show that at the condition of ≥80% rate of vermicular cast iron, the change of the rate of vermicular cast iron can＇t remarkable affect the mechanical properties such as tensile strength and hardness of vermicular graphite cast iron, and the decrease of the length-width ratio of graphite can effectively improve the tensile strength and hardness of vermicular graphite cast iron. When the rate of vermicular cast iron are ≥80% and the length-width ratio of graphite is dropped in the scale of 5-9, the pearlite volume fraction plays the most important roles on the tensile strength and hardness of vermicular graphite cast iron, and the higher the pearlitc volume fiaction, the better the mechanical properties such as tensile strength and hardness of vermicular graphite cast iron.

关 键 词：蠕墨铸铁 力学性能 金相组织 石墨形态 蠕化率 

分 类 号：TG255[金属学及工艺—铸造]