C70S6钢胀断连杆掉渣缺陷的分析
Analysis on Drop-Dregs Defect of C70S6 Fracture Splitting Connecting Rod
李杰 1徐翔宇 1刘增平 2田钱仁 1付建勋1
作者信息
- 1. 上海大学 材料科学与工程学院 先进凝固技术中心,省部共建高品质特殊钢国家重点实验室,上海 200444
- 2. 承德建龙特殊钢有限公司,河北 承德 067201
- 折叠
摘要
掉渣缺陷是C70S6 非调质钢胀断连杆的主要质量问题.为了探究掉渣的原因,对比分析了有无掉渣缺陷的两个C70S6 胀断连杆的化学成分及含量,采用金相显微镜和扫描电镜观察分析了两胀断连杆的断口形貌、断口附近钢中非金属夹杂物和显微组织.结果表明:1#(掉渣)钢中N元素偏低,适当提高N元素含量有利于提高连杆胀断性能;连杆中非金属夹杂物主要为MnS,2#(未掉渣)连杆中夹杂物比 1#的更细小、数量更多,尤其是断口末端位置,导致 2#连杆塑性低于 1#的,有利于胀断;C70S6 胀断连杆显微组织为铁素体+珠光体,1#连杆珠光体占比为 97%～99%,中间区存在晶粒大小不一的混晶组织,过高的珠光体含量和混晶组织是造成连杆掉渣的主要原因.
Abstract
The drop-dregs defect is the main quality problem of C70S6 non-quenched and tempered steel fracture splitting connecting rod.In order to explore the causes of drop-dregs,the chemical composition and content of two C70S6 connecting rods with and without drop-dregs were compared and analyzed.The fracture morphology,non-metallic inclusions and microstructure of the steels near the fracture were observed and analyzed by means of metallographic microscope and scanning electron microscope.The results show that the content of N in the 1#(drop-dregs)steel is low.Properly increasing the content of N is conducive to improve the expansion and fracture performance of connecting rod.The non-metallic inclusions in the connecting rods are mainly MnS.The inclusions in the 2#connecting rod are smaller and more numerous than those in the connecting rod 1#,especially at the end of the fracture,and it causes the plasticity of the 2#(without drop-dregs)connecting rod is lower than that of the connecting rod 1#,and it is conducive to fracture splitting.The microstructure of C70S6 fracture splitting connecting rod is ferrite+pearlite,and 1#connecting rod pearlite accounts for 97%-99%.There is mixed crystal structure with different grain sizes in the middle area.Too high pearlite content and mixed crystal structure are the main reasons for connecting rod drop-dregs defect.
关键词
掉渣/C70S6钢/胀断连杆/夹杂物Key words
drop-dregs/C70S6 steel/fracture splitting connecting rod/inclusions引用本文复制引用
基金项目
国家自然科学基金资助项目(51874195)
国家自然科学基金资助项目(51671124)
出版年
2024
NETL
NSTL
万方数据