11Cr17涡轮增压器齿头装配开裂分析和工艺改进  

Cracking analysis and process improvement of 11Cr17 turbocharger gear head assembly

作　　者：蒋炜彤 黄瑶[1] 王雷刚[1] 刘守生 JIANG Wei-tong;HUANG Yao;WANG Lei-gang;LIU Shou-sheng(School of Material Science and Engineering,Jiangsu University,Zhenjiang 212000,China;Kunshan Huizhong Machine Co.,Ltd.,Kunshan 215300,China)

机构地区：[1]江苏大学材料科学与工程学院,江苏镇江212000 [2]昆山惠众机电有限公司,江苏昆山215300

出　　处：《塑性工程学报》2021年第6期212-218,共7页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(51775249)。

摘　　要：针对11Cr17涡轮增压器齿头与轴杆在冷过盈装配过程中的开裂问题进行了分析,借助电感耦合等离子体光谱仪、X射线能谱分析仪、场发射扫描电子显微镜和洛氏硬度计等观察和检测了开裂齿头的化学成分、断口宏微观形貌、微观金相组织和硬度,结合流线实验和Deform软件分析了锻造时流线的形成过程。结果表明,材料的化学成分和金相组织符合要求,但在断口表面有炉渣类夹杂物呈现流线状分布。结合锻造流线实验结果发现,表面炉渣类夹杂物的分布形貌与锻造流线形貌一致。通过有限元分析揭示了齿头锻造过程中锻造流线的形成过程,难变形的炉渣类夹杂物受锻造应变力而沿着锻造流线分布,破坏了基体的连续性。齿头的锻造流线良好,但是销孔经过机加工后,流线的连续性被破坏,流线和夹杂物出现在销孔机加工表面,导致齿头冷过盈装配时的脆性断裂。最后,基于齿头装配开裂的原因,设计了齿头与轴杆一体式锻造方案来代替机加工后冷过盈装配的方案,以确保齿头和轴杆连接处基体组织的连续性,避免内部缺陷暴露。The cracking problem of 11Cr17 turbocharger gear head and shaft during the cold interference assembly process was analyzed.With the help of inductively coupled plasma spectrometer,X-ray energy spectrum analyzer,field emission scanning electron microscope and Rockwell hardness tester,the chemical composition,macro and micro morphology of the fracture,micro metallographic structure and hardness of the cracked gear head were observed and tested. The streamline formation process during forging was analyzed by the combination of streamline experiment and Deform software. The results show that the chemical composition and metallographic structure of the material meet the requirements,but there are slag inclusions on the surface of fracture showing a streamline-shape distribution. Combined with the results of the forging streamline experiment,it is found that the distribution morphology of slag inclusions on the surface is consistent with the forging streamline morphology. The formation process of the forging streamline in the forging process of gear head was revealed by finite element analysis. The difficult-to-deform slag inclusions are distributed along the forging streamline under the forging strain force,which destroys the continuity of the matrix. The forging streamline of gear head is good,but after the machining of pin hole,the continuity of the streamline is destroyed. The streamline and inclusions appear on the machined surface of pin hole,resulting in the brittle fracture of gear head during cold interference assembly. Finally,based on the reason for the cracking of gear head,an integrated forging scheme of the gear head and shaft was designed to replace the scheme of cold interference assembly after machining,and then to ensure the continuity of matrix structure at the connection of gear head and shaft and avoid exposure of internal defects.

关 键 词：脆性断裂 夹杂物 工艺缺陷 工艺改进 

分 类 号：TG111.91[金属学及工艺—物理冶金]