两种合金密封环与浸渍石墨配副的损伤失效  

Damage Failure of Two Alloy Seal Rings Paired with Impregnated Graphite

作　　者：郑靖[1] 何佳欣 雷磊 杨丹[1] 黄元宝 张尔卿 张车宁 ZHENG Jing;HE Jiaxin;LEI Lei;YANG Dan;HUANG Yuanbao;ZHANG Erqing;ZHANG Chening(Key Laboratory of Advanced Technologies of Materials,Ministry of Education,Southwest Jiaotong University,Chengdu 610031,China;Sinoseal Holding Co.,Ltd.,Chengdu 610045,China)

机构地区：[1]西南交通大学材料先进技术教育部重点实验室,四川成都610031 [2]中密控股股份有限公司,四川成都610045

出　　处：《西南交通大学学报》2025年第2期411-417,共7页Journal of Southwest Jiaotong University

基　　金：国家重点研发计划(2018YFB2000800)。

摘　　要：某石油化工泵分别采用Cr合金密封环和YG-6硬质合金密封环,在300~400℃与浸渍石墨密封环配副,发现Cr合金密封环长期服役仍能保持良好的密封性能,而硬质合金密封环运行一段时间后发生气体泄漏.为探究2种合金密封环服役性能差异的缘由,对失效密封环进行表面形貌、化学成分与力学性能表征,分析失效机制.研究结果表明:Cr合金密封环材质为含Cr的马氏体钢,未作表面强化处理,表面硬度和弹性模量分别为(629.8±14.2)HV30和(244.7±17.4)GPa,与浸渍石墨配副接触区出现以轻微犁削效应为主的环形磨斑,磨损表面粗糙度显著降低;硬质合金密封环表面硬度和弹性模量分别为(1475.3±60.1)HV30和(815.3±57.2)GPa,密封环表面残余应力高,存在氧化腐蚀诱导的材料脆化,配副接触区无明显磨损,但出现氧化开裂导致的块状缺损;Cr合金密封环表面的低刚度和高粗糙度导致其配副接触区发生磨粒磨损,但磨损表面存在打磨抛光行为,与浸渍石墨配副仍能保持良好的密封性能,而YG-6硬质合金密封环表面高残余应力和高温服役环境诱导的材料氧化脆化,导致配副接触区发生开裂破坏,密封失效.Cr alloy seal ring and YG-6 cemented carbide seal ring were used to pair with impregnated graphite seal ring in a petrochemical pump at 300-400℃,respectively.It was found that the Cr alloy seal ring maintained good sealing performance for a long-term service,while gas leakage occurred to the cemented carbide seal ring after a short time of service.To explore the reasons for the difference in service performance of two kinds of alloy seal rings,the surface morphologies,chemical compositions,and mechanical properties of the failed seal rings were characterized,and their failure mechanisms were analyzed.The results show that the Cr alloy seal ring is made from martensitic Cr-containing steel without surface strengthening treatment,and the surface hardness and elastic modulus are(629.8±14.2)HV30 and(244.7±17.4)GPa,respectively.On its contact area with impregnated graphite,an annular wear scar characterized by a slight ploughing effect is observed,and the surface roughness of the wear significantly decreases.The surface hardness and elastic modulus of the cemented carbide seal ring are(1475.3±60.1)HV30 and(815.3±57.2)GPa,respectively.There exists high residual stress and material embrittlement induced by oxidative corrosion in the seal ring surface.No obvious wear occurs on the contact area with impregnated graphite,but blocky defects caused by oxidation cracking appear.Due to low stiffness and high surface roughness,the Cr alloy seal ring suffers from abrasive wear on its surface with impregnated graphite,but the wear surface has grinding and polishing behaviors,maintaining its good sealing performance when paired with impregnated graphite.For the YG-6 cemented carbide seal ring,defects by cracking occur in the contact area with impregnated graphite under the action of the high surface residual stress and the material oxidation and embrittlement induced by high temperatures,resulting in sealing failure.

关 键 词：密封环 CR合金 硬质合金 失效分析 磨粒磨损 氧化脆化 

分 类 号：TB42[一般工业技术] TH117.1[机械工程—机械设计及理论]