Cr12MoV模具钢渗氮层服役过程中不同磨损阶段的摩擦学特性  

Tribological Properties of Nitriding Layer of Cr12MoV Die Steel in Different Wear Stages during Service

作　　者：何晓荣 黎秋萍 刘少鹏 沈明学 HE Xiao-rong;LI Qiu-ping;LIU Shao-peng;SHEN Ming-xue(School of Material Science and Engineering,East China Jiaotong University,Nanchang 330013,China;Key Laboratory of Conveyance and Equipment,Ministry of Education,East China Jiaotong University,Nanchang 330013,China)

机构地区：[1]华东交通大学材料科学与工程学院,南昌330013 [2]华东交通大学载运工具与装备教育部重点实验室,南昌330013

出　　处：《表面技术》2022年第8期243-251,271,共10页Surface Technology

基　　金：国家自然科学基金(52061012,51805170);江西省杰出青年基金(20212ACB214003);江西省创新创业大学生训练计划(202010404005)。

摘　　要：目的分析经渗氮处理后Cr12MoV模具钢的显微结构,以及不同取样厚度处渗氮层的摩擦学特性,了解渗氮处理对Cr12MoV模具钢耐磨性的影响,为服役过程中不同磨损阶段渗氮层的磨损行为提供理论依据。方法采用气体渗氮法对Cr12MoV模具钢进行恒温渗氮处理,研究渗氮处理对Cr12MoV模具钢显微结构的影响,以及不同取样厚度处渗氮层的磨损行为,并分析不同取样厚度处渗氮层的磨损机理。结果经渗氮处理后Cr12MoV模具钢的表面会形成一层厚度约为120μm的致密渗氮层,材料的表面硬度从3.65 GPa提高至12 GPa,磨痕深度从3.5μm降至0.35μm。随着取样厚度的增加,试样的磨损量会逐渐增加,但均远低于未渗氮试样,其中渗氮层的最大磨损量约为120μm^(3),为基体材料磨损量的1/10;渗氮影响层的最大磨损量约为330μm^(3),为基体材料的1/3,可见采用气体渗氮处理可显著增强Cr12MoV模具钢的耐磨性。此外,在磨损过程中Cr12MoV模具钢的表面磨损较严重,出现了大块撕裂损伤,主导磨损机理为疲劳磨损;经渗氮处理后试样表面的损伤较轻微,主导磨损机制为磨粒磨损。随着取样厚度的增加,试样表面的磨损现象逐渐加剧,磨损机制由磨粒磨损逐渐转变为疲劳磨损。结论渗氮处理可以在Cr12MoV模具钢的表面生成一层致密的渗氮层,渗氮层的磨损量会随着取样厚度的增加先减少后持续增加,说明在服役过程中渗氮层的耐磨性呈先增强后减弱的趋势。Cr12MoV can be considered as one of the most widely used cold working die steel due to its excellent comprehensive performance,such as good hardness and toughness,and high compressive strength.However,the cold working die steel often withstand extremely high circulating pressure,cutting force and high impact force during industrial applications,resulting in the production of crack sources such as scratching and peeling on the surface,which ultimately leads to the failure of cold working die.Generally,nitriding treatment is one of the most economic methods to enhance the comprehensive performance of cold working die steel,but the present researches mainly focus on the effects of nitriding process parameters on the microstructure evolution,hardness and wear resistance of die steel,few studies are dedicated to the tribological properties and corresponding wear mechanism of die steel at different wear stages after nitriding treatment.In order to understand the effect of nitriding treatment on the wear resistance of Cr12MoV die steel and provide a theoretical basis for the wear behavior of nitriding layer in different wear stages during service,the microstructure of Cr12MoV die steel after nitriding treatment and the tribological characteristics of nitriding layer at different sampling thickness are analyzed.The Cr12MoV die steel is treated by gas nitriding at constant temperature,the effect of nitriding treatment on the microstructure of Cr12MoV die steel and the wear behavior and corresponding wear mechanism of nitriding layer at different sampling thickness are studied in detail.The results show that a compact layer with a thickness of about 120μm is formed on the surface of Cr12MoV die steel,resulting in the increased microhardness from 3.65 GPa to 12 GPa,while the depth of wear marks reduces from 3.5μm to 0.35μm.With the increase of the distance between the sampling position and the coating surface,the abrasion loss of the sample increases gradually,but it is still far lower than that of the substrate.Among th

关 键 词：CR12MOV模具钢 气体渗氮 显微硬度 耐磨性 磨损机理 

分 类 号：TG156.82[金属学及工艺—热处理]