金属热处理 ›› 2021, Vol. 46 ›› Issue (10): 237-241.DOI: 10.13251/j.issn.0254-6051.2021.10.043

• 表面工程 • 上一篇    下一篇

45钢表面激光碳合金化层的组织与性能

李海涛1, 张蕾涛1, 夏慧芸1, 戴姣燕2, 徐金富1,2   

  1. 1.长安大学 材料科学与工程学院, 陕西 西安 710061;
    2.宁波工程学院 材料与化学工程学院, 浙江 宁波 315211
  • 收稿日期:2021-05-05 出版日期:2021-10-25 发布日期:2021-12-08
  • 通讯作者: 徐金富,教授,博士,研究生导师,E-mail: xjf7413@ sina.com
  • 作者简介:李海涛(1997—),男,硕士研究生,主要研究方向为激光表面改性,E-mail: 196129592@qq.com
  • 基金资助:
    宁波市2025重大专项(2019B10084)

Microstructure and properties of laser carbon alloyed layer on 45 steel surface

Li Haitao1, Zhang Leitao1, Xia Huiyun1, Dai Jiaoyan2, Xu Jinfu1,2   

  1. 1. School of Materials Science and Engineering, Chang'an University, Xi'an Shaanxi 710061, China;
    2. School of Materials and Chemical Engineering, Ningbo Institute of Engineering, Ningbo Zhejiang 315211, China
  • Received:2021-05-05 Online:2021-10-25 Published:2021-12-08

摘要: 利用激光合金化技术在45钢表面制备了碳合金化层,借助OM、XRD和显微硬度计等研究了最佳工艺下合金化层的组织和性能,并与利用传统气体渗碳技术制备渗碳层的结果进行了对比。结果表明:影响合金化层硬度的主次顺序为激光功率>搭接率>扫描速度;随着激光功率、扫描速度、搭接率的增大,合金化层的硬度均呈先增后减的趋势;当激光功率为1.5 kW、扫描速度为500 mm/min、搭接率为40%时,合金化层硬度最高,其厚度为600 μm,组织由针状马氏体、碳化物(M7C3、Fe3C)以及少量残留奥氏体组成,平均硬度约为617 HV0.3,热影响区厚度为400 μm,组织为马氏体以及残留奥氏体,平均硬度约为432 HV0.3,基体组织由铁素体和珠光体组成,硬度约为201 HV0.3;与传统气体渗碳工艺相比,激光碳合金化具有组织细小、高效、绿色环保等优势,是未来一个重要的发展方向。

关键词: 激光合金化, 正交试验, 合金化层, 渗碳, 显微硬度

Abstract: Carbon alloyed layer was prepared on the surface of 45 steel by laser alloying process. The microstructure and properties of the alloyed layer under the optimal process were studied by means of OM, XRD and microhardness tester. The microstructure characteristics and efficiency of gas carburizing and laser carbon alloying were compared. The results show that the effect of each parameter on hardness of the alloyed layer is as follows: laser power > lap rate > scanning speed. With the increase of laser power, scanning speed and lap rate, the hardness of the alloyed layer increases first and then decreases. When the laser power is 1.5 kW, the scanning speed is 500 mm/min and the lap rate is 40%, the hardness of the alloyed layer is the highest, the thickness of alloyed layer is capable of reaching 600 μm, the microstructure is composed of acicular martensite, carbide (M7C3, Fe3C) and a small amount of residual austenite, and the average hardness is about 617 HV0.3, the thickness of HAZ is 400 μm, microstructure is composed of martensite and retained austenite, and the average hardness is about 432 HV0.3, the microstructure of matrix is composed of ferrite and pearlite, the hardness is about 201 HV0.3. Compared with the traditional gas carburizing process, laser carbon alloying has the advantages of fine structure, high efficiency, green and environmental protection. It is an important development direction in the future.

Key words: laser alloying, orthogonal experiment, alloyed layer, carburizing, microhardness

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