热处理工艺对热镀锌热成形22MnB5钢锌层组织结构与表面氧化物的影响
Effect of heat treatment process on microstructure and surface oxides of zinc coating galvanized on 22MnB5 hot formed steel
赵景轩 1梁健 1张玲玲 1范龙龙 1熊自柳 2沈春光 1苗斌 1郑士建1
作者信息
- 1. 河北工业大学材料科学与工程学院,天津 300401
- 2. 河钢材料技术研究院,河北 石家庄 050023
- 折叠
摘要
用扫描电镜(SEM)及能谱仪(EDS)等方法系统表征了22MnB5热成形钢在不同奥氏体化温度和保温时间下镀锌层的微观形貌与表层氧化物分布.结果表明,奥氏体化温度超过850℃后,镀锌层的厚度增加,发生由纯Zn相向α-Fe(Zn)的组织转变,且与基体之间界面模糊.奥氏体化温度由850℃升高至900℃时,锌层厚度随奥氏体化温度的升高而增加,氧化锌颗粒更加密集,彼此连接团聚;当奥氏体化温度提高到900℃以上,镀锌层中出现大尺寸的富Mn氧化物.奥氏体化时间由4 min延长至8 min时(奥氏体化温度920 ℃),表面氧化程度增加,氧化物尺寸增大且彼此连接成层,裸露出α-Fe(Zn)层,对锌层保护作用降低,致使氧元素扩散至锌层内部,形成富Mn氧化物.
Abstract
Microstructure and surface oxide distribution of the galvanized layer of 22MnB5 hot formed steel were systematically characterized by scanning electron microscope(SEM)and energy dispersive spectroscope(EDS)at different austenitizing temperatures and holding time.The results show that when the austenitization temperature exceeds 850℃,the thickness of the galvanized layer increases,and a microstructure transformation occurs from pure Zn phase to α-Fe(Zn),and the interface with the matrix is blurred.As the austenitizing temperature rises from 850 ℃ to 900 ℃,the thickness of the zinc layer grows with the increase of temperature,and the zinc oxide particles become denser,interconnecting and agglomerating.When the austenitization temperature exceeds 900 ℃,large-sized Mn-rich oxides begin to emerge within the galvanized layer.When the austenitization time extends from 4 min to 8 min(austenitization temperature of 920 ℃),the degree of surface oxidation increases,the oxides increase in size and connect to each other in layers,resulting the α-Fe(Zn)layer being exposed and reducing the protective effect on the zinc layer,causing oxygen atoms to diffuse into the interior of the zinc layer to form Mn-rich oxides.
关键词
热成形钢/镀锌层/奥氏体化/氧化物/结构Key words
hot formed steel/zinc coating/austenitizing/oxide/microstructure引用本文复制引用
基金项目
校企合作项目(HG2021123)
校企合作项目(HG2021104-JS-2022-16)
出版年
2024
NETL
NSTL
万方数据