2205双相不锈钢包埋粉末渗硼性能研究

目的 提高2205双相不锈钢的硬度和耐蚀性能.方法 2205双相不锈钢采用固体包埋粉末渗硼,于马沸炉中分别在830、860、890℃下保温5 h;在860℃下保温3、5、7 h,随炉冷却到室温.用金相显微镜、扫描电镜观察渗硼层的形貌和测定渗硼层的厚度,用维氏硬度计测定渗硼层的硬度,用纳米压痕仪测定渗硼层不同深度的硬度,用X射线衍射仪分析渗硼层的物相组成,评定渗硼层与基体的结合力,做不同介质下耐蚀性对比试验.结果 渗硼层与基体结合牢固,破坏等级评为一级,渗硼层主要由Fe2 B单相组成.在860℃下保温不同时间,渗硼层的厚度及硬度均随时间的增长而逐渐增大;在不同温度下保温5 h时,渗硼层的厚度及硬度随温度的升高而逐渐增大.渗硼后试样在质量分数都为10%的HCl和NaCl溶液中耐蚀性提高,在质量分数均为10%的H2 SO4、NaOH和HNO3溶液中耐蚀性变差.结论 固体粉末包埋法渗硼工艺改善了2205双相不锈钢的表面组织和性能,有效提高了其硬度及耐蚀性.

Properties of Pack Boriding for 2205 Duplex Steel

Objective To improve the hardness and corrosion resistance of 2205 duplex steel. Methods Solid powder embed-ding boronizing was conducted for 2205 duplex steel and kept warm for 5 h in muffle furnace at 830℃, 860℃, 890℃ respective-ly;and cooled to room temperature with the furnace after insulation at 860 ℃ for 3 h, 5 h, 7 h. The cross-section morphology of the boriding layer and the thickness of the boriding layer were analyzed by metallography and SEM. The surface hardness of bori-ding layer was tested by Vickers hardness tester, the hardness at different depth of boriding layer was tested by Nanoindentation tester, the phase structure of boriding layer was analyzed by X-ray diffraction, and the binding force of the boriding layer and sub-strate was evaluated. Comparative corrosion resistance tests of the boriding layer were conducted in different mediums. Results The boriding layer was firmly bonded to the substrate as the dentate structure, and the damage grade was 1. The boriding layer was mainly composed of Fe2 B. When the temperature was 860℃ , the thickness and hardness of the boriding layer gradually increased with time. When the time was 5 h, the thickness of the boriding layer gradually increased with temperature, but the hardness of the boriding layer increased at first and decreased later with increasing temperature. The corrosion resistance of the sample after the bo-riding treatment increased in 10% HCl and 10% NaCl but decreased in 10% H2 SO4 , 10% NaOH, 10% HNO3 . Conclusion Sol-id powder embedding boronizing process improved the surface microstructure and properties of 2205 duplex steel, and it could ef-fectively improve the hardness and corrosion resistance of 2205 duplex steel.