FSP表面改性球墨铸铁组织及抗冲蚀磨损性能

Microstructure and Erosion Wear Resistance of Ductile Cast Iron Surface Modified by FSP

对铁素体基球墨铸铁实施搅拌摩擦加工(FSP),利用硬度仪、SEM、EPMA、XRD及冲蚀磨损试验机,研究了FSP对铁素体基(FB)球墨铸铁组织演化的影响,以及冲蚀磨损角度对两种铸铁耐冲蚀磨损性能的影响。研究表明,FB球铁经FSP后,热机影响区内石墨因搅拌作用而拉长,其他区域石墨维持球状形貌。距离搅拌摩擦表面越远,基体中马氏体及残留奥氏体含量越低,硬度相应的越低,热影响区(HAZ)内马氏体以及残留奥氏体生成于石墨周边,其余部分为铁素体。FB球铁随着冲蚀磨损角度增大,抗冲蚀磨损性能提高。而FSP球铁冲蚀磨损率曲线呈双峰形态,20°及45°冲蚀角度下耐冲蚀磨损性能较好。

The ferritic-based ductile iron was subjected to friction stir processing (FSP).The effects of FSP on the microstructure evolution and erosion wear angle on the erosion wear resistance of ferriticbased ductile iron were investigated by hardness tester,SEM,EPMA,XRD and erosion wear tester. The results reveal that graphites in the TMAZ of the FSP ductile iron are elongated by stirring,and graphites in the other regions maintain a spherical morphology.As the distance from the FSP surface increases,the content of martensite and retained austenite in the matrix is decreased,and the hardness correspondingly become lower.The martensite and retained austenite in the HAZ are formed around the graphite,and the rest area is ferrite.The FB ductile iron has an increased erosion wear resistance as the erosion wear angle increases.The erosion wear rate curve of FSP ductile iron presents bimodal,and the erosion wear resistance under the erosion angle of 20°and 45°is better.When the erosion angle is less than 50°,the erosion wear resistance of FSP ductile iron is better than that of FB ductile iron;on the contrary,the erosion wear resistance of FB ductile iron is better than that of FSP ductile iron.