高氮奥氏体钢的粉末冶金工艺  

Powder metallurgy process of high nitrogen austenitic steel

作　　者：王金龙[1] 崔大伟[2] 曲选辉[3] 

机构地区：[1]潍坊学院建筑工程学院,山东潍坊261061 [2]潍坊学院机电与车辆工程学院,山东潍坊261061 [3]北京科技大学材料科学与工程学院,北京100083

出　　处：《金属热处理》2013年第9期29-33,共5页Heat Treatment of Metals

基　　金：国家自然科学基金(51004077);山东省优秀中青年科学家奖励基金(BS2010CL046)

摘　　要：采用机械合金化、渗氮以及粉末冶金压制-烧结工艺制备了0Cr18Mn12Mo3N高氮奥氏体钢。结果表明,用机械合金化和渗氮相结合工艺获得的近球形高氮钢粉末,具有良好的压缩性和成形性,在650 MPa压制力下压坯的相对密度高达76.2%。随着烧结温度的提高,粉末压坯烧结体的密度持续增加,氮含量则不断降低;当温度提高到1250℃时,烧结方式以液相烧结为主,烧结2 h足够使粉末致密化过程完成,此时可获得相对密度为97.2%,氮含量高达0.80wt%的烧结体,继续增加烧结温度对烧结体密度增加作用不大,却会造成氮含量急剧降至不能维持奥氏体单相组织。烧结体经1150℃×1.5 h固溶处理水淬冷却后获得全部奥氏体组织,且奥氏体晶粒细小,其屈服强度和抗拉强度分别达到598 MPa和882 MPa,显著优于传统粉末冶金高氮奥氏体钢。High nitrogen 0Cr18Mn12Mo3N anstenitic steel was fabricated by mechanical alloying, nitriding and powder metallurgical pressing-sintering techniques. The results show that nearly spherical composite powders obtained by the combination of mechanical milling and nitriding have good compressibility mid formability, and relative density of their compact can reach 76.2% under the pressure of 650 MPa. It is found that with sintering temperature increasing, the relative density of the sintered samples increases, whereas the nitrogen content decreases. When the temperature is increased up to 1250 ℃, compact sintered for 2 h is densified based on the liquid phase sintering mechanism with a favorable combination of the relative density 97.2% and the nitrogen content 0.80wt%. Further increase of sintering temperature is of no significance because it can only increase the relative density slightly but lead to too low nitrogen content to maintain a single-phase austenite microstructure. After solution at 1150 ℃ for 1.5 h followed by water-quenching, high nitrogen austenitic steels reveal a fully austenite structure with fine grain size, and their yield strength and ultimate strength can reach 598 MPa and 882 MPa respectively, which are superior to conventional powder metallurgical high nitrogen austenitic steels.

关 键 词：粉末冶金 机械合金化 高氮奥氏体钢 

分 类 号：TG142.71[一般工业技术—材料科学与工程]