高氮不锈轴承钢碳化物演变规律及球化机制  

Carbides evolution and spheroidization mechanism of high nitrogen stainless bearing steel

作　　者：张志慧[1,2] 杨卯生[2] 孙世清[1] 王艳江[1,2] 

机构地区：[1]河北科技大学材料科学与工程学院,河北石家庄050018 [2]钢铁研究总院特钢所,北京100081

出　　处：《材料热处理学报》2017年第9期104-113,共10页Transactions of Materials and Heat Treatment

基　　金：国家"863"计划资助项目(2012AA03A503)

摘　　要：采用SEM和TEM研究不同保温温度及时间下高氮不锈轴承钢中碳化物的演变规律,并对碳化物变化进行表征及分析。结果表明:预备组织中碳化物主要沿晶界分布,尺寸主要集中在0.4~0.8μm。在600、700和750℃保温时,碳化物的视场面积个数逐渐减少而视场面积分数逐渐增加。低于800℃保温时,少量碳化物沿晶界析出;高于800℃保温时,碳化物沿晶界和位错析出,并有少量Cr_2N析出。900℃保温时,碳化物的视场面积个数和视场面积分数减少,碳化物形成元素回溶到基体中。低于750℃保温过程中,钢中碳化物发生粗化临界尺寸为0.8μm,长棒状碳化物以自身球化的方式球化长大,碳化物圆整度频数最大值由0.65增加到0.80。钢中碳化物在700℃保温10 h时球化效果较明显。The evolution of carbides in high nitrogen bearing steels treated at different temperatures for different time was studied by scanning electron microscopy（ SEM） and transmission electron microscopy（ TEM）,and the change of the carbides was characterized and analyzed.The results show that the carbides in the pre-treatment microstructure mainly distribute along the grain boundary,and the sizes mainly range from 0.4 to 0.8 μm.When the holding temperatures are 600 ℃,700 ℃ and 750 ℃,the number of the view field of the carbides decreases gradually,and the percentage of the view field area increases gradually.When the holding temperature is lower than800 ℃,the carbides precipitate along the grain boundaries,and when higher than 800 ℃,the carbides precipitate along the grain boundaries and dislocations,with a small amount of Cr_2N precipitates.When the holding temperature reaches 900 ℃,the number of the view field and the percentage of the view field area of the carbides decrease,and the carbide forming elements dissolve back into the matrix.When the holding temperature is lower than 750 ℃,the critical size of the carbides for coarsening is 0.8 μm,and the self spheroidization of the long rod-like carbides occurs,and the maximun value of roundness frequency of the carbides increases from 0.65 to 0.80.The spheroidization effect of the carbides in the steel is relatively obvious when holding at 700 ℃ for 10 h.

关 键 词：高氮不锈钢 碳化物 析出 粗化 球化 

分 类 号：TG142.7[一般工业技术—材料科学与工程]