21-2N气阀钢板材断裂失效分析  

Fracture Failure Analysis of 21-2N Valve Steel Plate

作　　者：王俏俏 龚志华[1] 李康雪 Wang Qiaoqiao;Gong Zhihua;Li Kangxue(Materials and Metallurgy School,Inner Mongolia University of Science and Technology,Baotou 014010,China)

机构地区：[1]内蒙古科技大学材料与冶金学院(稀土学院),内蒙古包头014010

出　　处：《特钢技术》2021年第3期30-32,36,共4页Special Steel Technology

摘　　要：通过元素光谱分析、光学显微镜(OM)及扫描电子显微镜(SEM)等手段,对轧制过程中开裂的21-2N板材进行综合分析。结果表明,失效板材断口呈沿晶断裂特征,断裂后发生氧化;组织观察发现晶界有大量的网状碳化物并伴随晶界裂纹出现,判断失效原因是轧制过程中温度过低,导致晶界析出大量的网状碳化物。通过热力学计算及实验室模拟,提出21-2N终轧温度应控制到1000℃以上温度,避免晶界析出网状碳化物,从而弱化晶界,导致开裂,且轧制加热温度低于1150℃,避免晶粒粗大。Analysis on fracture failure of 21-2N plate cracked on line was carried out by means of optical microscope(OM),scanning electron microscopy(SEM)and elemental spectrum analysis.The results showed that the fracture surface of the failed plate exhibited intergranular fracture characteristics,and oxidation occurred after fracture;a large number of network carbides and accompanying grain boundary cracks were found in the microstructure observation.The failure reason was that the temperature was too low during the rolling process,which resulted in a large amount of network precipitation on the grain boundary.Through ther-modynamic calculations and laboratory simulations,it is proposed that the final rolling temperature of 21-2N should be controlled to a temperature above 1000°C to avoid the precipitation of network carbides on the grain boundaries,which weaken the grain boundaries and cause cracking.bviously,and the center segregation index can be controlled within 1.08,which can completely meet the rolling requirement.

关 键 词：21-2N 沿晶断裂 网状碳化物 

分 类 号：TG142.15[一般工业技术—材料科学与工程]