论文部分内容阅读
测试了熔点～700℃温度区间含铌钛钢X-52连铸坯的高温延塑性．根据断口形貌、组织以及钢中析出物等的变化情况分析了该钢的脆化机理．结果表明：在熔点～700℃温度区间，X-52钢存在2个脆性区，熔点～138℃的第Ⅰ脆性区，925～825℃的第Ⅲ脆性区．细小的NbCN沿奥氏体晶界的动态析出是造成第Ⅲ区脆化的主要原因．可通过向钢中添加少量的钛，以降低晶界处细小的NbCN的析出量，防止光共析铁素体在奥氏体晶界呈网状析出而改善钢的热塑性．
The high temperature ductility of the niobium-containing titanium steel X-52 billet at the melting point ~ 700 ℃ was tested. The embrittlement mechanism of the steel was analyzed according to the changes of fracture morphology, microstructure and precipitates in steel. The results show that there are two brittle zones, the first brittle zone of melting point ~ 138 ℃ and the third brittle zone of 925 ~ 825 ℃ in the temperature range of melting point to 700 ℃. The dynamic precipitation of fine NbCN along the austenite grain boundaries is the main reason for the embrittlement of Zone III. By adding a small amount of titanium to the steel to reduce the amount of precipitated NbCN in the grain boundary and prevent the photoeutectoid ferrite from reticularly precipitating at the austenite grain boundary to improve the thermoplasticity of the steel.