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研究了钼、钒、铌对10％Cr铁素体耐热钢持久强度的影响。以0.05％C-10％Cr为基,加2％Mo可提高持久强度10～12kgf/mm~2,在0.05％C-10％Cr-2％Mo基础上单独加0.091％V或0.055％Nb可提高持久强度2～6kgf/mm~2,复合加钒和铌强化效果最大,持久强度提高4～10kgf/mm~2。持久强度的提高是由钼的固溶强化和钼、钒、铌的沉淀强化引起的。钢中的主要析出物有沿晶界、马氏体板条边界析出的M_(23)C_6和在铁素体内、晶界、马氏体内析出的Fe_2Mo、M_6C。Fe_2Mo、M_6C对维持高温长时间持久强度有重要贡献。这些析出物的聚集和长大将导致持久强度的降低。所以,持久强度的高低取决于钢中析出物的种类、大小、分布和聚集速度。
The effect of molybdenum, vanadium and niobium on the tenacity of 10% Cr ferritic heat-resistant steel was studied. With 0.05% C-10% Cr as base, the addition of 2% Mo increases the tenacity at 10-12 kgf / mm ~ 2. Adding 0.091% V or 0.055% Nb alone to 0.05% C-10% Cr-2% Mo Can improve the lasting strength of 2 ~ 6kgf / mm ~ 2, compound plus vanadium and niobium to maximize the strengthening effect, lasting strength increased 4 ~ 10kgf / mm ~ 2. Long-lasting strength improvement is caused by the solid solution strengthening of molybdenum and the precipitation strengthening of molybdenum, vanadium and niobium. The main precipitates in steel are M_ (23) C_6 precipitated along the grain boundaries and martensite slab boundaries and Fe_2Mo and M_6C precipitated in ferrite, grain boundary and martensite. Fe2Mo, M_6C to maintain long-term high temperature strength have a significant contribution. Aggregation and growth of these precipitates will result in a reduction of the lasting strength. Therefore, the level of long-lasting strength depends on the type of precipitates in steel, size, distribution and aggregation rate.