Al对T91耐热钢蠕变性能的影响

EFFECT OF ALUMINUM ON CREEP RUPTURE PROPERTY OF T91 HEAT-RESISTANT STEEL

沪产 T91钢脱氧后残留在钢中的铝含量相对较高 ,它优先与氮结合 ,影响了起析出强化作用的(Nb,V) (C,N)析出数量 ,是引起持久强度降低的原因之一。沿晶界分布的 Al N是蠕变空洞的形核核心 ,它还促进在其上形核的 M2 3C6 开裂形成空洞 ,对沪产 T91钢蠕变脆性的产生有重要影响。为提高国产 T91钢的性能 ,必须选择适宜的脱氧方法 ,限制脱氧时加入的铝含量。

The decrease in creep rupture strength of domestic T91 steel results partly from relatively higher residual aluminum content, because the preferential combination of aluminum with nitrogen affects the precipitation hardening by (Nb, V)(C,N). Besides, AlN particles along grain boundaries play an important role in creep brittleness, because AlN not only provides nucleation site for creep cavities, but also accelerates the cracking of M 23 C 6 nucleated on AlN. In order to improve properties of domestic T91 steel, it is necessary to choose proper deoxidation technology and restrict aluminum content during deoxidation.