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CrMoV汽转机转子用钢的成份是: C Cr Mo V Si Mn P S Sn Ni 0.29 0.99 1.26 0.25 0.58 0.70 0.039 0.005 0.006 0.01 经1010℃奥氏体化控制冷却到室温,在700℃回火6小时,主要是贝氏体。在520℃长期时效过程中,碳化物的转变顺序是,Fe_3C+VC→Fe_3C+VC+Mo_2C+M_(23)C_6→Fe_3C+VC+Mo_2C+M_(23)C_6+M_6C。早期生成的Fe_3C呈长条状存在于晶界和晶内,VC呈微粒状沿晶界和位错线析出(图1)。Fe_3与铁素体基体满足Bagaryatsku关系,VC与基体符合Baker—Nutting取向关系。时效3000小时,基体中又出现有针状分布的M_(02)C(图2),它与基体的取向关系符合Pitsch。—Schrader关系。同时有M_(23)C_6出现在晶界处,同基体间的取向关系除有一种与曾报导过的相同外,还发现有另一种取向关系:
CrMoV steam turbine rotor steel composition is: C Cr Mo V Si Mn PS Sn Ni 0.29 0.99 1.26 0.25 0.58 0.70 0.039 0.005 0.006 0.01 After austenitizing 1010 ℃ cooling to room temperature, tempering at 700 ℃ for 6 hours, the main Is bainite. In the long-term aging at 520 ℃, the order of carbide transformation is: Fe 3 C + VC → Fe 3 C + VC + Mo 2 C + M 23 C 6 → Fe 3 C + VC + Mo 2 C + M 23 C 6 + M 6C. Fe 3 C formed in the early stage was present in the grain boundaries and in the grains. The VC grains were precipitated along grain boundaries and dislocations along the grain boundaries (Fig. 1). The Fe_3 and the ferrite matrix satisfy the Bagaryatsku relationship, and the VC and the matrix conform to the Baker-Nutting orientation relationship. After aging for 3000 hours, M_ (02) C (Fig. 2) appeared in the matrix with needle-like distribution. Its orientation relationship with the substrate accorded with Pitsch. -Schrader relationship. At the same time, M_ (23) C_6 appears in the grain boundary, except for one kind of orientation relationship with the matrix, which is the same as the one reported, and another orientation relationship is found: