冷却方式对T91钢连铸坯组织及性能的影响

采用不同冷却方式(随炉冷、沙冷、等温冷、空冷及雾冷)处理T91钢连铸坯,研究冷却速度(2.5~18℃/min)对该合金组织及性能的影响。研究表明:经同一奥氏体化过程后,冷却速度对钢材的组织转变影响较大,缓冷(2.5~4℃/min)时,组织为较多的先共析铁素体和少量板条马氏体;随冷却速度增加(6~18℃/min),马氏体增多,铁素体减少。通过研究发现,缓慢冷却能够大幅提高铸坯的塑性及韧性,塑性最大可提高81.25%,韧性最大可提高22.61%,等温冷却对后序轧管是有利的。

Effect of cooling method on microstructure and properties of high-alloy-casting steel T91

The effects of cooling method such as cooling-in-furnace,sand-cooling,isothermal-cooling and air-cooling and fog-cooling on the microstructure and properties of high-alloy-casting steel T91 have been investigated.The results show that after the same austenization process,microstructure obtained after cooling depends largely on the cooling velocity;lath-like martensite and proeutectoid ferrite structures can be obtained when the cooling velocity is in 2.5~4 ℃ /min;with increasing cooling velocity,the lath-like martensite increases largely and proeutectoid ferrite decreases.It can also be indicated that,the toughness can be improved greatly at low cooling velocity,the maximum value of plastic property and toughness increases by 81.25% and 22.61%,respectively.In addition,isothermal cooling is beneficial to the next rolling.