临界奥氏体区变形对Q235钢显微组织的影响

Influence of Deformation at the Temperature of Critical Austenite Region on Microstructure of Q235 Steel

以Q2 35钢为研究对象 ,在Gleeble 35 0 0热模拟试验机上进行了奥氏体临界温度 (Ar3)附近不同变形温度和变形后不同冷却速度对Q2 35钢显微组织影响的试验研究。研究发现 ,随着变形温度降低 ,冷却速度的增加 ,铁素体晶粒越细 ,但当变形温度低于Ar3时 ,会形成混晶组织 ;变形后较慢冷却还会产生带状组织 ,临界奥氏体区变形有利于避免魏氏组织。试验结果显示 ,在奥氏体临界温度 (Ar3)附近轧制、轧后快冷可在Q2 35钢中获得超细晶粒。

The influence of deformation temperature at critical austenite region and its cooling rate on microstructure of Q235 steel was researched with the Gleeble-3500 thermal simulator, microscope and SEM. The results show that the ferrite grain becomes finer when the deformation temperature reduces and the cooling rate increases. But some mixed micro-structure appears when the deformation temperature is below Ar3 and the band structure appears when the cooling rate is very slow after deformation. Deformation at critical austenite region can avoid producing widmanstatten microstructure. The results indicate that the ultrafine grain can be obtained through rolling at critical austenite region and fast cooling.