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采用一种特定的控轧控冷技术,在中厚板实验轧机上制备了具有表层超细组织的厚钢板。钢坯在较低温度(1150℃)奥氏体化。钢坯经过第一阶段变形后,钢板表层加速冷却至Bs点以下。厚板中心具有较高温度,使钢板表层回温至两相区,钢板表层重新奥氏体化。由于回温温度较低,以及由于微合金元素形成的碳氮化物对奥氏体晶界的钉扎作用,因此回温形成的奥氏体晶粒细小。回温后在相变点附近进行第二阶段变形,钢板表层发生形变诱导铁素体相变,形成了超细的铁素体晶粒。第二阶段变形以后以10℃/s的冷却速度冷却到450～550℃,钢板中心的组织为较为粗大的铁素体和珠光体组织。
Using a specific controlled rolling and controlled cooling technology, a thick steel plate with superfine microstructure was prepared on a plate mill. The billet is austenitized at a lower temperature (1150 ° C). After the first stage billet deformation, accelerated cooling of the steel surface below the Bs point. Plate center has a higher temperature, so that the surface temperature of the steel plate to the two-phase zone, re-austenitic steel plate surface. Due to the low tempering temperature and the pinning effect on the austenite grain boundaries due to the carbonitride formed by microalloying elements, austenite grains formed by tempering are small. After the temperature change in the second phase near the transformation point of deformation, deformation of the steel surface induced deformation of ferrite, the formation of ultrafine ferrite grains. The second stage of deformation after the cooling rate of 10 ℃ / s to 450 ~ 550 ℃, the center of the steel plate for the more coarse ferrite and pearlite.