低碳贝氏体型特厚调质高强钢强韧化机理研究

Research on Strengthening and Toughening Mechanism of Low Carbon Bainitic Q & T Heavy Plate

采用低碳贝氏体的成分设计和调质工艺开发出100 mm厚460 MPa级调质钢板。结果表明:淬火后沿钢板厚度方向获得了一系列低碳中温转变组织,此类组织使钢具有高的韧性和塑性,而回火过程中软化和强化机制的共同作用使钢强度的变化表现出明显的规律性,因此通过调质处理能够获得良好的强韧性匹配和较低的屈强比;与传统调质钢相比,经过较低温度的回火既能获得优良的低温韧性,合金元素的作用得到了充分发挥,适于生产强度级别相对较低的特厚调质钢板。

The 460 MPa plate with thickness of 100 mm was developed by the composition design of low carbon and quenching and tempering processing. The results show that intermediate transformation products which make the steel with high toughness and plasticity can be obtained along the thickness direction after quenching. Strength of the steel tempered at different temperatures shows a remarkable regularity because of the interaction of softening and hardening mechanism, so the steel quenched and tempered at appropriate temperature has excellent strength, toughness and lower yield ratio. Compared with the conventional quenched and tempered steel, the steel exhibits more excellent low temperature toughness after tempering at a lower temperature, which make the effect of alloying elements fully play. This technique is applied in the production of relatively lower strength heavy plate by quenching and tempering.