280VK冷轧高强钢退火过程的组织演变及析出机理

对热轧态280VK微合金高强钢经冷轧后取样,在不同温度下进行退火处理。对退火试样组织进行SEM、TEM、EBSD观察,以及析出物含量测定和力学性能测试分析,揭示退火工艺对冷轧高强钢组织结构、织构演变和力学性能的影响。结果表明,试验钢经退火处理后,基体中产生大量TiC析出粒子;随着退火温度升高,基体晶粒度减小,析出粒子尺寸增大但数量减少,屈服强度、抗拉强度降低,伸长率升高。热力学计算表明,试验钢中析出相的优先级顺序为TiN＞AlN＞TiC,析出相以TiC为主。

Microstructure evolution of 280VK cold-rolled high-strength steel and precipitation mechanism during annealing process

In order to reveal the effect of annealing process on microstructure, texture evolution and mechanical properties, the hot-rolled microalloyed high-strength steel 280VK was cold-rolled and then annealed at different temperatures, then the microstructure was observed by SEM, TEM and EBSD, meanwhile the content of precipitates and mechanical properties were measured and analyzed. The results show that after annealing, a large number of TiC precipitated particles are generated in the matrix of the tested steel. As the annealing temperature increases, the grain size increases, the average size of precipitated particles increases but the number decreases, the tensile strength and yield strength decrease, while the elongation increases. Thermodynamic calculation shows that the priority order of the precipitates in the tested steel is TiN>AlN>TiC, and TiC is the main one.