退火温度对非调质960 MPa高强钢组织和性能的影响

为了稳定热轧高强钢的组织和性能,需进行退火处理。了解不同的温度对组织的影响规律至关重要,为此对相同终轧温度条件下退火温度对非调质960 MPa高强钢组织和性能的影响进行研究。结果表明,试验钢在不同退火温度下处理后,均得到回火马氏体组织,并出现明显的纤维组织,使得马氏体板带具有明显的方向性,且随着退火温度的升高马氏体组织粗化。经不同退火温度处理后,试验钢的强度在RD方向(轧制方向)的下降趋势低于TD方向(轧件宽度方向),说明TD方向的强度对温度变化较敏感;同时随着退火温度的升高,伸长率和冲击韧性在RD方向为先升后降,在TD方向伸长率持续升高,冲击韧性几乎不变。综合考虑,确定退火温度为500 ℃时为最佳退火工艺方案。

Effect of annealing temperature on microstructure and properties of non-quenched and tempered 960 MPa high-strength steel

In order to stabilize the microstructure and properties of hot rolled high-strength steel, annealing treatment is required. It is very important to understand the influence rules of different temperatures on the microstructure. Therefore, the effect of annealing temperature on microstructure and properties of non-quenched and tempered 960 MPa high-strength steel under the same final rolling temperature was studied. The results showed that the tempered martensite structure and obvious fiber structure were obtained after the test steel was treated at different annealing temperatures, which made the martensite strip has obvious directivity, and the martensite structure coarsened with the increase of annealing temperature. After different annealing temperature treatment, the strength of the test steel in rolling direction(RD) decreased less than that in transverse direction(TD), indicating that the strength in TD direction was sensitive to temperature changes. At the same time, with the increase of annealing temperature, the elongation and impact toughness first increased and then decreased in RD direction, and the elongation continued to increase in TD direction, and the impact toughness was almost unchanged. Considering comprehensively, the optimal annealing process was determined as annealing temperature of 500 ℃.