12.9级调质耐候螺栓钢的淬火温度优化

Quenching temperature optimization of grade 12.9 quenched and tempered weathering bolt steel

对12.9级调质耐候螺栓钢进行了系列温度(850~1000℃)的淬火试验,观察了系列温度淬火后试验钢的微观组织及亚结构,结合力学性能试验结果,讨论了12.9级调质耐候螺栓钢的微观组织与力学性能的关系。结果表明:随着淬火温度的升高,试验钢马氏体组织的Packet和Block尺寸逐渐增大,马氏体板条宽度变化不大;经不同温度淬火及600℃回火后试验钢的抗拉强度和硬度均呈现增大的趋势,而冲击韧性则呈现降低的趋势。在本文试验条件下,满足12.9级调质耐候螺栓性能要求的最佳淬火温度为900℃。

The quenching tests of 12.9 grade quenched and tempered weathering bolt steel at different temperatures(850-1000℃)were carried out,and microstructure and substructure of the experimental steel after quenching at different temperatures were observed.Combined with the test results of mechanical properties,the relationship between microstructure and mechanical properties of the 12.9 grade quenched and tempered weathering bolt steel was discussed.The results show that with the increase of quenching temperature,the size of martensitic Packet and Block of the experimental steel gradually increases,and the width of martensitic lath changes little.After quenching at different temperatures and tempering at 600℃,the tensile strength and hardness of the experimental steel show an increasing trend,while the impact toughness shows a decreasing trend.Under the test conditions in this paper,the best quenching temperature to meet the performance requirements of the grade 12.9 quenched and tempered weathering bolt is 900℃.