中文摘要：

通过SEM、室温拉伸试验分析了20CrNi2Mo钢经900～1200℃淬火＋200℃回火后的显微组织及力学性能。结果表明：随淬火温度的升高,20CrNi2Mo钢原奥氏体晶粒尺寸增加,强度和硬度降低,塑性有所增加。不同淬火温度下,马氏体板条间均会形成一层很薄的残留奥氏体薄膜,而且随淬火温度的提高,薄膜的分岔和弥散分布特征更加明显。拉伸断裂方式为韧性断裂,且放射区韧窝尺寸随淬火温度升高而增大。

英文摘要：

Microstructure and mechanical properties of 20CrNi2Mo steel after quenching at 900-1200 ℃ and tempering at 200 ℃ were analyzed by means of SEM and tensile tests at room temperature,respectively. The results show that with the rise of quenching temperature,both the grain size of the original austenite and the plasticity of the steel increases,but the strength and hardness decrease. A thin film of retained austenite is all formed between martensite lath at different quenching temperatures,and characteristics of bifurcation and dispersion distribution for the film become more obvious as the quenching temperature increase. The tensile fracture mode is of ductile feature,and the dimple size at the radial zone increases with the rise of quenching temperature.