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利用萃取复型分析技术研究了V-Ti微合金油井管钢中第二相粒子的尺寸、形貌、数量和成分等特征及其对显微组织和力学性能的影响。结果表明,V-Ti微合金钢中存在大量弥散分布的第二相粒子。尺寸较大的粒子近似方形,含Ti量较高而含V量较低;尺寸较小的粒子近似圆形,含V量较高而含Ti量较低或不含Ti。这些粒子增加了裂纹源的分布密度,降低了钢的韧性。通过提高淬火温度至890℃,减少未溶第二相粒子的数量,增强回火析出强化效果,而且没有使奥氏体晶粒过分长大,从而改善了试验钢的力学性能。
The effects of the size, morphology, amount and composition of the second phase particles in V-Ti micro-alloyed oil well tubular steel on the microstructure and mechanical properties were studied by using extraction complex analysis. The results show that a large number of dispersed second phase particles exist in V-Ti microalloyed steel. Larger sized particles are approximately square with higher Ti content and lower V content. Smaller particles are approximately circular with higher V content and lower Ti content or no Ti content. These particles increase the distribution density of the crack source and reduce the toughness of the steel. By increasing the quenching temperature to 890 ℃, the number of undissolved second phase particles can be reduced, tempering precipitation strengthening effect can be enhanced, and austenite grains can not grow excessively, so the mechanical properties of the test steel are improved.