调质工艺对压裂泵阀箱30CrNi2MoV钢组织和性能的影响

Effect of quenching-tempering process on microstructure and mechanical properties of 30CrNi2MoV steel of frac-pump fluid end

针对石油压裂工艺中压裂泵阀箱失效疲劳开裂现象,采用SEM、硬度实验、拉伸实验和示波冲击等实验方法,研究了不同回火温度下调质处理对阀箱材料用钢30CrNi2MoV 钢的显微组织和力学性能影响,找到较好的强韧性配合,提高阀箱材料寿命.结果表明,30CrNi2MoV 阀箱钢冲击功和裂纹扩展功等关键指标均随回火温度的升高而升高,30CrNi2MoV 钢韧性主要决定于冲击裂纹扩展功.调质组织对30CrNi2MoV钢冲击裂纹萌生功影响较小,对裂纹扩展功有着较大的影响.研究表明,30CrNi2MoV 钢经过880℃油淬,620-650℃回火后空冷,合金元素充分溶解,碳化物细小弥散分布得到均匀稳定的回火索氏体组织,其硬度达到较佳的使用范围（37．2-40．5 HRC）,且具有较好的强韧性配合,能够较好地满足压裂泵阀箱钢使用要求.

Cracking failure of frac-pump fluid end easily occur in fracture operation in the oil fields.Influence of different heat treatment processes on microstructure and mechanical properties of frac-pump fluid end 30CrNi2MoV steel were investigated by means of scanning electron microscope,rockwell hardness test,tensile test,impact test.The changing rules of plasticity,hardness,strength and impact toughness of 30CrNi2MoV steel at different heat treatment processes were analyzed.The results show that the impact energy,crack propa-gation energy will all increase as the temperature increase.The toughness of 30CrNi2MoV steel was mainly de-pendent on the crack propagation energy.The effect of quenched-and-tempered microstructure on impact crack initiation energy was less,but the effect of that on crack propagation energy was great.Alloy elements are fully dissolved under oil quenching at 880 ℃,when tempered at 620-650 ℃,dispersive tiny carbide stable and the u-niform and tempered sorbite is obtained.The optimum hardness range of （37.2-40.5 HRC）,excellent combina-tion of strength and toughness was also obtained,which can satisfy basic application of frac-pump fluid end steel.