混砂车砂泵叶轮失效分析及改进方案

Failure analysis and improvement scheme of the sand pump impeller of fracturing blender truck

为了提高砂泵叶轮的使用寿命及砂泵效率,对失效砂泵叶轮的金相组织、化学成分进行分析,并对不同部位进行硬度测定,结果表明砂泵叶轮材料为中锰球铁。失效分析表明砂泵叶轮表面磨损属于冲蚀磨损和气蚀磨损,而冲蚀磨损占主导地位,除磨损对材料造成破坏外,本身缺陷也降低了叶轮的抗剥落能力。最终选用高铬铁作为叶轮材料。为了改善碳化物形态,提高基体硬度,选用淬火加热速度小于100℃/h,950～980℃保温1.5～2.0h出炉空冷。为了消除残余奥氏体及应力,采用450～500℃回火工艺,选用镶铸工艺铸造,使用寿命由0.5a提高到1a。

In order to improve the life of impeller and the efficiency of sand pump,the metallography structure and chemical composition of the failure impeller are analyzed and the hardness measurement for different location is carried out.The results show that the impeller material is medium manganese ductile cast iron.And the failure analysis indicates that the surface wears of the impeller are erosion wear and cavitation wear with the erosion wear dominant.Besides the breakage caused by wear,the self drawback reduces the anti-peeling ability of the impeller.The high chromium cast iron is chosen as the impeller material finally.In order to improve the carbide form and increase the base hardness,the quench heating temperature is chosen to be less than 100 ℃/h,the heat preservation time is 15~20 h under the temperature of 950~980 ℃,and it is cooled in the air after being taken out of the furnace.The temper technology of 450~500 ℃ is used for eliminating residual austenite and stress.The inlay casting technique is selected,thus the working life is increased from half a year to one year.