磁研磨法抛光40Cr钢管件内表面的影响因素

Influencing Factors on Polishing Inner Surface of 40Cr Steel Pipe Fittings with a Magnetic Grinding Method

针对磁研磨法抛光铁磁性管件内表面时的磁屏蔽问题,研制出一套磁力光整加工装置。对4种形状的磁极模型进行有限元分析,研究磁极形状、磁极转速及运动状态对抛光效果的影响,并以40Cr钢为材料进行试验验证,利用扫描电子显微镜观察加工前后工件的微观表面形貌。结果表明:磁极为环形磁极且与工件反向旋转、磁极转速为2 000r/min时加工效果好、加工效率较高;表面粗糙度值可降到Ra 0.25μm以下;工件内表面的微裂纹、凹坑等表面缺陷基本被去除,表面质量得到明显改善。由此表明,利用磁极内置的方法可以很好的解决磁屏蔽问题,并获得良好的表面加工质量。

To solve the magnetic shielding problem on the polishing inner surface of ferromagnetic pipe fittings with a magnetic grinding method,a magnetic abrasive finishing equipment was developed. Four types of magnetic pole models were analyzed by finite element analysis. The influence of the shape, speed and movement state of the magnetic pole on polishing effect were studied. 40Cr steel was taken as the experimental material for experimental verification, and the surface morphologies before and after processing were observed by using a microscope. The results show that the pro- cessing effect is better and the machining efficiency is higher when the magnetic pole is annular, the rotate direction of the pole and workpiece is opposite, and the magnetic pole rotate speed is 2 000 r/min. The surface roughness of the work- piece decreases below 0.25 /~m. The micro cracks and potholes on the inner surface of the workpiece are perfectly re- moved and the quality of the workpiece surface is obviously improved by comparing the surface morphology before and af- ter processing. The magnetic shielding problem can be effectively solved using the poles built-in method and better pro-cessing surface can be obtained.