基于不同冲击频率条件下的套管磨损表面分形特征及磨损机制研究

Investigations on Fractal Characteristics and Wear Mechanism of the Surface of Casing Wear Based on Different Impacting Frequencies

选取TP140套管在自行研制的套管磨损试验机上进行磨损试验,利用表面形貌仪测量在不同冲击频率条件下的套管表面磨损形貌,选用结构函数法考察磨损形貌的分形特征,使用拟合误差法确定分形曲线的无标度区间并计算分形维数,利用扫描电子显微镜分析其磨损机制。结果表明:在不同冲击频率条件下的套管表面形貌存在明显的分形特征,但分形维数会随频率的不同而有所变化。从光学图像和扫描电镜图像可以看出磨损机制主要有粘着磨损和犁沟。

The wear experiment of TP140 casing was conducted on the self-developed casing wear tester. The surfaces topography of casing wear under different impacting frequencies were tested by the surface profiler. Fractal scaleless range was determined by fitting the fractal curves calculated through construction function and was used to further calculate fractal parameters. The wear mechanism was examined through SEM. The results show that under different impacting frequencies, there are clear fractal characteristics in the worn surface of casing wear and the fractal parameter would change in accordance with the variations of the impacting frequencies. Judged from the optical and SEM images, we could say that the predominant wear mechanisms are adherence wear and plowing.