An Investigation on Eddy Current Pulsed Thermography to Detect Surface Cracks on the Tungsten Carbide Matrix of Polycrystalline Diamond Compact Bit

Abstract

Polycrystalline diamond compact (PDC) bits are commonly used drill bits in the petroleum drilling industry. Cracks often occur on the surface of a bit, which may result in the unexpected suspension of the drilling operation, or even accidents. Therefore, the detection of surface cracks on PDC bits is of great importance to ensure continuous drilling operation and to prevent accidents. However, it is extremely difficult to detect such cracks by visual inspection or other traditional nondestructive testing (NDT) techniques due to the small size of cracks and the irregular geometry of bits. As one emerging NDT technique, eddy current pulsed thermography (ECPT) can instantly detect surface cracks on metal parts with irregular geometry. In this study, the feasibility of ECPT of detecting surface cracks on the tungsten carbide matrix of PDC bits was investigated. A successive scanning detection mode is proposed to detect surface cracks by using ECPT with a low power heating excitation unit and small-size coils. The influence of excitation duration on the detection result was also investigated. In addition, principal component analysis (PCA) was employed to process the acquired IR image sequences to improve detection sensitivity. Finally, the whole shape of a crack was restored with processed images containing varied cracks segments. Based on the experimental results, we conclude that the surface cracks on the tungsten carbide matrix of PDC bit can be detected effectively and conveniently by ECPT in scanning mode with the aid of PCA.

Temperature Diffusivity Measurement and Nondestructive Testing Requiring No Extensive Sample Preparation and Using Stepwise Point Heating and IR Thermography

“…Thermographic approaches to nondestructive testing (T-NDT) seem promising for a wide variety of specific applications [3][4][5][6][7]. They can be multifunctional, multiscale, and contactless [20,24,35,[79][80][81][82][83][84]. Pulsed techniques have a number of advantages over quasi-stationary ones [20,24,69,79,80,85] such as higher information content, higher spatial resolution, higher sensitivity to inhomogeneities, on the other hand, they require more powerful heat sources, higher resolution of data acquisition system, and more sophisticated thermal-physical models and data processing algorithms.…”

A Defect Detection Method for the Surface of Metal Materials Based on an Adaptive Ultrasound Pulse Excitation Device and Infrared Thermal Imaging Technology

“…However, in engineering practice, microcracks on the metal surfaces are difficult to be directly observed by human eyes. erefore, nondestructive testing methods such as ultrasound, radiation, penetration, infrared, and eddy current are often used for regular testing [2][3][4][5][6]. Among them, ultrasonic testing is suitable for various types of workpieces, which can detect surface cracks, internal cracks, and quantify cracks [7][8][9][10][11].…”

3D Numerical Simulation of Rock Cutting of an Innovative Non-Planar Face PDC Cutter and Experimental Verification

“…Currently, polycrystalline diamond compact (PDC) bits are mainly used for drilling soft to medium hard formations. While in hard abrasive formations serious failures, such as chipping, broken cutter and falling off of the PDC, often occur and the drilling effect is not satisfactory [1][2][3][4], which is difficult to meet the exploration and development needs of unconventional resources in deep formations [5,6]. To improve the performance of conventional PDC bits in deep formations, a series of approaches has been conducted on the material refinement and the design method supplement, such as increasing the number of cutters and blades [7], optimizing diamond packing [8] and using high-temperature and high-pressure (HT/HP) sintering for higher diamond volume in the PDC layer [9,10].…”