Effect of Different Post-weld Heat Treatments Used in Brazing in PDC Bit Cutters

Polycrystalline Diamond Compact (PDC) drill bits have been widely used in petroleum and coal mining. This paper focuses on the experimental research of using different temperatures for post-weld heat treatment. We found that the element diffusion and homogeneity in the seam was improved when the temperature was 500 degrees C. Observation of the seam microstructures by scanning electron microscopy (SEM) indicated that the silver brazing filler metal has dipped into the different base metals effectively when the post-weld heat treatment was 500 degrees C. The experiment proved that post-weld heat treatment was an effective process to improve strength. The shear strength was 169.06MPa when the brazing joint had undergone the 500 degrees C post-weld heat treatment. The result of microstructure analysis and the result of shear strength tests both prove that the brazing joint stress concentration is released in the higher temperature post-weld treatment. Using this process the PDC drill bits will remain in good condition when working under the ground.