Metallography and Failure Analysis Methods for Brazed Cutting Tools in Oil & Gas Drilling

Silver brazing alloys have been ubiquitous in downhole tools used in the oil and gas drilling for decades. With relatively low melting temperature and decent mechanical properties, these alloys can be brazed to several different base metals from tungsten carbide to low alloy and stainless steels to copper-based alloys. However, these complex alloy combinations are often discussed in terms of their macroscale joint strength while little attention is focused on developing failure analysis methods to study microscale interactions at interfaces as well as connecting joint strength to fracture surface features and manufacturing practices. Methods of sample preparation will be discussed, along with SEM and EDX techniques used to characterize fracture surfaces.