Cutting Tool Development Using a Novel Non-traditional Manufacturing Process

The mechanical processes involved in mining, mineral and aerospace industries often cause significant wear to the components and equipment. The premature wear and failure of components can result in unscheduled downtime and derive non-negligible economic costs. It is estimated that about half of the total maintenance cost in mining is due to the manufacture of damaged parts and the other half due to downtime and labour. As a result, it is important to identify methods of rapid manufacture of components without compromising physical properties and wear performance. To date, many researchers have used laser based additive manufacturing technology to manufacture components using various alloy steels with hardness values of 1000 HV. This study focuses on manufacture of cutting tools using carbide composites via Directed Energy Deposition (DED) additive manufacturing technique to achieve hardness values exceeding 1100 HV with a homogenous microstructure. A set of commercially available powders were identified, and comprehensive experiments were carried out to study the effects of process parameters to obtain a near-defect-free deposit. Following preliminary trials, the pre-alloyed Metco 1030 A powder, rich in vanadium carbides and molybdenum borides, was chosen to produce defect free deposit. The claddings were initially deposited on a 1020 steel substrate before substituting with a 4140-steel substrate. The process parameters were optimized for component-level fabrication. Heat treatment experiments were carried out to study the effects of tempering temperature on the laser cladded deposits. The laser cladded deposits were characterized in relation to the presence of surface and internal defects, microstructure, chemical composition, and microhardness. Wear performance tests were carried out in accordance with ISO 8688 standards. The results from this study showed that DED can be used to manufacture a near-defect-free cutting tool. Single track, single layer deposits showed a high mean hardness value of 1182 HV0.5. A tempering temperature of 550 °C for a duration of 90 min increased the overall clad hardness by 10%. During wear testing, the additively manufactured tool showed a 1.5 times higher wear resistance than that of a conventionally manufactured M2 High Speed Steel tool.