Remanufacture of hot forging tools and dies using laser metal deposition with powder and a hard-facing alloy Stellite 21®

Abstract

Additive Layer Manufacturing (ALM) processes are attracting interest in the forging industry due to their potential suitability for remanufacturing and repair of tools and dies. The ALM process known as Laser Metal Deposition with powder (LMD-p) can be used to provide a hard-facing alloy repair to hot forging tools. This is particularly important on complex tool geometries due their superior wear resistance. The Advanced Forming Research Centre (AFRC) has established a low cost standard test method to evaluate abrasive and adhesive wear on hot forging H13 tool steel dies on an industrial scale 160 kJ Schuler screw press. The bespoke tool design allows researchers to benchmark new and novel coatings, lubricants and additive layers against a known standard. Furthermore, AFRC metrology standard methods ensure repeatability and reproducibility of benchmark results. To evaluate the performance of LMD-p for remanufacturing of hot forging tools and dies, a cobalt based alloy (Stellite 21 ®) was selected. Stellite 21 ® is widely used as a hard-facing alloy as it provides excellent machinability coupled with superior wear characteristics. AFRC standard dies were coated with LMD-p Stellite 21 ®. The LMD-p coating was then machined to final geometry and then subjected to hot forging under AFRC standard conditions to compare to benchmark wear characteristics. Adhesive and abrasive wear was evaluated. It was shown that the Stellite 21 ® LMD-p additive layer performed better in both adhesive and abrasive conditions than standard H13 tools steel dies.

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“…Traditionally, repairing worn-out tools or damaged parts is done by welding a new chunk of material that has to be brought to size using various machining processes, an example being presented in Figure 7 [48]. Depending on the part or tool geometry, these processes can take a long time, come at a great cost, or could be virtually impossible.…”

“…A set of advanced methodologies for the remanufacturing of complex geometry and expensive parts via reverse engineering, free-form surface modelling, laser additive repairs, and machining involves the integration of 3D non-contact scanning methods. It ensures the re-design of damaged parts, adaptive free-form surface reconstruction to create the digital model of a laser additive manufacturing process containing slicing, metrology, path planning, and a subsequent multi-axis machining operation, as shown in the Figure 7 [2,[45][46][47][48][49][50][51].…”

“…It ensures the re-design of damaged Figure 7. Mould repair using powder laser deposition before and after finishing [48].…”

“…A handful of companies have started offering repair services making use of selective laser melting (SLM) and laser cladding (LC) technology [17,45,50]. The parts to be repaired need processing until a straight plane surface is obtained on which the missing features are to be added using AM [47,48]. The advantages of this technology include the fact that the entire process is performed in an enclosed and controlled chamber, allowing for precise control over parameters like internal temperature, pressure, air flow, and most of all, air mixture, with the possibility of lowering oxygen levels dramatically so as to avoid oxidising.…”

“…ability 2019, 11, 5494 11 , adaptive free-form surface reconstruction to create the digital model of a laser addi facturing process containing slicing, metrology, path planning, and a subsequent multiining operation, as shown in the Figure 7 [2,[45][46][47][48][49][50][51]. handful of companies have started offering repair services making use of selective la ng (SLM) and laser cladding (LC) technology [17,45,50].…”