Additive Manufacturing of Parts for Harsh Environments

Abstract

Manufacturing parts by additive processes that can adequately function in harsh environments presents several challenges. This technical report presents initial results of a study investigating the merits of using additive manufacturing (AM) to produce steel parts and the process parameter optimization to make them suitable for use in corrosive environments. Specifically, a centrifugal pump casing and a cylindrical connector part were analyzed for production by AM with the intent to make them suitable for use in oil and gas industry in Qatar. The initial stage of the study involved analyzing the amount of material wasted during subtractive manufacturing. For the subtractive manufacturing phase of the project, a mold for a semicircular part of a centrifugal pump's volute was machined using subtractive methods. Defects like corrosion in the semicircular bowl-like structure made it necessary to replace it. Based on the findings, it can be stated that about 40% of the total material utilized in the fabrication process was deemed as wastage while producing a component of 12 cm². The cylindrical part given its benign complexity was measured by hand and modeled using SolidWorks and printed using ABS plastic. The pump casing was also modeled but given its complex geometry and size, a 40% scaled down version was machined by the team. Whilst our primary objective was to scan the part, we encountered significant difficulties due to limitations caused by the reflection of metal, making it difficult to capture certain parts of the connector with the camera. However, despite these challenges, we were able to make some initial progress with 3D scanning and generate some results. While not meeting our complete scanning requirements, it represents a positive step towards our end goal. Consequently, we have adopted alternative methodologies to overcome these obstacles and continue our efforts towards achieving our ultimate goal. An optimization study was then conducted to determine the best print parameters to achieve the required porosity level of less than 0.5% as per industry standards. A design of experiments (DoE) approach was used to vary the power and speed of the AM process and analyze the porosity level of the parts produced. The results indicated that a power of 200 W and a speed of 800 mm/s produced the lowest porosity level. In conclusion, this study highlights the importance of optimizing AM parameters for industrial parts in harsh environments to reduce material waste and achieve required quality standards. The study results demonstrate that a DoE approach is effective in determining optimal parameters for specific parts and environments. Future work could focus on further optimization of the AM process parameters and mechanical property analysis of the parts produced.