Session: Government Agency Student Posters

Paper Number: 172891

Repair of Ss316l Substrates Using Cold Spray Additive Manufacturing: A Study on Surface Defect Restoration and Bond Strength Evaluation 

Stainless steel 316L (SS316L) is utilized in critical parts for many different applications, including the nuclear, chemical processing, marine, and aerospace sectors, because of its exceptional corrosion resistance, high strength, and superior formability. However, during the operation SS316L components can undergo localized damage, wear, or material loss, which is costly to replace and causes downtime. Welding of these parts using conventional thermal methods normally has undesirable effects such as residual stress, thermal distortion, and microstructural alteration in the heat-affected zone. Cold Spray Additive Manufacturing (CSAM), a solid-state process that accelerates metallic powders at supersonic velocity onto a substrate, is a highly promising process for repairing metallic parts without melting or thermal degradation of the base material. This study investigates the potential to repair surface voids in SS316L substrates that were artificially damaged by precision milling with CSAM. Various geometric defects such as rectangular grooves and circular cavities were machined at the top surface of SS316L plates to simulate common types of service-induced damage using a HAAS CNC milling machine. This ensured repeatability and accuracy in the damaged area geometry. The geometry of the damage patterns stepped geometries, pockets, and rectangular slots—was created on Autodesk Fusion 360. The same software was also utilized for generating the corresponding toolpaths, which assisted with optimizing machining strategies for consistency and precision in all the specimens. This orderly procedure was used to facilitate the production of complex CSAM repair process. These defects were then repaired by CSAM via deposition of gas-atomized SS316L powder under optimized spraying parameters. The repair process was carried out using a Warpspee3D cold spray additive manufacturing system.

The repaired specimens were subjected to a series of tests to establish the deposition quality and the effectiveness of the repair. To confirm the dimensional accuracy of the 3D printed parts, the repaired parts were first 3D scanned and compared to the original CAD model.  The modified ASTM D1002 standard for determining the bond strength between the deposited material and base metal was then followed when conducting the tensile shear testing. The outcome confirmed that SS316L parts' surfaces can be successfully repaired and restored using CSAM with minimal flaws and high bond integrity. The findings demonstrated that the bond strengths are comparable to those found in previous studies for comparable repairs. The results showed that the bond strengths are comparable to the values reported in the literature for similar repairs. This research demonstrates the feasibility of CSAM as a low-temperature and reliable method for stainless steel components with benefits in process control, material conservation, and structural integrity.

Presenting Author: Abishek Kafle University of Houston

Presenting Author Biography: Abishek Kafle is a mechanical engineer and researcher specializing in additive manufacturing, robotics, and automation. As a Ph.D. candidate at the University of Houston, he is actively engaged in innovative research on Cold Spray Additive Manufacturing (CSAM), robotic 3D printing systems, and floating aquatic plant technologies for environmental applications. Abishek has experience at Kathmandu University's Design Lab, where he has helped advance the healthcare technology, and turbine production. Additionally, he also has the experience of working with design of Pico satellite subsystems. CNC machining, 3D printing, and simulation programs like SolidWorks, ANSYS, and MATLAB are among his technical skills. In addition to being a co-author of several peer-reviewed publications, he has received national and worldwide recognition for his outstanding engineering design and creativity.

Authors:

Abishek Kafle University of Houston
Weihang Zhu University of Houston