Metal-arc spray re-manufacturing materials-process-durability studies

• Main Author: Tan, Alexander Wei Long.
• Other Authors: Pang Hock Lye, John
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/53275
• Institution: Nanyang Technological University

Re-manufactured components are expected to perform to exacting specifications of their brand new counterparts. This project investigates the effectiveness of the Twin Wire Arc Spray process, synonymous with the re-manufacturing industry. Machined surface-finish cast iron coupon specimens and grit-blasted cast iron specimens were subjected to the Twin Wire Arc Spray process. These specimens were refined and subjected to fatigue testing. The Machined surface-finish cast iron coupon specimens exhibited de-lamination immediately after undergoing the Twin Wire Arc Spray process. For the grit-blasted cast iron specimens that had undergone the exact same process, de-lamination occurred only when the coating layer was increased beyond 1.5mm. The propensity for de-lamination to occur is ever-present regardless of surface preparation methods, and is highly detrimental to components. De-lamination of the coating from a substrate severely undermines the fatigue life of a component as reflected in this project. Grit-blasting a substrate prior to metal spraying can improve the adhesion strength at the coating-substrate interface thereby improving the fatigue life of the component, provided that de-lamination does not occur. Pre-heating and the incorporation of ridges and grooves onto the substrate can also reduce the likelihood of de-lamination