Advanced active-gas 3D printing of 436 stainless steel for future rocket engine structure manufacture

During this study a novel means to fabricate a rocket engine combustion chamber was developed. Here the shape of this rocket engine component has been fabricated using prototype 3D metal active gas deposition technology. The manufacturing process is based upon an argon gas fused deposition process for producing complex component geometries. This process uses multi-pass deposition employing stainless steel 436 alloy as the feed material. The structures created during this process were metallographically characterised to understand the microstructural properties produced during fabrication. The engine combustion chamber casing was fabricated and later machined to produce a smooth precision finish. The chamber casing features high resolution details with fine control of the process resulting in micron-scale precision. This allowed for the creation of wall structures and hollow internal sections. It was by allowing the structure to cool precisely between each layer that resulted in no loss in precision due to imposed cooling stresses on this large-scale structure. It is this factor which is of significant importance towards the formation of complex components. The process developed was a paramount means towards the fabrication of robust structures.