Abstract
This thesis describes an investigation into the deployment of Cold Metal Transfer based Wire Arc Additive Manufacturing (CMT-WAAM) for manufacturing steel stiffening structures. This process can provide tailored mechanical properties and significantly reduce the waste associated with traditional methods while enabling greater design and manufacturing freedom.This work will aim to investigate (i) the capabilities of CMT against conventional gas metal arc welding (GMAW) for WAAM, (ii) the evolution of specimen geometry and microstructure with layer wise deposition, (iii) the application control strategies for stiffener properties and geometry, (iv) the performance of WAAM fabricated stiffeners against benchmark machined from solid specimens.
Minimal differences were observed between the process modes, however, CMT did show to have small gains in geometric and deposition stability over GMAW at lower travel speeds.
An analysis of multilayer specimens with varying heat input and dwell period settings applied showed the ability to manipulate the microstructures and properties to a degree. This analysis also allowed for the selection of a parameter set which would provide minimal requirement for machining whilst maintaining productivity and providing the greatest volume fraction of acicular ferrite forming in the initial layers.
WAAM fabricated + machined specimens tested under 4-point bending showed to have the highest yield strength and greatest ductility though machined from solidEN3B specimens provided the greatest peak load of the machined specimen sets.
Thesis is embargoed until 28th February 2027
| Date of Award | Feb 2025 |
|---|---|
| Original language | English |
| Sponsors | Department for the Economy |
| Supervisor | Cormac Mc Garrigle (Supervisor), Shaun McFadden (Supervisor) & Justin Quinn (Supervisor) |
Keywords
- WAAM additive manufacturing