Optimizing process parameters in Wire Arc Additive Manufacturing (WAAM) is essential for high-quality, cost-effective ER70S-6 steel components. This study investigated the impact of travel speed (TS) on porosity and microhardness. Inappropriate parameter selection led to defects like discontinuous beads and irregular layers. Importantly, lower TS (120 mm/min) resulted in significantly higher porosity (15.58%) due to increased heat input and trapped hydrogen. Conversely, higher TS (180 mm/min) yielded a substantial reduction in porosity (2.04%), highlighting its role in controlling pore formation. Microhardness exhibited a complex relationship with TS and location, with faster cooling in bottom and top regions leading to higher values (216 HV). Additionally, increasing TS increased microhardness throughout the deposit (197 HV) due to reduced heat input and faster cooling. Both image processing and density measurements confirmed the effectiveness of TS in controlling porosity, revealing a decrease in pore number and size with increasing TS. These findings emphasize that optimizing WAAM process parameters, particularly TS, is crucial for achieving minimal porosity and desired microhardness in ER70S-6 steel deposits, ultimately leading to high-quality, low-cost components