Air suspension components are critical elements of automotive chassis and are commonly fabricated by welding 6061-T6 aluminum using 4043 filler wire with the cold metal transfer (CMT) process. Variations in vehicle architecture necessitate different groove angles and matching parameter windows. This study aims to elucidate how groove angle and heat input govern weld quality to inform process optimization. Two groove angles (120° and 90°) were investigated under distinct heat-input conditions (denoted 120-H and 90-L). Characterization covered chemical composition, macroscopic morphology, porosity, microstructure, hardness, and mechanical properties. The key novelty lies in elucidating the relationship between liquation cracking and metal flow lines, which jointly govern crack propagation. Integrating evidence from porosity measurements, crack characterization, and numerical simulations indicates that the 120-H parameter set requires further optimization. Overall, the results underscore the pivotal roles of groove angle and heat input in CMT welding of 6061-T6 aluminum and provide a basis for process parameter optimization in air suspension manufacturing.

This study investigates various factors that influence the cold-cracking ratio (CCR) of flux-cored arc welds through Y- and y-groove tests. Factors affecting the CCR include the alloy component, diffusible hydrogen content, microstructure, hardness, and groove shape. In weld metals (WMs; WM375-R and WM375-B) of a low-strength grade, the diffusible hydrogen content has a more significant effect on the CCR than the carbon equivalent (C_eq) and microstructure. However, the combined effects of the microstructure and diffusible hydrogen content on the CCR are important in high-strength-grade WM. The CCR of the WM increased upon increasing C_eq and the strength grade because hard martensite and bainite microstructures were formed. Moreover, y-groove testing of the 500 MPa grade WM revealed a more significant CCR than that of the 375 MPa grade WM. Therefore, in high-strength-grade WMs, it is necessary to select the groove shape based on the morphology in the real welds.

As a critical component of rocket systems, the grid fin is widely applied in the aerospace industry. Compared to traditional manufacturing methods and other additive manufacturing (AM) techniques, wire arc additive manufacturing (WAAM) is more advantageous in its time and cost efficiency, especially when it is utilized in the large-scale production of components. Given the significant effect of the welding strategies on the quality of manufactured parts, we investigated two distinct WAAM printing orientations, horizontal, or lie (L), and perpendicular, or stand (S), using a small-scale model. The feasibility of these two printing approaches was evaluated by analyzing the surface quality, microstructure, and mechanical properties at the junctions of the grid fin. Furthermore, a finite element analysis (FEA) was adopted to simulate and analyze the main factors, including the temperature distribution, deformation, and stress profiles at the welding joints, in both AM strategies. The integrated approach adopted in this study provides important insights for optimizing the application of WAAM in grid fin manufacturing. In summary, our results indicate that while the L mode is easily manufacturable and exhibits stable properties, the S mode holds significant market potential if its welding parameters are optimized.