Optimization of GMAW Process Parameters in Ultra-High-Strength Steel Based on Prediction

Abstract

Ultra-high-strength steel (UHSS) is a complex and sophisticated material that allows the development of products with reduced weight but increased strength and can assist, for example, in the automotive industry, saving fuel in vehicles and decreasing greenhouse gas emissions. Welding UHSS has a certain complexity, mainly due to the higher alloys and heat treatments involved, which can result in a microstructure with higher sensitivity to welding. The primary purpose of the current work was to select the best parameters of the gas metal arc welding (GMAW) for welding the S960 material based on prediction methods. To achieve the expected results, a finite element analysis (FEA) was used to simulate and evaluate the results. It was found that the welding parameters and, consequently, the heat input derived from the process greatly affected the UHSS microstructure. Using FEA and estimating the extension of the heat-affected zone (HAZ), the peak temperature, and even the effect of distortion and shrinkage was possible. With an increase in the heat input of 8.4 kJ/cm, the estimated cooling rate was around 70 °C/s. The presence of a softening area in the coarse grain heat-affected zone (CGHAZ) of welded joints was identified. These results led to an increase in the carbon content (3.4%) compared to the base metal. These results could help predict behaviors or microstructures based on a few changes in the welding parameters.

The Effect of Shielding Gas Consumption and Electric Current on the Tensile Strength of SGC440 in Gas Metal Arc Welding (GMAW)

“…This is demonstrated by a current setting of 160 Amperes resulting in a tensile strength of 465.33 N/mm², and for a current setting of 200 Amperes, a tensile strength of 476.5 N/mm² is obtained. These results indicate that moderate electric current yields maximum tensile strength in the welding process [7][8][9][10]. The results of welded specimens with different CO₂ flow rates, as shown in Figure 6, yielded the highest tensile strength with a CO₂ flow rate of 10 liters/minute, while the lowest tensile strength result was obtained from a CO₂ flow rate of 5 liters/minute, with each achieving tensile strengths of 499.83 N/mm² and 497.17 N/mm², respectively.…”

Deflection Intelligent Prediction for High-Strength Steel Saddle Plate Forming Applicable to Reducing Ship Weight

“…The deformation of L-beams is caused by the combined action of the transformation strain and the cooling shrinkage strain. Netto, A. et al [5] established a numerical calculation model for the welding of high-strength steel and optimized the process parameters. Obers, S. et al [6] proposed a finite element simulation model for nonlinear plastic materials to analyze the effect of the yield-to-tensile strength ratio on the plastic stress concentration factor.…”