Cheng Ma

A coupled crystal plasticity finite element–representative volume element framework was developed to quantify texture evolution during finish rolling of 70S‐6 welding wire steel. The constitutive response of the BCC {110} slip family was calibrated using GLEEBLE‐3500 hot‐compression data, and microscale simulations were performed for simplified schedules involving 2, 4, and 6 passes, final rolling temperatures of 860–900 °C, and rolling speeds of 0.5–1.5 V _p , where V _p denotes the industrial reference speed. Pass number exerted the dominant control over texture evolution: increasing the schedule to six passes at constant total reduction reduced the maximum pole‐figure intensity by 47%, decreased the primary‐slip activity fraction by 17%, nearly doubled secondary‐slip activity, and lowered the texture‐anisotropy index from 0.41 to 0.18. In contrast, higher final rolling temperature mainly redistributed slip‐system activity, produced only modest texture weakening, with a 7% reduction in maximum intensity over 40 °C, and substantially alleviated stress concentration. Increasing rolling speed to 1.5 V _p promoted secondary‐slip activation, consistent with strain‐rate‐sensitive flow, and reduced pole‐figure sharpness by 10%. These results identify 6 passes, 880 °C, and 1.0 V _p as an effective processing window for obtaining a weaker, more isotropic texture with reduced stress heterogeneity.

The aim of this work is to investigate the influence of different welding technologies on the mechanical properties and corrosion resistance of welded joints of SGH340D + ZMA steel with a Zn–Mg–Al (ZMA) protective coating. Two different welding technologies were used: the gas metal arc welding(GMAW) process at a welding speed of 0.8 m/min and laser welding at speeds of 2 and 4 m/min. Mechanical properties were determined using tensile testing and hardness testing. Corrosion resistance was estimated using a salt spray test. Residual stresses were determined experimentally using the drill hole method. The highest residual stresses were measured in GMAW-welded joints, while the lowest were measured in laser-welded joints at a speed of 4 m/min. The sample welded by laser at a speed of 4 m/min exhibited hardness values close to the upper acceptable limit, indicating that further increases in welding speed without preheating may lead to excessive hardness. All samples exhibited good corrosion resistance in a salt chamber. According to the results, increased welding speed reduced residual stresses but increased the risk of brittle fracture.

With the advancement of welding technology, the demand for 70S-6 welding wire steel has steadily increased in industries such as construction, automotive, pressure vessels, and line pipe manufacturing. To optimize the production process of the target material, this study utilized the finite-element software ABAQUS to numerically simulate the multi-pass finish rolling process of 70S-6 welding wire steel. The study investigates the effects of the key rolling parameters—pass distribution (8/10/12 passes), finish rolling temperature (860/880/900 °C), and rolling speed (0.5 Vp/1.0 Vp/1.5 Vp, here Vp denotes the reference industrial rolling speed) on the rolling force, temperature field, and equivalent stress/strain during finish rolling. The results show that the increased number of passes homogenizes deformation, reduces local stress concentration and enhances mechanical properties. Specifically, 12 passes reduce the peak rolling force from 250,972 N to 208,124 N, significantly enhancing stress and temperature uniformity across the section. Increasing the finish rolling temperature lowers the pass-averaged flow stress and attenuates rolling-force fluctuations. At 880 °C, the simulated core–surface temperature gradient is minimal (50 °C), whereas at 900 °C the gradient increases (80 °C) but the rolling-force histories exhibit a lower peak level and smaller low-frequency oscillations; thus 880 °C is preferable when through-thickness thermal uniformity is targeted, while 900 °C is more suitable when a smoother load response is required. Increasing the finish rolling speed from 0.5 Vp to 1.5 Vp reduces the peak rolling force from 233,165 N to 183,665 N and significantly damps low-frequency load oscillations. However, it concurrently intensifies stress localization at the outer-surface tracking points P3/P4, which are in direct contact with the rolls, where the local equivalent stress approaches 523 MPa, even though the overall strain distribution along the bar length becomes more uniform. Overall, the optimal processing window is identified as a 12-pass schedule, a finish rolling temperature of 880–900 °C, and a rolling speed of 1.0–1.5 Vp, which can improve both rolling quality and temperature and stress and strain uniformity.