Experiments and Numerical Simulations of the Annealing Temperature Influence on the Residual Stresses Level in S700MC Steel Welded Elements

Abstract

The article presents the results of research on the influence of temperature and time changes of the annealing process on the values and distribution of stresses in the simulated heat-affected zone of S700MC steel welded joints. For this purpose, tests were carried out on a thermal cycle simulator, as well as heating the prepared samples in accordance with the recorded welding thermal cycles, and then annealing at temperatures from 200 to 550 °C. The stresses values in the tested samples before and after the annealing process were measured by using X-ray diffraction (XRD). The performed tests were verified with the results of numerical analyses using the finite element method (FEM) performed in the VisualWeld (SYSWELD) environment as, on the one hand, the verification of the obtained results, and, on the other hand, the source of data for the development of a methodology for conducting analyses of heat treatment processes of S700MC steel welded structures. Also presented are three examples of numerical analyses for Gas Metal Arc (GMAW), laser and hybrid welding and then the annealing process of the obtained joints at selected temperatures. The main purpose of the work was to broaden the knowledge on the influence of annealing parameters on the values and distribution of stresses in welded joints, but also to signal the possibility of using modern software in engineering practice.

Influence of Preheating Temperature on Structural and Mechanical Properties of a Laser-Welded MMC Cobalt Based Coating Reinforced by TiC and PCD Particles

“…In the case of the composite tested, this condition was met for the preheating temperature of 300 • C. To obtain a crack-free surfaced coating, it was necessary to select the preheating temperature and control the inter-pass temperature. Preheating the material before surfacing reduces shrinkage stress [39] and the hardness in the heat-affected zone [40], while also reducing the risk of hydrogen cracks [41]. In the analyzed case, the factors that influenced the necessity to use preheating were the high carbon equivalent value, CEV = 0.66% and the high-power density of the heat source, which translated into low linear welding energy.…”

Possibilities to Use Physical Simulations When Studying the Distribution of Residual Stresses in the HAZ of Duplex Steels Welds

“…Generally, in the case of structural steel welded joints, significant compressive stresses' peaks at greater distances from the fusion line outside the HAZ are noted. These stresses are changed to tensile ones in the HAZ, while there is a significant decrease of tensile stresses in the area of maximum temperatures [20,[24][25][26]. Exactly such a shape of the residual stresses was determined also during the physical simulations of welding steel X2CrMnNiN21-5-1.…”

“…From the authors point of view, a temperature of 550 • C appears to be a suitable compromise between the reduction of mechanical properties and the magnitude of residual stresses. The own influence of post-welding heat treatment (PWHT) after the welding of duplex steels was also dealt with in other works, not in terms of the elimination or redistribution of residual stresses, but in light of microstructure [27] and corrosion resistance [24,27].…”

Influence of Welding Parameters and Filler Material on the Mechanical Properties of HSLA Steel S960MC Welded Joints

“…The loss in mechanical properties was also caused by partial dissolution of the fine dispersion precipitates and their uncontrolled reprecipitation. Excessive growth of the mentioned precipitates and loss of their ability to inhibit grain growth was also an important factor [36,37]. The temperature of Ac1 was determined to be 759 °C, and the temperature of Ac3 was 858 °C, by dilatometric tests of investigative steel.…”