Majid Tavoosi, Sajad Arjmand, Saied Solgi,
Volume 4, Issue 1 (Journal OF Welding Science and Technology of Iran 2018)
Abstract
The influence of heat-input and pre-heat treatment on the structure, mechanical and corrosion behaviors of 2205 duplex stainless steel joint by means of GMAW process was the goal of this study. In this regards, the welding process was done using different heat input in the range of 0.6 to 1.4 kJ/mm and different pre-heating treatments in the range of 25 to 100 oC. The microstructural properties of prepared samples were evaluated using x-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Based on archived results, the microstructure of as-welded samples were combinations of Widmaneshtaten austenite which nucleated from boundaries and growth toward central part of ferrite grains. By increasing the heat-input, the percentages of ferrite and austenite phases decreased and increased, respectively. In this condition, the highest value of strength and ductility was achieved in as-weld samples with medium (1.0 kJ/mm) heat-input. The corrosion studies showed that the heat-input has negligible effects on corrosion behaviors of 2205 duplex stainless steel joint. It was also found that the pre-heating treatment has adverse effect on the mechanical properties of the junction.
S. Arjmand, Gh. R. Khayati, Z. Rajabi,
Volume 11, Issue 1 (Journal OF Welding Science and Technology 2025)
Abstract
In order to improve hardness and wear resistance of St60 steel substrate, NiCrMo welding wire was coated on its surface using gas tungsten arc welding (GTAW) process. Welding characteristics were considered to create a coating with maximum hardness and wear resistance and minimum defects. The results showed that the microstructure of the composite coatings mainly contains of α-Mo, NiMo and blade phases. By increasing in the arc current from 90 to 110 A, porosity and non-uniformity in microstructure of the coatings increased and the sample coated with the arc current of 90 A showed a more uniform microstructure and fewer defects. The average hardness of the coatings was obtained in the range of 218-227 HB (substrate's hardness is approximately equal to 152 HB). The sample prepared with arc current of 90 A showed the least weight loss and the sample prepared with arc current of 110 A showed the greatest weight loss. The wear mechanism of the substrate was mainly abrasive wear and the wear mechanism of the coatings was mainly abrasive and adhesive wear, with the lowest wear products related to the sample prepared with arc current of 90 A and therefore, this sample showed the greatest wear resistance.
