A. Abbasian - Department of Materials and Metallurgical Engineering, Technical and Vocational University (TVU), Tehran, Iran
A. Ravangard - Department of Mechanical Engineering, Technical and Vocational University (TVU), Tehran, Iran
I. Hajian Nia - Department of Materials and Metallurgical Engineering, Technical and Vocational University (TVU), Tehran, Iran
S. Mirzamohammadi - Department of Materials and Metallurgical Engineering, Technical and Vocational University (TVU), Tehran, Iran

In this research, the heat treatment and production of high-strength advanced TRIP۱۱۰۰ steel were investigated and then the mechanical properties of the welds of this steel were evaluated by spot welding. For this purpose, the effect of rolling process and heat treatment of alloy steel sheets to achieve the ultra-high strength TRIP۱۱۰۰ steel microstructure was discussed. Microstructural examinations by Scanning Electron Microscopy (SEM) identified ferrite with bainite phases and martensite in matrix. The microstructural characteristics were examined using SEM microscopy with Electron Backscatter Diffraction (EBSD) analysis. The EBSD results showed that the type and orientation of the grains changed and the fraction of high-angle to low-angle boundaries in the present steel varied due to the presence of different phases. The EBSD results showed the acceptable rate of primary austenite in the structure according to the phaseology of this method. Having desirable mechanical properties was one of the most important results of this study, which at the same time maintained impact resistance and mechanical strength.

TRIP۱۱۰۰ steel, Mechanical properties, Microstructure, EBSD, Fracture behavior