Welding process of S700MC high strength steel

Objective S700MC has a good application prospect in the field of rail transit. In this paper, weldability and weld performance of S700MC high strength steel are studied, and feasibility of the technology in application is explored. Methods Welding process is optimized from mechanical properties and metallographic structure. Weldability of S700MC high strength steel is studied with different welding materials and welding parameters, and the optimal welding parameters are obtained. Then, it is compared with welded joints of Q460ME and 16MnDR, which are two commonly used materials in the field of rail transit. Results Two-layer and two-pass welding process is used with a single-pass welding heat input of around 1 kJ/mm, weld strength can reach 94.8% of base metal, and comprehensive performance is excellent. Under stable welding process conditions, fatigue performance of welded joints do not deviate greatly due to change of material, and it is much higher than the standard value. Conclusion The research verifies feasibility of application of high-strength steel welding technology, and it obtains good results, which has great guiding significance for practical application.