Articles written in Sadhana
Volume 45 All articles Published: February 2020 Article ID 0054 Original Article (Mechanical Sciences)
Thermomechanically controlled processed steels have gained attention increasingly by many industries. In this research S700MC steel is successfully welded using low power pulsed Nd:YAG laser and the microstructure and mechanical properties are investigated. It is shown that the average power and overlapping factor both affect the weld geometry. Full penetration with double-sided welding achieved on 2 mm thick plates autogenously. Optical metallographic methods and SEM/EDS were used to evaluate the resulting microstructures.The evaluations revealed that the weld metal microstructure contains different morphologies of ferrite such as acicular, allotriomorphic and Widmansta¨tten as well as bainaite and martensite structure in the weld zone. Also, no noticeable heat affected zone was detected near the fusion zone of the weldments. In addition tomicrostructures investigation, micro hardness and tensile tests were performed to evaluate mechanical properties. Hardness measurement results exhibit higher hardness values in weld zone than that of in the base metal. The tensile test revealed a ductile fracture behavior which happened in the base metal, due to proper weld zone microstructure. The strength and elongation of the prepared joints were 774 ± 14 MPa and 26.5 ± 2.5%, respectively.