Authors : H. Wibowo, M.N. Ilman and P.T. Iswanto
Abstract: The use of certain welding techniques to reduce distortion in the welding of thin plates to the hull of a ship has become one of the most recent objects of research. One of the alternative welding techniques developed is called the DC-LSND (Dynamically Controlled Low Stress No-Distortion) technique. The investigation concerned here was aimed at studying the effect of DC-LSND double cooling on the distortion, microstructure and mechanical properties in A36 steel welded joints. The DC-LSND double cooling treatments were performed by cooling the HAZ (Heat Affected Zone) behind the welding torch by using cryogenic liquid nitrogen. A sequence of tests was carried out involving distortion measurement, microstructure examination, hardness measurement and tensile testing in combination with SEM fractography. The results showed that DC-LSND double cooling treatments affected transverse distortion significantly. The strength of the welded joint was improved by the DC-LSND double cooling treatments, based on the results of the tensile testing and the hardness. The microstructure was also refined by increasing the acicular ferrite phase.
H. Wibowo, M.N. Ilman and P.T. Iswanto, 2018. Microstructure and Mechanical Properties of DC-LSND Double Cooling on A-36 Steel Welded Joints. Journal of Engineering and Applied Sciences, 13: 7341-7347.