Research of dissimilar welding from SA 335 P91 to SA 106 Gr B steels which has different chemichal composition

P91 is one of the most preferable alloyed steel at power plant projects because of its creep, toughness and corrosion strength. Welding of this high-alloyed steel to 106 Gr. B which is low alloyed carbon steel to connect to auxiliary system is a common faced industrial problem. That is why, it is critical and special process to weld this materials to each other. To solve the problem, there are two type of different methodology. The first one is gradual transition with similar pipes and the second approach is buttering. In this study, we have researched weldability of P91 to 106 Gr. B by buttering method with using a test coupon has diameter of 610 mm and 17,47mm thickness. At first step, P91 has been cladded by P22 (ER90S-B3) and weld has been performed between this P22 layer and 106 Gr. B. Condition of this weld beam was evaluated by macrograpy, tensile test, bend test, charpy notch test and hardness test. The results obtained from these tests are satisfactory according to international standards and codes.