Investigation of structural-phase transformations in metal of welded joints of reactor plants for nuclear icebreakers

The method of mathematical modeling was used to determine the rate of cooling of the heataffected zone at performing assembling welded joints of reactor plants for nuclear icebreakers via preliminary surfacing. With the hardening-deformation dilatometer, an imitation effect of thermal cycles was carried out in various sections of the preliminary surfacing metal, made with three types of welding consumables: carbon steel, silicon-manganese steel and nickel-alloyed steel. Investigations of the structure and hardness of the samples after the imitation effect of thermal welding cycles have been carried out. It has been established that the Sv-06AA carbon steel wire in the entire range of cooling rates provides a ferrite-pearlite structure of the deposited metal. Manganese silicon steel welding wire Sv-08MnSi in a wide range of cooling rates provides the structure of the deposited metal in the form of acicular ferrite, while wire alloyed with nickel steel Sv-10MnNi forms acicular and quasi-polygonal ferrite.

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