Abstract
This paper aimed to investigate the influence of post-weld heat treatment on the microstructure of the Mangalloy – carbon steel (C45) bimetal joint. The materials have been successfully bonded through the method of explosive welding by using ammonal explosive containing 3 % aluminum powder. The obtained bimetal joint was subjected to two different types of post-weld heat treatments: stress-relief annealing (620 °C/90 min) and normalizing (910 °C/30 min). To investigate the influence of the heat treatment on their microstructure, the joints have been subjected to light and scanning electron microscope observations, as well as, the microhardness analysis. It has been reported that stress-relief annealing caused the formation of carbides in the Mangalloy layer on the grain boundaries and joint line. At the same time, normalizing resulted in the recrystallization of Mangalloy and the dissolution of cementite together with the formation of ferrite-pearlite microstructure in the C45 steel layer.

Key words
explosive welding, ammonal, heat treatment, steel, Mangalloy, microstructure

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