The effect of heat treatment on the structure and properties of metallic layered composite materials formed by explosive welding of heterogeneous steels thin plates

Three types of metal laminated composite materials consisting of alternating plates of durable and plastic steels are formed by explosive welding. In order to increase the structural strength indicators, the derived composite materials are heat treated. Compositions containing maraging steel are subjected to artificial aging for 3 hours at 490 ° C . Compositions containing tool steel are quenched in oil at 880 ° C and then tempered at 550 ° C . The mechanical properties of the materials are determined by its structure. Carried out static and dynamic mechanical tests confirmed the positive effect of heat treatment on the properties of the layered composite materials, in spite of the diffusion zones formation in the structure. During heat treatment of multilayer materials, obtained by explosive welding of chrome-nickel austenitic steel and structural tool steel thin plates, an explicit gradient structure is formed, and characterized by the presence of several zones with different structure. An accelerate formation of these zones during heating contributes to the non-equilibrium structure of materials in the heat-affected zone of a width of about 100 μm, which is formed as a result of severe plastic deformation of dynamically interacting steel billets. The width of the diffusion zones along weld profile waves is derived from the different degrees of plastic deformation. It is established experimentally that the effect of the deformation and heat treatment processes on the nature of the hardening of chromium-nickel, maraging and tool steels differs sharply. The results of the microhardness measuring in the central areas of the plates indicate that chromium-nickel steel is hardened by explosive welding on 42%. In the soak process at 490 °C its microhardness is practically unchanged. Maraging steel conversely is undisposed to hardening during welding and is hardened on aging stage at 490 °C by 53%. The mechanism of maraging steel hardening is due to the formation of intermetallic particles. The microhardness of the tool steel during explosion welding is increased by 32. Heat treatment allows to further raise the microhardness level of the tool steel by 48%. It has been shown experimentally that there is a difference in average 30% of the stress limit values, compared with calculated values obtained by using the rule of mixtures. Difference in the level of the stress limit values is due to the work hardening that occurs during the dynamic interaction of steel billets.

maraging steel, carbon steel, chrome-nickel stainless steel, explosive welding, laminated composite materials, heat treatment