SPECIAL ASPECTS OF STRUCTURE FORMATION OF A TRANSITION ZONE IN A LAYER COMPOSITE PRODUCED BY EXPLOSION WELDING

Abstract

The paper presents the research on special aspects of structure formation in the transition zones of a layer metal material made of structural carbon and alloy stainless steels with an internal protector. The authors specify the order of layers arrangement. As an industrial method of producing such a material, the explosion welding technology was selected, which ensures the production of three-, four- and six-layer materials with one and two internal protectors per one explosion. The selection of optimal process parameters was carried out using computer modeling in the LS-DYNA software product. By calculation, the authors determined the main technological parameters of the process, which provide in the contact zone at each interlayer boundary the ratio of the amplitude of the generated waves to their length in the range from 0.3 to 0.5. Mechanical tests of multilayer workpieces were carried out. The shear strength of layers was from 320 to 410 MPa, the ultimate tensile strength of the main layer was from 520 to 710 MPa, the impact resistance was from 290 to 740 kJ/m2, and the bending angle under static loading was 140 degrees and higher. The authors determined the phase composition and characteristics of the crystallographic structure of transition zones of a layer metal material with an internal protector. The study identified the presence of γ-Fe with a face-centered crystal lattice, two cubic structures, one hexagonal, and one orthorhombic. On the samples with artificial pitting, the authors determined their influence on the rate of anodic dissolution of a protective layer when contacting with an aggressive environment. The study shows that the interlayer boundaries with a homogeneous structure and minimal thickness have the highest corrosion resistance.