Research of the microstructure features of rolled specimens made of 08YUR steel with an estimate of its effect on hydrogen accumulating for determining the “fish scale” defect tendency which is formed on enameled rolled products

This article examines the reasons for the formation and factors influencing the development of such a defect as “fish scales”. This effect is the main problem of enameled products that have found wide application in the domestic environment. The defect “fish scales” is a detachment of enamel from rolled metal. The appearance of delamination leads to the appearance of crescent-shaped depressions in the enamel layer, which remain in the places of enamel rebound. Rebound points (or as they are called: gouges) reach 1-10 mm in width and can violate both the surface integrity of the enamel layer and the metal. On the basis of research by Klerding, Hoff and others, it was determined that “fish scales” originate due to the pressure of hydrogen gas, which is released from the metal. The reason for the formation of hydrogen accumulations is due to the technological parameters of the preparation of the material, the composition of the enamel, etc. Within the framework of this work, studies were carried out to determine the degree of dependence between the indicators of hydrogen absorption and the chemical composition of samples prepared for testing. The studies were carried out on enamelled samples of 08YuR (chemical composition: 0,04-0,07% C; 0,32% Mn; 0,04% Si; 0,020% S; 0,015% P; 0,02% Cr; 0,02% Ni; 0,050% Cu; 0049% Al; 0,0063% B) grade steel with different hydrogen embrittlement indices. After carrying out metallographic tests of the samples under study using a metallographic inverted microscope, X-ray microscopic analysis, it was found that with an increase in the percentage of carbon and manganese, the indicator of the tendency of steel to hydrogenation increases, which increases the resistance to the formation of a “fish scales”. There is an inverse relationship between the content of nickel, molybdenum, niobium and the propensity of the metal to hydrogen saturation, that is, the propensity to hydrogen saturation decreases with an increase in the content of these elements.