Обеспечение высокой стойкости к межкристаллитной коррозии холоднокатаных труб из стали 02Х18Н11 (304L)

Problem definition. Currently, it is necessary to develop scientifically substantiated technological measures ensuring high resistance to intergranular corrosion (IGC) of cold-rolled tubes made of 02Cr18Ni11 (304L) steel. Methodology. Methods of optical metallography, chemical analysis, tests of IGC resistance according to standard GOST 6032 and mechanical properties (tensile tests) were used. Findings. Structure, chemical composition and resistance to IGC of tube billets made of imported 02Cr18Ni11 steel were investigated. It was established that microquantities of boron admixtures (0,0025 %) had a negative influence on resistance of 02Cr18Ni11 steel to IGC in strong oxidizing media. Processes of structure formation in the course of production of hot-extruded and cold-rolled tubes and their influence on IGC resistance were investigated. Corrections to thermal treatment and deformation schedules in making cold-rolled tubes were introduced. High resistance of commercial tubes to IGC was ensured. Originality. Scientific ideology based on literature analysis, theory and practice of tube production and the grain boundary engineering principle was proposed and realized which made it possible to increase IGC resistance of tubes made of chrome-nickel austenitic steels. Practical value. Results of this research work were introduced at PJSC «Centravis Production Ukraine», Nikopol. Actual economic effect measures ≈ 1,500,000 hryvnias.