Increasing of durability of mechanical seals of oil and gas centrifugal pumps using tungsten-free cermet with Cu-Ni-Mn binder

Abstract

Abstract The rational materials selection for friction pairs is an important prerequisite in promoting of reliable operation of mechanical seals used in centrifugal pumps. The experience of mechanical seals exploitation shows that most preferable is combination of “hard” and “soft” materials. As “hard” materials ceramics based on SiC, Al2O3, Si3N4, are the most commonly employed and for “soft” materials metal alloys, composites and carbon materials are widely used. In this study chromium carbide based composite metal-ceramic material with copper-nickel-manganese binder was developed for using in mechanical seals rings friction couples with silicon carbide (SiC) ring. Metal-ceramic sealing rings were manufactured by infiltration of pre-sintered porous chromium carbide skeletons with Cu60-Ni20-Mn20 melt at 1150 °C in protective (argon) atmosphere. Results of experimental investigations and theoretical modelling of heat transfer during friction, show significant advantages of proposed materials combination over ceramic-ceramic pairs through its better tribological characteristics and resistance to thermal shock. Industrial testing allows us to conclude that using of mechanical seal rings of proposed materials combination almost completely prevents failures of sealing rings surfaces caused by thermal cracking.