Design and engineering of a laboratory-industrial setup for low-temperature liquid carbonitriding with an integrated ammonia neutralization system

Abstract

This paper presents a comprehensive engineering development of a setup for surface hardening of components using non-toxic liquid carbonitriding. The technology is based on the use of potash and urea melts, which ensure the formation of a wear-resistant ε-phase at temperatures of 540–580 °C. The main focus is placed on solving the problem of technosphere safety — specifically, the localization and neutralization of surge ammonia emissions occurring during the melt regeneration process. The design of cubic furnaces with double-layer lining, a crucible made of 12Х18Н10Т steel with a gravity discharge unit, and the calculation of a closed-cycle packed scrubber with a gas purification efficiency of 98 % are described. The proposed automation system, based on PID control and gas monitoring, allows the operation of the setup in the conditions of research laboratories. Engineering results confirm the possibility of obtaining diffusion layers with a depth of up to 0.5 mm and a surface microhardness of up to 1100 HV while fully complying with environmental standards.