Selection of the most favorable hard-facing technology based on metallographic and tribological investigations

Abstract

Damage to the working parts of machines and equipment in operation is inevitable and cannot be avoided. These are complex tribological processes. In environments where operating conditions are more rigorous, changes in the shape of working parts occur due to friction, wear, impact forces, elevated temperatures, corrosion, and other influencing factors; thus, after a certain period, the working part must be replaced or reconditioned. To eliminate downtime-often of expensive equipment-the part can be replaced with a new one or repaired by welding and returned to the production process. Procurement time is often very long, depending on the mass and geometry of the part, which is why repair hardfacing is frequently used to shorten downtime. This paper, using a specific example, made of a special type of cast steel, details the correct selection of the most suitable filler materials, welding processes, and optimal welding technology for a critical working part with a relatively short service life. First, model tests are carried out on test specimens by hardfacing with various filler materials. The obtained results are then evaluated, primarily based on metallographic examinations and tribological tests. Based on these results, the most favorable technology is selected and "transferred" to the actual part. The final choice of technology is made by monitoring the working part under real operating conditions.