Influence of Heat Treatment on the Key Service Properties of Built-Up Welding Layer on Pinch Rollers

In order to meet the needs of pinch rollers and prolong the service life, investigations were conducted on the Stellite delstain-442 built-up welding layers in use and the proposed replacement of Stellite Multipass-249 and Stellite Multipass-224HC built-up welding layers. The microstructure and fracture morphology of three different materials after different heat treatment temperatures were observed. The variations of high-temperature mechanical properties under different test temperature were compared. The results indicated that the brittleness of 249 and 224HC built-up welding layers was quite high and limited their applications in pinch roll system although the anti-wear properties and surface hardness of 249 and 224HC were superior relative to 442. For now, the comprehensive performance of 442 built-up welding layers was more suitable to be applied in pinch roll system, but further modifications on 442 built-up welding layers must be carried out to gain more excellent mechanical and anti-wear properties based on sacrifice of partial plasticity through composition regulation, microstructure regulation and optimization of heat treatment.