Study on cast-weld process and composite interface of bimetal composite roll sleeve

Abstract

A new method, named bimetal cast-weld composite process, was used to produce the roll sleeves in this works. The roll sleeves comprised the flexible low alloy steel (LAS), the low melting point cast iron surfacing layer (Surfacing layer) and the hard high chromium cast iron (HCCI). The microstructure and mechanical properties of bimetals were characterized. Results showed that the melting point of surfacing layer varied gradiently in range of 1249–1463 °C. When the casting process was finished, surfacing layer disappeared. A straight metallurgical composite layer between LAS and HCCI was formed by controlling the temperature field, which was composed of pearlite. Besides, the microhardness value from LAS to HCCI had a smooth transition, and the impact fracture location was about 6.4 mm away from the composite layer at HCCI. Notably, the diffusion of C atoms and Cr atoms occurred on composite layer, whose diffusion direction was from HCCI to LAS. The width of composite layer was about 20 μm, and no defects such as micro-holes and inclusions were observed.

Keywords

• Microstructure characteristics
• Bimetal
• Surfacing layer
• Interface
• Composite layer