Experimental study on wear and friction of work roll material with 4% Cr and added Ti in cold rolling
Cold rolling is one of the most essential elements in the manufacture of flat products of metals. Work roll wear is always a topic of interest to many researchers. In this paper, the disc-to-disc tests of the material with 4% Cr and that with 4% Cr + Ti were carried out respectively under the conditions of dry contact and emulsion lubricant of 3.9% Quakerol N680-2-DPD. The wear and friction patterns were discussed by correlating the disc surface morphologies and the microstructures of both materials. The surface roughness of the disk of the material with 4% Cr + Ti deteriorates much slower than that with 4% Cr under the condition of lubrication. The material with 4% Cr + Ti is characterised as carbonitrades precipitated in a fine tempered martensite matrix while coarse carbides (M7C3) exist in the material with 4% Cr. The disk of the material with 4% Cr + Ti wears differently to that with 4% Cr. Delamination may become an important wear mechanism earlier in the case of 4% Cr than that of 4% Cr + Ti. Micro spalling and pitting occur after 120 min of wear in the case of 4% Cr, but not in the case of 4% Cr + Ti until 330 min. Detached carbides are responsible for the abrasive wear on both discs at the late stage. Ti alters the friction pattern due to surface regeneration that resulted from the abrasive effect of carbonitrades. Generally, the wear-resistance of roll material may be improved by 175% by introducing added Ti. The outcome is beneficial for developing new materials for prolonging the service life of the cold work roll.