INFLUENCE OF PVD TI/TIN COATINGSON FAILURE MODES OF CR12MOV MANDREL ROLL IN COLD RING ROLLING

• 作 者: HuaLin;JiaGcngwei;MaoHuajie;ZhaoYumin;
• 机 构: Department of Mechanical Engineering,Wuhan University of Technology
• 出 处: INternational Conference on Product Design and Manufacturing
• 发表日期: 2007年期

　　Cold ring rolling is a kind of advanced green manufacturing technology and the mandrel roll is one of the most important parts in cold ring rolling facility.In this paper,the failure-mechanism of Cr12MoV mandrel roll is studied and compared respectively with that before and after PVD Ti/TiN Coating by using SEM,EDS and TEM and etc.The results show that main failure mode of mandrel roll is surface fatigue wear before PVD Ti/TiN Coating which fatigue cracks initiate at the site of surface or sub-surface defects.But for the mandrel roll after PVD Ti、TiN Coating failure mode transfers into fatigue fracture.Such kinds of fatigue cracks always initiate at sub-surface defects and the morphology of carbide in subsurface layer plays an important role for fatigue cracks initiation.The morphology of carbide in sub-surface layer can be changed due to PVD Ti/TiN Coating during rolling which is beneficial to improve the service life of mandrel roll.