4段式圧延機用複合ワークロールにおける圧延中の内部応力と疲労損傷評価

抄録

In hot rolling mills, bimetallic rolls consisting of HSS and DCI are extensively used because of their excellent hardness and wear resistance although fatigue failure study is not available. To extend the roll life service, in this study, a three-dimensional finite element method is applied to investigate the rolling stress of the work roll in the four-high rolling mill. To clarify the mechanical stress, zero residual stress is assumed. Then, the fatigue strength is discussed by focusing on several critical points inside of the work roll. The effect of the crown profile at the backup roll surface is clarified as well as the effect of the wear profiles at the work roll surface. It may be concluded that the most critical point is located at the HSS/DCI boundary point B₀²⁷⁰ where (r,z)=(270 mm,0) because the largest stress amplitude appears due to the contact of rolled steel. Another critical point is located at B₇₅₀²⁷⁰ where (r,z)=(270 mm,750 mm) due to the contact of backup roll.