Residual Deflection Mechanism for Back-Up Roll Consisting of Shrink-Fitted Sleeve and Arbor

Abstract

First, back-up rolls for rolling require toughness, particularly in the shaft portion, and high-hardness in the sleeve portion. The back-up rolls are classified into two types; one is a single-solid type, and the other is a shrink-fitted construction type consisting of a sleeve and an arbor. The shrink-fitted back up roll has several advantages, for example, different materials can be chosen and the arbor can be reused by replacing the damaged sleeve. Therefore, the shrinkfitted back-up rolls are economical. However, residual deflection becomes a major problem for the shrink-fitted back-up roll. Elucidating the mechanism of the occurrence of residual deflection and devising countermeasures are important issues. Unfortunately conducting a real experiment is difficult because of much time and huge cost. In this paper, we reproduce this phenomenon by elastic FEM analysis, establish a simulation method, and elucidate the mechanism behind underlying residual deflection.

Numerical Simulation on Interfacial Creep Generation for Shrink-fitted Bimetallic Roll

“…In the previous study, 4) Noda et al have studied the relationship between slippage and residual deflection in axial direction for the back-up roll composed of the shrink-fitted sleeve and the shaft. They have indicated that the residual deflection is similar to the relative slippage between the sleeve and the shaft.…”

“…From the stress distributions τ rθ and μσ r along the shrink-fitted surface, they have discussed the relative slippage condition. 4) Eventually, they have reported that the stress quasi-equilibrium region τ rθ ≅ | μσ r | at the shrink-fitted surface causes the residual deflection. In this research, the slippage in the circumferential direction is targeted, and the slippage direction differs from the study by Noda et al (axial slippage).…”

“…Furthermore, the sleeve wear resistance can be improved independently without loosening the shaft ductility. On the other hand, this shrink-fitted structure has several peculiar problems such as residual bend deformation, 4) fretting fatigue cracks at the sleeve end and sleeve fracture due to the circumferential sleeve slippage. 5,6) The circumferential slippage sometimes occurs even though the resistance torque at the interface is larger than the motor torque.…”

Fatigue Failure Analysis for Bimetallic Work Roll in Hot Strip Mills

“…Rolling technology is developing and advancing further although seemingly mature. [ 1–13 ] Figure 1 shows the rolling roll in roughing stands of hot rolling stand mills. By replacing the conventional single‐material rolls, bimetallic work rolls are developed through improving wear resistance and heat crack resistance.…”