Adopting YJ356-S and YJ358-S welding wires developed by Welding Research Institute of MCC, the wrapper rolls and deep camber rolls used for rolling mill are repaired,and the surfacing technologies are par- ticularly researched.

Withdrawal roll and wrapper rolls were strengthened by build-up welding against their short- life,using PYY125 tube welding wire+SSD welding flux as build-up welding materials.

By analyzing wrapper roll's AJC action and control,the AJC system is designed and its mathematic modeling,emulation analysis and analogue loading verification are conducted.

The paper introduces a hot strip coiler with hydaulic wrapper rolls ciupled with new coiling process,which operates with position control and pressure control,and can affored to autostep,so,its configuration will be more compact.

Based on theoretical analyses and experiments,main reasons have been discovered that cause excessive impact load on the wrapper roll of down coiler.

The study on the positional parameters of the forming roller and the supporting roller in coilbox;