Back up roll is generally of large size and heavy weight. It is hard to be manufactured. Back-up roll is used to support work roll by reducing the work roll's diameter and enhancing its rigidness. It helps to reduce the deformation of work roll thus enhancing the plates' precision and quality. With the roll's surface contacting with work rolls for a long service time, back-up roll have to bear large contact stress and shear stress, the 2 forces of which will cause back-up roll to get deformed or worn.

Back-up roll works to undertake rolling pressure, so it must be competent in strength, heat resistance and abrasion resistance. Our production line for rolling mill rolls mainly includes smelting, forging, heat treatment, flaw detection, and machining. The rolls are manufactured in accordance with JB/T 6401-1992 large forged rolls standards.

Common materials
Cr3, Cr5

Manufacturing Process
Smelting – Forging – Heat Treatment after Forging – Roughing – Preliminary Heat Treatment – Final Treatment – Finishing – Packaging

Quality Control
1. Apart from the required chemical elements, we have strictly tested some harmful elements such as P, S, Pb, Sn, As, Sb, and Bi, as well as some gas or non-metallic debris like H, O, and N in the selting process.
2. Strict forging technique is required to meet the nondestructive testing requirements. The forged blanks will be given normalizing and spheroidizing treatment to refine the grains and remove the network carbides, and get a spherical pearlite structure.
3. Preliminary and surface heat treatment is conducted on materials to achieve great comprehensive mechanical properties, and high toughness of back-up rolls.
4. CNC equipment is adopted for high processing accuracy.

Features of Back-Up Rolls
1. The back-up rolls made by TongYu are of high compressive strength and rigidness to bear the large rolling force and the peak load.
2. With good toughness, the back up rolls won't go broken or cracked easily.
3. The back-up features good wear resistance and fatigue resistance.
4. It is designed with uniform structure and hardness.