4 Hi Skin Pass Mill: A Key Equipment for Improving the Surface Quality and Performance of Strip Steel

The 4 hi skin pass mill is one of the important equipment in the production of cold-rolled strip steel, mainly used to improve the surface quality, mechanical properties, and plate shape of the strip steel. It plays an indispensable role in the steel industry, especially in the production of high-end strip steel products. This article will provide a detailed introduction to the working principle, structural characteristics, application advantages, and importance of the 4 hi skin pass mill in steel production.

What Is a 4 Hi Skin Pass Mill？

The 4 hi skin pass mill is a cold rolling equipment typically used for light pressing of annealed strip steel. Its core structure includes two working rolls and two support rolls, which process the strip steel through light pressing (usually with a pressing rate of 0.5% -3%). Unlike traditional cold rolling mills, the main purpose of Skin Pass Mill is not to significantly reduce the thickness of the strip steel, but to improve the surface quality, mechanical properties, and plate shape of the strip steel through light pressing.

The Working Principle of the 4 Hi Skin Pass Mill

The working process of the 4 hi skin pass mill mainly includes the following steps:

1. Uncoiling: Feed the annealed strip steel coil into the unit.

2. Light pressure processing: The strip steel is processed by light pressure and tension through the gap between the work roll and the support roll.

3. Surface treatment: During the processing, the surface of the strip steel will become smoother, while removing the oxide layer and defects generated during annealing.

4. Coiling: The processed strip steel is rewound for future use or storage.

The 4 hi skin pass mill ensures the surface quality, mechanical properties, and plate shape of the strip steel meet the requirements by precisely controlling the roll gap, tension, and rolling force.

The Structural Characteristics of the 4 Hi Skin Pass Mill

1. Four roll structure:

The 4 hi skin pass consists of two working rolls and two support rolls. The work roll is in direct contact with the strip steel and is responsible for surface processing; The support roller is used to enhance the stiffness of the work roller and prevent deformation of the roller body.

2. High precision control system:

The modern skin pass mill is equipped with an advanced automation control system that can accurately adjust rolling force, tension, and roll gap, ensuring stability and consistency in the processing.

3. Lubrication and cooling system:

The 4 hi skin pass mill equipment is equipped with lubrication and cooling systems to reduce friction and heat during the rolling process, extend roll life, and improve the surface quality of the strip steel.

4. Plate shape control device:

By using devices such as bending rollers and tilt adjustment, the 4 hi skin pass mill can effectively improve the shape of the strip steel and eliminate defects such as wavy edges and warping.