Learn cold rolling mill components, functions and maintenance

Cold rolling mills mainly roll coils or pickled steel from pickling lines with cooling oil at ambient temperature. Cold rolling mills produce steel and stainless steel, aluminum, foil and copper. There are many types of rolling mills, such as 2-High, 4-High, 6-High, 12-High, 20-High, Sendzimir mill, etc. (there are many types in terms of shape control operation).

Cold rolling mill composition

A cold rolling mill is generally composed of a working mechanism and a transmission mechanism.

The working mechanism is composed of frame, roll, roll bearing, roll adjustment mechanism, guide device, rolling seat and other parts.

The transmission mechanism is composed of a gear frame, a reducer, a roller, a coupling shaft, a coupling and other parts.

Cold rolling machine working principle

The cold rolling mill uses an electric motor to drag the steel bar, and the load-bearing roll and the work roll of the cold rolling mill jointly apply force to the two sides of the steel bar. The purpose of rolling out cold-rolled ribbed steel bars with different diameters is achieved by changing the size of the gap between the two rolls.

Bearing roller: The bearing roller of the cold rolling mill is the one closest to the stand. When producing ribbed steel bars, this roller plays the role of supporting the steel bars and evenly dispersing the gravity of the steel bars and the work rolls. On the load-bearing roller, so that the lower surface of the steel bar is ribbed.

Work roll: The work roll of the cold rolling mill is on the top of the load-bearing roll, which is the farthest from the stand, so the roll mainly plays the role of rolling the steel bar supported by the load-bearing roll when producing ribbed steel bars. As a result, ribs are formed on the upper surface of the steel bar.

Cold rolling mill machine advantages

In the process of rolling cold-rolled ribbed steel bars, the cold-rolling mill equipment can cold-work the warp, weft and direction of the base material at the same time. At the same time of pressing, it still retains enough elongation performance, so that the geometric parameters and four material indicators of cold-rolled ribbed-rolled steel bars can be used in important industrial and civil buildings with first-class safety level, saving steel consumption and reducing building prices; among them The geometric parameters refer to the flattening thickness of the steel bar, the section width-thickness ratio, the area reduction ratio and the pitch, and the material indicators refer to the tensile strength, the conditional yield value, the elongation and the cold bending ratio.

Rolling mill plant main functions

1. Convexity, Flatness and Edge Drop Control

The crown, flatness and edge drop controls determine and correct the frame through feedback measurements from the flatness sensor and edge sensor, maintaining strip flatness and quality.

2. Automatic Thickness Control (AGC)

The automatic thickness control system precisely controls the strip thickness by means of the rolling force and speed of the stand from one or more thickness and speed sensors. Common velocity types include feed-forward AGC, feed-back AGC, and mass flow control.

3. Roller Eccentricity Compensation Control (ECC)

Eccentricity compensation control reduces the effects of backup roll irregularities. ECC uses pattern recognition technology to modify the gap position to compensate for roller eccentricity.

4. Tension Control

Tension control optimizes the strip tension between the stand, uncoiler and tension coiler, resulting in a high-quality product.

5. Continuous thickness variation (FGC)

Continuous thickness variation may perform the control operations required to achieve a smooth transition from one tape thickness to another. Typically, these product thickness changes will be done at the weld or cut point between coils.

6. Cold Mill Setup (CSU)

The cold mill setup calculates the reference and gain values for the process regulator used to roll a specific product. Process references are optimized to provide distribution of power, pressure and tension between the frames to produce high quality products. These reference values include speed, tension, force and thickness settings. Gain values include gains for the thickness and tension control system.

Steel rolling mill maintenance

1. The electrical parts of the cold rolling mill should always be cleaned of dust and debris.

2. The moving parts should be checked frequently to see if the tightening is loose and reasonable.

3. Before starting each shift, check whether the electrical system of the cold rolling mill is normal, and check each oil tank, including whether the oil level is normal, and whether the oil filling parts are filled with oil.

4. During the production process of the cold rolling mill, it cannot be used beyond the limit to avoid damage to some mechanical parts of the cold rolling mill. It should be rolled according to the rolling standard to ensure the safe use of the cold rolling mill equipment and the qualification of the products.