The rolling mill step pad is a key component in the rolling mill equipment, mainly used to adjust the gap between the rolling rolls, control the thickness of the rolled piece, and optimize the stability and product quality of the rolling process. Its core role is reflected in the following aspects:

1、 Thickness adjustment and precision control

1. Dynamically adjust the gap between the rolling rolls

The step pad is driven by a hydraulic system, which can achieve rapid switching or continuous adjustment between the steps, thereby accurately controlling the gap (i.e. roll gap) between the upper and lower rollers.

For example, in the production of hot-rolled strip steel, the adjustment accuracy of the step pad can reach ± 0.01mm, ensuring that the thickness of the rolled piece meets the design requirements.

2. Compensate for roll wear and thermal expansion

During the rolling process, the surface of the rolling mill rolls will wear due to friction and high temperature, and the roll diameter will change due to thermal expansion. The step pad compensates for these changes by adjusting the roll gap in real time, maintaining the stability of the thickness of the rolled piece.

Data support: According to statistics from a certain hot rolling plant, the fluctuation range of rolled thickness has decreased from ± 0.15mm to ± 0.05mm after using step pads.

2、 Process optimization and adaptability improvement

1. Quick switching of multi specification products

The stepped design of the step pad allows the rolling mill to quickly switch between rolling specifications of different thicknesses by adjusting the position of the step pad without stopping.

Case: In the production of cold-rolled silicon steel, the step pad can switch the thickness from 0.35mm to 0.50mm within 5 minutes, significantly improving production efficiency.

2. Adapt to different rolling process requirements

Reversible rolling: In a reversible rolling mill, step pads can be used in conjunction with roll reversal to achieve bi-directional rolling while maintaining roll gap accuracy.

Continuous rolling mill: In the continuous rolling mill, the step pad is linked with the AGC (automatic thickness control) system to achieve coordinated thickness control between multiple stands.

3、 Equipment protection and extended lifespan

1. Disperse rolling force and reduce local stress

The stepped pad contacts the memorial archway and roll bearing block in a large area to evenly distribute the rolling force and avoid equipment damage caused by local stress concentration.

Comparative experiment: after the use of step cushion, the peak stress of the memorial archway window is reduced by 40%, and the crack occurrence rate is reduced by 60%.

2. Absorb vibration and impact

The elastic elements of the stepped pad (such as the pressure equalization pad) can absorb vibrations and impacts during the rolling process, protecting the rolling mill transmission system and bearings from dynamic load damage.

Effect: After using step pads in a certain medium thick plate rolling mill, the fatigue life of the main drive shaft was extended by more than twice.

4、 Special function extension

1. Shape control assistance

In the six high rolling mill, the step pad can be used in conjunction with the intermediate roll bending device to improve the plate shape by adjusting the roll gap shape (such as controlling edge waves and middle waves).

Application: In the production of automotive panels, the linkage between step pads and bending roller systems reduces the defect rate of panel shape from 8% to below 2%.

2. Temperature compensation function

In high temperature rolling (such as hot rolled stainless steel), the step pad can compensate the thermal deformation of the roll and memorial archway and maintain the stability of the roll gap through the matching design of the thermal expansion coefficient.

Data: After using step pads on a stainless steel hot rolling line, the thickness difference between the head and tail of the rolled piece decreased from 0.2mm to 0.05mm.

5、 Typical application scenarios

1. Hot rolled strip production line

The combination of stepped pads and AGC systems of roughing and finishing mills enables continuous rolling from 150mm thick slab to 2mm thin strip, with a thickness accuracy of IT7 level.

2. Cold rolled silicon steel production line

The step pad is adjusted at high frequency (more than 10 times per second), combined with a laser velocimeter and tension control system, to produce high magnetic silicon steel with a thickness tolerance of ± 0.005mm.

3. Medium thick plate rolling mill

The stepped pad is linked with the hydraulic pressure reduction system to achieve large reduction rolling (single pass reduction rate can reach 30%), while controlling the uniformity of plate thickness within ± 0.1mm.

6、 Technological development trends

1. Intelligent upgrade

Integrate displacement sensors and pressure sensors to achieve real-time monitoring and adaptive adjustment of the state of the step pad.

Case: A certain intelligent rolling mill automatically optimized rolling process parameters through step pad data feedback, reducing energy consumption per ton of steel by 5%.

2. Application of composite materials

The stepped pad is manufactured using a composite plate with carbon steel base and stainless steel coating, which balances strength and corrosion resistance, and extends the service life to more than 10 years.

3. Lightweight design

By topology optimization and finite element analysis, the material usage of non critical parts of the step pad can be reduced, resulting in a decrease in the overall weight of the rolling mill (by 15% -20%).