Rolling Mill Roll Pass Formula Design

Roll pass design in a rolling mill and formulas may modify based on the kind of rolling mill (hot or cold) and the material use. It requires numerous expertise calculations as follow,

1.Roll diameter calculation. There is no common "roll pass formula" for mill roll diameter, which is determined by several factors such as the required reduction ratio, material properties, and rolling process type.

2. The reduction ratio formula. The reduction ratio (R) is (inlet thickness - outlet thickness) /inlet thickness. The ratio determines the degree of deformation in each pass and influences the rolling sequence.

3. Roll force calculation needs yield strength, friction coefficient, roll radius, and roll material reduction. A common formula is the Sims formula.

4.Pass schedule design: this design work requires the number of passes, reductions, and roll pass geometry, which is resulted in empirical data, simulation tools, and engineering judgment.

Roll pass design is a specialized field in metallurgy and mechanical engineering. It requires a detailed understanding of material behavior, rolling processes, and mechanical design principles. TINVO has the engineering experience and sources for customers’ roll pass design. Send us your requirements by email: sales@tinvogroup.com

How does the material property influence the rolling mill roll pass design?

An ideal rolling mill roll pass design is actually significantly influenced by material qualities in following factors.

1. Yield Strength and Tensile Strength
In order to make materials deformation with higher yield and tensile strengths, larger roll forces is required. This affects the strength of the rolling mill components as well as the roll diameter design. It is necessary to use larger roll diameters to achieve the higher forces.
In order to avoid too much stress on the material and the rollers, the pass schedule may need to be modified to disperse the deformation more gradually.

2. Ductility

Higher ductility materials may be shaped more easily, enabling greater reductions in each pass. If so, a simpler and fewer passes of ductile iron roll pass design is gained. If excessive ductility isn't controlled, it can also lead to issues like wavy or cracked edges. Optimize the roll pass geometry can prevent defects and ensure uniform deformation.

3. Hardness

Hard materials make design challenges for roll pass systems because it takes more energy for them to deform. The rollers materials could be sufficiently durable to resist deterioration. In order to minimize contact area and lower friction, need to modify the roll pass geometry. This can lower the forces for rolling.

4. Thermal conduction
the materials with a high thermal conductivity can release heat more quickly during rolling. This has an impact on the temperature distribution of materials and mill roll, and then could alter the characteristics and the performance of the rolls material.

The designer needs to consider the properties of heat transfer of the rolling mill roll pass design in hot rolling processes, which can guarantee appropriate temperature control and prevent flaws or cracking.

5. Grain Texture
The deformation of roll materials can be resulted in its grain structure. It seems more difficult to distort fine-grained materials than coarse-grained ones. In order to guarantee uniform deformation and reduce the chance of flaws, the rolling mill roll pass design possibly need to be modified to account for the size and orientation of the grain.