Classification and selection of rolls

1. Classification of rolls

There are many ways to classify rolls, the main ones are:

1) According to product types, they include strip steel rolls, profile steel rolls, wire rod rolls, etc.;

2) According to the position of the rolls in the rolling mill series, they are divided into blank rolls, rough rolls, finishing rolls, etc.;

3) According to the roller function, it can be divided into scale breaking roller, perforated roller, smoothing roller, etc.;

4) According to the roll material, there are steel rolls, cast iron rolls, carbide rolls, ceramic rolls, etc.;

5) According to the manufacturing method, there are cast rolls, forged rolls, cladding rolls, nested rolls, etc.;

6) According to the state of the rolled steel, it is divided into hot rolling rollers and cold rolling rollers. Various classifications can be combined accordingly to give the rolls a clearer meaning, such as centrifugally cast high chromium cast iron work rolls for hot rolled strips.

2. Selection of rollers

Commonly used roll materials and uses are shown in the table. The performance and quality of a roll generally depends on its chemical composition and manner of manufacture and can be assessed by its organizational, physical and mechanical properties and the type of residual stress present inside the roll (see Roll Inspection). The use effect of rolls in rolling mills not only depends on the roll material and its metallurgical quality, but also on the usage conditions, roll design, operation and maintenance.

The use conditions of rolls in different types of rolling mills are very different. The factors causing the differences are:

1) Rolling mill conditions. Such as rolling mill type, rolling mill and roll design, pass design, water cooling conditions and bearing types, etc.;

2) Rolling conditions such as rolled product varieties, specifications and deformation resistance, reduction system and temperature system, output requirements and operations, etc.;

3) Requirements for product quality and surface quality, etc.

Different types of rolling mills and rolling mills of the same type with different operating conditions have different performance requirements for the rolls used. For example, the billet and slab blooming mill rolls must have good torsional and bending strength, toughness, bite, and heat resistance. Crack resistance, thermal shock resistance and wear resistance; while the tropical finish rolling stand requires high hardness of the roll surface, resistance to indentation, wear resistance, resistance to spalling and resistance to thermal cracking.

Leave a Reply

Your email address will not be published. Required fields are marked *