Roll: description, production technology and plants

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

Metallurgy is one of the main branches of modern production. It is thanks to it that colossal financial revenues go to the state budget, because steel and iron products, as a rule, are exported and form the foreign exchange earnings of both the plant or plant itself and the country. There are various metallurgical enterprises, the working cycle of which can be both full and incomplete. But in any case, the final stage of the metallurgical cycle will be the rolling of metal in order to obtain the profile required for the consumer. It is in the rolling shops that beams, channels, rails and so on are produced. Rolls are the main elements of any rolling mill. Plants of the metallurgical complex are simply unthinkable without them, so we will talk about rolls in detail in this article.

General Description

Metal rolling is a rather complicated, energy-intensive operation that requires special skills and knowledge from the staff. Compression of the material, which produces a rolling roll, allows you to achieve certain dimensions of the processed profile. It is important to know that the rolls in the process of their work take on an impressive force that occurs directly in the process of the entire rolling line. That's whyThe rolling roll is the most worn part of any rolling mill.

Parts and Features

All rolls have three main components, including:

• Barrel roll. It is she who is in direct contact with the hot and processed metal. The barrel has two main linear parameters - length (L) and diameter (ØD).
• Necks (bearing parts) - located on the sides of the barrel and rest on the roll bearings. Also characterized by length and diameter.
• Drive end.

For a rolling mill, the main indicators are: nominal diameter, collar diameter and working diameter. Where the roll is to be rotated by a universal type spindle, its drive end will be in the form of a blade or a cylinder. The drive end will have a type of cross if the rotation of the roll with the help of a club is provided (the presence of an intermediate coupling is required).

Rolls for sheet metal

Sheet rolling rolls, the manufacture of which is a rather laborious process, perform rolling of strips and strips. The barrel of such rolls is smooth, made in a cylindrical shape.

Section rolls are used for the manufacture of shaped material, which can have both round and square sections (I-beams, corners).

Barrels of rolling rolls are made slightly convex if they are intended for cold rolling of thin sheets. ATIn other cases, for hot rolling, the roll barrel is given a concave shape. This is done because at the moment the metal moves along the roll, the barrel will heat up and straighten.

Rolls for long products

The barrel of such rolls has special recesses (streams), which repeat the profile of the metal subsequently rolled. The streams of a pair of rolls, when connected to each other, form a caliber. The barrel length of the profiled rolls depends on the width of the rolled workpiece and the sizing conditions.

Short rolls are characterized by nominal diameter and barrel length. If the mill has many stands and rolls of different diameters, then the diameter of the finishing stand rolls will be dominant.

According to purpose, varietal rolls are divided as follows:

• For heavy duty swaging mills.
• For heavy section and rail beam mills.
• For medium sections.
• For small sections.
• For wire mills.
• For strip mills.

Centrifugal casting

Modern production of rolls as one of the main methods involves the method of centrifugal casting. This method is very expensive, but it fully allows to compact to the maximum the structure of the metal of the outer surface, which is the working one at the roll. This approach can significantly increase the service life of the product.

For this method, a special machine is used, which has a horizontal axis of rotation of the formcentrifugal casting. The form itself is mounted on support rollers. The drive rollers are mounted in such a way that they fully ensure the synchronization of the rotation process. The safety roller located at the top has a gap relative to the rolling rim of the form itself. There are damping pads between the rollers and the hub to absorb vibration. Reducing the level of vibration and shape fluctuation reduces the likelihood of marriage to zero.

Casting of rolls by centrifugal method is carried out from high-alloy cast iron. Metal is poured into a mold rotating around its vertical axis, the volume of which is within 95% of the entire volume of the working layer of the rolling roll.

The indisputable advantages of centrifugal casting are:

• Ensuring high swath density.
• Improve roll wear resistance.
• No shells, voids, non-metallic inclusions, slag.

Forging method

This is the most expensive method of producing rolls, which nevertheless makes it possible to strengthen the entire body of the roll as much as possible. This greatly improves reliability and durability.

Forging itself is carried out on special automated complexes designed and manufactured using advanced technologies. The capacity of these units can be up to 150 MN.

The rolls obtained in this way are most often used in blooming and slabbing, as well as section mills. These steel rolls have an increased coefficientfriction at the moment of contact with the rolled workpiece. This nuance is extremely important for high reduction stands.

Forging itself involves the following operations:

• Ingot Billeting.
• Draft.
• Broach.
• Forging to the size of the forging.

The processing of rolls after forging involves complex heat treatment, the final stage of which is certainly surface hardening and tempering.

Titanium production

Today Russia is one of those countries that regulate the world market of steel and alloys. Therefore, the closest attention is paid to the creation of components and parts for metallurgy in the country. In particular, the Magnitogorsk Rolls Plant is one of the leaders in the production of these products.

In July 2016, new high-performance crucible induction furnaces were launched at this enterprise. These high-tech units will make it possible to produce complexly alloyed alloys and reduce the amount of consumed ferroalloys and charge. At the same time, the reduction in electricity consumption will be about 10%. The melting mode can be carried out with a frequency of 250 Hz, and finishing and mixing - with a frequency of 125 Hz. Compliance with environmental requirements is also important: these furnaces will reduce harmful emissions by 2.6 times.

In general, the Ural enterprise regularly supplies the roll market with its products and is an actively developing enterprise.

Sverdlovsk giant

You can't ignore the Kushvinsky plant of rolling rolls. Its products are all types of rolls, bandages for them. At the plant, rolling mill rolls are produced using working layer materials such as:

• Indefinite.
• Indefinite improved with special carbides.
• High Chrome Iron.
• High Chrome steel.
• HSS.

The necks and the core of the plate-rolling rolls are produced from extra strong cast iron.

Rolls for section rolling mills are produced on the basis of bainitic and pearlitic alloy cast irons with nodular or lamellar graphite.

Ukrainian producers

There are three main roll mills in Ukraine: Dnepropetrovsk, Lutuginsky and Novokramatorsk roll mills.

Dneprovsk plant has the widest range of roll production, not only for metallurgy, but also for other industries. Very often, the company works for a specific customer, involving its highly qualified specialists from the technical department to create various drawings and new models of rolls.

Before the outbreak of hostilities in the Donbass in 2014, the Lutugino Rolls Plant was consistently among the best. Its products were supplied not only to all metallurgical enterprises of Ukraine, but also to many neighboring countries and Europe. However, the military conflict led to the fact that the plant was stopped. suffered andfixed assets of the enterprise. But still, in 2015, the company managed to re-launch the enterprise, and today it has begun to receive orders from the Russian Federation.

Quality control of swaths

In the process of production, absolutely every rolling roll without fail passes the procedure of technical quality control of its manufacture. Particular attention is paid to:

• The chemical composition of the source material.
• Analysis of the structure of the material of the product (roll).
• Analysis of centricity and geometric dimensions.
• Controlling the degree of hardness of the working layer of the roll.
• Control the degree of roughness of the working surface.
• Analysis of the metal structure of the surface layer.

Packaging

All rolling rolls (factories producing them have appropriate quality certificates) are delivered to the consumer in special packaging. This container often consists of wooden boxes with partitions, inside which rolls are laid and securely fastened with tie elements. Manufacturers also pay close attention to the packaging container, because poor fastening of the rolls and the lack of proper protection of the working and seating surfaces of an industrial product may well lead to negative consequences in terms of the quality of the rolls.

Conclusion

Rolls, the production technology of which was discussed in detail above, have a significant impact on the products obtained with their help. Therefore, the world's leading manufacturersrentals pay special attention to this element. Each head of a metallurgical enterprise is well aware that the final profitability of the entire production will largely depend on the technical condition of the rolling mill as a whole and rolling rolls in particular.