The main phases in the iron and still manufacturing process are:

• crusching and screening
• sintering and pelletizing
• continuous melt
• rolling

Crushing and screening:

The blocks of minerals extracted from the mines and quarries are usually very irregular and need reshaping to obtain acceptable and uniform dimensions.

The reshaping is achieved by means of two different manufacturing phases: crushing first and screening later.

Special bearings are used in the manufacture of those elements; bearings subjected to considerable  bumps and radial accelerations whose housing are generally stressed in a considerable way; bearings pushed to the maximum allowed rotation speed.

Not to forget the external working environment in which the bearings are used - usually a very wet and dusty one – not suitable for an optimal use of bearings.

Sintering and pelletizing:

The mineral, broken into very small pieces, is supplied in the blast furnace through the top of the furnace itself.

Depending on the consistency of the material different terminologies are used: sintering or pelletizing.

Sintering is referred to minerals whose dimension is higher than 0.3 mm.

Pelletizing is referred to minerals whose consistency is very similar to dust from which small spheroids (10-20 mm diameter) are obtained.

The working conditions are usually characterized by high loads, high temperatures, low speed and an extremely polluted environment.

Continuous melt:

At the end of the process in the furnace the steel is poured in a ladle firstly and in a tundish later on. Finally it is transferred, through appropriate flues, to the ingot moulds.

The ingot mould walls are made of copper; they are cooled by means of water to rapidly waste the heat.

A cooling system, a dragging system, a straightening system and finally a cutting system are positioned below the ingot mould.

The final outcome of the continuous melt process is called billet or slab.

Extrememly high working temperatures (about +900° C out of the cooling plant), heavy loads, humidity and dust are typical aspects in this phase of steel production.

Rolling:

After trimming the billets are stored and sent to the rolling plant.

The objective of the process is to permanently deform the metal (plastic deformation).

The result can be obtained through hot or cold rolling.

Hot rolling is the typical process almost all the metals undergo before undergoing other manufacturing processes.

This is mainly the reason why it is considered the first step in the process chain to turn the metal into a finished good.

The bearings mounted in the rolling stands are generally suitable for heavy loads and bumps, high vibrations, high temperatures and extremely high rotation speed.

Used bearings: