Cold Rolling is most often used to decrease the thickness of plate and sheet metal. It is a method of cold working a metal. When metal is cold worked, microscopic defects are nucleated through out the deformed area. These defects can be either point defects (a vacancy on the crystal lattice) or a line defect (as extra half plane of atoms jammed into a crystal). As defects accumulate through deformation, it becomes increasingly more difficult to slip, or the movement of defects, to occur. This results in hardening of a metal.

If enough line defects accumulate, a grain may split into two or more grains in order to minimize the strain energy of the system, When large grains split into small grains and the alloy hardens. If cold work is continued, the hardened metal may fracture.
During cold rolling, metal absorbs a great deal of energy, some of this energy is used to nucleate and more defects (and subsequently deform the metal). The remainder of the energy is released as heat.

A metal that has been hardened by cold rolling can be softened by annealing. Annealing will relieve stresses, allow grain growth and restore the original properties of the alloy. After annealing, the metal may be further cold rolled with fracturing i.e. Tempering or Skin Pass rolling.

Cold rolled metal is given a rating based on the degree it was cold worked. “Skin rolled” metal undergoes the least rolling, being compressed only 0.5 – 1.0 % to harden the surface of the metal and make it more easily workable for later processes. Higher rating are quarter hard, half hard and full hard, in the last of these, the thickness of the metal is reduced by 50%.

- Fit to purpose solution designed according to customer internal cycle and reference market.
- Environmentally friendly solutions
- Inherently safe equipment which is easy to maintain.
- A high level of automation to reduce manpower and improve plant performance.
- A design able to meet markets medium and long term market requirement.

An answer to the above requirement is a new stand design that give the plant operator high flexibility to cope in an easy and competitive way, with all the different expectations of their customers. ASML has selected the 4 high Cold Rolling Reversible Mill having the above characteristics.

The automotive industry is one of the most demanding market area for Cold Rolled sheet and in last 10 to 15 years a variety of new steel grades had to be developed to answer to the need coming from this important sector of the world economy. The automotive industry requires continuous progress in safety, fuel economy, dent resistance and comfort. However, safety and comfort involve supplementary equipment and can be in contradiction with the pursuit of high car body weight. In order to solve this contradiction, formability and high strength requirements increase continuously leading to the development of new steel grades.

The steel producers have invested heavily in research activity to satisfy these needs and to protect the use of steel against other materials such as alumunium, Now, at the beginning of new millennium, we can say that battle against the material competitors has been won.

On the other hand, the request of both hot and cold mill operators for softer and harder grades in the same plant is pushing existing plant above their design limits. This in turn, is pushing plant suppliers to find the most economical and flexible ways to update plants or to invest in new mills.

The newly developed rolling stands the answer to the production of new steel grades mainly for the automobile industry. It has the following advantages:

Aisha steel mills comprises of the following main technology components:

The push - pull pickling line besides removing the scale remaining on the material following in the previous hot process, (Hot Rolled Coil) also trims the edges of the Hot Rolled Process Strip to be sold in as Hot Rolled and Pickled Condition.

The Push Pull Pickling Line Process is Characterized by high turbulence in the pickling bath to improve the efficiency of scale removing.

The Cold Reversing / Skin Pass mill is the link between a rolling mill and a temper mill that increases the flexibility of this mill.

The four high stand configuration with Work Roll heavy bending system gives optimal finish shape and flatness. In Skin Pass mode the mill will demonstrate impressive results relating to shape control and mill productivity. The average shape obtained shall be better at high rolling speed. The mill coolant system has been designed to obtain high mill reduction and excellent surface cleanliness. This makes it possible to deliver the rolled coils directly to the batch annealing facilities without any need for an intermediate cleaning stage. Only a small portion of cold rolled coils meant for automobiles shall be additionally cleaned at the Electrolytic Cleaning Line.

Distinctive characteristic of the Batch Annealing Facility is the operation in Hydrogen atmosphere generated by means of the supplied hydrogen plant.

The Recoiling line has the double function of inspecting the coil and correcting the material flatness by means of the tension levellor installed.

With above mentioned characteristics Aisha Steel Mills Limited will be a state of Art High Tech Cold Rolling Mill. It will be located in Pakistan Steel Downstream Industrial Estate.

It will Produce 220,000 metric tones of cold rolled coils in the first phase which will subsequently be increased to 350,000 metric tones in the second phase. A portion of this cold rolled will also be galvanized in the second phase.

Aisha Steel shall be targeting the automotive, engineering and home appliances industry for its products and will produce cold rolled coils ranging from 0.15 mm to 1.5 mm thickness.