Rolling - Industrial Process - Mechanical

Summary

The video script details the hot rolling process of steel, essential for shaping due to its resistance when cold. Steel is heated to the right temperature in a furnace, then rolled between massive mill stands exerting tens of millions of Newtons. The layout of rolling mills varies, with different roll arrangements for products like flat strips or construction sections. After hot rolling, steel is cooled and may undergo cold rolling for thinner, flatter products, often with added coatings for protection and aesthetics.

Takeaways

• 🔥 Steel is resistant to shaping when cold, so it's rolled hot to ensure malleability.
• 🔧 The process involves heating steel to the right temperature in a furnace with multiple temperature control zones.
• 🏗️ Hot rolling squeezes the steel between rolls to achieve the desired thickness and shape, requiring immense forces.
• 🛠️ Mill stands, equipped with powerful electric motors and robust bearings, apply the necessary pressure during rolling.
• 🔄 Rolling mills can have different layouts, from single to multiple stands, arranged side by side or in a line.
• 📏 Mill rolls can be plain for flat products like cladding or profiled for construction sections like beams and columns.
• 🔄 Different roll arrangements are used depending on the product, such as two-high, three-high, and four-high stands.
• 🏭 Universal beam mills feature both horizontal and vertical rolls to bear on the steel simultaneously for accurate rolling.
• ♻️ After hot rolling, steel is cooled and prepared for further processing like cold rolling or dispatch.
• 🔄 Cold rolling is a subsequent process used to produce thinner, flatter products with improved forming properties and surface finish.

Q & A

Why is steel rolled while it's hot?

Steel is rolled while it's hot because it is highly resistant to shaping when cold. Hot rolling ensures the steel is at the correct temperature for shaping and rolling.

What is the purpose of the furnace in the steel rolling process?

The furnace is used to heat the steel to the correct temperature for rolling. It has several temperature control zones that the steel travels through to reach the optimal temperature.

What forces are exerted by the rolls during the hot rolling process?

During hot rolling, the rolls exert forces of tens of millions of Newtons, equivalent to the weight of thousands of tons, to achieve the desired thickness and shape of the steel.

What are Mill stands and what is their role in the hot rolling process?

Mill stands are massive bearings mounted in housings of enormous strength and driven by powerful electric motors. They are used to squeeze the steel between rolls to achieve the final thickness and shape.

How does the layout of a Rolling Mill vary?

The layout of a Rolling Mill can vary from a simple single stand Mill to several stands positioned either side by side or in a line, depending on the product being rolled.

What types of mill rolls are used for different steel products?

Mill rolls can be plain for flat products like strip used for cladding, or profiled for sections like beams and columns used in construction.

What is the simplest roll arrangement used in a rolling mill and for what type of product is it used?

The simplest roll arrangement is a two-high stand, which is mainly used for long products such as sections.

How do four-high stands differ from two-high stands in terms of roll arrangement?

Four-high stands have two work rolls in contact with the steel supported by larger backup rolls. This arrangement prevents distortion caused by the rolling face and provides greater accuracy for rolling flat products.

What is a Universal beam Mill and how does it differ from other mills?

A Universal beam Mill includes stands with both horizontal and vertical rolls bearing on the steel simultaneously, allowing for the rolling of complex shapes.

What is the purpose of cold rolling of strip and how does it differ from hot rolling?

Cold rolling of strip is used to produce a thinner, flatter product than is possible on a hot mill, down to a thickness of 0.15 mm. It also allows for better forming properties, surface finish, and can be coated with materials like zinc, tin, or plastic for protection and decorative purposes.

How is the rolled steel prepared for further processing or dispatch after the hot rolling process?

After hot rolling, the steel is cooled in a way appropriate to its end use and then prepared for further processing or dispatch, which may include cold rolling or coating.

Outlines

00:00

🔥 Hot Rolling of Steel

The paragraph discusses the process of hot rolling steel, which is essential for shaping due to its resistance when cold. Steel is heated in a furnace, passing through temperature control zones to reach the optimal temperature for rolling. The process involves applying immense forces, equivalent to thousands of tons, using mill stands with powerful electric motors and bearings. The layout of the rolling mill can vary, and the rolls can be plain for flat products like cladding or profiled for construction sections. The paragraph also touches on different roll arrangements like two-high, three-high, and four-high stands, each serving specific product requirements. After hot rolling, steel may undergo cold rolling to achieve thinner, flatter products with improved forming properties and surface finish. Cold rolling also allows for coating the steel with materials like zinc for corrosion protection, tin for cans, or plastic coatings for additional protection and aesthetics.

Keywords

💡Hot Rolling

Hot rolling is a metalworking process in which metal stock, such as steel, is shaped and compressed between rolls at elevated temperatures. This process is essential for steel to be malleable enough to be shaped. In the video, hot rolling is described as a process where steel is fed into a furnace and rolled while hot to achieve the desired thickness and shape, with the rolls exerting forces equivalent to thousands of tons.

💡Furnace

A furnace is an enclosed chamber where heat is generated and controlled to process materials, such as steel, at high temperatures. In the context of the video, the furnace is used to heat the steel to the correct temperature for rolling, ensuring it is workable and can be shaped effectively.

💡Mill Stands

Mill stands are the structural components of a rolling mill where the actual rolling of steel takes place. They consist of massive bearings and powerful electric motors that drive the rolls. The video mentions that mill stands can vary in layout and configuration, from simple single stands to more complex arrangements, and are essential for exerting the necessary force to shape the steel.

💡Rolls

Rolls in a rolling mill are the large cylindrical devices that apply pressure to the steel to shape it. They can be plain or profiled, depending on the product being manufactured. The video explains that rolls are responsible for squeezing the steel to achieve the final thickness and shape, with different roll arrangements for various products.

💡Tens of Millions of Newtons

This phrase refers to the immense force, measured in Newtons, that the rolls must exert during the hot rolling process. In the video, it is used to emphasize the scale of the forces involved in shaping steel, equivalent to the weight of thousands of tons, highlighting the industrial strength required for such processes.

💡Cold Rolling

Cold rolling is a process similar to hot rolling but performed at room temperature. It is used to produce thinner, flatter products with improved surface finish and forming properties. The video mentions that cold rolling can achieve a thickness down to 0.15 mm and is often used for products that require a higher quality finish or coatings.

💡Cladding

Cladding is a material used as a covering for the exterior or interior of structures, often for aesthetic or protective purposes. In the video, cladding is mentioned as one of the products that can be made from flat steel, which is produced by rolling.

💡Beams and Columns

Beams and columns are structural elements used in construction to support loads. The video discusses how profiled rolls in a rolling mill can produce steel sections like beams and columns, which are essential for the construction industry.

💡Universal Beam Mills

Universal beam mills are a type of rolling mill designed to produce steel sections with specific profiles, such as I-beams or H-beams. The video describes these mills as having both horizontal and vertical rolls that bear on the steel simultaneously, allowing for the production of complex steel shapes used in construction.

💡Coating

Coating in the context of the video refers to the application of a protective or decorative layer onto the surface of the rolled steel. Examples include zinc for corrosion protection, tin for can manufacturing, and plastic coatings or paint for additional protection and aesthetics. This process enhances the functionality and longevity of the steel products.

💡Corrosion

Corrosion is the gradual deterioration of a material, often a metal, due to chemical reactions with its environment. The video mentions that cold-rolled steel can be coated with zinc to protect it from corrosion, which is a critical consideration in the longevity and performance of steel products used in various applications.

Highlights

Steel's resistance to shaping when cold necessitates hot rolling.

Hot rolling ensures steel is at the correct temperature for shaping.

Steel is heated in a furnace with multiple temperature control zones.

Mill stands apply tens of millions of Newtons of force during hot rolling.

Rolls are mounted in strong housings and driven by powerful electric motors.

Rolling Mill layouts can vary from single to multiple stands.

Mill rolls can be plain for flat products or profiled for construction sections.

Two-high stands are mainly used for long products like sections.

Three-high stands are used for light sections and bars with a back-and-forth rolling process.

Four-high stands provide greater accuracy for flat products with two work rolls and backup rolls.

Universal beam Mills have both horizontal and vertical rolls for simultaneous steel bearing.

Rolled steel is coiled and prepared for further processing or dispatch.

Cold rolling of strip produces thinner, flatter products than hot rolling.

Cold rolled strip has better forming properties and surface finish.

Cold rolled strip can be coated with zinc for corrosion protection, tin for cans, or plastic coating for protection and decoration.

Transcripts

steel is highly resistant to shaping

when it's cold and for that reason it is

generally rolled whilst it's

hot to make sure the steel is at the

correct temperature for rolling it is

fed into a furnace here it travels

through several temperature control

zones until it's at the correct

temperature and ready for

rolling whatever the product the

principles of hot rolling are the same

steel is squeezed between rolls until

the final thickness and shape are

achieved to do this the rolls must exert

forces of tens of millions of Newtons

equivalent to a weight of thousands of

tons the rolls therefore run in massive

bearings mounted in housings of enormous

strength and driven by powerful electric

motors these are known as Mill stands

the layout of a Rolling Mill can vary

from a simple single stand Mill to

several stands positioned either side by

side or in a line the mill rolls

themselves can either be plain for flat

products such as strip used for products

such as cladding or profiled for

sections being beames and columns for

use in

construction Mill stands have various

roll Arrangements depending on the

product being

rolled the simplest Arrangement is a two

high stand used mainly for long products

such as

sections for light sections and bars

three High stands are sometimes used

with the steel passing one way through

the bottom Gap and back through the top

toop

Gap four high stands have two work rolls

in contact with the steel supported by

larger backup rolls to prevent

Distortion caused by the Rolling face

these give greater accuracy for Rolling

flat products such as

plate Universal beam Mills include

stands with both horizontal and vertical

rolls bearing on the steel

simultaneously the rolled steel is then

Co in a way appropriate to its end use

and prepared for further processing or

dispatch one of the further processes is

Cold Rolling of strip this is used to

produce a thinner flatter product than

is possible on a hot Mill down to a

thickness of

0.15

mm forming properties and surface finish

of cold rolled strip is better it can

also be coated with zinc to protect it

from corrosion with tin for cans and

with a plastic coating or paint for

protection and decorative purposes