Unit 8

Annealing

Steel acquires the desired mechanical properties through annealing in an inert atmosphere at a temperature of about 700˚C. There are two possibilities: the coils are either annealed in the batch annealing furnace (BAF) or in the continuous annealing and processing line (CAPL).

In the batch annealing section, the steel coils are positioned on furnace supports. Up to four coils are stacked on top of each support. The stack is protected from the atmosphere by a protective cover around which the actual annealing hood is positioned. The air present inside the protective cover is replaced by a reducing gas (pure hydrogen or a mixture of hydrogen and nitrogen) to protect the sheet and prevent it from rusting during the annealing process. The gas also acts as a heat transfer medium. The annealing temperature depends upon the steel grade required, but will be about 700 ˚C. After annealing, the hood is removed and replaced by a cooling hood with a ventilator at the top, which cools the steel. The entire process takes several days.

Exercise 1:

Please select technical terms from the text below and translate them:

Annealing

Steel acquires the desired mechanical properties through annealing in an inert atmosphere at a temperature of about 700˚C. There are two possibilities: the coils are either annealed in the batch annealing furnace (BAF) or in the continuous annealing and processing line (CAPL).

In the batch annealing section, the steel coils are positioned on furnace supports. Up to four coils are stacked on top of each support. The stack is protected from the atmosphere by a protective cover around which the actual annealing hood is positioned. The air present inside the protective cover is replaced by a reducing gas (pure hydrogen or a mixture of hydrogen and nitrogen) to protect the sheet and prevent it from rusting during the annealing process. The gas also acts as a heat transfer medium. The annealing temperature depends upon the steel grade required, but will be about 700 ˚C. After annealing, the hood is removed and replaced by a cooling hood with a ventilator at the top, which cools the steel. The entire process takes several days.

 

Ikona iDevice Answer Key: Exercise 1
Suggested answers:

–

-

-

-

-

-

-

–

–

–

–

  

The continuous annealing process is designed as a fast method of providing the steel with homogenous and uniform heat treatment that should generate steel properties that are at least as good as of those resulting from the conventional batch annealing process. As implied by the term “continuous annealing and processing line”, the process entails more than just annealing: within ten minutes, a cold rolled coil is degreased, annealed, tempered in the skinpass mill, inspected and finished according to the requirements of the customer. In addition to the time saved by the continuous annealing process, there are also certain steel grades that can only by produced by continuous annealing.
Ikona iDevice Exercise 2:
To do exercise 2, please scroll down to the end of the unit. It precedes exercise 6. Do the exercise and return back.
  

Ikona iDevice Exercise 3:
Please translate into Czech:

Heat treatment - (Zušlechťování oceli)

Degreasing -

Tempering -

Skinpass -

 

  

In the continuous annealing line, the coils are welded to each other by a mesh seam weld so that a fully continuous strip can pass through the entire installation. First of all, the strip is completely degreased. After rinsing and drying, the strip arrives in the accumulator linking the discontinuous entry section and the continuous furnace section. In the furnace, the strip is heated to a temperature of about 700 - 800 ˚C, depending upon the metallurgical requirements. This annealing temperature is maintained for a short period only. In the first cooling stage, the temperature is reduced to approx. 400 ˚C and the strip is held at this temperature for a fixed period of time. This constitutes the accelerated ageing or over ageing of the steel. Finally, the strip is cooled down further. The entire annealing process only takes a few minutes. After the exit accumulator, the strip passes through a temper rolling stand or skinpass mill where it acquires the required elongation, surface roughness and flatness. The side trimmer trims it to the required width. After inspection, oiling and stamping, the strip is cut to the required weight by the cropper shears and coiled.

Exercise 4:

Translate the following text into Czech:

In the continuous annealing line, the coils are welded to each other by a mesh seam weld so that a fully continuous strip can pass through the entire installation. First of all, the strip is completely degreased. After rinsing and drying, the strip arrives in the accumulator linking the discontinuous entry section and the continuous furnace section. In the furnace, the strip is heated to a temperature of about 700 - 800 ˚C, depending upon the metallurgical requirements. This annealing temperature is maintained for a short period only. In the first cooling stage, the temperature is reduced to approx. 400 ˚C and the strip is held at this temperature for a fixed period of time.

Ikona iDevice Answer Key: Exercise 4

  

Ikona iDevice Exercise 5:
Please translate into Czech:

Accelerated ageing - (materiálu)

Temper rolling stand -

Elongation -

Surface roughness -

Flatness -

Side trimmer -

Stamping -

  

The annealed coils from the batch annealing section still have to obtain their elongation, surface roughness and flatness in the skinpass mill. Cropping shears in front of the coiler cut the strip to the correct coil weight, and the welds made prior to the skinpass mill are also removed at this stage.

If necessary, the cold rolled coils can be transported to the inspection line. The main purpose of these inspection lines is an additional control of the strip surface. At the same time as the edges are trimmed, the strip is marked and oiled and if necessary, the weight of the coil can be adjusted by cutting or welding.

The annealed cold rolled steel is packaged to protect it during transport and storage. After packaging, a label with the relevant data is attached. Now the material is ready to be dispatched to the customer.
Ikona iDevice Exercise 6:
To do exercise 6, please scroll down to the end of the unit. It precedes "Points to remember". Do the exercise and return back.
  

Coating
 
For many applications, the customer requires coated material. This may be electrolytic coating, hot dip coating or organic coating.

For hot dip coating, full hard cold rolled coils or hot rolled coils are used. For electroplating, completely finished, annealed cold rolled coils are used. Organic coating can be applied to annealed cold rolled coils or to coils with a metallic coating

Exercise 7:

Please translate the following text into Czech:

Coating
For many applications, the customer requires coated material. This may be electrolytic coating, hot dip coating or organic coating.
For hot dip coating, full hard cold rolled coils or hot rolled coils are used. For electroplating, completely finished, annealed cold rolled coils are used. Organic coating can be applied to annealed cold rolled coils or to coils with a metallic coating.

Ikona iDevice Answer Key: Exercise 7

  

Coating in general can guarantee a longer lifespan for thinner grades of steel sheet in a relatively aggressive environment and an improved corrosion resistance. A coating is therefore applied to the steel substrate to achieve this. Because coated steel is such a versatile product, it has applications in many different sectors including the automotive industry, building , white goods, packaging etc. ( outer body panels for automotive and domestic appliances, automotive body parts, roof and wall cladding, exhaust systems, heat shields, diesel tanks, one-sided enameling in furnaces, profile systems, culverts, silos, grain dryers, greenhouses, doors, chimneys, ducts etc.)
Ikona iDevice Exercise 8:
Please translate into Czech:

Steel substrate - ( )

Automotive industry -

White goods - ( , )

Domestic appliances -

Cladding - / /

Exhaust systems -

Heat shields -

Diesel tanks -

Enameling -

Culvert - /

 

 

 

  

Ikona iDevice Exercise 2:
Read the text below and fill in the missing words:
The continuous process is designed as a fast method of providing the steel with homogenous and uniform heat that should generate steel that are at least as good as of those resulting from the conventional process. As implied by the term “continuous and processing line”, the process entails more than just annealing: within ten minutes, a cold rolled coil is , annealed, in the skinpass mill, inspected and finished according to the requirements of the customer. In addition to the time saved by the continuous process, there are also certain steel that can only by produced by .
  

Ikona iDevice Exercise 6:
Read the text below and fill in the missing words:
The annealed coils from the annealing section still have to obtain their , surface and flatness in the mill. Cropping in front of the cut the strip to the correct coil weight, and the made prior to the skinpass mill are also removed at this stage.

If necessary, the cold rolled can be transported to the inspection line. The main purpose of these lines is an additional control of the strip . At the same time as the edges are , the strip is and and if necessary, the weight of the coil can be adjusted by cutting or .

The annealed cold rolled steel is to protect it during transport and storage. After packaging, a with the relevant data is attached. Now the material is ready to be to the customer.
  

Ikona iDevice Points to remember:
- Annealing in an inert atmosphere helps cold rolled coils to acquire the desired mechanical properties.

- There are two types of annealing: Batch annealing and Continuous annealing

- For many applications, the customer requires coated material. This may be electrolytic coating, hot dip coating or organic coating.

- Coating has applications in many different sectors including the automotive industry, building , white goods, packaging etc.

Glossary:

 

English Czech
Coating Povlakování
Batch annealing Dávkové žíhání
Weld Svar
Electrolytic coating Galvanické pokovování
Hot dip coating Žárové pokovování
Hot dipping Pokovení v ohni
Hot dip galvanizing Žárové pozinkování
Electroplating Galvanické / Elektrolytické pokovování
Culvert Propustek; Kanál pro kabel
Tempering Popouštění

 

Ikona iDevice Gallery:
Zobrazit obrázek Annealing
Annealing
Zobrazit obrázek Annealing
Annealing
Zobrazit obrázek Batch Annealing
Batch Annealing
Zobrazit obrázek Bell-type Furnaces
Bell-type Furnaces
Zobrazit obrázek Continuous Annealing Line
Continuous Annealing Line
Zobrazit obrázek Electrolytic Coating
Electrolytic Coating
Zobrazit obrázek Coated Coils
Coated Coils
Zobrazit obrázek Coated Sheets
Coated Sheets

Sources:

Applebaum, M, Everything You Always Wanted to Know About Steel. A Glossary of Terms and Concepts, Summer 1998, Solomon Smith Barney Inc., 2000

Coigne, P., Construction Market, ArcelorMittal Brussels, ArcelorMittal University - Understanding Steel, 2009

Fousse, D.,Packaging, ArcelorMittal R&D Mezieres, ArcelorMittal University - Understanding Steel, 2009

Meseure, K., Steel Making, ArcelorMittal R&D Gent, ArcelorMittal University - Understanding Steel, 2009


PC Translator. CD-ROM. Korytná:LangSoft & SOFTEX Software, 2007

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http://www.arcelormittal.com/fce

http://www.arvedi.it/

http://www.bchistory.org/beavercounty/SteelMakingEtc/SteelMaking.html

http://www.eef.org.uk/default.htm

http://www.myarcelormittal.com

http://www.onesteel.com/

http://www.pdmsteel.com/index.html

http://www.steel.org/

http://www.steel-training.co.uk

http://www.stemcor.com/default.aspx

http://www.uss.com/corp/index.asp