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Questions and Answers
What effect does recrystallisation of metal crystals have on steel?
What effect does recrystallisation of metal crystals have on steel?
What is the primary purpose of heating steel to 600–700°C during the heat process?
What is the primary purpose of heating steel to 600–700°C during the heat process?
What is produced through the electroplating process described?
What is produced through the electroplating process described?
What is the final thickness of the steel slab after it is rolled from 250 mm to 2 mm?
What is the final thickness of the steel slab after it is rolled from 250 mm to 2 mm?
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What is the process involved in creating Electrolytic Tinplate (ETP)?
What is the process involved in creating Electrolytic Tinplate (ETP)?
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What is the primary ingredient for steel that is obtained through iron making?
What is the primary ingredient for steel that is obtained through iron making?
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What is formed as a by-product during the iron and steel making process when unwanted elements combine?
What is formed as a by-product during the iron and steel making process when unwanted elements combine?
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Which method is specifically used to lower the carbon content in iron to create steel?
Which method is specifically used to lower the carbon content in iron to create steel?
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What is the approximate temperature reached in a Basic Oxygen Furnace during the steel-making process?
What is the approximate temperature reached in a Basic Oxygen Furnace during the steel-making process?
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Which of the following components contributes to the strength of steel?
Which of the following components contributes to the strength of steel?
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What is the predominant composition of pig iron?
What is the predominant composition of pig iron?
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Which process is primarily utilized in modern steel-making for its efficiency and ability to handle large capacities?
Which process is primarily utilized in modern steel-making for its efficiency and ability to handle large capacities?
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What percentage of scrap steel is typically used in an Electric Arc Furnace?
What percentage of scrap steel is typically used in an Electric Arc Furnace?
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What is the primary function of internal coatings in cans?
What is the primary function of internal coatings in cans?
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Which method of can production is characterized by a single drawing process?
Which method of can production is characterized by a single drawing process?
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What is a requirement for internal coating materials in food cans?
What is a requirement for internal coating materials in food cans?
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Corrosion in food cans can occur due to which of the following factors?
Corrosion in food cans can occur due to which of the following factors?
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What is a potential consequence of improper internal coating application?
What is a potential consequence of improper internal coating application?
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What process is used to refine bauxite ore to obtain aluminum oxide?
What process is used to refine bauxite ore to obtain aluminum oxide?
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What characteristic of pure aluminum requires the use of alloying agents?
What characteristic of pure aluminum requires the use of alloying agents?
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Which structure is designed to withstand internal and external pressure without permanent distortion?
Which structure is designed to withstand internal and external pressure without permanent distortion?
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What type of materials are 3-piece cans typically made from?
What type of materials are 3-piece cans typically made from?
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What is the primary function of the sealing gasket compound in can manufacturing?
What is the primary function of the sealing gasket compound in can manufacturing?
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Which process is involved in the reduction of aluminum oxide to release pure aluminum?
Which process is involved in the reduction of aluminum oxide to release pure aluminum?
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What can affect the deformation behavior of the can end?
What can affect the deformation behavior of the can end?
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What indicates that aluminum can materials are not suitable for high acid or alkali foods?
What indicates that aluminum can materials are not suitable for high acid or alkali foods?
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What is the main cause of discolouration in canned cranberries?
What is the main cause of discolouration in canned cranberries?
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Which compound is responsible for corrosion in canned products containing acidic ingredients?
Which compound is responsible for corrosion in canned products containing acidic ingredients?
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Which of the following conditions helps to prevent discoloration due to the formation of iron phosphate?
Which of the following conditions helps to prevent discoloration due to the formation of iron phosphate?
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What role do synthetic dyes play in the corrosion of cans?
What role do synthetic dyes play in the corrosion of cans?
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What is the primary source of nitrates in canned foods?
What is the primary source of nitrates in canned foods?
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What method can significantly reduce oxidation and corrosion in canned products?
What method can significantly reduce oxidation and corrosion in canned products?
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How do anthocyanins contribute to food preservation challenges?
How do anthocyanins contribute to food preservation challenges?
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Why are enameled cans not suitable for acid products?
Why are enameled cans not suitable for acid products?
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What is the primary consequence of thermal processing in canning?
What is the primary consequence of thermal processing in canning?
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How does the rate of chemical reactions change with temperature in storage conditions?
How does the rate of chemical reactions change with temperature in storage conditions?
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What is the effect of the enamel coating in food cans?
What is the effect of the enamel coating in food cans?
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What must ECCS be combined with for effective food packaging?
What must ECCS be combined with for effective food packaging?
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What is a characteristic of aluminum cans in food packaging?
What is a characteristic of aluminum cans in food packaging?
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What types of products should not be packed in aluminum cans due to corrosion concerns?
What types of products should not be packed in aluminum cans due to corrosion concerns?
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What component is crucial for the performance of enameled food cans?
What component is crucial for the performance of enameled food cans?
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What is a consequence of aluminum cans being exposed to high pH cleaning solutions?
What is a consequence of aluminum cans being exposed to high pH cleaning solutions?
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Study Notes
Metal Packaging Materials
- Metal packaging is a key topic in food packaging technology (FST 648).
- The presentation outlines the advantages and disadvantages of using metal containers, specifically focusing on steel and aluminum.
- Key aspects of manufacturing, including steel production, can fabrication, and corrosion, are discussed.
Introduction
- In 1804, Nicholas Appert developed a method to preserve food in containers by partially cooking and sealing in glass bottles.
- This technique initially used glass, but later transitioned to tin cases.
- Appert's work led to the advancement of food preservation methods.
- Philip de Girard played a crucial role in suggesting replacing glass bottles with tin cases.
Advantages of Metal Containers
- Flexibility in processing enables customized filling and sterilization.
- Excellent sealing properties, particularly double seaming techniques, offer reliability and maintain the integrity of contents.
- Canned foods have extended shelf life making them ideal for maintaining quality in storage.
- High-rate production makes metal containers suitable for large-scale food processing.
- High corrosion resistance surface with bright appearance, particularly when coated with tin.
- Coating adheres well to the base metal, preventing any deformation or flaking.
Disadvantages of Metal Containers
- Empty metal containers occupy significant storage space.
- Canned goods take up considerable shelf space during storage and distribution.
- Metal containers, if not coated, need protection from moisture and humidity.
- Steel is not easily recycled.
- Cans are often limited to specific shapes and sizes.
- Modern consumers often perceive metal containers as less aesthetically pleasing.
Steel Manufacturing
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Steel production involves an extraction process in a blast furnace, converting iron ore into molten iron (reduction process).
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The blast furnace uses raw materials like iron ore, coke, and fluxes.
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The process involves heating the raw materials to generate temperature of ~1800°C.
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Molten iron (pig iron) is then drained and further processed to make steel.
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Slag, a by-product, is also drained and used in construction materials.
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Different methods are used for steelmaking, such as Basic Oxygen Furnace (BOF) and Electric Arc Furnace (EAF).
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BOF and EAF processes refine pig iron or sponge iron to create steel.
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Steelmaking processes involve various stages including the casting, hot rolling, cold rolling and annealing.
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Electroplating is utilized in coating steel with tin for producing tinplate (ETP) or chromium for electrolytic chromium-coated steel (ECCS).
Can Manufacturing
- The process to transform sheet steel/aluminum into can involves a series of steps, including flattening processes.
- The material undergoes various stages to create the desired shape and size, including a stamping procedure
- Different can designs (3-piece or 2-piece) use variations of processes to produce lids, bodies and bases.
Metal Can Fabrication (3-piece/2-piece)
- 3-piece cans consist of a separate lid, bottom, and body. These parts are individually created and then joined together.
- Different types of seaming operations, such as welded and soldered joins, are employed in the production of cans. Double seam operations are crucial for the integrity of can construction.
- 2-piece cans are seamless and created using different metal shaping fabrication processes such as drawn ironing and drawn redrawn.
Corrosion of Metal Cans
- Corrosion in metal cans can result from chemical reactions between the container's contents and the metal itself, or from reactions between metal and external environment.
- Highly corrosive foods, such as fruit juices, can accelerate metal corrosion.
- Storage temperature and oxygen are also factors that can influence corrosion rates.
- Protective coatings and enameling are used in can fabrication to mitigate corrosion.
- Different metals (steel, aluminum, tin) have varying resistance to corrosion.
Food Composition as Corrosion Factor
- Factors in food compositions that influence corrosion include acidity, the presence of sulfur components, nitrates, phosphates, plant pigments, synthetic coloring, and copper.
- Types of food and the pH level are important factors affecting corrosion. Oxygen and thermal processing steps also play important roles.
- Food components like organic acids and certain types of sulfur compounds can accelerate corrosion rates.
Additional Notes
- The slides cover various aspects of metal packaging, from raw material sources to manufacturing processes to corrosion prevention.
- Types of protective coatings and their roles in preventing corrosion are explored in detail.
- Various specific manufacturing approaches such as electrolytic tinning (ETP) and electrolytic chromium coating (ECCS) for steel, and aluminum production are also covered.
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Description
Test your knowledge on the processes involved in steel manufacturing, including recrystallisation, heating, electroplating, and more. This quiz covers essential aspects of metallurgy and the primary ingredients necessary for steel production. Perfect for students learning about materials science and engineering.
