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Coated Sheet Basics
If you're looking for coated sheet information for commercial and residential framing, please visit the GalvInfo Center at http://www.galvinfo.com.
A Program of the International Lead Zinc Research Organization, Inc., the GalvInfo Center is a resource for information on the use and performance of metallic-coated steel sheet products -- products coated with zinc-containing coatings.
Economical
- Pound for pound steel is the most economical metal roofing and siding material
- Today, steel is a high tech, engineered material
- The life cycle costs of steel framing is very attractive
- Steel companies in the USA are competitive worldwide in regards to quality and cost
Strong
- Steel is strong
- Highest strength to weight ratio of any building material
- Available in minimum yield strengths up to 80ksi
Durable
- Steel lasts: Resistant to wet or dry rot and insects.
- Steel can be designed to resist high damage from wind, snow loads and seismic conditions.
Recycled Content
- Steel is the most highly recycled material on the face of the earth!
- Nearly 64% of all steel scrap in North America is recycled annually
- 60.7% of all steel packaging is recycled
- 81% of all steel appliances is recycled
- 97.6% of all steel automobiles is recycled
- When steel framing has completed its useful life it can be easily recycled and not landfilled
- Steel framing has a minimum recycled content of 25%
Production Sequence
Steel is made by two general processes:
- Integrated Steelmaking
- Electric Furnace Steelmaking
U. S. Steel produces framing, truss plates and connectors by the Integrated Steelmaking process
- Molten iron is made in a blast furnace
- The iron is refined into steel
- The steel is continuously cast into slabs
- The slabs are rolled into Hot Rolled coils
- The Hot Rolled coils are cold reduced
- The cold rolled coils are metallic coated (Galvanized, GALVALUME®, Galfan, Aluminum Coated)
Blast Furnace
Iron ore, limestone and coke are refined inside a blast furnace.
Melt Shop
The molten iron is transferred to a Basic Oxygen melt shop where it is combined with steel scrap and alloying elements and further refined into steel.
Steel Slab Casting
Molten steel is then continuously cast into large slabs.
Hot Strip Mill Control Room
This is a view of the control room for part of the Hot Strip mill.
This illustrates that the steelworker of today's modern, high tech steel industry may not be the type worker you might think of from past history. Today's steelworkers must be able to solve complex problems and be able to make quick decisions in these high speed, computer-controlled operations. All operations from the Blast Furnace to the finished product are closely controlled to meet stringent process control parameters. Our employees establish these parameters according to our customer's needs and make sure that all production steps are in conformance.
Continuous Cast Slab
This is a continuous cast slab entering the Hot Strip mill where it is rolled into a Hot Rolled coil.
Slab in Roughing Stands
This is the same slab passing through the roughing stands on its way to the finishing rolls.
Cold Reduction Mill Control Room
This is a view of the control room for a Cold Reduction mill.
Cold Reduction Mill
The Hot Rolled Pickled coils enter this mill on the left and pass through 6 cold reduction stands, then exit to the right where the coils are banded and sent to the Hot Dip line.
Hot Dipped Coating Process
- The cold rolled strip is cleaned in a caustic bath
- Continuously annealed in a high temperature furnace
- Immersed in a bath of molten zinc, aluminum-zinc, etc.
- Coating thickness is controlled by high pressure computer-controlled air knives
- Strip is cooled and flattened by tension leveling
- Surface quality is enhanced by temper rolling
- Coatings are applied to resist corrosion during transit and storage.
Hot Dip Line
This is a view of the entry end of a Hot Dip Galvanized/GALVALUME® line.
Please notice that
(1) It is big and long.
(2) The Cold Rolled coils are staged ahead of the line ready to be coated.
(3) These Cold Rolled coils are welded end to end and proceed through various processing steps that are determined by the ordered specification and processing employed by our customer. Out the other end of the line, about a quarter of a mile away, the Galvanized or GALVALUME® is recoiled, tested, packaged and shipped to our customer or outside processor.
Cold Rolled Coil
This is a close-up of a Cold Rolled coil being charged into the Hot Dip line.
Cleaning Section
The Cold Rolled or Hot Rolled and Pickled Strip (depending on ordered thickness) enters the Coating Line and all rolling solutions, lubricants and other surface contaminates must be removed to insure metallic coating adherence and proper surface quality.
The strip moves through a series of heated caustic solutions and is rinsed prior to entry into the Continuous Annealing Furnace.
Annealing Furnace
This is the horizontal Annealing Furnace where the strip cleaning process is completed and the strip is continuously heat treated to achieve the specified mechanical properties. The extent to which the fast moving strip is heated depends upon the ordered specification and end use processing requirements.
Air Knives
The Air Knives control the thickness of the metallic coating through a closed loop process between a coating thickness measuring instrument, a process computer and the Air Knives. The measuring instrument determines the metallic coating thickness. The process computer compares that to the order specification and adjusts the airflow through the Air Knives in relationship to the specification and the speed of the strip through the knives. The high velocity air flow strips the excess zinc or aluminum/zinc from the strip to achieve the desired coating thickness.
Temper Mill/Tension Leveler
Depending upon the ordered specification and application the Temper Mill may be used to smooth the metallic coating surface. Prepainted Galvanized or GALVALUME® generally undergoes Temper Rolling.
The Tension Leveler stretches the strip beyond its yield point in order to improve the strip's flatness. This can be beneficial to many product applications.
Roll Coater
The Roll Coater applies a very thin coating of acrylic to both sides of the metallic coated strip in the production of USS ACRYLUME® and ACRYZINC®. This process is carefully controlled to achieve uniform acrylic coating coverage and thickness.
Following the acrylic application the strip passes through a drying furnace to achieve proper curing of the acrylic coating.
Coating Line Exit End
At this point the finished Galvanized or GALVALUME® strip is recoiled, tested, packaged and prepared for shipment to our customer or outside processor for a variety of processes which might include painting, slitting, cutting to length, etc.
Coating Chemistries
- Galvanized - 100% zinc
- GALVALUME® - 55% aluminum, 45% zinc
- Galfan - 95% zinc and 5% aluminum
Coating Weights
- Galvanized for roofing is produced in either G60 or G90 coating weights
- G stands for Galvanized
- 60 and 90 stand for 0.6 or 0.9 of an ounce coating per sq. ft. total both sides
- GALVALUME® is produced in either AZ50 or AZ55 coating weights
- AZ stands for Aluminum/Zinc
- 50 and 55 stand for 0.5 or 0.55 of an ounce coating per sq. ft. total both sides
Common Coated Sheet Specifications
- General requirements for hot dipped coated sheets - ASTM A924
- Hot dipped Galvanized sheets - ASTM A653
- GALVALUME® Sheets - ASTM A792
- Galfan - ASTM A875
Metallic Coatings
Metallic coatings are used to resist corrosion.
Two general types of metallic coatings:
- Sacrificial - coating reacts to protect steel in corrosive media
- GALVALUME®
- Galvanized
- Galfan
- Barrier - coating provides barrier against corrosive media and is not as reactive
- GALVALUME®
- Aluminum Coated
GALVALUME®
- GALVALUME® is a unique combination of both a sacrificial and barrier coating
- The zinc provides protection on exposed edges and places where the coating may become scratched
- The aluminum provides an excellent barrier to corrosive media
Why Build with Steel?
- Pound for pound steel is a very economical metal roofing and siding material
- The life cycle costs of steel framing are very attractive
- Steel is strong
- Steel lasts
- Steel is the most highly recycled material on the face of the earth!
- 64% of all new steel in the USA is made from recycled steel
Coated Sheet Basics
If you're looking for coated sheet information for commercial and residential framing, please visit the GalvInfo Center at http://www.galvinfo.com.
A Program of the International Lead Zinc Research Organization, Inc., the GalvInfo Center is a resource for information on the use and performance of metallic-coated steel sheet products -- products coated with zinc-containing coatings.
Economical
- Pound for pound steel is the most economical metal roofing and siding material
- Today, steel is a high tech, engineered material
- The life cycle costs of steel framing is very attractive
- Steel companies in the USA are competitive worldwide in regards to quality and cost
Strong
- Steel is strong
- Highest strength to weight ratio of any building material
- Available in minimum yield strengths up to 80ksi
Durable
- Steel lasts: Resistant to wet or dry rot and insects.
- Steel can be designed to resist high damage from wind, snow loads and seismic conditions.
Recycled Content
- Steel is the most highly recycled material on the face of the earth!
- Nearly 64% of all steel scrap in North America is recycled annually
- 60.7% of all steel packaging is recycled
- 81% of all steel appliances is recycled
- 97.6% of all steel automobiles is recycled
- When steel framing has completed its useful life it can be easily recycled and not landfilled
- Steel framing has a minimum recycled content of 25%
Production Sequence
Steel is made by two general processes:
- Integrated Steelmaking
- Electric Furnace Steelmaking
U. S. Steel produces framing, truss plates and connectors by the Integrated Steelmaking process
- Molten iron is made in a blast furnace
- The iron is refined into steel
- The steel is continuously cast into slabs
- The slabs are rolled into Hot Rolled coils
- The Hot Rolled coils are cold reduced
- The cold rolled coils are metallic coated (Galvanized, GALVALUME®, Galfan, Aluminum Coated)
 |
Blast Furnace Iron ore, limestone and coke are refined inside a blast furnace. |
 |
Melt Shop The molten iron is transferred to a Basic Oxygen melt shop where it is combined with steel scrap and alloying elements and further refined into steel. |
 |
Steel Slab Casting Molten steel is then continuously cast into large slabs. |
 |
Hot Strip Mill Control Room This is a view of the control room for part of the Hot Strip mill. This illustrates that the steelworker of today's modern, high tech steel industry may not be the type worker you might think of from past history. Today's steelworkers must be able to solve complex problems and be able to make quick decisions in these high speed, computer-controlled operations. All operations from the Blast Furnace to the finished product are closely controlled to meet stringent process control parameters. Our employees establish these parameters according to our customer's needs and make sure that all production steps are in conformance. |
 |
Continuous Cast Slab This is a continuous cast slab entering the Hot Strip mill where it is rolled into a Hot Rolled coil. |
 |
Slab in Roughing Stands This is the same slab passing through the roughing stands on its way to the finishing rolls. |
 |
Cold Reduction Mill Control Room This is a view of the control room for a Cold Reduction mill. |
 |
Cold Reduction Mill The Hot Rolled Pickled coils enter this mill on the left and pass through 6 cold reduction stands, then exit to the right where the coils are banded and sent to the Hot Dip line. |
Hot Dipped Coating Process
- The cold rolled strip is cleaned in a caustic bath
- Continuously annealed in a high temperature furnace
- Immersed in a bath of molten zinc, aluminum-zinc, etc.
- Coating thickness is controlled by high pressure computer-controlled air knives
- Strip is cooled and flattened by tension leveling
- Surface quality is enhanced by temper rolling
- Coatings are applied to resist corrosion during transit and storage.
 |
Hot Dip Line This is a view of the entry end of a Hot Dip Galvanized/GALVALUME® line. Please notice that (1) It is big and long. (2) The Cold Rolled coils are staged ahead of the line ready to be coated. (3) These Cold Rolled coils are welded end to end and proceed through various processing steps that are determined by the ordered specification and processing employed by our customer. Out the other end of the line, about a quarter of a mile away, the Galvanized or GALVALUME® is recoiled, tested, packaged and shipped to our customer or outside processor. |
 |
Cold Rolled Coil This is a close-up of a Cold Rolled coil being charged into the Hot Dip line. |
 |
Cleaning Section The Cold Rolled or Hot Rolled and Pickled Strip (depending on ordered thickness) enters the Coating Line and all rolling solutions, lubricants and other surface contaminates must be removed to insure metallic coating adherence and proper surface quality. The strip moves through a series of heated caustic solutions and is rinsed prior to entry into the Continuous Annealing Furnace. |
 |
Annealing Furnace This is the horizontal Annealing Furnace where the strip cleaning process is completed and the strip is continuously heat treated to achieve the specified mechanical properties. The extent to which the fast moving strip is heated depends upon the ordered specification and end use processing requirements. |
 |
Air Knives The Air Knives control the thickness of the metallic coating through a closed loop process between a coating thickness measuring instrument, a process computer and the Air Knives. The measuring instrument determines the metallic coating thickness. The process computer compares that to the order specification and adjusts the airflow through the Air Knives in relationship to the specification and the speed of the strip through the knives. The high velocity air flow strips the excess zinc or aluminum/zinc from the strip to achieve the desired coating thickness. |
 |
Temper Mill/Tension Leveler Depending upon the ordered specification and application the Temper Mill may be used to smooth the metallic coating surface. Prepainted Galvanized or GALVALUME® generally undergoes Temper Rolling. The Tension Leveler stretches the strip beyond its yield point in order to improve the strip's flatness. This can be beneficial to many product applications. |
 |
Roll Coater The Roll Coater applies a very thin coating of acrylic to both sides of the metallic coated strip in the production of USS ACRYLUME® and ACRYZINC®. This process is carefully controlled to achieve uniform acrylic coating coverage and thickness. Following the acrylic application the strip passes through a drying furnace to achieve proper curing of the acrylic coating. |
 |
Coating Line Exit End At this point the finished Galvanized or GALVALUME® strip is recoiled, tested, packaged and prepared for shipment to our customer or outside processor for a variety of processes which might include painting, slitting, cutting to length, etc. |
Coating Chemistries
- Galvanized - 100% zinc
- GALVALUME® - 55% aluminum, 45% zinc
- Galfan - 95% zinc and 5% aluminum
Coating Weights
- Galvanized for roofing is produced in either G60 or G90 coating weights
- G stands for Galvanized
- 60 and 90 stand for 0.6 or 0.9 of an ounce coating per sq. ft. total both sides
- GALVALUME® is produced in either AZ50 or AZ55 coating weights
- AZ stands for Aluminum/Zinc
- 50 and 55 stand for 0.5 or 0.55 of an ounce coating per sq. ft. total both sides
Common Coated Sheet Specifications
- General requirements for hot dipped coated sheets - ASTM A924
- Hot dipped Galvanized sheets - ASTM A653
- GALVALUME® Sheets - ASTM A792
- Galfan - ASTM A875
Metallic Coatings
Metallic coatings are used to resist corrosion.
Two general types of metallic coatings:
- Sacrificial - coating reacts to protect steel in corrosive media
- GALVALUME®
- Galvanized
- Galfan
- Barrier - coating provides barrier against corrosive media and is not as reactive
- GALVALUME®
- Aluminum Coated
GALVALUME®
- GALVALUME® is a unique combination of both a sacrificial and barrier coating
- The zinc provides protection on exposed edges and places where the coating may become scratched
- The aluminum provides an excellent barrier to corrosive media
Why Build with Steel?
- Pound for pound steel is a very economical metal roofing and siding material
- The life cycle costs of steel framing are very attractive
- Steel is strong
- Steel lasts
- Steel is the most highly recycled material on the face of the earth!
- 64% of all new steel in the USA is made from recycled steel
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