MODULE 2.2 - STEEL 1

What is the difference between METAL and STEEL?

 Metal - refers to a class of chemical elements characterized by their luster, malleability, ductility, and electrical conductivity.

 Steel - a specific type of metal that is primarily composed of iron and carbon.

Any of a class of elementary substances, such as gold, silver, or copper, all of which are crystalline when solid and many of which are characterized by opacity, ductility, conductivity, and a unique luster when freshly fractured.

TLDR: Refers to a class of chemical elements characterized by their luster, malleability, ductility, and electrical conductivity.

Metal

An alloy of iron and carbon. It is one of the most widely used metals due to its strength and versatility, and affordability.

TLDR: A specific type of metal that is primarily composed of iron and carbon.

Steel

DIVISIONS 5 OF METALS

2 Types of Metals

Ferrous Metals and Non-Ferrous Metals

Contains iron as their primary constituent. They are magnetic and exhibit properties such as strength, durability, and conductivity.

Ferrous Metals

A malleable, ductile, magnetic, silver-white metallic element from which pig iron and steel are made.

Iron

Relatively soft iron that is readily forged and welded, having a fibrous structure. A very low-carbon form of iron used for decorative purposed.

Wrought Iron

Hard, brittle, nonmalleable iron-based alloy. It is known for its excellent casting properties and is used in applications such as engine block, pipes, and cookware.

Cast Iron

Metals that do not contain significant amounts of iron. They are non-magnetic and have various properties.

Non-Ferrous Metals

A metal made by combining two or more metallic elements, especially to give greater strength or resistance to corrosion.

Alloy

The only non-ferrous metal that is liquid at room temperature.

Mercury

A ductile, malleable, silver-white metallic elements that is used in forming many hard, light alloys. It has natural resistance to corrosion due to is transparent film of oxide on its surface. It should be isolated from alkaline materials and other metals to prevent galvanic action.

It is also widely used in sheet forms for secondary building elements.

Aluminum

ACP

Aluminum Cladding Panel

The electrical and chemical process of thickening the oxide coating to increase corrosion resistance. During this process, the naturally light and reflective surface of the aluminum can be dyed with any color.

Anodizing

Widely used for electrical wiring, water piping, and in the manufacture of alloys, as bronze and brass. Its color and resistance to corrosion also make it an excellent roofing and flashing material. It corrodes aluminum, steel, and stainless steel.

Being cathode, will not corrode. It is one of the best electrical conductors.

Copper

An alloy of copper and zinc, known for its golden color and corrosion resistance. Used for windows, railings, trim, plumbing fitting, and finish hardware.

Brass

An alloy of copper, tin, and aluminum. It is strong, corrosion resistant, and historically significant. The green color comes from a natural patina formed on the copper surface due to oxidation.

Bronze

Process of Patination

 Fresh Copper

 Initial Oxidation

 Further Oxidation

 Patina Formation

Process of Patination: Reddish-brown color

Fresh Copper

Process of Patination: Exposure to air creates copper oxide, which is reddish.

Initial Oxidation

Process of Patination: Turns to black copper oxide

Further Oxidation

Process of Patination: Reaction with carbon dioxide and sulfur compounds in the air creates greenish copper carbonate.

Patina Formation

A heavy, soft, malleable, bluish-gray metallic element used for flashing, sound isolation, and radiation shielding. Although it is the heaviest of the common metals, its pliability makes it desirable for application over uneven surfaces. It is widely used in electrical power cables, batteries, and soldering. Dust and vapors are toxic.

Lead

A medium to low strength metal with a very low melting point. It can be machined easily. It is most used in galvanizing, applying a protective zinc coating to prevent rust.

Zinc

Very soft and malleable, ductile with low tensile strength. Often used to coat steel to prevent corrosion.

Tin

Can occur between to dissimilar metals when enough moisture is present for electric current to flow. The electric current will tend to corrode one metal while plating the other. The severity of it depends on how far apart the two metals are on the series table.

Galvanic Action

Steel Construction

Advantages

 Combines high strength and stiffness with elasticity

 Steel is 100x stronger than concrete in resisting tensile stresses.

 Precise and predictable

 Light in proportion to its strength

 Well suited to rapid construction, highly repetitive building frames

Steel Construction

Disadvantages

 Corrodes in certain environments

 Loses strength during severe fires

Timeline: The Bessemer process, patented in the 1850s, allowed for mass production of steel by removing impurities from iron ore.

Industrial Revolution

Timeline: Ancient civilizations used wrought iron and cast iron for various structural application.

Early Use

Timeline: Gustave Eiffel’s construction of the Eiffel Tower in 1889, using wrought iron showcased the potential of steel in large-scale structures.

Development of Structural Steel

Air is blown into a vessel of molten iron to burn out the impurities. A large batch of iron could be made into steel in about 20 minutes.

Bessemer Process

Also known as the “Siemens-Martin process”, was a significant advancement in steelmaking during the 19th and early 20th centuries. It involved melting pig-iron along with scrap steel and iron ore in a large furnace called an open hearth.

Open-hearth Method

Landmark buildings such as Empire State Building used steel frame construction, enabling buildings to rise to unprecedented heights.

Skyscrapers and Bridges

 The first steel framed building in the world

 Design by William LeBaron Jenney

 One of the earliest skyscrapers built in Chicago, 1895.

 The steel framing was fireproofed with masonry and the exterior facings were supported on steel frames.

Home Insurance Company Building

 The world’s first reinforced concrete skyscraper in 1903.

 The development of steel reinforcement allowed concrete to bear greater loads and resist tension, making taller and more durable buildings possible. This paved the way for modern highrise construction.

Ingalls Building

A crucial determinant of the properties of any ferrous metal

Carbon content

Hard but brittle metal

Too much carbon

Malleable and relatively weak metal

Too little carbon

Has a high tensile strength; resistant to breaking or deforming under tension

Strength

Durable and resistant to wear, degradation, and corrosion.

Durability

Steel can be easily shaped, formed, and fabricated.

Versatility

Can be easily shaped without breaking. Ideal for manufacturing processes.

Malleability

Can undergo significant deformation before rupturing. Allows it to be stretched or bent without breaking.

Ductility

A malleable alloy of ironthat contain less than 2% carbon. Has a carbon content less than that of cast iron and more than that of wrought iron

Steel

Can be joined together using various weld techniques. Allows for the construction of large and complex structures by welding smaller components.

Weldability

Can transfer heat efficiently.

Thermal Conductivity

While not as conductive as metal, steel still has good electrical conductivity suitable for electrical applications where strength and durability are also required.

Electrical Conductivity

Can be melted down and reused to create new steel products without losing its properties.

Recyclability

Unalloyed steel in which the residual elements are controlled. Any increase in carbon content increases the strength and hardness of the steel but reduces its ductility and weldability.

Carbon Steel

Refers to a carbon steel to which various elements have been added in a sufficient amount to obtain particular physical or chemical properties.

Alloy Steel

A high strength, low alloy steel that forms an oxide coating when exposed to rain or moisture

Weathering steel

An alloy steel containing 10-20% tungsten for increased hardness and heat retention at high temperatures.

Tungsten steel

A corrosion-resistant alloy of iron that contains atleast 10.5% chromium. The chromium forms a thin oxide layer on the surface, which prevents rust and corrosion.

Stainless steel

Regular iron or steel coated with a layer of zinc to protect it from rust and corrosion. The zinc layer acts as a sacrificial coating, it corrodes instead of the underlying metal.

Galvanized Iron

Two Main Methods of galvanization

1. Hot-Dip Galvanization

2. Electro-Galvanization

Steel is dipped in molten zinc, creating a thick, durable zinc coating.

Hot-Dip Galvanization

A thin layer of zinc is applied using electrolysis, resulting in a smoother finish but less durability.

Electro-Galvanization

Galvanized and Stainless Steel

Process of Converting Iron Ore to Steel

Raw Materials

 Iron Ore

 Limestone

 Coal

Process of Converting Iron Ore to Steel

1. Smelting

2. Blast Furnace

3. Coke

4. Slag

5. Molten iron is drawn off at the bottom of the furnace and held in a liquid state for processing into steel.

To melt or fuse ore in order to separate the metal constituents

Smelting

Produced in a Blast Furnace charged with alternating layers of iron ore, coke, and crushed limestone

Cast iron

A large vertical furnace for smelting iron from ore, in which combustion is intensified by a continuous blast of air through the fuel

Blast Furnace

The solid residue of coal left after destructive distillation, used as a fuel

Coke

The vitrified matter left as a residue of limestone by smelting of iron ore. Also called “cinder”.

Slag

Most steel that is converted from iron is manufactured by?

Basic oxygen process

Scrap steel from which structural steel is made comes mostly from?

Junk cars

A piece of metal ready to be drawn, pressed, or machined into a finished product

Beam Blank

A bar of steel reduced from continuous casting to dimensions suitable for further rolling

Bloom

Steel Shapes

Wide flange

 Used for most beams ad columns, superseding the older I-beam shape

 Manufactured Tall and Narrow for beams; Squarish for columns and foundation piles

 Ex: W8x18 - The first number is nominal depth in inches, second number is weight in lbs/ft

W shape

Also known as S-shape and American standard beam

 Structurally less efficient than wide flange because of structural limitations stemming from its production method

 Ex: S18x70 - S denotes an I-beam shape; first number is nominal depth in inches; second number is weight in lbs/ft

I-beam

American standard channel

 Are on of the more common types of metal channels and widely used in building, wall, roof, and ceiling support. The term C channel encompasses a wide variety of channel types, dimensions, and sizes since sheet metal can be roll-formed t fit any specific requirements.

C-shape

Equal and unequal leg angles

 Extremely versatile

 Can be used as members of roof truss paired with gusset plates at the joints, diagonal braces of steel frame, wide flange support

L shapes

Structural tee cut from W shape

WT shape

Square, rectangular, circular

HSS (Hollow Structural Section)

Square, round, and flat

 Commonly used for railngs, accent walls, welding, window grills, fence

Structural Bars

Commonly used for window frames, construction work, fences, garage door, metal furniture

Zee Bar or Z-bar