Metallic Materials: Classification, Iron, Steel, and Casting

Metallic Material Classification

Metallic materials are classified in several ways:

• By chemical composition (e.g., steel or bronze).
• By use (e.g., light-alloy steel, light alloys).
• By manufacturing process (e.g., sintered materials).
• By main applications (e.g., for ships, plates).

Forms of Iron Materials

Iron can exist in various forms, including:

• Forged iron
• Cast iron
• Steel
• Conglomerate iron

Non-Ferrous Material Classification

Non-ferrous materials are classified into:

• Heavy Alloys: Copper, lead, zinc.
• Light Alloys: Aluminum, titanium.
• Ultra-Light Alloys: Magnesium, beryllium.

The Catalan Forging Process

The Catalan forging process utilized a small furnace or fireplace where wood or charcoal combustion was alternated with iron ore. Combustion, enhanced by air jets from bellows, generated high temperatures that facilitated the reduction of large quantities of iron.

Forging Materials in Ancient Times

Materials from ancient times were forged to produce iron, a process that helped maintain proper oxidation control.

Characteristics of Cast Iron

Cast iron is a material that is melted and molded. However, it is not easily cleaned and is brittle.

Applications of Cast Iron

Cast iron was primarily used for molding parts.

Abraham Darby and Coke Smelting

Abraham Darby pioneered the use of coke for smelting iron. This innovation allowed for higher furnace loads and temperatures, resulting in a greater flow of molten metal.

Defining Ore and Gangue

• Ore: A naturally occurring mineral or rock from which a valuable metal or mineral can be extracted.
• Gangue: The commercially worthless material that surrounds, or is mixed with, a desired mineral in an ore deposit (e.g., earth, lime, silica).

Understanding Slag

In a blast furnace, a specialized device, layers of minerals and coke are regularly loaded. To remove impurities, fluxing agents are added to the mixture. The reaction generates slag, which is a byproduct containing the impurities.

What is Pig Iron?

Pig iron is an iron alloy with a high carbon content and many impurities. It is very brittle and is primarily used as an intermediate product for manufacturing other iron-based materials.

Pig Iron Processing in Converters

Pig iron is processed in converters through a refining process. This process removes excess carbon and other unwanted impurities to achieve a desired chemical composition, after which the material can solidify.

Advantages of Continuous Casting

Continuous casting offers several advantages: it allows for the creation of continuous profiles, supports multi-line production, and eliminates the need for primary rolling, leading to significant cost savings.

Carbon Content in Cast Iron

Cast iron alloys typically have a carbon content ranging between 1.76% and 6.67%.

Classification of Castings

Castings are generally classified as:

• Standard Castings: Such as gray cast iron and white cast iron.
• Alloy Castings: Castings with specific alloying elements.
• Special Castings: Castings that undergo special treatments.

Carbon Content in Steel

Steel typically has a carbon content ranging between 0.03% and 1.76%.