Extrusion uses ductile materials that can withstand large plastic deformation without cracking. Common raw materials include metals such as aluminum, copper, magnesium, steel, and their alloys, as well as non-metals like plastics and rubber.

The selection of raw material depends on factors such as extrudability, strength, temperature resistance, and end-use application.

Raw Materials for Extrusion

The raw material for extrusion depends on the type of extrusion process (metal, polymer, ceramic, or food extrusion). However, all extrusion materials must possess sufficient plasticity, flowability, and strength to deform and pass through the die without cracking.

1. Requirements of Raw Materials for Extrusion

An ideal extrusion material should have:

Good plastic deformation ability
Low flow stress
Uniform microstructure
Resistance to cracking
Suitable melting or softening temperature
Good surface finish capability

2. Metallic Raw Materials for Extrusion

2.1 Aluminum and Aluminum Alloys

Most widely used extrusion material

Forms Used

Cast billets
Homogenized billets

Common Alloys

1xxx (pure aluminum)
6xxx (Al–Mg–Si)
7xxx (Al–Zn–Mg)

Reasons for Use

Low extrusion force
Excellent ductility
Lightweight
Corrosion resistance

Applications

Window frames
Heat sinks
Structural profiles
Automotive components

2.2 Copper and Copper Alloys

Forms Used

Billets
Rods

Types

Pure copper
Brass
Bronze

Properties

High electrical and thermal conductivity
Good corrosion resistance

Applications

Electrical conductors
Plumbing tubes
Heat exchangers

2.3 Steel and Steel Alloys

Forms Used

Cylindrical billets

Types

Carbon steel
Alloy steel
Stainless steel

Characteristics

High strength
Requires hot extrusion
High extrusion forces

Applications

Seamless pipes
Structural components
Automotive parts

2.4 Magnesium Alloys

Very lightweight
Good extrudability
Used in aerospace and automotive industries

2.5 Lead and Tin

Very soft materials
Easily extruded at room temperature

Applications

Radiation shielding
Cable sheathing

3. Polymer (Plastic) Raw Materials for Extrusion

Plastics are extruded in pellet, powder, or granule form.

3.1 Thermoplastics (Most Common)

Polyethylene (PE)
Polyvinyl chloride (PVC)
Polypropylene (PP)
Polystyrene (PS)
Nylon

Characteristics

Soften when heated
Can be re-melted
Continuous extrusion possible

Applications

Pipes
Films
Sheets
Insulation

3.2 Thermosetting Plastics

Epoxy
Phenolic resins

Note: Limited use due to non-remelting nature.

4. Ceramic Raw Materials for Extrusion

Forms Used

Fine powders
Mixed with binders and plasticizers

Materials

Alumina
Zirconia
Silicon carbide

Characteristics

Extruded in plastic state
Require drying and sintering

Applications

Insulators
Catalyst supports
Tiles

5. Composite Materials for Extrusion

Types

Fiber reinforced polymers
Metal matrix composites

Raw Material Form

Pellets
Pre-mixed compounds

Applications

Structural components
Aerospace and automotive parts

6. Food Industry Raw Materials (Food Extrusion)

Common Materials

Cereals (corn, wheat, rice)
Proteins
Starches

Applications

Pasta
Snacks
Pet food

7. Forms of Raw Materials Used in Extrusion

Material Type	Form
Metals	Billets, rods
Plastics	Pellets, granules, powder
Ceramics	Powder + binder
Food	Flour, starch

8. Pre-treatment of Raw Materials

Metals

Casting
Homogenization
Pre-heating
Surface cleaning

Plastics

Drying
Mixing additives (stabilizers, plasticizers)

Ceramics

Mixing with binders
De-airing

9. Summary

Raw materials for extrusion vary widely but must be capable of plastic flow under compressive force. Metals are used in billet form, polymers as pellets, and ceramics as powder-binder mixtures. Proper material selection and pre-treatment ensure defect-free extrusion and high-quality products.