7075 Billet Aluminum VS 4140 Steel

2024-09-20 by Cherry

In modern manufacturing, 7075 Billet Aluminum VS 4140 

steel is two very representative materials, each with 

unique characteristics, and are widely used in die-casting

machines. Understanding the application of these two 

materials in the die-casting process can not only improve

production efficiency, but also optimize the performance

of the final product.

Characteristics of 7075 Billet Aluminum 

7075 Billet Aluminum is a high-strength aluminum alloy 

material, which contains alloying elements such as zinc

and magnesium. 

This combination of ingredients gives it extremely

high strength - close to the strength of many sheets 

of steel, while maintaining some excellent properties 

of aluminum, such as lightweight and good corrosion 

resistance.

7075 aluminum alloy is one of the aluminum alloys widely

used in the aerospace and automotive industries. The 

main components include aluminum, zinc, magnesium, and a

small amount of copper. Its main characteristics are 

as follows:

1. High strength: The tensile strength and yield strength 

of 7075 aluminum alloy are very high, suitable for 

structural parts that require high strength.

2. Lightweight: Compared with steel, 7075 aluminum alloy

has a lower density, which can effectively reduce the

overall weight of the product and improve the performance

of the product.

3. Good corrosion resistance: After surface treatment, 7075 

aluminum alloy can effectively resist oxidation and 

corrosion and is suitable for harsh environments.

4. Good machinability: 7075 aluminum billets are easy to 

machine and weld, making it easy to manufacture complex

parts.

Working principle of die casting machine

A die-casting machine is a device specially used to inject 

molten metal into a mold to form a casting. It's basic 

working process is as follows:

1. Melting metal: Heat 7075 aluminum billets or 4140 steel

to a molten state and prepare for die casting.

2. Injection into mold: Inject molten metal into a pre-prepared

mold under high pressure to ensure that the metal can

quickly fill the mold cavity.

3. Cooling and solidification: In the mold, the molten metal

quickly cools and solidifies to form a casting.

4. Remove the casting: open the mold after cooling and take 

out the formed casting.

4. Post-processing: The casting may require subsequent 

processing, such as machining or surface treatment, to meet

the final product standards.

Relationship between 7075 Billet Aluminum and die

casting machine

1. The pressure system of the die-casting machine plays a

decisive role in the die-casting process of 7075 Billet 

Aluminum 

Due to the high strength of the 7075 aluminum billet, the 

die casting machine needs to provide sufficient pressure 

to ensure that the aluminum billet can smoothly fill the 

mold cavity. It is like pushing a stubborn child into a 

specific space and sufficient force must be applied. 

The injection pressure of the die-casting machine must

be precisely controlled. If the pressure is insufficient,

the 7075 aluminum billet may not be able to fill the mold, 

resulting in defects in the casting, such as lack of meat 

or incomplete shape.

2. Moreover, the melting point of 7075 aluminum billet is 

relatively high, which puts strict requirements on the 

temperature control system of the die-casting machine

The die-casting machine needs to be able to heat the mold to

a suitable temperature range to ensure that the 7075

aluminum billet maintains good fluidity during the die-casting

process. 

Just like a chef must accurately control the heat when

cooking a delicate dish. If the mold temperature is too 

low, the fluidity of the 7075 aluminum billet will

deteriorate, and cold shut will easily occur, just like 

water will freeze at low temperatures and cannot flow 

smoothly; while too high a temperature may cause the 

aluminum billet to overheat, affecting its final mechanical

properties.

3. In terms of molds, due to the high strength of 7075 

aluminum billets, the material, and structural strength 

requirements of the molds used by the die-casting machine

are also very high

The mold must be able to withstand high pressure during

the die-casting of 7075 Billet Aluminum and must ensure

sufficient wear resistance. 

Because during the die-casting process, the wear of the

7075 Billet Aluminum on the mold is relatively serious.

If the mold is not durable, frequent mold replacement will

not only increase production costs but also affect production

efficiency.

Application of 7075 Billet Aluminum in die-casting

machine

The application of 7075 Billet Aluminum in die-casting 

machine is mainly reflected in the following aspects:

1. Aerospace field: Due to the high strength and lightweight

characteristics of 7075 aluminum alloy, it is widely used 

in die casting of aircraft parts, such as fuselage brackets

and connectors.

2. Automotive industry: In the automotive industry, 7075 

aluminum alloy is used to manufacture engine components 

and body structural parts, which can effectively improve 

fuel efficiency.

3. Sports equipment: 7075 aluminum alloy is widely used in the

manufacture of high-end sports equipment, such as bicycle

frames and ski equipment, due to its excellent strength-to-weight

ratio.

Characteristics of 4140 steel

4140 steel is a medium-carbon alloy steel. It is known for 

its good toughness, strength, and wear resistance. It is also

a low-alloy high-strength steel with the main components of 

iron, carbon, chromium, and molybdenum. Its main characteristics

include:

1. Excellent strength and toughness: After heat treatment, 4140

steel shows extremely high strength and toughness, suitable

for heavy-load applications.

2. Good wear resistance: This steel has excellent wear resistance

and is suitable for working conditions that need to withstand

wear.

3. Suitable heat treatment performance: 4140 steel can achieve 

different hardness and strength through heat treatment, and

has strong process flexibility.

4. Good weldability: Under appropriate welding conditions, 4140

steel can achieve high-quality welding connections.

Application of 4140 steel in die-casting machines

The application of 4140 steel in die-casting machines is mainly

concentrated on the manufacture of heavy-duty mechanical 

parts, which is specifically reflected in:

1. Mechanical equipment: The high strength and wear resistance 

of 4140 steel make it an ideal material for key components 

in mechanical equipment, such as gears, shafts, and connecting

rods.

2. Construction industry: In some load-bearing structures, 4140

steel is widely used in die-casting machines to manufacture

high-strength support components.

3. Mold manufacturing: 4140 steel is suitable for mold 

manufacturing due to its good wear resistance and hardness, 

which improves the service life of the mold.

A 7075 Billet Aluminum vs 4140 steel in die casting

There are some similarities between the use of 7075 aluminum

billet and 4140 steel in die casting, but there are also 

significant differences.

1. The melting point of 4140 steel is much higher than that

of 7075 aluminum billet, which means that the die-casting

machine needs a higher temperature to keep 4140 steel in 

a liquid state that can be die-cast. The heating system of

the die-casting machine must be powerful enough to meet 

the die-casting needs of 4140 steel. This is like melting 

a harder piece of ice, which requires more heat.

2. In terms of pressure, 4140 steel requires greater 

pressure to push it to flow in the mold during die-casting 

due to its higher density and hardness. The clamping force 

of the die-casting machine also needs to be increased accordingly

to prevent the molten steel from overflowing from the gap

of the mold under high pressure, and there must be a stronger

force to restrain it.

4140 steel has a greater impact force on the mold during the

die-casting process than 7075 aluminum billet, which requires

the die-casting machine's mold to have higher impact resistance.

The design and manufacture of the mold must take into account 

the special circumstances of 4140 steel die-casting, such

as increasing the wall thickness of the mold and using better

quality mold materials. Otherwise, the mold is easily damaged

during the die-casting process, resulting in the production 

interruptions.

3. From the perspective of product performance, the parts 

die-cast from 7075 Billet Aluminum has the advantage of 

lightweight and corrosion resistance, and are suitable for

parts with weight requirements and harsh environments in 

aerospace, automobile manufacturing, and other fields, such

as aircraft wing structures or automobile engine parts. 

The parts die-cast from 4140 steel have higher strength 

and wear resistance, and are often used to manufacture 

some parts that need to withstand high loads and high 

wear, such as gears or shaft parts of heavy machinery.

However, both 7075 Billet Aluminum and 4140 steel face

some challenges in the application of die-casting machines.

For die-casting machines, how to accurately control parameters

such as pressure, temperature, and speed to adapt to the 

characteristics of these two different materials is an urgent

problem to be solved. Moreover, with the continuous improvement

of product quality requirements, the performance of die-casting

machines also need to be continuously improved.

1. In terms of cost, the raw material cost of 7075 aluminum 

billet is relatively high, but due to its lightweight, 

it can save transportation and energy costs to a certain extent

in some weight-sensitive applications. 

The raw material cost of 4140 steel is relatively stable, 

but due to its greater difficulty in die-casting, it may 

lead to a high scrap rate in the die-casting process, thereby

increasing production costs. The efficiency and stability of

the die-casting machines play a key role in controlling costs. 

If the die-casting machine can operate efficiently and 

stably, and reduce the scrap rate, the die-casting cost

of both 7075 aluminum billet and 4140 steel can be 

effectively controlled.

2. In terms of environmental protection, the recycling of 

7075 Billet Aluminum is relatively easy, and the waste 

generated during the die-casting process is relatively 

small. There is also a certain process for recycling 4140

steel, but due to its complex composition, more processing 

steps may be required during the recycling process.

If the design and operation of the die-casting machine 

can be more environmentally friendly, such as using a more

efficient heating system to reduce energy consumption, 

or using a more advanced exhaust gas treatment system to 

reduce pollution emissions, it will help improve the 

environmental performance of these two materials in the 

die-casting process.

Synergistic application of 7075 Billet Aluminum 

and 4140 steel

In some complex application scenarios, 7075 Billet Aluminum 

and 4140 steel can form a synergistic effect. By combining

these two materials, manufacturers can take advantage 

of the lightweight 7075 aluminum alloy and the strength

advantages of 4140 steel to create higher-performance 

composite products.

For example, in the aerospace field, 7075 aluminum alloy 

can be used for non-load-bearing parts, while 4140 steel

is used for structural parts that bear heavy loads. 

This combination can ensure the overall strength of the

structure while reducing weight.

Future development trend

With the advancement of science and technology, the 

application prospects of 7075 Billet Aluminum and 4140 

steel in die-casting machines is broad. In the future, 

the continuous development of materials science will 

promote the performance of these two materials, and

more advanced alloy formulas and manufacturing processes

may be introduced to further enhance their application

effects in die-casting machines.

In addition, environmental protection and sustainable 

development will also become an important trend in the 

future manufacturing industry. The recyclability of 7075

aluminum alloy and the durability of 4140 steel give 

it an advantage in green manufacturing.

Conclusion

In short, the application of 7075 Billet Aluminum and 4140

steel in die-casting machines has its characteristics,

and the application of 7075 Billet Aluminum and 4140 steel 

in die-casting machines demonstrates a deep understanding

and flexible application of material properties in modern

manufacturing. 

They all rely on precise control and high performance 

of die-casting machines to achieve efficient die-casting

production. At the same time, die-casting machines are

constantly being improved and optimized according to the

application requirements of these two materials, and a

mutually dependent and mutually reinforcing relationship

has been formed among the three.

By effectively utilizing the characteristics of these two 

materials, manufacturers can improve production efficiency, 

optimize product performance, and meet diversified market 

needs. Understanding their characteristics and applications 

can help companies gain an advantage in the fierce market 

competition and lay a solid foundation for future technological

innovation and product development.

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