7075 Aluminum VS Steel：Which is Better

Aluminum alloy AA 7075 and steels belong to entirely different classes of materials. Their superiority depends upon their application. AA 7075 is the strongest alloy among 7xxx series and have very high strength to weight ratio. This property makes it a special alloy for multiple applications and raise the question of compression with steels. Steels, on the other hand, have various sub-classes i.e. plain carbon steels, low alloy steels, stainless steels, tool steels and ultra-high strength steels which are designed for particular applications.

 

In this article, you will find a detailed technical comparison of both type of materials based on their properties, applications and fabrication.

 

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AA 7075 Alloy

Different Types of Steel

Chart of the Differences Between 7075 Aluminum and Steel

7075 Aluminum and Steel Chemical Properties

7075 Aluminum and Steel Physical Properties Chart

7075 Aluminum vs Steel: Mechanical Properties

Which is 7075 Aluminum and Steel More Expensive

When to Use 7075 Aluminum or Steel Fitting

Why Choose Tuofa for Custom 7075 Aluminum and Stainless Steel Parts

 

 

 

AA 7075 Alloy

 

AA 7075 is an alloy of Zinc in Aluminum. Other important alloying elements of chemical composition of AA 7075 include magnesium, copper and chromium. AA 7075 is strongest in T6 condition. Required mechanical properties are achieved using specific heat treatment process. Generally, the alloy is solution treated at about 460 ˚C followed by water quenching. After achieving super saturated solid solution of AA 7075, it is artificially aged at 120-160 ˚C for several hours based of the size and thickness of the part. This condition of AA 7076 is called T-6 condition which is mostly used in aerospace, automotive and structural applications.

 

 

 

Different Types of Steel

 

Steel is a class of material in which properties of pure iron are improved using various type of alloying elements. Major classes of steels involve:

 

1. Plain carbon steels e.g. 1045
2. High strength low alloy steels e.g. 4340
3. Stainless steels e.g., SS 420, SS321, 17-7 Ph etc.
4. Tool steels e.g., D2, H13, K-105 etc.
5. Ultra high strength steels e.g., Maraging 400

 

 

Each class of steel has its own characteristic applications based on their properties. Steel usually have very high strength and hardness as compared to AA 7075. However, low strength to weight ration than AA7075 limit their use in particular application, especially where weight is prime concern for designers.

 

 

 

Chart of the Differences Between 7075 Aluminum and Steel

 

Steels and AA 7075 have remarkable differences based on their chemical composition, mechanical properties and physical properties.

 

 

AA 7075 has FCC crystal structure and can be drawn in several shapes with an ease as compared to steel. Though, corrosion resistance of AA 7075 inferior to many other aluminum alloys but far better than many steels except few stainless steels.

 

 

 

7075 Aluminum and Steel Chemical Properties

 

Chemical properties of AA 7075 and steels depends upon their chemical constituents. AA 7075 form a protective film over its surface which stops further oxidation. On the other hand e.g. plain carbon steel and tool steels, are prone to excessive oxidation as they form a loose oxide layer over their surfaces which don’t protect further oxidation. As far as, stainless steels are concerned e.g. SS 321, SS 316L, they are more chemically stable than AA 7075 as they form strong protective layer of oxide to restrict further oxidation.

 

 

 

7075 Aluminum and Steel Physical Properties Chart

 

There are appreciable differences in physical properties of both material types. The most prominent properties are given in below table:

 

 

 

High strength-to-weight ratio

 

AA 7075 has high strength to weight ratio than steels. This property make AA 7075 a prominent competitor of steels in application where weight reduction is inevitable e.g., aerospace applications. The strength to weight ration of AA 7075 solely depends upon its heat treatment condition. In all such applications, T6 temper condition is used. On the other hand, steels have inferior strength to weight ration due to their high density. The unit of this property is N/m³.

 

 

Are 7075 aluminums stronger than steel

 

The answer is “No”. Though AA 7075 is strongest in aluminum family but usually steels are far stronger than AA 7075 e.g., AISI 1045, SS 420, SS316, 17-7Ph, Maraging steel, SAE 4140, SAE 4340 etc. However, there are very few steel grades, whose tensile strength in annealed condition is comparable with AA 7075 e.g. AISI 1015, AISI 1020 etc. But as a rule it can be stated that steels are stronger than AA 7075.

 

 

Corrosion resistance

 

Aluminum alloys are popular because of their exceptionally high corrosion resistance. However, in case of AA 7075, presence of copper make it less corrosion resistance than other alloys of its family. It causes inter-granular corrosion. Sometimes protective coatings are applied in AA 7075 to protect it from corrosive environment.

 

Steels except stainless steels, are highly corrosive in nature. They form a porous layer of oxide over their surface which degrade with time and cause further corrosion. They cannot be used in field without corrosion protection.

 

 

Resistance to deformation

 

 AA 7075 is easily drawable and can be formed in several shapes. Usually, the shaping process of this grade is carried out in solution treatment condition (O-condition). Once the final shape is achieved, aging is performed to achieve superior mechanical properties. AA 7075 alloy’s tendency to deformation is superior to steels.

 

 

 

7075 Aluminum vs Steel: Mechanical Properties

 

Mechanical properties of AA 7075 and steels are remarkably different and found different set of application. AA 7075 is used in aerospace application where high strength is required in addition to light weight e.g. in fabrication of fuselages, wings, helicopter rotor blades etc.

 

 

*Properties are in T6 condition

 

The mechanical properties of steels are solely depends upon the grade of steel. The broad ranges of mechanical properties mentioned in the table covers all grades of steel from AISI 1010 to Ultrahigh strength steels.

 

 

Weldability

 

Weldability of AA 7075 is not too good as compared to other grades of its family. Usually, it is welded in O-condition because it will lose its strength in the weld region when welded in aged condition. Usually welding rods having low copper content are preferred for its welding. On the other hand, steels having less percentage of carbon have far better weldability than AA 7075, while steels having high strength and higher percentage of carbon have inferior weldability than AA 7075.

 

 

Machinability

 

AA 7075 has moderately good machinability as compared to high strength steels. However, its machinability is more challenging when compared with other aluminum alloys.

 

 

 

 

 

 

Which is 7075 Aluminum and Steel More Expensive

 

As far as simple grades of steels e.g. AISI 1030, AISI 1045 or SAE 8620 are concerned, AA 7075 is more expensive than these steels. However, several high strength grades of steel which require special refining techniques e.g. stainless steels, 17-7 Ph, maraging steels are far more expensive than AA 7075.

 

 

 

When to Use 7075 Aluminum or Steel Fitting

 

It is entirely depends upon application. AA 7075 steel fittings are usually used where moderate strength, light weight, better corrosion resistance, good weldability and non-magnetic properties are essential. Contrarily, steels fitting are usually less expensive, have high strength, high weight, magnetic and relatively poor corrosion resistance.

 

 

 

Why Choose Tuofa for Custom 7075 Aluminum and Stainless Steel Parts

 

Tuofa has specialization in manufacturing of high purity aluminum alloy AA 7075 with precise control in product geometry. Stainless less pasts of various grads are also available of customized requirements. Our expert’s consultancy will be beneficial to our clients at many level regarding finance and time saving.

 

 

 

FAQs

 

l7075 T6 aluminum vs steel

 

AA 7075 has exceptionally high strength to weight ratio as compared to steels. However, steels are usually stronger alloys than AA 7075.

 

 

Which is stronger aluminum or steel?

 

Usually steel is stronger than AA 7075 steel. However, strength of few grades of steel e.g. AISI 1010, AISI 1015 etc. are comparable with AA 7075.