What Is Difference Between Stainless Steel And Aluminum
Updated: 11 Dec 2024
Stainless steel and aluminum are widely used daily, from life to industry. Both stainless steel and aluminum have good corrosion resistance, and their performance is very similar. However, some products or projects require the most suitable aluminum alloy or stainless steel. So to choose which material, you can first understand the difference between them.
Strength
Stainless steel is always stronger than aluminum in the same shape and thickness. The tensile strength of stainless steel alloys is usually 515MPa-1300MPa, while the tensile strength of aluminum is 100MPa-400MPa. Of course, the strength of both can be increased through other treatments, but in terms of strength only, stainless steel is better than aluminum.
Weight
This is a clear advantage of aluminum. In most cases, the weight of an aluminum part is about one-third of the weight of the same part made of stainless steel. The specific density of the two varies depending on the specific alloy and may be affected by design choices. But in all cases, aluminum is lighter than stainless steel.
Ductility
Suppose you need a specific shape to meet your needs. In that case, the plasticity of the material is a very important factor. In this regard, aluminum is superior to stainless steel in plasticity, and aluminum is easier to form, cut, bend, etc.
Corrosion resistance
Both stainless steel and aluminum have excellent corrosion resistance. Much like the chromium oxide layer on stainless steel, aluminum can form a passivated aluminum oxide layer, reducing corrosion. Stainless steel's corrosion resistance is more extensive and powerful than aluminum, especially in acidic, alkaline and marine environments. Stainless steel can better resist various types of corrosion, including pitting, crevice corrosion and stress corrosion cracking. However, in some specific applications, aluminum also has unique advantages due to its light weight and good oxidation resistance. Which material to choose ultimately depends on the specific application environment and corrosion conditions.
Conductivity
Although the actual conductivity will vary depending on the use scenario and environmental conditions, aluminum has better conductivity in the same scenario and environment than stainless steel. When pulled into the wire, aluminum can even be comparable to copper in some aspects.
Thermal conductivity
Thermal conductivity is also affected by the use scenario and environmental conditions. Under the same conditions, aluminum has better thermal conductivity than stainless steel. However, the melting point of aluminum is lower than the softest stainless steel. Most aluminum alloys become very soft at around 400°C, while 304 stainless steel melts at around 1400°C. Therefore, stainless steel is a better choice for high temperature (500-1000°C). However, aluminum has the best thermal conductivity in low temperature environments, so it is best for heat sinks and HVAC components.
Welding
Aluminum is much more difficult to weld than stainless steel. Aluminum alloys are soft, highly sensitive, and have an oxide layer that insulates. In the molten state, impurities easily affect aluminum, which can lead to porous, fragile welds. And aluminum oxides' melting point is higher than aluminum's, so removing oxides before welding is also a challenge. Due to its high thermal conductivity and low melting point, aluminum is less machinable than other metals and can easily lead to burn-through. Stainless steel welding is much easier; it has higher heat resistance and lower sensitivity.
Magnetism
Suppose your requirement for the material non-magnetic reaction,n. In that case, aluminum is the material most suitable because aluminum alloys do not contain iron. The magnetism of stainless steel is affected by the metal elements it contains. All ferritic grades of stainless steel will have a certain degree of magnetism. Its magnetism varies according to the content of metal elements.
Cost
Aluminum's raw material and processing costs are generally lower than those of stainless steel. However, stainless steel may be more cost-effective in certain applications when considering durability and maintenance costs. The choice of which material depends not only on the initial price but also on its long-term use cost and specific application requirements.
If you have strict requirements on strength, corrosion resistance, high-temperature resistance, and welding performance, stainless steel is the best choice; if you focus on conductivity, thermal conductivity, lightweight, plasticity, non-magneticity, and cost, aluminum is more suitable. If you are unsure about the choice of material, please contact us, and we will provide you with professional advice.
Stainless steel is always stronger than aluminum in the same shape and thickness. The tensile strength of stainless steel alloys is usually 515MPa-1300MPa, while the tensile strength of aluminum is 100MPa-400MPa. Of course, the strength of both can be increased through other treatments, but in terms of strength only, stainless steel is better than aluminum.
Weight
This is a clear advantage of aluminum. In most cases, the weight of an aluminum part is about one-third of the weight of the same part made of stainless steel. The specific density of the two varies depending on the specific alloy and may be affected by design choices. But in all cases, aluminum is lighter than stainless steel.
Ductility
Suppose you need a specific shape to meet your needs. In that case, the plasticity of the material is a very important factor. In this regard, aluminum is superior to stainless steel in plasticity, and aluminum is easier to form, cut, bend, etc.
Corrosion resistance
Both stainless steel and aluminum have excellent corrosion resistance. Much like the chromium oxide layer on stainless steel, aluminum can form a passivated aluminum oxide layer, reducing corrosion. Stainless steel's corrosion resistance is more extensive and powerful than aluminum, especially in acidic, alkaline and marine environments. Stainless steel can better resist various types of corrosion, including pitting, crevice corrosion and stress corrosion cracking. However, in some specific applications, aluminum also has unique advantages due to its light weight and good oxidation resistance. Which material to choose ultimately depends on the specific application environment and corrosion conditions.
Conductivity
Although the actual conductivity will vary depending on the use scenario and environmental conditions, aluminum has better conductivity in the same scenario and environment than stainless steel. When pulled into the wire, aluminum can even be comparable to copper in some aspects.
Thermal conductivity
Thermal conductivity is also affected by the use scenario and environmental conditions. Under the same conditions, aluminum has better thermal conductivity than stainless steel. However, the melting point of aluminum is lower than the softest stainless steel. Most aluminum alloys become very soft at around 400°C, while 304 stainless steel melts at around 1400°C. Therefore, stainless steel is a better choice for high temperature (500-1000°C). However, aluminum has the best thermal conductivity in low temperature environments, so it is best for heat sinks and HVAC components.
Welding
Aluminum is much more difficult to weld than stainless steel. Aluminum alloys are soft, highly sensitive, and have an oxide layer that insulates. In the molten state, impurities easily affect aluminum, which can lead to porous, fragile welds. And aluminum oxides' melting point is higher than aluminum's, so removing oxides before welding is also a challenge. Due to its high thermal conductivity and low melting point, aluminum is less machinable than other metals and can easily lead to burn-through. Stainless steel welding is much easier; it has higher heat resistance and lower sensitivity.
Magnetism
Suppose your requirement for the material non-magnetic reaction,n. In that case, aluminum is the material most suitable because aluminum alloys do not contain iron. The magnetism of stainless steel is affected by the metal elements it contains. All ferritic grades of stainless steel will have a certain degree of magnetism. Its magnetism varies according to the content of metal elements.
Cost
Aluminum's raw material and processing costs are generally lower than those of stainless steel. However, stainless steel may be more cost-effective in certain applications when considering durability and maintenance costs. The choice of which material depends not only on the initial price but also on its long-term use cost and specific application requirements.
If you have strict requirements on strength, corrosion resistance, high-temperature resistance, and welding performance, stainless steel is the best choice; if you focus on conductivity, thermal conductivity, lightweight, plasticity, non-magneticity, and cost, aluminum is more suitable. If you are unsure about the choice of material, please contact us, and we will provide you with professional advice.
