Stainless steel and aluminum alloy have good corrosion resistance, and are used more and more widely in modern construction. So the same corrosion resistance, stainless steel and aluminum alloy what is the difference in performance, how to choose the most reasonable?
What is Stainless steel?
Iron based alloys containing more than 12% chromium are called stainless steel. It is distinguished by its high content of chromium. Stainless steel contains at least 10.5% chromium to improve corrosion resistance and strength. Stainless steel is an extremely versatile material. It is preferred in situations where both steel properties and corrosion resistance are required.
Stainless steel resistant to air, steam, water and other weak corrosive media and acid, alkali, salt and other chemical corrosive media corrosion of steel. Called stainless acid steel. In practical application, the steel that is resistant to weak corrosive medium is often called stainless steel, and the steel that is resistant to chemical medium corrosion is called acid resistant steel. Due to the difference in chemical composition, the former is not necessarily resistant to chemical media corrosion, while the latter generally have no rust. The corrosion resistance of stainless steel depends on the alloying elements contained in the steel.
The Main Advantages of Stainless Steel
- Physical properties: heat resistance, high temperature resistance, low temperature resistance and even ultra-low temperature resistance;
- Chemical properties: chemical and electrochemical corrosion resistance in steel is the best, second only to titanium alloy;
- Process performance: plasticity is very good, can be processed as a variety of plates, pipes and other profiles, suitable for pressure processing;
What is Aluminum alloy?
Aluminum is a silver-white and shiny metal, density 2.702g/cm 3, melting point 660.37℃, boiling point 2467℃. A general term for aluminum – based alloys. The main alloying elements are copper, silicon, magnesium, zinc, manganese, and the minor alloying elements are nickel, iron, titanium, chromium, lithium, etc.
Aluminum alloy has low density, but high strength, close to or more than high-quality steel, good plasticity, can be processed into a variety of profiles, with excellent electrical conductivity, heat conduction and corrosion resistance, widely used in industry, the amount of only steel. Aluminum alloy is divided into two categories: cast aluminum alloy, used in the cast state; Deformed aluminum alloy, can withstand pressure processing, mechanical properties higher than the cast state. Can be processed into various forms, specifications of aluminum alloy.
The Main Advantages of Aluminum Alloy
- Low density: The density of low density aluminum is about 2.7g/cm3, which is only higher than the second lightest metal of magnesium in the metal structure material, and only 1/3 of iron or copper. It is distinct advantage of aluminum alloy.
- High plasticity: High plastic aluminum and its alloy have good ductility, which can be made into various types, plates, foils, tubes and wires by pressure processing means such as extrusion, rolling or drawing.
- Good conductive: The electrical conductivity and thermal conductivity of aluminum are second only to silver, gold and copper. For example, according to the electric conduction capacity of metal of equal mass, aluminum is almost twice that of copper.
- Easy to recycle: Aluminum melting temperature is low, 660° с, the waste is easy to regenerate, the recovery rate is very high, recycling energy consumption is only 3% of smelting.
13 Differences Between Aluminum and Stainless Steel
The biggest difference between stainless steel and aluminum alloy is that Stainless steels contain at least chromium to increase corrosion resistance and strength, while Aluminum alloys do not. Aluminum alloys are widely used in industry because of its good corrosion resistance, ductility，processability, weldability and electrical conductivity.
Aluminum VS Stainless Steel #1: Chemical Elements
The main elements of aluminum alloy are aluminum, silicon, copper, magnesium and zinc. According to the different content of each element, the aluminum alloy parts formed are different in performance. Stainless steel is cast from steel, in the smelting process to add chromium, nickel, manganese, silicon, copper and other metals, chromium is the main alloy element.
Aluminum VS Stainless Steel #2: Melting Point
The melting point of aluminum alloy is 660°C, and the melting point of stainless steel is 1450-1535°C.
Aluminum VS Stainless Steel #3: Resistance to Corrosion
Stainless steel is made up of elements such as iron and chromium, an additive that helps resist corrosion, whereas ordinary steel corrodes very easily. Therefore, it is necessary to spray paint or powder coat the steel to prevent rust and corrosion.
Aluminum is highly oxidized and its surface forms a passivation layer due to oxidation which makes it highly resistant to corrosion.
Aluminum VS Stainless Steel #4: Cost
Aluminum alloy is cheaper than stainless steel. Because the price of stainless steel and aluminum alloy have different models and processing technology, the normal use of 304 stainless steel price and 6061 aluminum alloy, the same weight under the price difference between the two is not big, the same volume because of the density of stainless steel, the price is higher than aluminum alloy. Of course, the factor of raw materials should be considered, and the price difference between waste recycling production and raw material production is also relatively large.
Aluminum VS Stainless Steel #4: Physical Property
The density of aluminum alloy is low, the weight of the same volume is smaller than stainless steel; The strength of aluminum alloy is similar to that of stainless steel. The hardness of aluminum alloy is lower than stainless steel, and the plasticity is better than stainless steel.
The tensile strength of aluminum alloys is generally between 170-310 MPa, while that of stainless steel is often etween 540-980 MPa.
Aluminum VS Stainless Steel #5: Ease of fabrication
Machinability of any material refers to the degree of difficulty in processing the material. Aluminum alloys are more difficult to machine than steels. They can be cast, forged, stamped and welded. Stainless steels can be cold worked, hot worked, forged and cast.
Aluminum VS Stainless Steel #6: Heat Resistance
The melting point of stainless steel in 1200 to 1500 degrees Celsius, the melting point of aluminum alloy in 500 to 800 degrees Celsius, The heat resistance of aluminum alloy is lower than stainless steel, and it cannot be used in high temperatures environment for a long time. Aluminum alloy can only withstand about 200 ℃ for a short period of time and about 150 ℃ for a long period of time.
Aluminum VS Stainless Steel #7: Appearance and Magnetism
Stainless steel surface color bright, aluminum alloy surface is dim, common stainless steel materials in life can shine, and aluminum alloy will not reflect; Stainless steel is usually weakly magnetic, while aluminum alloy is non-magnetic.
Stainless steel and aluminum alloy have different characteristics on the basis of corrosion resistance. When purchasing, it can be selected according to the use scenario and functional requirements.
Aluminum VS Stainless Steel #8: Heat Resistance Magnetism
The melting point of stainless steel in 1200 to 1500 degrees Celsius, the melting point of aluminum alloy in 500 to 800 degrees Celsius, The heat resistance of aluminum alloy is lower than stainless steel, and it cannot be used in high temperatures environment for a long time. Aluminum alloy can only withstand about 200 ℃ for a short period of time and about 150 ℃ for a long period of time.
Aluminum VS Stainless Steel #9: Electrical Conductivity
Aluminum is a good conductor of electricity and is known for its conductive properties. Because of its lightweight characteristics, it is often used in high voltage overhead power lines, automotive radiators and air conditioning units.
Aluminum VS Stainless Steel #10: Weight Ratio
One of the biggest differences is the weight of the material. Compared with aluminum, steel has a much higher density, which causes its weight to soar. Mild steel is lighter than carbon steel, but aluminum is much lighter anyway. Aluminum is therefore a much lighter but stronger material than steel in terms of weight.
Aluminum VS Stainless Steel #11: Surface Finishes
Stainless steel surface treatment has surface polishing treatment, surface whitening treatment, surface plating; Aluminum alloy treatment includes electroplating, spraying, anodic oxidation and so on.
Aluminum VS Stainless Steel #12: Ductility
Aluminum alloy is generally hard alloy, small deformation, light weight, failure common brittle fracture, short fatigue life. The ductility of stainless steel is better, the elasticity is good, it can be deformed, the weight is large, and the deformation and destruction are common.
Aluminum VS Stainless Steel #13: Applications
Stainless Steel are commonly used in the following industries:
- Food and beverage
- Automotive
- Construction
- Medical equipment
- Appliances
- stainless steel cookware
Aluminum alloys are used in many different industries as well, some of these include:
- Transportation
- Aerospace
- Packaging
- Building and construction
- Electrical applications
- Machinery and equipment
FAQs
Q: What is the biggest difference between stainless steel and aluminum alloy?
A: The biggest difference is in their weight. Aluminum is much lighter than steel, which makes it ideal for use in a variety of applications where weight is a concern.
Q: What are the benefits of aluminum over stainless steel?
A: Aluminum has a number of benefits over stainless steel, including being lighter in weight, more corrosion resistant, and having better thermal conductivity.
Q: What are the disadvantages of aluminum?
A: Aluminum has a lower melting point than steel and is not as strong, making it less suitable for use in high-temperature or high-pressure applications. Additionally, aluminum is not as conductive as steel.
Author
Gavin Leo is a technical writer at Aria with 8 years of experience in Engineering, He proficient in machining characteristics and surface finish process of various materials. and participated in the development of more than 100complex injection molding and CNC machining projects. He is passionate about sharing his knowledge and experience.