A straightforward way to tell the difference between aluminium and stainless steel is based on their appearances. Aluminium are generally grey in colour with a dull texture. On the other hand, stainless steel is relatively shiny, and often has a tint that is more silver than grey.
Appearance: Stainless steel usually has a shinier, polished look compared to the more matte finish of aluminum. Also, stainless steel often has a brushed finish. Sound Test: Tapping the bottle can produce different sounds. Aluminum tends to have a more dull sound, while stainless steel has a clearer, ringing sound.
Certain metals in their natural states such as aluminium, copper, brass, lead gold, and silver don't attract magnets due to the fact they are weak metals. However, properties including iron and steel can be added to these metals in order to make them magnetic.
After being washed, aluminum tends to dull slightly, while stainless steel usually stays bright.
Stainless steel water bottles are heavier than aluminum. This is because of the double-walled insulation and sturdier build of stainless steel bottles. Though aluminum water bottles are lighter than stainless, it does not make them too perfect for your outdoor activities because they provide no insulation.
It depends on what type of stainless you're using. Some steels are only weakly magnetic, and some are not magnetic at all. Austenitic stainless steels like 304 or 316 stainless are good examples of this. A ferritic stainless like 430 stainless steel, on the other hand, is ferromagnetic.
So the “magnet test” is to take a magnet to your stainless steel cookware, and if it sticks, it's “safe”—indicating no nickel present—but if it doesn't stick, then it's not safe, and contains nickel (which is an austenite steel).
Some stainless steels are magnetic, and others are not. The defining factor of magnetism comes down to the the steel's microstructure. Martensitic stainless steels (which have a ferritic microstructure) are magnetic. Austenitic stainless steels contain nickel and are non-magnetic.
However, surprising as it may sound, one property that aluminium does not possess is magnetism. Pure aluminium is, in fact, paramagnetic, much like other common metals including gold and copper. This means that it does not produce a magnetic field on its own and it cannot be made into magnets.
Strength and Durability: Stainless steel is denser and harder than cast aluminum, making it stronger and more durable. Cast aluminum is lightweight and less dense, which makes it less strong but more malleable.
Aluminum is also a much softer metal than steel, and this property is easy to test if you don't mind scratching the piece of metal. Press a key into a piece of unknown metal that may be aluminum or steel. If the piece is aluminum, it will scratch easily and deeply with light pressure.
There is a common misconception that the best way to check if a fastener, or any item for that matter, is made out of stainless steel is to place a magnet next to it. Many people believe that if the magnet sticks, then the fastener is not stainless steel. This is not the case.
Magnets can be anything you want them to be, but some could risk scratching your stainless steel if they are pointy and sharp. Otherwise, there is no reason to think that they will harm your fridge immediately or over time.
As mentioned, polished stainless steel is recognized by its bright, shiny, reflective appearance, while satin stainless steel is identified by its low sheen, and soft, frosted matte finish.
So, the best ways to find out if your can is aluminium or steel are to either look for the 'alu' symbol or find a magnet. If the can is attracted to the magnet, you've got steel!
The Mohs scale, which rates hardness, places aluminum at 2.75 and stainless steel between 5.5 and 6.5. This means stainless steel is harder, hence resistant to scratches from aluminum.
In certain cases, yes. Magnets will stick to black stainless steel if the steel at its core is ferromagnetic. Whether or not magnets stick to black stainless steel also depends on whether the coating of the finish is thin enough to allow a magnet to cling to it.
Under normal circumstances, aluminium is not magnetic, mainly because of its crystal structure. It's referred to as a paramagnetic material along with other metals like Magnesium and Lithium.
Aluminum isn't magnetic, and so a magnet's all you need to tell the difference. If the magnet sticks, it's steel. If not, it's (probably) aluminum. Strictly, steel is an alloy, and there are non-magnetic alloys of steel, including some stainless steel.
Appearance and Shine: Stainless steel has a distinctive shine and appearance. It is typically smooth, bright, and reflective. The surface should be free of stains, corrosion spots, or coatings, which are signs that it might not be genuine stainless steel.
Since most food-grade stainless steels are austenitic, food handling products are typically non-magnetic. One exception is kitchen knives, which are often made from magnetic martensitic stainless steel. For food-grade stainless steel racks, non-magnetic austenitic grades are generally preferred.
Many common metals such as aluminum, copper, brass, gold, silver, titanium, tungsten, and lead are not ferromagnetic. They cannot be made into magnets and will not be attracted to magnetic fields.
Identification with a Magnet
Chromium-nickel stainless steel is generally non-magnetic in the annealed state, and some may be magnetic after cold working.
Conductivity Tests
While stainless steel is typically poor at conducting electricity, aluminum excels. To conduct such an exam, use a multimeter set on resistance or conductivity and touch any metal with its probes - low conductivity indicates stainless steel, while high conductivity indicates aluminum.
Appearance – Aluminum has a softer, more matte finish while stainless steel is shiny and reflective. Oxidation – Aluminum is more prone to oxidation than stainless steel. This means that it's more likely to form a white, powdery film on the surface over time.