If you are in search of a metal with a high resistance to corrosion, materials like aluminum square bar and stainless steel come to mind. Both are excellent for certain conditions, but is one superior to the other in every way? Let’s take a closer look at the differences between stainless steel and aluminum.
Corrosion Properties
Stainless steel is created from iron, nickel, chromium, copper and magnesium. Chromium is responsible for stainless steel’s amazing resistance to corrosion. Stainless steel is basically non porous and this makes it very resistant to many kinds of corrosion.
Aluminum resists oxidation and this is why it doesn’t rust. However, it can oxidize and this can cause pitting. In highly corrosive atmospheres (which are caustic in nature) aluminum will being to break down and corrode.
Strength
By nature, steel is stronger than aluminum. However, aluminum alloy like 7075 is nearly as strong as steel. In fact, when you look at the weight to strength comparisons between steel and aluminum, aluminum is the better choice and this is why you will find it in many aircraft applications today. 7075 aluminum can be made into aluminum square bar, extruded into many shapes, machined and also made into large support beams. These beams provide great strength and support and there are no rust problems to be concerned with.
Conductive Properties
Aluminum is one of the best conductors of electricity. In fact, aluminum rod is drawn into wire for high voltage power transmission, because it is a cost effective option over copper. Aluminum is also an excellent heat conductor and you will see many automotive radiators and air conditioning coils made from aluminum these days.
Cost
If you need a non corrosive metal for your business, aluminum is a much cheaper option than stainless steel. Unlike materials like aluminum square bar and rod (which are produced in large amounts), stainless steel is too expensive for many commercial applications. However, it is the preferred material for many types of food and beverage operations because it can be sterilized.
Working with Stainless Steel and Aluminum
If you need a metal you can easily mold and shape, aluminum is the hands down choice. It has very malleable and this is the reason you will see it used on many types of aircraft. Stainless steel is much harder and brittle and not easy to form or work with.
Stainless steel is not difficult to weld and some aluminum alloys cannot be welded. However, alloys like 6061 aluminum can be welded. In addition, stainless steel is capable of withstanding higher temperatures than aluminum.
