From：Xiamen Hosingtech Auto Parts Co., Ltd Release time：2018-09-28
difference between aluminum and stainless steel pipe and tube
Metal pipe and tubing are everywhere in automotive, aerospace, industrial, architectural, research, and medical applications. Aluminum and stainless steel are common pipe and tube materials, and each has attributes that make it the right choice for a given industry.
The most common aluminum alloys used for tubing and pipe are 2024, 3003, 5052, 6061, 7075. Their principle alloying elements of copper, manganese, magnesium, silicon, and zinc lend each alloy slightly different physical and mechanical attributes.
For instance, engineers specify alloys 2024, 6061, and 7075 for aircraft structures because of their high strength-to-weight ratios and good fatigue resistance. Untreated 2024 and 7075 are prone to corrosion, while 6061 is innately corrosion-resistant and easier to weld. 7075 provides higher strength with less weight, but costs more.
Alloy 3003 is good for applications that need corrosion resistance and high strength with less of an emphasis on ductility. And for applications that rely on many joints, you might choose highly weldable 5052.
As with steel, alloy composition alone doesn’t tell the whole story. The exact properties of a given aluminum alloy also depend on its temper or heat-treatment history. Temper O indicates the alloy is used as annealed, at its highest ductility and lowest strength. Tempers beginning with “T,” like T3, T4, and T6, involve heat treatments. Cold working or aging steps often follow to strengthen the metal by toughening it on the grain or molecular level.
Once you’ve chosen the right aluminum alloy and temper for your application, your next steps will be specifying its size and any additional fabrication operations. Aluminum tubing ODs typically range from 0.062 in. to 3.00 in. with wall thicknesses from 0.010 in. to 0.250 in. Aluminum tubing suppliers can cut, bend, flare, and fabricate tube to your requirements.
Stainless Steel 101
For applications that lend themselves to stainless steel, you’re sure to find a grade that works from the wide range of iron-carbon-chromium alloys covered by that term. The most common steel pipe and tube grades are T304 and T316, part of the 300 series of stainless steel alloys in which austenitic iron alloys with nickel in addition to the chromium and carbon.
T304 is considered the classic stainless steel alloy. Also known as 18/8, it contains 18% chromium and 8% nickel. T316 is another familiar alloy, especially in food service and medical applications; it contains molybdenum for additional corrosion protection.
The properties of a given alloy depend greatly on its heat-treatment and cold working history. To obtain a specific property or physical attribute for your tubing, check with a metallurgist or tubing specialist who can guide you to the right combination of alloy and processing for your application.
Tubing specialists can also advise you on tubing size and fabrication processes. Stainless steel tubing comes in fractional and metric outer diameters (ODs) ranging from 1/16 to 8 in. for tubing and to as small as 0.008 in. for hypodermic applications. Fabrication can include bending, coiling, end forming, welding, and cutting.
Once you have the right stainless steel tubing installed in your application, you might start to think about what to do with it at the end of its useful life. Although the alloying elements that go into stainless steel make it difficult to recycle, rest assured that about 50% of all new stainless steel is fabricated from melted down steel scrap.