Riveted Joints vs. Welded Joints
Structural integrity is an important concept in aviation. In fact, it’s probably the most important concept in aviation. So, you’d imagine that when it comes to things like fasteners, welding, which is a relatively reliable method of fastening, is preferable to rivets. But that’s not the case. Airplanes are manufactured with riveted joints instead of welded.
Rivets, just like welding, are used to permanently join two components together. They’re mechanical fasteners with a cylindrical shaft and a head at one end. Upon installation, the tail is struck and flattened, creating a new “head” and permanently securing two components together. The original head is called the factory head and the new head is called the shop head or buck-tail.
One reason that airplane manufacturers use riveted joints instead of welded joints is that the aluminum body of the aircraft is not heated tolerant. Aluminum is lightweight, inexpensive, and readily available, making it ideal for airplane manufacturers who want to create lighter and more fuel-efficient airplanes. Unfortunately, aluminum is weaker when exposed to heat. So, welding, instead of increasing structural integrity, decreases it.
Riveted joints are also stronger and more durable. While we’d like to think that welding is superior in reliability, welded joints are actually weaker because only the exterior of the components is joined together. On the other hand, rivets connect the two components from the inside, which makes them stronger. And since airplanes fly at about 550 mph at an altitude of about 30,000 to 40,000 above sea level, subjecting them to severe stress, strength and durability are really important.
Riveted joints are also easier to inspect. Aviation requires regular inspection and maintenance in order to ensure safety. It’s harder to inspect a welded joint because machinery must be used to test the joined components. On the other hand, a riveted joint is easy to visually inspect. All you have to look for is that the two connected components are secured. No machines or devices are necessary.
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