Alcoa Fastening Systems & Rings White Paper - Welding vs Fastening Vibration-Resistant, Direct-Tension Lockbolts Change The Equation For years, welding was seen as the only way to ensure the integrity of joints in demanding load-bearing or high-vibration structures. So, companies manufacturing heavy-duty equipment or fabricating large, metal structures continued to employ the universally accepted process of welding joints together. However, today there are alternatives to welding, one of the foremost being direct-tension installed, swaged lockbolts, such as the HuckBolts® currently offered by Alcoa Fastening Systems. These unique engineered fasteners, proven in such demanding applications as truck suspensions and chassis, railroad track crossings, and heavy defense vehicles, are now being used in a number of products and structures where welding was once the only option. Welding – Proven, But Not Without Drawbacks While welding is proven to be one of the surest processes for securing a joint, there are a number of issues relating to it. To begin, the welding process is very time consuming, particularly in situations where in-depth inspection procedures are required. Welding also requires skilled, often highly paid, technicians. And in some industries, such as oil and gas, quality welders are both difficult to find and to retain. The heat generated by welding can often reduce the strength of the metals being joined, and damage critical surface coatings. In addition, welding dissimilar metals or pieces of varying sizes can be a challenge. Welding also often requires an on-going process of inspection, with many of these procedures being both costly and time consuming. And as most companies who make extensive use of welding as part of their manufacturing or fabrication process have discovered, the removal and/or rework of a weld can be problematic. Last, but most assuredly not least, welding is a dirty, dangerous process. Safety is a critical issue, since many fires have been started by a random spark created while welding. At the same time, spent rods and other remnants of the welding process are an ongoing housekeeping issue in shops where welding is performed on a regular basis.

Alcoa Fastening Systems & Rings White Paper - Welding vs Fastening Engineered Lockbolts – An Alternative To Welding Over the past 30 years, engineered lockbolts – such as Alcoa Fastening Systems’ HuckBolts – have replaced welding in more and more heavy demanding applications. Today, one can find advanced HuckBolt fasteners doing the job in a wide range of applications that once solely belonged to welding. Structural HuckBolts, offered in a wide range of sizes (up to 1-3/8”) and materials, consist of a pin and a collar. These advanced fasteners are installed using a direct tension technique, in...

Alcoa Fastening Systems & Rings White Paper - Welding vs Fastening There are a number of reasons why many manufacturers of heavy equipment are actively investigating the possibility of using direct-tension lockbolts in their assembly process. To begin, even taking into consideration the need to drill a hole, installing a lockbolt is significantly faster than welding a joint. And a quick visual inspection is all that is required to confirm the accuracy and quality of the installation. In addition, an operator requires a minimal amount of training in order to be proficient in the installation of...

Alcoa Fastening Systems & Rings White Paper - Welding vs Fastening Eliminating the Effects of Vibration continued In contrast, conventional nut and bolt fasteners leave a slight gap between the crest and root of the threads when installed. This gap becomes problematic when exposed to transverse vibration, and can allow for rapid loss of clamp. Chart 3 Standard Bolt The swaged collar forms over the lock thread, and eliminates the gap. Regular nuts and bolts have gap, which allows for loosening by vibration. Another key difference between HuckBolt and conventional fastener installations is found...

Alcoa Fastening Systems & Rings White Paper - Welding vs Fastening Huck Structural Blind Rivets For applications where only one side of the joint material is accessible, performance-engineered Huck structural blind fasteners can often meet design requirements. These blind fasteners can deliver the shear and tensile strength to meet the demands of a number of heavy-duty applications. Available in diameters ranging from 3/16” to 3/4”, these fasteners offer a combination of strength and vibration resistance, easy installation, and a high level of safe operation. Huck® BOM® Summary It should be noted...