Invented more than 2,000 years ago, threaded fasteners are still the most important detachable hardware used in machinery design and assembly. They can be found on practically any mechanical component, frequently holding together very critical parts. With more than 300 billion fasteners being consumed in the U.S. every year in assembly applications from automobiles and aircraft to household appliances, it is crucial that these fasteners provide predictable, uniform performance by staying tight once they are installed.
Despite centuries of improvement, threaded fasteners still fail. Fastener failure results from one of two causes. Tension relaxation is frequently caused by temperature changes, and involves the expansion and contraction of bolts and substrate materials, which reduce bolt tension and clamping force in the assembly. A second cause of fastener failure is self-loosening, which is caused by lateral sliding motion between fastener contact surfaces. While many mechanical methods, such as spring washers, wire retainers and locking bolts, have been developed in an effort to prevent uncontrolled loosening of fasteners, mechanical locking methods add substantial cost to the fastener assembly and cannot prevent the sliding motion that causes self-loosening.
Chemical threadlocking adhesives can inexpensively and permanently prevent threaded fastener failure. Introduced nearly 50 years ago by Loctite Corporation, these single component anaerobic adhesives are unique liquid resins that harden (or cure) to a tough solid when exposed to metal ions in the absence of air. This anaerobic cure mechanism allows the adhesive to flow and evenly settle to fill the grooves of threaded fasteners without curing prematurely. Any excess threadlocker that overflows the threads during application will remain liquid, and therefore can be easily wiped away.
As a liquid threadlocker cures, it forms polymer chains that find their way into every tiny imperfection in the threads. Thread friction increases with the application of threadlockers as a result of the interfacial connections that key to the surface roughness of the metal. The adhesive completely fills the microscopic gaps between interfacing threads to positively lock and seal threaded assemblies, preventing lateral movement and protecting the joint from corrosion that can result from moisture, gasses and fluids. Just a few drops of liquid threadlocker will keep a fastener torqued down in an assembly until the user wants it to come apart. Whereas threadlockers provide 100 percent contact between metal parts, a typical nut and bolt assembly may have as little as 15 percent metal-to-metal contact.
Threadlocking adhesives are highly reliable, low-cost materials that improve torque control, reduce galling and provide lubricity to achieve controlled torque during assembly. Available in different strengths for different applications, threadlockers will hold critical clamp load pressures even in the most severe environments. These adhesives offer high shear strength, good temperature resistance, rapid cure, easy dispensing and good vibration resistance.
Need a thread locker for pipe repair or pipe wrap? Do visit us for more information on choosing the correct thread locker for your threadlocking needs.
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