Both Loctite C5-A Copper-Based Anti-Seize and Loctite Silver Grade Anti-Seize are designed for either maintenance or equipment manufacturing applications, and can be used on bolts, bushings, pipes, fittings, flanges, manifolds, nuts, studs, heat exchangers, valves, steam lines, union retainers, and clamps.

The Department of the Navy (Naval Sea Systems Command) recently granted MIL-PRF-907F qualification status to two anti-seize products from Henkel Corporation. Formulated to prevent seizing, galling, and corrosion on metals, Loctite C5-A Copper-Based Anti-Seize and Loctite Silver Grade Anti-Seize resist high temperatures, heavy loads, chemicals, fluids and vibration, and are available in general-purpose, metal-free, food-grade, marine-grade and high-purity formulas.

Loctite C5-A Copper-Based Anti-Seize can be used on copper, brass, cast iron, steel, all alloys including stainless steel, all plastics, and all non-metallic gasketing materials to protect metal parts from rust, corrosion, seizing, and galling at temperatures up to 1800°F (982°C). Henkel’s exclusive lead-free formula suspends copper and graphite into this high-quality lubricant that allows all mated parts — studs, bolts, flanges and gaskets — to be removed more easily in cleaner and better condition. The copper-colored lubricant can be applied at temperatures as low as -20°F (-29°C).

Similarly, Loctite Silver Grade Anti-Seize is a heavy-duty, petroleum-based lubricant that resists temperatures up to 1600°F (871°C), and is designed for long-term durability. Fortified with graphite and metallic flake, this silver-colored lubricant is inert and will not evaporate or harden in extreme cold or heat.

In addition to these two Mil-Spec conforming anti-seize products, Henkel offers a full range of anti-seize formulas including general purpose, metal-free, food-grade, marine-grade, and high-purity materials.

Henkel
www.henkelna.com/antiseize

The post Loctite Anti-Seize lubricants from Henkel receive Navy qualification appeared first on Windpower Engineering & Development.

Ed Fisher, Senior Market Application Engineer

Henkel Corp.

Tower manufacturers can ensure that bolts will never loosen, reducing maintenance issues and opportunities for worker injury, by applying threadlockers to all bolts, such as those that secure the ladder treads and hold the ladder sections to the tower as well as those functioning on moving parts in the turbine.

Damage and mechanical failures on wind turbines happen most often on blades, in gear boxes, on generators, drive trains, and brake assemblies all of which are housed in the nacelle. Access to these areas on a large commercial turbine requires that maintenance professionals climb a series of ladders that can take them more than 300 feet up.

So how the ladder and treads are secured to the tower deserves close attention. For instance, it should perform as a part of the tower assembly and not a series of separate parts added after tower construction. Maintenance workers can fall if the ladder is not unitized, sturdy, and stable. Such a fall would mean certain injury and possible death.

Why threaded assemblies fail

Thermal cycling, movement, and vibration can cause threaded fasteners to loosen over time. The normal contact area of mating threads presents a problem because it is a surprisingly small percent. Without appropriate protection, fasteners can fail.

Even when its blades are at rest, a wind turbine is a moving structure. High winds that rotate the blades also sway the tower and nacelle, generating mechanical stress and vibration that affect the entire structure from the tip of the highest blade down to the base. In addition, structural elements expand and contract when subjected to operating temperatures that range from sub-zero to more than 100°F.

Threadlockers completely fill the voids between interfacing threads, thereby preventing the micro movements that lead to loosening.

Vibration is the number one cause of threaded fastener loosening. Failure occurs when clamp load is not maintained. Clamp force must be adequate at the time the fastener is assembled and remain at that level throughout the useful life of the fastener.

In addition to vibration, a fastener’s ability to stay tightly fixed is impared by the natural existence of gaps between the mating thread surfaces. These tiny gaps allow micro movements that eventually loosen mated parts and result in a loss of clamp load. Clamp load must be maintained over the life of the assembly.

How to prevent failure

Anaerobic threadlockers are single-component adhesives that when applied to metals cure in the absence of air into tough thermoset plastics. Threadlockers completely fill the voids between interfacing threads, preventing the micro movements that lead to loosening. Threadlockers provide 100% contact between metal parts while a typical untreated nut and bolt assembly can have as little as 15% metal to metal contact. These adhesives maintain clamp load on the fastener until the bond is intentionally broken.

Anaerobic adhesives can lock and seal dozens of fasteners on the yaw and main rotor bearings, and nacelle panels.

Threadlocking adhesives are the most reliable method to ensure a threaded assembly remains locked and sealed for its entire service life. Available in a variety of strengths, they offer excellent temperature resistance, rapid fixture and cure speeds, and easy dispensing.

Now consider the nacelle. Bolts there hold the panels together, letting this important enclosure endure vibration and exposure. Inside the nacelle, hundreds of threaded fasteners secure moving parts on generator components.

Threadlockers also act as lubricants during fastener tightening, so instead of dissipating torque as friction and heat, the adhesives improve the conversion of applied torque to high clamp load. Once cured, threadlockers provide a reliable seal and prevent leaks, galling, and corrosion that can seize threads.

Advancements in threadlockers

Recent advances in the stability and reactivity of anaerobic chemistry have resulted in gel, stick, and tape formulations. Semi-solid sticks and tapes work well in difficult areas, such as vertical and overhead applications where liquids could be too messy or could migrate. Dry-to-the-touch and packaged on a roll, tape threadlockers can be pre-applied to threaded fasteners for future use or applied during maintenance operations.

The latest adhesives are formulated to provide improved oil tolerance and excellent performance without primers. Primerless formulations are ideal for use on plated and stainless fasteners because they eliminate cleaning and priming operations and cure rapidly for immediate use. Oil-tolerant formulations are ideal for use in gearboxes and other moving parts exposed to lubricants.

Recently developed high lubricity anaerobics effectively reduce friction and reliably convert torque energy into increased clamp load. These are especially effective for large diameter, high

Doug Leswcarbeau

Ed Fisher

strength fasteners that provide high clamp load. WPE

The post How threadlockers reduce failure and improve safety on wind structures appeared first on Windpower Engineering & Development.

Products include:

• Structural bonding adhesives

• Component sealers

• Threadlockers

• Surface and corrosion protection coatings

• Nonslip safety coatings

• Base grouts

• Cable sealants

• Flange sealants and retaining compounds

• Blade and part cleaners

For a blade tip repair, the company suggests Loctite UK 1351 B25 (Structural Bonder) GL-certified, cartridge-dispensed polyurethane with 50 minutes of working life. Loctite UK 1370 B10, a polyurethane putty, has a work life of 10 minutes and can be sanded in 30 minutes.

Repairing rotor-blade-tip damage provides an example of catalog contents. Such damage can be significant and structural in nature, requiring a new tip or a structural patch for the repair.  To apply:

• Surface should be clean, dry and abraded.

• Damaged substrate material should be removed from the repair area.

• Bond in the structural patch using Loctite UK 1351 B25 structural bonding adhesive.

• Sand or grind the edges of the patch.

• Mix the Loctite UK 1370 B10 Putty and apply using a trowel to smooth the product over the damaged area.

• Sand after 30 minutes.

For the complete 19-page brochure, http://2014pdfs.s3.amazonaws.com/Henkel/LT-6531.pdf

Loctite
www.henkel.com

The post Loctite issues a Windpower Maintenance Solutions Guide to O&M Products for Blades, Nacelles, Towers, and Bases appeared first on Windpower Engineering & Development.