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Lubrication Solutions for Threaded Connections

For over half a century, OEM designers, maintenance teams, and material engineers have trusted the MOLYKOTE® brand for performance lubrication solutions for threaded connections.

Table of Contents

Molykote Lubricants from DuPont

 Formulated for extreme loads and harsh environments, MOLYKOTE® lubricants are ideal for normal service lubrication. They deliver extended benefits as compared to conventional lubricants, such as: 

  • Long component life
  • Extended durability
  • Long maintenance intervals
  • Time and cost savings 

Antala Ltd. is the UK and Ireland’s premier supplier of the MOLYKOTE® brand and we offer a wide portfolio of products for a vast array of applications. 

“Harsh environments, heavy loads, and extreme speeds can challenge your productivity. MOLYKOTE® brand solutions for threaded connections help keep your equipment and processes moving smoothly.” 

Performance Solutions for Threaded Connections

Threaded connections offer several advantages, including — but not limited to — convenient disassembly, repeated use of a fastener, and accurate re-assembly. However, without proper lubrication, those advantages can be lost, giving rise to significant equipment challenges and reliability concerns.
By preventing: 

  • Inconsistent coefficients of friction, resulting in inconsistent bolt tension
  • Stick-slip
  • Stress corrosion cracking 
  • Fretting 
  • Galling
  • Seizing

MOLYKOTE® brand lubricants can help your threaded connections perform well in service, from initial assembly through repeated disassembly. They are specifically formulated to withstand harsh conditions, perform in a wide range of service temperatures, and resist the effects of heavy loads, salt-spray, or other contaminants. 

The Benefits of Proper Lubrication

Lubricants serve to reduce friction and wear, protect against corrosion and dissipate heat. The use of carefully selected lubricants can help circumvent some of the common failure mechanisms associated with threaded connections. Some key functions of proper lubrication are:

  • Providing a consistent coefficient of friction (µ).
    • On mating surfaces, this enables designers and applicators to minimise the complexity of obtaining proper connector preload forces and torque specifications. 
    • Limits the effects of temperatures and load variations, reducing fatigue failure rates. 
  • Forming barriers between substrates and oxygen gas layer.
    • Prevents undesirable scale formation of thread surfaces.
  • Providing protective layers to mating surfaces.
    • Reduces the effects of oxide layer depletion, reducing the occurrence of fretting, galling, seizing, and shearing. 
    • Decreases exposure to corrosive, hydrogen-rich and low-melting metal environments, reducing stress corrosion cracking as well as hydrogen and solder embrittlement. 

Molykote Anti-seize Pastes Provide Consistent Coefficient of Friction:

Product Name µt µc K*
MOLYKOTE® G-n METAL ASSEMBLY PASTE/SPRAY 0.078 0.085 0.15
MOLYKOTE® G-n PLUS PASTE 0.12 0.06 0.14
MOLYKOTE® G-RAPID PLUS PASTE/SPRAY 0.10 0.06 0.13
MOLYKOTE® 1000 PASTE 0.13 0.08 0.17
MOLYKOTE® M-77 PASTE 0.12 0.12 0.20
MOLYKOTE® P-37 PASTE  0.142 0.091 0.18
MOLYKOTE® P-40 PASTE 0.16 0.08 0.18
MOLYKOTE® P-74 PASTE 0.117 0.078 0.16
MOLYKOTE® P-1900 PASTE 0.10 0.10 0.17
MOLYKOTE® U-n PASTE  0.11 0.11 0.18

*All values and calculations in this table were calculated by using the K-Factor formula and are based on a standard, ⅝ inch UNF fastener. 

Torque

Proper bolt torque is required to achieve appropriate bolt tension and elongation. Torque must overcome all sources of friction before elongation can occur. Thread and bolt-head friction can be reduced and made consistent by adding a lubricant. Required torque calculations for proper bolt elongation are made based on threaded fastener geometry and friction of thread and load-bearing surfaces. The friction factor applied to torque calculations is referred to as K-Factor. Both thread and bolt-head friction coefficients are used to calculate K-Factor, so it is through lubrication that friction and K-Factor can be controlled to ensure proper bolt tension and elongation are achieved for a derived torque value. In assembly, the torque energy is first consumed by overcoming friction. The remaining energy is consumed by bolt elongations (which provides the clamping forces). Without proper lubrication, too much torque is used to overcome friction, resulting in insufficient bolt elongation. 

Failure Mechanisms Defined

Unequal coefficients of friction (µ)

  • High µ of mating surfaces (head, nuts, shank, and threads) can result in increased twisting of the fastener and reduced clamping force. 
  • Low µ of mating surfaces can result in excessive bolt elongation. 

Stick-slip

  • The difference between static friction and kinetic friction when two surfaces are in contact. 

Stress corrosion cracking

  • At high temperatures, sulphur diffuses into grain boundaries, producing high stress points. The sulphur then combines with nickel (of alloy steels) to form sulphide crystals. These crystals grow, increasing the stress and creating larger cracks. 

Fretting

  • When vibration induces wear of oxide layers, the oxide particles clog internal clearances, leading to seizure.

Galling

  • During sliding contact, the oxide layers, the oxide particles, clog internal clearances, leading to seizure. 

Seizing

  • Caused by fretting, oxide-free surfaces cold weld under extreme pressure, preventing disassembly. 

Not All Lubricants are Created Equally

Different by design

Greases, Anti-seize Pastes and Anti-friction Coatings are each uniquely formulated to meet different, on-the-job challenges and keep equipment running strong. Grease formulations have high concentrations of base oils, which create the lubricating film between surfaces required to reduce friction and prevent wear. Anti-seize Paste and Anti-friction Coating formulations are different. The base oil in these materials simply carry the high concentration of solid lubricants directly to the point of lubrication.

These solid lubricants are not subject to evaporation, and as temperature or pressure increases, the lubricating films maintain their thickness — providing effect, reliable, and long-term lubrication of the threaded surface. To ensure assembly and disassembly of threaded connections over time, the lubricant must stay in place, even under harsh environments. MOLYKOTE® brand Anti-seize Pastes and Anti-friction Coatings offer long-term, effective solutions.

These lubrication solutions form a protective layer between threaded surfaces, easing assembly and disassembly, while protecting against wear and corrosion that can lead to connection failure. Greases are designed to bleed base oils, which provide lubrication. But in threaded connections, the lubricant may not carry high load and the base oil will evaporate, reducing grease life.

Anti-seize Pastes contain a high concentration of solid lubricants for protecting industrial components from galling, fretting corrosion, stick slip, seizure, or damage. They provide corrosion protection, water washout resistance, and a consistent coefficient of friction. These solid lubricants remain in place — even at high temperatures and under heavy loads — to help with long-term lubrication. To ensure optimal solutions for threaded connections, the appropriate MOLYKOTE® Anti-seize Paste needs to be selected for the application conditions. 

Anti-friction Coatings are paint-like products that form a slippery film that covers surface roughness. This optimises friction control, even under extreme loads and working conditions. However, the effectiveness and surface life of an AFC is greatly impacted by the surface pre-treatment of the component, such as degreasing, phosphating, sandblasting, and anodising. 

Typical Properties of Solid Lubricants Used in Anti-seize Paste and Anti-friction Coating Formulations

By combining different types of solid lubricants in paste formulations, we get increased protection from fretting corrosion, increased load-carrying and wear prevention. The sum of what they can do together is superior to what they offer separately. 

Graphite
High temperature stability
Good lubrication under humidity 
Low coefficient of friction at high loads
Protects against fretting corrosion
Molybdenum Disulphide (MoS2)
High load carrying capacity
Wide temperature range
Excellent adhesion
Protects against fretting corrosion
Friction decreases with increasing load
Prevents stick-slip 
Not for use in humid environments
Polytetrafluoroethylene (PTFE)
Colourless
Low load carrying capacity
Low coefficient of friction at low loads
Good chemical resistance
Good at reducing sliding friction
Copper 
High load carrying capacity
High temperature stability 
Should not be used with stainless steel above temperatures of 1000℃ (1832℉)
May promote galvanic corrosion
White Solids
Protects against fretting corrosion
Suitable for high temperatures
Excellent adhesion

Anti-seize Pastes

MOLYKOTE® brand Anti-seize Pastes are high-performance products specially formulated for harsh conditions. Unlike conventional greases or compounds, MOLYKOTE® Anti-seize Pastes create and maintain a lubricating layer, despite extreme loads and temperatures. MOLYKOTE® pastes provide: 

  • Wear protection
  • Reliable performance across wide temperature ranges
  • Consistent coefficient of friction (µ)
  • Water washout resistance
  • Corrosion protection
  • Immediate lubrication once applied
  • Long-term lubrication

Easy, quick, and accurate application of Anti-seize Pastes can be achieved by brushing or dispensed pumping. Some Anti-seize Pastes are also available in spray/aerosol form. 

Anti-friction Coatings

MOLYKOTE® brand Anti-friction Coatings are useful for parts exposed to dusty environments or inaccessible areas where long-term lubrication is desired. The parts can be pre-lubricated in a clean environment to reduce handling during field assembly operations. MOLYKOTE® brand AFCs are formulated to offer these benefits after curing: 

  • Dry lubrication 
  • Coating that is non-flammable
  • Film that does not attract dirt and dust 
  • Additional corrosion protection
  • Long-term lubrication without evaporation 
  • Effective lubrication even after prolonged service life

Application methods include hand or drum spraying, dipping, centrifuging, brushing, roll coating, or printing. The best application method is at the discretion of the end user and depends on the geometry of the part being coated. 

Is Dry Lubrication Needed?

  • YES — my application is exposed to dust, dirt, debris and would benefit from dry lubrication. 
    • Choose MOLYKOTE® brand Anti-friction coatings
  • NO 
    • Choose MOLYKOTE® brand Anti-seize Pastes. 

Can Your Part Be Thoroughly Cleaned and Dried?

  • YES — choose MOLYKOTE® Anti-friction Coatings
  • NO — Consider MOLYKOTE® Anti-seize Pastes. 

Selecting the Right Lubricant

The MOLYKOTE® Anti-Seize pastes and Anti-friction Coatings (AFCs) presented in this brochure are specially formulated as solutions for threaded connections, helping deliver long-term protection, reliability, and productivity. While MOLYKOTE® Anti-seize Pastes and MOLYKOTE® AFCs offer many similar benefits, they perform best in specific applications: 

  • The performance of MOLYKOTE Anti-seize Pastes does not require extensive surface preparation, so they are especially useful in the field. 
  • MOLYKOTE® AFCs must be applied to surfaces that can be thoroughly cleaned and dried, and are often prepared in a clean environment as an engineered solution to help improve maintainability. 

When used together, MOLYKOTE® Anti-seize Pastes and AFCs can deliver synergistic performance. You can use the following tables to select the MOLYKOTE® lubricant that best satisfies your needs. For more information and technical specifications, contact Antala’s team of technical experts. 

MOLYKOTE® Brand Anti-seize Pastes Selection Table

Using Anti-seize Pastes is one of the best ways to reduce and control friction in threaded connections, ensuring long-term performance and easy disassembly and reassembly. To determine the appropriate Anti-seize Paste, consider the load, environment, temperature, and speed of your application. Below is a general description of MOLYKOTE® Anti-seize Pastes that DuPont identifies as the best solutions for threaded connections. 

Molykote® Brand Anti-Seize Pastes Selection Table

MOLYKOTE® Brand Anti-friction Coatings Selection Table

Using an AFC is one of the best ways to reduce and control friction in threaded connections, ensure long-term performance and easy disassembly and reassembly. To determine the appropriate AFC, remember to consider service requirements, the desired coating method and the specific advantage for different applications. Below are general descriptions of MOLYKOTE AFCs that DuPont identifies as the best solutions for threaded connections. 

Molykote® Brand Anti-Friction Coatings (AFCs) Selection Table

Source: MOLYKOTE® Technical Papers.

Antala Ltd and MOLYKOTE® Solutions for Threaded Connections

Antala Ltd. is the UK’s premier supplier of Molykote speciality lubricants, and our technical experts are here to help you find the best solutions for your requirements. To speak directly with the lubricants expert in your area, contact Antala here, via our website, or call us on 0161 494 1345.

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