Molykote brand lubrication

Dow Corning

MOLYKOTE® Specialty Lubricants from Dow Corning … Smart Lubrication™ Solutions for Threaded Connections

Bolted flange joints and threaded connections in the oil and gas industry must withstand especially harsh environments and extreme temperatures. Such bolted joints and screw fittings are critical for maintaining equipment productivity and operational reliability. Without proper lubrication, they can seize and cause equipment damage, contributing to increased downtime and repair costs.

Molykote® brand specialty lubricants from Dow Corning are a leading choice as assembly aids for bolted flange joints and threaded connections. They provide long-term lubrication under heavy loads, prevent seizing even after long periods of use at high temperatures, and maintain their lubricity without becoming brittle to enable easy, non-destructive dismantling of components for service.

Molykote lubricants are called Smart Lubrication™ solutions. They not only deliver trusted performance in severe-duty applications, which cause many traditional lubricants to fail, they are backed by more than 60 years of industry innovation and expertise and total customer support. Two case studies in this article detail some of the strong advantages of Molykote Smart Lubrication.

Molykote anti-seize paste helps an oil drilling equipment manufacturer reduce thread failures

When engineers at an oil drilling company started experiencing unacceptable failure rates in stainless steel threaded connections on its massive oil drilling equipment, the situation created some serious problems. Each time the stainless drill components had to be removed from service for repair at a specialty machine shop offsite, the firm not only incurred the expense of extra labor, shipping and refacing the damaged threads, it also lost the critical sections for up to a week of field service.

Steerable rotary drilling systems are comprised of multiple segments, with critical sections made of stainless steel. Each stainless component is secured with 4-1/2" or 6-5/8" API threaded connections, tightened to standard torque values of 32,000 and 62,000 ft-lb, respectively.

Identifying the Problem. As this company moved toward commercializing its newest generation of rotary steerable drilling systems, one of its design teams consulted with Dow Corning to investigate possible causes for the thread damage and connection failures. They used a traditional anti-seize paste that apparently was being squeezed out and failing under the extremely high torque required to assemble the components.

The investigation revealed that the traditional anti-seize paste contained a number of different metals-based lubricating solids, including chromium, copper, nickel and molybdenum. Stainless steel also contains molybdenum, chromium and nickel, which do not react well with oxygen; therefore, only very thin metal-oxide layers are formed. Once the oxide layer is damaged by abrasion, the oxide-free metal seizes under extreme pressure. In addition, the solid lubricants found in the traditional paste re-form oxide layers, which are again removed during abrasion. The cycle continues in such a manner that oxide layers and abraded particles build up. The resulting clogged thread clearances prevented easy disassembly of the metal components – the root cause of the bolt failures.

Another part of the problem involved the fact that many traditional pastes contain sulfur, phosphorous, zinc and lead-based compounds. These can cause stress-corrosion cracking and thread embrittlement. Both conditions can lead to grain-boundary cracks in metal bolt and screw threads that propagate until bolt fracture occurs. According to the company’s records, its bolt failure rate was around 25 percent.

Finding a Solution. Dow Corning and engineers of this drilling company worked together to develop a list of criteria for the application. They knew they would need an anti-seize compound formulated to provide adhesion to the stainless steel connections that could create and maintain an effective lubricating film despite the extreme loads, contaminants and temperatures of an oil-drilling environment. Further, the formulation should have low sulfur and halogen content, with a minimum of phosphorous, zinc, lead and other metals that can contribute to stress cracking or embrittlement of the metal.

The replacement material selected was Molykote® P-37 Paste, an ultra-pure anti-seize lubricating compound that is designed specifically for austenite steel and steel alloy threaded connections. The high-viscosity paste forms a continuous lubricating film with high contact adhesion that withstands extreme forces of drilling applications, contributing to excellent sealing and facilitating disassembly without thread deformation. The formulation has proven so successful that the drilling company reported an immediate drop in thread-related failures of more than 50 percent.

Molykote® P-37 Anti-Seize Paste. The paste selected to solve thread seizures achieves excellent load-carrying capacity over a wide temperature range of -40°C to 1400°C (-40°F to 2550°F). It contains a synergistic blend of metal-free solid lubricants that delivers outstanding seize protection, even under severe operating conditions. It is approved and commonly used on threaded connections by manufacturers of power plant turbines and steam valves, which are notoriously difficult lubrication applications.
 
Molykote P-37 paste delivers outstanding purity with less than 200 ppm total halogen content (including chlorine, fluorine and bromine) and less than 250 ppm sulfur content (sulfur contributes to stress-corrosion cracking). In addition, the high-purity metal-free solid lubricants in this paste provide better protection from solder embrittlement, making non-destructive disassembly more likely.

The odorless gray metal-free paste is extremely stable under difficult service conditions, giving it excellent durability. It is not classified as hazardous waste upon disposal, and poses no known health or environmental risks from transportation or use. Standard personal protection (safety glasses at minimum) and industrial housekeeping procedures are recommended.

Molykote lubricating paste delivers high-pressure solution for oil & gas exploration company

An oil and gas exploration company required substantially tighter flanges on transport piping and flow meters to enable a drastic increase in the pressurized transport of LNG gas through its pipelines. This company is currently producing 10 million cubic meters of gas per day. Daily production capacity from the field is 125,000 barrels of condensate and more than 18 million cubic meters of rich gas. The pressure and temperature in the reservoir – at around 900 bar and 170°C (338°F) respectively – are higher than on any other field so far developed.

The Challenge. The company’s need was to transport increased volumes of liquid natural gas from its offshore drilling rigs to the mainland by increasing the pressure from 300 bar, which is normally used for gas pipelines, to 800 bar with peaks up to 900 bar. The challenge was to do so while avoiding any gas leakage over the course of the high-pressure delivery pipelines.

This LNG delivery application required a specialty lubricant to aid assembly and enhance reliability of the critical sealing flanges for the pipelines and flow meters. The flanges were fitted with galvanized L7 stud bolts. The selected lubricant needed to withstand the harsh offshore environment, while also enabling the high-torque clamping forces needed for reliable sealing. It also needed to maintain long-term corrosion protection, lubricity and friction control for easy service disassembly.

The exploration company and Molykote team worked together to identify an effective solution. The threaded flange connections presented specific lubricant requirements. These included consistent and standardized torque, reliable lubrication of galvanized bolts, and absolutely no leakage of the high-pressure gas. The lubricant would also need to be environmentally friendly and meet the company’s specifications. In addition, the Molykote technical team would be required to provide lubricant testing capabilities as well as technical support and application advice.

The Solution. The lubricant selected was Molykote® G-Rapid Plus Paste. This black paste of solid lubricants in mineral oil provides effective, reliable lubrication from -35°C to 450°C (-31°F to 842°F) and met all user specifications for the flange bolts on pipeline fittings and flow meters.

Each flange is typically tightened with 16 bolts and the average size of the bolts is between M 24 and M 60. By applying Molykote G-Rapid Plus Paste, the customer gained accurate, constant coefficient of friction readings and was able to use a consistent tightening torque. In addition, the Molykote technical team was able to organize, perform and manage the necessary testing and to deliver technical training to the company’s staff. The team continues to monitor and assess the in-service application.

Adherence to Protection: Molykote Lubricating Pastes. Molykote lubricating pastes contain high concentrations of solid lubricants that form tenacious adhering films. Unlike oils and greases that are squeezed out of the lubricating contact areas, Molykote pastes will reliably stay in place to maintain torque and long-term lubrication and prevent equipment damage, even under extreme loads, low speeds, high temperatures and other harsh environmental conditions.

Molykote: 60 years of smart lubrication

For more than 60 years, Molykote lubricants from Dow Corning have been Smart Lubrication solutions for many of the world’s most demanding lubrication challenges. Often called “miracles lubes,” Molykote specialty lubricants were initially based on MoS2 solid lubricants and have since been expanded to include a wide range of other solid lubricants, as well as solutions based on silicone compounds, mineral oils and synthetics. The common elements in all of these offerings are unmatched lubricant innovation, application expertise and trusted performance.

Especially valued in today’s high-performance oil and gas industry, the Molykote line of specialty lubricants includes greases for severe-duty lubrication, anti-seize pastes for threaded connections, anti-friction coatings for long-term lubrication of inaccessible parts, silicones for light-duty lubrication in adverse environments and fluorosilicones for outstanding oil and gas resistance on a wide range of process equipment from compressors to vacuum pumps.

With dedicated global research and development operations on five continents, Molykote lubricants offer the best in assembly and maintenance technology for threaded connections and so much more. They are formulated to help you achieve the highest levels of equipment productivity and operation reliability with the lowest levels of service downtime and repair expense. Molykote Smart Lubrication from Dow Corning has a heritage of success in the world’s oil and gas industry.
                               
Learn More about Molykote Specialty Lubricants
Molykote Specialty Lubricants from Dow Corning are available worldwide. The extensive product line and service capabilities can help you solve or prevent your toughest lubrication challenges. To learn more about these Smart Lubrication solutions, contact a local representative, visit www.molykote.com or email industrial@dowcorning.com. You can reach the Molykote Technical Information Center at:
+49 (0)611 237 778 (English)
+49 (0)611 237 779 (German)
+49 (0)611 237 773 (French)

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