MODENGY coatings in the threaded connections of the pipes for oil production

The Modengy company produces more than 15 types of the anti-friction solid lubricating coatings that implement the unique solid lubrication technology.

MODENGY coatings form on the parts a polymer film saturated with highly fine particles of the solid lubricating materials such as molybdenum disulfide (MoS₂), tungsten disulfide (WS₂), polytetrafluorethylene (PTFE), graphite, metal oxides in different ratios and combinations.

Provided preliminary surface preparation is properly performed, the coating adheres to the material of the base tightly without neither slipping off nor destructing in the course of time. The protective layer of 20±5 µm thickness is considered as the most efficient from the perspective of separating and lubricating properties.

Treatment of the mating parts with the anti-friction solid lubricating coatings enables to reduce their friction coefficient and to prevent scuffing appearing. A number of MODENGY coatings can be used to prevent metals and their alloys against spontaneous destruction by the impact of the chemically aggressive media.

MODENGY coatings are applied to solve the following tasks in the oil production industry:

• Increasing service lifetime of the threaded connections of the pipes and clutches due to stabilizing friction coefficient and preventing scuffing at screwing/ unscrewing
• Preventing metals corrosion
• Surface treatment instead of phosphating

MODENGY 1001, MODENGY 1002, MODENGY 1005, MODENGY 1014 coatings are recommended to be used on the oil production pipes.

The task of preventing corrosion is not relevant for the threaded connections of the pipes made of stainless steels. All four coatings will contribute to increasing their service lifetime, however the experts especially mark out MODENGY 1001.

Due to content of molybdenum disulfide, this coating is effectively works out even at very high contact loads. It cures at room temperature just within 10 to 15 minutes, and is available in the form of aerosol cans. It enables to use the coating in the field conditions: where there is no special equipment for applying and curing this compound.

MODENGY 1002 coating can be used both to extend service lifetime of the pipe threaded connections, and as alternative for phosphating, which is quite an effective procedure but labour consuming and environment unfriendly one.

MODENGY 1002 has passed all required trials, the latest one has been completed in this year already. The coating was applied onto the dry, cleaned from the traces of the technical fluids thread of the casing pipe, and clutch. The compound was curing without heating.

Later on, three cycles of screwing/unscrewing of the connection with the force of 1500 N•m in presence of the lubricant for thread sealing were held. Plastic strain was registered after the 4th screwing at the torque of 4400 N•m, and at the same time no trace of the coating wear was revealed.

Fig. 1. MODENGY 1002 coating after the 3rd screwing (on the left) and after the 4th screwing (on the right)

MODENGY 1005 and MODENGY 1014 coatings, well-proven as grease-free, are also applied to solve the tasks described above with no less success. They passed trials in the threaded connections of the drill pipes last year. The aim of those tests was to reveal service lifetime of the covered thread but without using the conventional lubricating materials.

The coatings were applied onto the surface after their preliminary Mn-phosphating. Screwing was held on the clutch-screwing machine with the force of 2400 N•m.

The photo below demonstrates the state of the nipple after the 190th cycle of screwing, this is how many cycles that makes the service lifetime period of the threaded connection covered with MODENGY 1005.

Fig. 2. Appearance of the nipple and clutch parts of the pipe covered with MODENGY 1005 coating

The MODENGY 1005 coating's result at accelerated tests in salt mist on the non-phosphated surface has made 720 hours.

MODENGY 1005 and MODENGY 1014 cure at heating, so it is recommended to use these coatings on the clutches that can be placed into the kiln by portions.

All in all, use of MODENGY anti-friction solid lubricating coatings has a great potential in the field of solving the tasks of the oil production industry. Due to their unique properties, they are gaining more and more popularity.