The sticking of tubing thread is due to the friction and interference of internal and external thread, and the surface temperature rises sharply, which makes the internal and external thread surface of tubing stick. Due to the relative displacement of the internal and external thread surface of the tubing in the process of screwing on and off, metal migration is often accompanied by screwing on. In order to reduce the friction interference between the internal and external threads, in addition to the use of thread grease such as J03 when making up the thread, the surface of the tubing is coated with dry film lubricant during the preparation or maintenance of the tubing to achieve a better matching effect of liquid lubrication and solid lubrication.
Base material treatment and composite film technology can significantly improve the wear resistance of phenolic epoxy bonded MoS2 dry film, increase the hardness of steel, sand blowing treatment of base material, increase the thickness of dry film, increase the curing temperature of dry film, and reduce the relative humidity of the environment, which is also conducive to improve the micro shock resistance and wear resistance of phenolic epoxy bonded MoS2 dry film, but the temperature above 200℃ will accelerate the oxidation of dry film and reduce the lubrication effect.
A solid lubricant coating containing molybdenum disulfide powder and resin binder is formed on the surface of the bolt rod and the box sleeve which are in contact with the unthreaded metal at the thread joint of the tubing. The coating is heated in sections at 70 ~ 150℃ and 150 ~ 380℃, and its Rockwell hardness is 70 ~ 140 and 500N / m or even higher. The wear caused by repeated tightening and loosening operation can be prevented without applying thread grease, so as to ensure high temperature. In addition, titanium oxide ultraviolet shielding particles are added to improve the rust resistance.