Torque rings are steel rings inserted into the couplings of standard API threaded and coupled tubing and casing connections. The ring provides a number of benefits, including a mechanical shoulder for the ends of the pin ends to increase torque capacity.
[pdf] use caustic soda solution (Concentration 8-10%) Heat to 60℃ and soak the handpiece for 24 hours. cooler Use a high-pressure water gun (pressure>15MPa) to back-flush the copper tube. replacement All-oil sealing ring Avoid corrosion by residual cleaning agents.
[pdf] 
