Pipe to be threaded is transferred from the warehouse of the Manufacturing Section to the warehouse of the Threading Section (1). Threading of tubing and casing is conducted in three lines with the main identical processes. In the second line unlike the first and the third lines, the additional inspection equipment is installed: magnetic particle inspection system of the pipe ends after threading, UT and flux leakage inspection system of the pipe body, hydro tester for hydrostatic testing on the full-length of pipe. The thread compound application, feeding into the line (2) and couplings pre-screwing are automated and ensure (taking into account the weight of coupling) a better quality of screwing and facilitate the personnel work.
Pipe after the incoming inspection is transported to the Drift Test Section (3) where the inside diameter is inspected throughout the entire length by means of cylindrical mandrel.
Threading the pipe is performed using pipe threading machines (4). The machines allow us to thread different types of thread (round, buttress, gas-tight). After threading, at the inspection stands the geometrical parameters are inspected to the normative documents requirements by means of measuring and/or special devices (5).
After the geometrical parameters testing, the pipe goes to the section where the thread compound is applied to the threaded end and thread protectors are screwed onto (6). After the first pipe threading machine, the thread protectors for protection during storage and transportation are applied to the threaded pipe ends. After the second pipe threading machine (7), the couplings (8) are screwed onto, then the pipe is transported to the screwing machine where the make-up with the specified torque takes place (9).
The threaded and coupled pipe is hydrostatically tested for leak-proofness of the joint. (10). The test pressure is continuously inspected and recorded during testing. Pipe successfully tested is transported to the weighing machine where in the beginning the thread compound is given to the thread surface of the coupling and thread protectors are applied on the entire length of internal thread to inhibit thread damage (11). Then, the pipe is weighed (12) at the weighing machine.
After measuring the mass, the pipe goes to the length-measuring machine. The data on the mass and length of each pipe enters the database of pipe marking and stamping machines, after that the marking is performed by one of the following methods: by paint-stenceling, stenceling using ink-spray printer painting, stamping or a combination of stamping and stencil markings (13).
After marking, pipe goes on the rolling-table to the Temporary Protection Coating Application Section (14). The coating is applied to protect the pipe outside surface from atmospheric corrosion during transportation and storage. Then, pipe goes to the Binding Section (15) where the pipes are tied in hexagonal bundles. The final pipe goes to the final products warehouse of the Threading Section (16).