PKNM manufactures a wide range of subs in accordance with API Spec. 7–1 and the customers’ design. All the products are made from steel the mechanical qualities of which correspond to API Spec. 7–1.
Subs are used to connect different parts of the drill stem or for connecting an instrument to it that has different type and size of the thread for performing drilling, servicing and geological surveys in oil-and-gas fields.
Subs’ types:
Adapter subs (with box and pin ends);
Box subs (both are box threads);
Pin subs (both are pin threads);
Elevator subs with flat shoulder for elevator;
Elevator subs with taper shoulder for elevator.
Subs are manufactured of different configurations. Threads can be both right and left. The heat-treatment is done with the help of a modern equipment INT4–630 / 1.0 and a complex volume heat-treatment “Nakal”. The material quality is checked on the complex impulse system of Ultrasonic tube Testing UPNK-2 and a special system of Ultrasonic Testing.
The subs are supplied having the hardened thread connection which is achieved by phosphatizing and thread root deep rolling. The subs’ threads are nitrided using the technology “Nitroprotect”. The thread connections are covered with anticorrosion coating.
