Tafuta ' ' kupata maudhui yanayofaa , ambayo inachukua sekunde }
Muhtasari:Toleo kubwa la udhibiti wa jukwaa hilo lina hitaji kubwa kwa uwezo wa shea wa uongozi wa jukwaa la pwani. Ili kusoma sab[Soma maandishi yote]
Muhtasari:According to the purpose, it can be divided into oil well pipe (casing, oil pipe and drill pipe), pipeline pipe, boiler [Soma maandishi yote]