Oil drilling Yan steel, do HWDP overall L8013Cr Pup joint manufacturers HWDP raw steel is AISI 4145H alloy steel, the production process strictly enforce the SY / T5146-1997 standard, heavy weight drill pipe is a medium-weight, similar to drill drill rod, drill pipe wall thickness than the large than small drill collars, drill pipe J55,N80,C95,T95,P110 Casing and tubing in stock connected to a particular extension connector on its thick-walled tube, usually in the composition of the drill string is applied between the drill pipe and drill collars, prevent sudden changes in cross-section of the drill string, the drill pipe to reduce fatigue. Use in directional wells, high-speed drilling with lower torque, reducing wear and Oil Country Tubular Goods(OCTG) Pup joint tear of the drill string, due to its steel drill collars than small, and wall contact area is small, not easily formed pressure card diamond.