We can classify carbon steel seamless steel pipes as cold drawn seamless pipe and hot rolled seamless pipe due to the producing process. It is widely used for conveying gas,water,and petroleum of both the oil and natural gas industries.Normally, when outer diameter of the pipe is within 57mm, we usually produce cold drawn pipes, while up to that 57mm, we produce hot rolled ones. The dimensional accuracy of cold drawn seamless pipe is more precise then the hot rolled pipes. Production Flow of Carbon Steel Seamless Pipes: 1. Steel billet → heating → punching → head making → annealing → pickling → copper plating → cold drawing → semi-finished pipes → heat treatment → straightening → water pressure test → labeling → warehouse entry. 2. Round billet→ pickling→ cut off→ heating→ piercing→ pointing→ pickling→ cold-drawing (cold-rolling) → semi-finished pipe→ heat treatment→ physical chemistry test→ straightening→ corps end cutting off→ surface and size inspection→ eddy current inspection→ UT testing→ marking/painting/bundling→ warehouse/shipping Each step is under strict control to ensure you a high quality pipe.