Cast iron pipe, pipe made of cast iron. Cast iron pipe used for water supply, drainage and gas transmission lines, including cast iron straight pipe and pipe fittings. Low labor intensity. According to different casting methods, it is divided into continuous cast iron pipe and centrifugal cast iron pipe, which is divided into sand and metal type two kinds of centrifugal cast iron pipe. It is divided into gray cast iron pipe and ductile cast iron pipe according to different materials. According to different interface forms, it can be divided into flexible interface, flange interface, self-anchored interface, rigid interface, etc. The flexible cast iron pipe is sealed with rubber ring; Flange interface cast iron pipe flange fixed, inner gasket rubber flange gasket seal; Rigid interface generally cast iron pipe bearing mouth is larger, straight pipe inserted, sealed with cement, this process has been basically eliminated.

Steel pipe production technology development began with the rise of the bicycle manufacturing, development of oil in the early years of the 19th century, two world war ships, boilers, aircraft manufacturing, after the second world war thermal power boiler manufacturing, chemical industry and the development of oil and gas drilling and transportation, effectively driving the steel pipe industry in the development of varieties, yield and quality.

Steel pipe is not only used to transport fluids and powdery solids, exchange heat, manufacture mechanical parts and containers, it is also an economical steel. It can reduce the weight, save 20 ~ 40% of the metal, and realize the industrial mechanized construction. Using steel pipe to manufacture highway bridge can not only save steel, simplify construction, but also greatly reduce the area of protective coating and save investment and maintenance cost.