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　　1.3mm Q235 Welded ERW Carbon Steel Pipe is also called carbon steel, which refers to iron carbon alloy with carbon content of Wc less than 2.11%. Carbon steel pipe usually contains a small amount of silicon, manganese, sulfur and phosphorus besides carbon.

　　Carbon steel pipe can be divided into three types according to its use: carbon structural steel, carbon tool steel and free cutting structural steel. Carbon structural steel can also be divided into engineering construction steel and machine manufacturing structural steel.

　　According to the smelting method, it can be divided into open hearth steel and converter steel.

　　According to deoxidation method, it can be divided into boiling steel (F), killed steel (Z), semi-killed steel (b) and special killed steel (TZ).

　　According to carbon content, carbon steel pipecan be divided into low carbon steel (WC < 0.25%), medium carbon steel pipe(WC 0.25% - 0.6%) and high carbon steel (WC > 0.6%).

　　According to the quality of steel, carbon steel can be divided into ordinary carbon steel pipe(containing higher phosphorus and sulfur), high quality carbon steel pipe(containing lower phosphorus and sulfur), high quality steel (containing lower phosphorus and sulfur) and high quality steel (containing lower phosphorus and sulfur) and high quality steel.

　　In general carbon steel pipe, the higher the carbon content, the greater the hardness, the higher the strength, but the lower plasticity.

　　2. Seamless steel pipe has hollow section, which is widely used as pipeline for conveying fluids, such as oil, natural gas, gas, water and some solid materials. Compared with solid steel such as round steel, steel pipe has lighter weight when its bending and torsional strength is the same. It is a kind of steel with economic section. It is widely used in manufacturing structural and mechanical parts, such as oil drill pipe, automobile transmission shaft, bicycle frame and steel scaffold used in construction to make ring parts, which can improve materials. The utilization rate, simplification of manufacturing process, material saving and processing hours have been widely used for manufacturing steel pipes.

　　Chemical composition of steel: The chemical composition of steel is one of the most important factors affecting the performance of seamless steel tube, and is also the main basis for formulating the process parameters of rolling and heat treatment of steel tube.

　　Alloy elements: intentional addition, according to use

　　Residual elements: steel control, proper control.

　　Harmful elements: strict control (As, Sn, Sb, Bi, Pb), gas (N, H, O)

　　External refining or electroslag remelting: Improve the uniformity of chemical composition and purity of steel, reduce non-metallic inclusions in billet and improve its distribution.

　　So the carbon steel pipe and seamless steel pipe are not material.

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