Pipeline material

This post was last edited by tjhxtgg on 2011-12-31 at 13:00. Carbon steel pipes are generally seamless pipes； Carbon steel (carbon content of 0.35% or less)

The carbon content in carbon steel grades is generally between 0.0218% and 2.11%

Carbon steel can be classified into low-carbon steel, medium-carbon steel, and high-carbon steel based on its chemical composition (i.e., carbon content). 　　(1) Low-carbon steel, also known as soft steel, has a carbon content ranging from 0.10% to 0.30%. It is easy to work with through processes such as forging, welding, and cutting, and is commonly used in the manufacture of chains, rivets, bolts, shafts, etc. 　　(2) Medium carbon steel 　　Carbon steel with a carbon content of 0.25%–0.60%. There are various products such as calm steel, semi-calm steel, and boiling steel. In addition to carbon, it may also contain a small amount of manganese (0.70%–1.20%). Based on product quality, it is divided into ordinary carbon structural steel and high-quality carbon structural steel. It has good hot working and cutting properties, but poor welding properties. Its strength and hardness are higher than those of low-carbon steel, whereas its plasticity and toughness are lower. It can be used directly as hot-rolled or cold-drawn material without heat treatment, or it can be used after heat treatment. Medium-carbon steel after quenching and tempering possesses excellent comprehensive mechanical properties. The maximum achievable hardness is approximately HRC55 (HB538), with σb ranging from 600 to 1100 MPa. Therefore, in various applications at moderate intensity levels, medium-carbon steel is the most widely used; aside from being used as building materials, it is also extensively employed in the manufacture of various mechanical parts. 　　(3) High-carbon steel Often referred to as tool steel, with a carbon content ranging from 0.60% to 1.70%; it can be hardened and tempered. Hammers, crowbars, etc. are made of steel with a carbon content of 0.75%; cutting tools such as drills, taps, and reamers are made of steel with a carbon content of 0.90% to 1.00%.