The API 5L line pipe
is a line pipe that belongs to the American petroleum standard. API SPEC 5L-2011 (line pipe specification) is compiled and issued by the American Petroleum Institute, and is commonly used all over the world. The main materials of the tube are L245, L290, L360, L415, L480, GR.B, X42, X46, X56, X65, X70, X80, X100, etc.
The line pipe transports the oil, steam, and water extracted from the ground through the line pipe to the oil and natural gas industrial enterprises. Line pipes include seamless pipes and welded steel pipes. The pipe ends have flat ends, threaded ends and socket ends; the connection methods are end welding, coupling connection, socket connection, etc.
Processing technology of API 5L line pipe:
With the development of pipeline steel plate technology and the advancement of welded pipe forming and welding technology, the application scope of pipeline welded pipe is gradually expanding, especially in the range of large-diameter group spacing. Occupying a leading position in the field of line pipes has restricted the development of stainless steel seamless line pipes. In 2004, the output of seamless line pipes
was about 400,000 tons. The steel grades include X42-70, and the varieties include onshore line pipes and subsea line pipes.
The production of high steel grade line pipe adopts microalloying heating treatment process. The production cost of stainless steel seamless pipe is significantly higher than that of welded pipe. With the improvement of steel grade, such as X80 and above steel grade line pipe, there is no limit on carbon equivalent. The conventional process of seam steel pipe is difficult to meet user requirements; each 12Cr1moV alloy pipe manufacturer is carrying out scientific research to improve the corrosion resistance of its line pipes and the stable performance in low temperature and high temperature environments.
Types of tempering of API 5L line pipe:
According to the different performance requirements of pipeline steel pipes and the different tempering temperature, tempering can be divided into the following types:
1. Low temperature tempering (150-250°C)
The structure obtained by low temperature tempering is tempered martensite. Its purpose is to reduce the internal stress and brittleness of quenched steel while maintaining the high hardness and high wear resistance of the quenched steel, so as to avoid cracking or premature damage during use. It is mainly used for various high-carbon cutting tools, measuring tools, rolling bearings and carburized parts, etc. The hardness after tempering is generally HRC58-64.
2. Medium temperature tempering (250-500°C)
The structure obtained by tempering at medium temperature is tempered troostite. Its purpose is to obtain high yield strength, elastic limit and high toughness. Therefore, it is mainly used for the treatment of various hot work molds, and the hardness after tempering is generally HRC35-50.
3. High temperature tempering (500-650°C)
The structure obtained by high temperature tempering is tempered sorbite. Traditionally, the heat treatment combining quenching and high temperature tempering is called quenching and tempering treatment, and its purpose is to obtain comprehensive mechanical properties with good strength, hardness, plasticity and toughness. Therefore, it is widely used in important structural parts of automobiles and machine tools, such as connecting rods, bolts, gears and shafts. The hardness after tempering is generally HB200-330.
Permanent Steel Manufacturing Co.,Ltd, as a professional seamless pipe supplier, integrates warehousing, sales, processing, and distribution. It specializes in the management of various seamless steel pipes, as well as the on-demand seamless steel pipes of special processes, special sizes and special materials. Custom-made products are used in various industrial fields such as engineering, coal mines, textiles, electric power, boilers, machinery, and military industries.