The A106 line pipe is a line pipe that belongs to the American petroleum standard. 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 steel 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.
With the development of pipeline steel plate technology and the advancement of welded pipe forming and welding technology, the application range of pipeline welded pipe is gradually expanding, especially in the range of large-diameter group spacing. The advantage of welded pipe Occupying a leading position in the field of line pipes has restricted the development of stainless steel seamless line pipes.
According to the different performance requirements of A106 line pipes and the different tempering temperature, tempering can be divided into the following types:
1. Low temperature tempering (150-250 degrees)
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, GB/T9711.1 pipeline steel pipes, rolling bearings and carburized parts, etc. The hardness after tempering is generally HRC58-64.
2. Medium temperature tempering (250-500 degrees)
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 GB/T9711.1 pipeline steel pipes and hot work molds, and the hardness after tempering is generally HRC35-50.
3. High temperature tempering (500-650 degrees)
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, GB/T9711.1 pipeline steel pipes, machine tools, such as connecting rods, bolts, gears and shafts. The hardness after tempering is generally HB200-330.