Line pipe size tolerance and standard

Line pipe size tolerance and standard Line pipe specification: 8-1240×1-200mm standard: API SPEC 5L Usage: used for gas, water and oil transportation in petroleum and natural gas industries。 API SPEC 5L-2007 (line pipe specification), compiled and issued by the American Petroleum Institute, is commonly used all over the world. Line pipe: The oil, gas or water that is output from the ground is transported to the petroleum and natural gas industrial enterprises through the line pipe. Line pipes include seamless pipes and welded pipes. The pipe ends have flat ends, threaded ends and socket ends; the connection methods are end welding, coupling connection, socket connection, etc. The main material of the tube is B, X42, X46, X56, X65, X70 and other steel grades. . Line pipe standard: API SPEC 5L-American Petroleum Institute Standard GB/T9711-China National Standard Use: Oxygen, water and oil conveying pipes used in petroleum and natural gas industries Mainly produce steel pipe grades: B, X42, X52, X60, X65, X70 L245 L290 L320 L360 L390 L450 L485 Line pipe size tolerance: 1.【Separate fire for line pipes】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 under the premise of maintaining high hardness and high wear resistance, 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.【Separate fire for line pipes】Medium temperature tempering (250-500 degrees) The structure obtained by tempering at medium temperature is tempered troostite. The 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. 【Separate fire for line pipes】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 automobiles, GB/T9711.1 pipeline steel pipes, machine tools and other important structural parts, such as connecting rods, bolts, gears and shafts. The hardness after tempering is generally HB200-330. Post time: Jan-30-2021 Type of pipe Out Diameter （D） （S） Pipe Body Out Diameter (mm) Allow Tolerance(mm) Out Diameter(mm) Allow  Tolerance(mm) ≥60.3且S＜20 ±0.75％ ≤73.0 ＋15％，－12.5％ ≥60.3且S≥20 ±1.00％ ＞73.0且S＜20 ＋15％，－12.5％ ＞73.0且S≥20 ＋17.5％，－10