What is ANSI seamless steel pipe?

　　ANSI seamless steel pipe‌ is a kind of seamless steel pipe produced in accordance with the standards of the American National Standards Institute (ANSI). The expression methods of its wall thickness grade series vary in different implementation standards. ANSI seamless steel pipes can withstand ultra-high pressure and are designed according to pressure requirements. They are usually used in high-temperature and high-pressure equipment such as high-pressure oil pipes and boiler tubes.

　　In addition, the internal and external surfaces of seamless steel pipes are smooth and uniform, with no welded seams, which further enhances its compressive strength and corrosion resistance, making seamless steel pipes the preferred material in multiple industries, including petrochemical industry, power station construction, In the machinery manufacturing, automobile industry, construction and shipbuilding industries, etc., due to its excellent performance and wide range of applications, the specifications and wall thickness of seamless steel pipes have an important impact on their performance and applications.

　　The methods of expressing the wall thickness grade series of ANSI seamless steel pipes mainly include the following:

　　‌Pipe schedule (Sch): This is a common expression method, where Sch is the ratio of the pipe design pressure to the material allowable stress at the design temperature multiplied by 1000 and rounded. For example, in the ANSI B36.10 standard, the wall thickness grades include ten grades such as Sch10, Sch20, Sch30, Sch40, Sch60, Sch80, Sch100, Sch120, Sch140, Sch160, and even special grades for stainless steel such as Sch5s and Sch10s. The wall thickness can be expressed in various ways, including millimeter values, pipe weight classification (standard weight pipe, thickened pipe and extra thick pipe), and determined by the corresponding table of pipe weight and wall thickness grade.

　　Pipe weight expression method:

　　This method divides the pipe wall thickness into three types, such as standard weight pipe (STD), thickened pipe (XS), and extra thick pipe (XXS), which helps to select the appropriate wall thickness grade according to different application requirements.

　　For example, for pipes with DN≤250mm, SCH 40 is equivalent to STD;

　　For pipes with DN<200mm, SCH 80 is equivalent to XS.

　　The main products of American standard seamless steel pipes are:

　　1. General purpose seamless steel pipe ASTM A53 GR.B

　　Steel grade: SA53 B

　　Specifications: 1/4″-28″, 13.7-711.2mm, SA53 GR.B

　　Tensile strength: ≥415 (MPa), yield strength: ≥240 (MPa)

　　Steel grade: GRAD B

　　Standard: ASTM A 53, suitable for pressure piping systems, pipeline pipes, general purpose pipelines, and high temperature operations with temperatures below 350℃.

　　There are two ways to indicate the specifications of American standard seamless steel pipes:

　　The first method is outer diameter*wall thickness (e.g. 114.3*6.02mm)

　　The second method is inch*number (e.g. 2”*SCH80)

　　There are three ways to indicate the wall thickness of American standard seamless steel pipes: pipe number, wall thickness size and pipe weight

　　1. The wall thickness is indicated by the pipe number "Sch".

　　2. The pipe number is the ratio of the design pressure of the pipe to the allowable stress of the material at the design temperature multiplied by 1000 and rounded. That is: Sch=P/[o]tx1000

　　3. ASME B36.10M wall thickness grades Sch10, Sch20, Sch30, Sch40, Sch60, Sch80, Sch100, Sch120, Sch140, Sch160 2. Indicated by the wall thickness size of American standard seamless steel pipes China, IS0, and Japan adopt some American standard seamless steel pipe standards

　　The main implementation standards of American standard seamless steel pipes are as follows:

　　API 5L seamless steel pipe for pipelines

　　ASTM A36/ASME SA-36 carbon structural steel

　　ASTM A53/ASME SA-53 uncoated and hot-dip galvanized welded and seamless nominal steel pipes

　　ASTM A106/ASME SA-106 seamless carbon steel nominal pipes for high temperature

　　ASTM A210/ASME SA-210 seamless medium carbon steel pipes for boilers and superheaters

　　ASTM A312 /A312M seamless and welded austenitic stainless steel pipes (304 and 306 stainless steel)

　　ASTM A335/ASME SA-335 seamless ferrite alloy steel nominal pipes for high temperature

　　ASTM A333/ASME SA-333 seamless and welded steel pipes for low temperature equipment

　　ASTM A500/ASME SA-500 round and special-shaped cold-formed welded and seamless carbon steel structural pipes

　　ASTM A519/ASME SA-519 seamless carbon steel pipe and alloy mechanical pipe

　　ASTM A29/ASME SA-29 hot-worked carbon steel pipe and alloy steel pipe

　　ASTM A179/ SA-179/SA-179M seamless cold-drawn low-carbon steel pipe for heat exchangers and condensers

　　ASTM A192/ SA-192/SA-192M seamless carbon steel boiler tube for high pressure

　　ASTM A209/SA-209/SA-209M seamless carbon-molybdenum alloy steel pipe for boilers and superheaters

　　ASTM A213/SA-213/SA-213M seamless ferritic and austenitic alloy steel pipe for boilers, superheaters and heat exchangers

　　American standard seamless steel pipe materials include:

　　1. API 5L seamless steel pipe for pipeline

　　Material includes: GR.B, X42, X52, X60, X65, X70

　　2. ASTM A36/ASME SA-36 carbon structural steel,

　　Material includes: A36 SA-36

　　3. ASTM A53/ASME SA-53 uncoated and hot-dip galvanized welded and seamless nominal steel pipe materials include: A53 GR.A, A53GR.B

　　4. ASTM A106/ASME SA-106 Seamless carbon steel nominal pipe for high temperature

　　Material includes: A106 GR.A, A106 GR. B, A106 GR.C, SA-106 GR.A, SA-106GR.B, SA-106 GR.C

　　5. ASTM A210/ASME SA-210 Seamless medium carbon steel pipe for boiler and superheater Materials include: SA-210A1, SA-210C, etc.

　　6. ASTM A335/ASME SA-335 Seamless ferrite alloy steel nominal pipe for high temperature Materials include: T/P11, T/P12, T/P91, T/P92, T/P22, T/P5, T/P9, T/P23

　　7.ASTM A333/ASME SA-333 Seamless and welded steel pipe for low temperature equipment

　　Material includes: A333 GR.6, etc.

　　8. ASTM A500/ASMESA-500 round and special-shaped cold-formed welded and seamless carbon steel structural pipes include: A500 GR.A, A500 GR.B

　　9. ASTM A519/ASMESA-519 seamless carbon steel pipes and alloy mechanical tubes

　　Material includes: 1020, 1040, 4130, 4140, 4340

　　10. ASTM A179/SA-179M seamless cold-drawn low-carbon steel pipes for heat exchangers and condensers include: SA-179M

　　11. ASTM A192/SA-192M seamless carbon steel boiler tubes for high pressure include: SA-192M

　　12. ASTM A209/SA-209M seamless carbon-molybdenum alloy steel pipes for boilers and superheaters include: SA-209M T1a

　　13. ASTM A213/SA-213M Seamless ferrite and austenite alloy steel pipes for boilers, superheaters and heat exchangers include: SA-213M T11, T12, T22, T23, T91

　　ANSI Seamless steel pipes (SMLS pipe) are made from steel ingots or solid tube blanks that are perforated into capillary tubes, and then hot rolled, cold rolled or cold drawn. Compared with ordinary steel pipes, seamless steel pipes have a higher pressure-bearing capacity. Therefore, in industrial production, pipes that need to withstand greater pressure generally use seamless steel pipes.