Specifications and grades of seamless steel pipes

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Ordinary steel pipe grades: DN15, DN20, DN25, DN32, DN40, DN50, DN70, DN80, DN100, DN125, DN150, DN200...

Stainless steel pipe grade:

Seamless steel pipe specifications and grades 32-38-40X3-4-6-8

Seamless steel pipe specifications and grades 42-48X3.5-4-5-8-10

Seamless steel pipe specifications and grades 51-60X3.5-5-6-7-9

Seamless steel pipe specifications and grades 76-89X4.5-6-8-10-12

Seamless steel pipe specifications and grades 108-133X5-6-8-10-12

Seamless steel pipe specifications and grades 159-168X7-8-10-14-18-26

Seamless steel pipe specifications and grades 194-219X6-8-12-20-26-38

Seamless steel pipe specifications and grades 245-273X10-12-14-16-22-15-40

Classification of seamless steel pipes: Seamless steel pipes are divided into two categories: hot-rolled and cold-rolled (dial) seamless steel pipes.

Seamless steel pipes Hot-rolled seamless steel pipes are divided into general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, geological steel pipes and other steel pipes.

In addition to general steel pipes, low- and medium-pressure boiler steel pipes, high-pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, and other steel pipes, cold-rolled (rolled) seamless steel pipes also include carbon thin-walled steel pipes, alloy thin-walled steel pipes, Stainless thin-walled steel pipes, special-shaped steel pipes. The outer diameter of hot-rolled seamless steel pipes is generally greater than 32mm, and the wall thickness is 2.5-75mm. The outer diameter of cold-rolled seamless steel pipes can be up to 6mm, and the wall thickness can be up to 0.25mm. The outer diameter of thin-walled pipes can be up to 5mm, and the wall thickness is less than 0.25mm. Cold rolling has higher dimensional accuracy than hot rolling.

General seamless steel pipe: It is made of hot-rolled or cold-rolled high-quality carbon structural steel such as 10, 20, 30, 35, 45, 16Mn, 5MnV and other low-alloy structural steel or 40Cr, 30CrMnSi, 45Mn2, 40MnB and other alloy steel. Seamless pipes made of 10 and 20 grade low carbon steel are mainly used for fluid transportation pipelines. Seamless tubes made of medium carbon steel such as 45 and 40Cr are used to manufacture mechanical parts, such as stressed parts of automobiles and tractors. Generally, seamless steel pipes must ensure strength and flattening tests. Hot-rolled steel pipes are delivered in a hot-rolled or heat-treated state; cold-rolled steel pipes are delivered in a heat-treated state.

Seamless steel pipes for low and medium pressure boilers: used to manufacture various low and medium pressure boilers, superheated steam pipes, boiling water pipes, water-cooled wall pipes and superheated steam pipes, large smoke pipes, small smoke pipes and arch brick pipes for locomotive boilers, etc. Hot-rolled or cold-rolled (dialed) seamless steel pipes are made of high-quality carbon structural steel. Mainly made of No. 10 and No. 20 steel, in addition to ensuring the chemical composition and mechanical properties, hydrostatic tests, curling, flaring, flattening and other tests are required. Hot-rolled products are delivered in a hot-rolled state, and cold-rolled (rolled) products are delivered in a heat-treated state.

High-pressure boiler steel pipes: High-quality carbon structural steel, alloy structural steel and stainless heat-resistant steel seamless steel pipes are mainly used to manufacture steam boiler pipes of high pressure and above. These boiler pipes often work under high temperature and pressure. The pipe will also undergo oxidation and corrosion under the action of high-temperature flue gas and water vapor. Therefore, the steel pipe is required to have high lasting strength, high oxidation resistance, and good organizational stability. The steel grades used are: high-quality carbon structure Steel grades include 20G, 20MnG, 25MnG; alloy structural steel grades 15MoG, 20MoG, 12CrMoG, 15CrMoG, 12Cr2MoG, 12CrMoVG, 12Cr3MoVSiTiB, etc.; rusty and heat-resistant steel commonly used 1Cr18Ni9, 1Cr18Ni11Nb high-pressure boiler tubes in addition to ensuring chemical composition and mechanical properties , it is necessary to conduct hydraulic pressure test one by one, as well as expansion and flattening tests. Steel pipes are delivered in heat treated condition. In addition, there are also certain requirements for the microstructure, grain size, and decarburization layer of the finished steel pipe.

Seamless steel pipes for geological drilling and oil drilling: In order to explore the underground rock structure, groundwater, oil, natural gas and mineral resources, drilling rigs are used to drill wells. The exploitation of oil and natural gas is inseparable from well drilling. Seamless steel pipes for geological drilling and oil drilling are the main equipment for drilling, mainly including outer core pipes, inner core pipes, casings, drill pipes, etc. Since drilling pipes have to go deep into the stratum of several thousand meters, the working conditions are extremely complex. The drill pipes are subjected to stresses such as tension, pressure, bending, torsion and uneven impact loads, as well as mud and rock wear. Therefore, pipes are required to It must have sufficient strength, hardness, wear resistance and impact toughness. The steel used for steel pipes is represented by "DZ" (the Chinese pinyin prefix for geology) plus a number one to represent the steel yield point. Commonly used steel grades include DZ45 45MnB and 50Mn; DZ50’s 40Mn2, 40Mn2Si; DZ55’s 40Mn2Mo, 40MnVB; DZ60’s 40MnMoB, DZ65’s 27MnMoVB. Steel pipes are delivered in heat-treated condition.

Petroleum cracking tubes: Seamless tubes used for furnace tubes, heat exchanger tubes and pipelines in petroleum refineries. Commonly used are high-quality carbon steel (10, 20), alloy steel (12CrMo, 15CrMo), heat-resistant steel (12Cr2Mo, 15Cr5Mo), stainless steel (1Cr18Ni9, 1Cr18Ni9Ti). In addition to verifying the chemical composition and various mechanical properties of steel pipes, steel pipes must also ensure water pressure, flattening, flaring and other tests, as well as surface quality and non-destructive testing. Steel pipes are delivered in heat treated condition. Stainless steel pipes: Hot-rolled and cold-rolled stainless steel pipes made of various stainless steels are widely used in petroleum and chemical equipment pipelines and stainless steel structural parts for various purposes. In addition to ensuring the chemical composition and mechanical properties, any steel pipe used to withstand fluid pressure It is necessary to ensure that the hydraulic pressure test is qualified. Various special steel pipes must ensure conditions according to regulations.

Seamless steel pipe implementation standards

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1. Seamless steel pipes for structural use: GB/T8162-2008 2. Seamless steel pipes for conveying fluids: GB/T8163-2008 3. Seamless steel pipes for boilers: GB3087-1999 4. High-pressure seamless pipes for boilers: GB5310-1995 ( ST45.8-ⅲ type) 5. High-pressure seamless steel pipe for fertilizer equipment: GB6479-2000 6. Seamless steel pipe for geological drilling: YB235-70 7. Seamless steel pipe for oil drilling: YB528-65 8. Seamless steel pipe for petroleum cracking Seamless steel pipe: GB9948-2006 9. Seamless pipe for oil drill collars: YB691-70 10. Seamless steel pipe for automobile half shafts: GB3088-1999 11. Seamless steel pipe for ships: GB5312-1999 12. Cold-drawn and cold-rolled precision Seamless steel pipe: GB3639-1999 13. Various alloy pipes 16Mn, 27SiMn, 15CrMo, 35CrMo, 12CrMov, 20G, 40Cr, 12Cr1MoV, 15CrMo

In addition, there are GB/T17396-1998 (hot-rolled seamless steel pipe for hydraulic props), GB3093-1986 (high-pressure seamless steel pipe for diesel engines), GB/T3639-1983 (cold-drawn or cold-rolled precision seamless steel pipe), GB /T3094-1986 (cold drawn seamless steel pipe special-shaped steel pipe), GB/T8713-1988 (precision inner diameter seamless steel pipe for hydraulic and pneumatic cylinders), GB13296-1991 (stainless steel seamless steel pipe for boilers and heat exchangers), GB/T14975 -1994 (stainless steel seamless steel pipe for structural use), GB/T14976-1994 (stainless steel seamless steel pipe for fluid transportation) GB/T5035-1993 (seamless steel pipe for automobile half-shaft casing), API SPEC5CT-1999 (casing and oil pipe specifications) etc.

As industrial processes and applications have matured, industry organizations have developed unique classifications and specifications for the pipe destined for service in those sectors.

There’s lots of overlap among the organizations’ published specs, and likely lots of confusion as well.

Buyers can improve their purchasing experience by learning more about how grades of steel are designated for piping and by understanding all the information that should be included on a purchase order.

ASTM and ASME

Both the American Society of Testing and Methods (ASTM) and the American Society of Mechanical Engineers (ASME) publish piping specs. ASTM and ASME pipe designations for grades of steel are very similar.

For example, A106 B is a spec published by ASTM (the ASME spec would be SA106 B). The “A” designates a ferrous material. ‘106’ is an arbitrary number that designates it as a seamless carbon steel pipe suited for high-temperature service. Then, grades (such as A, B or C) are assigned that indicate certain characteristics of the steel based on differences in its chemical makeup and mechanical properties.

Pipe sizes are described by using a pipe chart (ANSI/ASME B36.10 and API5L) that includes the outside diameter and wall thickness. The outside diameter can be referred by the nominal pipe size (NPS) or the actual dimension in inches and the wall by stating the schedule or the actual thickness in inches.

Note that while ASTM and ASME specs are largely identical, an important difference is that pipe meant for use in pressure systems sometimes requires different or additional quality tests before it complies with the ASME standard.

American Piping Products stocks a full range of A/SA106 and A/SA 53 carbon steel pipe.

AISI and SAE

The American Iron and Steel Institute (AISI) and the Society of Automotive Engineers (SAE) share a numbering system to classify steels. AISI/SAE designations only describe the chemical makeup of a steel. They do not include manufacturing, heat treating or testing information.

Using 1020 steel as an example, the first digit expresses the steel as a plain carbon steel. The second digit indicates there are no added alloys. The last two digits indicate the steel has around 0.20 percent carbon content.

For another example, a popular steel in the piping industry is 4130. The ’41’ indicates the steel contains chromium and molybdenum alloys. The ’30’ indicates the steel has around 0.30 percent carbon content.

Again, AISI/SAE designations only classify steels. For example, a buyer who says, “I need 100 feet of 4130” has not provided enough information. The buyer also needs to note specific production and testing information found in an ASTM or ASME spec to get exactly the pipe they need.

API

Pipe for use in the oil & gas industry are classified by the American Petroleum Institute’s (API) system.

API 5L is the most common standard to which line pipe in the oil and natural gas industry is rated. Because that’s merely a standard, additional information is needed to ensure purchase orders are executed accurately.

API 5L pipe is broken down into PSL1 and PSL2 delivery conditions; those conditions are further broken down into pipe grades, i.e. Grade B, X42, X52, X65, etc. Buyers should include the combination of the overarching standard, the delivery condition and the grade for the API5L pipe they need.

Study grades of steel

Buyers who place incomplete or inaccurate orders put their operations at risk of delays or cost overruns. When in doubt, consult with an engineer and refer to the industry standards that govern your application. Also be aware of other factors that play into your purchase:

• What manufacturer restrictions are in place that may impact your order?
• Are there any origin restrictions that you need to follow when buying?
• What pipe lengths and end finishes do you need?
• Are there specific chemistry requirements needed for the application?
• Are there age restrictions that may impact your order for export?

Suppliers need detailed purchase orders to ensure you get the right pipe the first time.

That’s why American Piping Products trains its experts to ask detailed questions to ensure you identify exactly what you need across all grades of steel and applications. Download our product catalog to see what we have in stock, and use this in-depth buyer’s guide as a resource as you consider any upcoming purchases.

Getting the right pipe starts here.

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