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The Correct Selection of Seamless Steel Pipes-Part 1
Sep 26, 2021
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Here are the correct selection of seamless pipes for carbon steel seamless pipes, low alloy steel seamless pipes and stainless steel seamless steel pipes. Let's first see the correct selection for carbon steel seamless pipes.
(1) Carbon steel seamless pipes
Material grades: a total of 4 kinds: 10, 20, 09MnV, 16Mn
Standards:
GB8163 Seamless steel pipes for fluid conveying
GB/T9711 Technical conditions of delivery of pipes for oil and gas industry
GB6479 High pressure seamless steel pipes for fertilizer equipment
GB9948 Seamless steel pipes for petroleum cracking
GB3087 Seamless steel pipes for low and medium pressure boilers
GB/T5310 Seamless steel pipes for high pressure boilers
GB/T8163:
Material grades: 10, 20, Q345, etc
Scopes of applications: the design temperature is less than 350℃
The pressure is less than 10MPa oil products, oil and gas and public media.
GB6479:
Material grades: 10, 20G, 16Mn, etc.
Scopes of application: oil and gas with design temperature of -40 - 400℃ and design pressure of 10.0 - 32.0MPa
GB9948:
Material grades: 10, 20, etc.
Scopes of application: it is not suitable for the occasions of GB/T8163 steel pipes.
GB3087:
Material grades: 10, 20, etc.
Scopes of application: superheated steam, boiling water and others of low and medium pressure boilers.
GB5310:
Material grades: 20G, etc.
Scopes of application: superheated steam medium of high pressure boilers
Inspection: chemical composition analysis, tension test, flattening test and water pressure test must be carried out on the steel pipe used for general fluid transportation.
GB5310, GB6479, GB9948: these three kinds of steel pipes are required to carry out flaring tests and impact tests. What’s more, the fluid transport tube must be tested. The manufacturing inspection requirements of these three kinds of steel pipes are quite strict.
GB6479 standard also makes special requirements for low temperature impact toughness of materials.
GB3087 steel pipes: In addition to the general test requirements of fluid conveying steel pipe, it also requires a cold bending test.
GB/T8163 steel pipes: In addition to the general test requirements for the steel pipes of GB/T8163 standard, flared test and cold bending test should be carried out according to the agreement requirements. These two kinds of pipes are not as strict as the first three kinds of pipes.
Manufacturing: GB/T/8163 and GB3087 steel pipes: open hearth furnace or converter smelting are adopted and there are relatively more its impurity composition and internal defects. GB9948 is smelted by an electric furnace. Most of them have been refined outside the furnace, with relatively few components and internal defects. The GB6479 and GB5310 standards themselves define the requirements for off-furnace refining, which has the lowest impurity composition and internal defects and the highest material quality.
The above several steel pipes are manufactured in a standard quality grade order from low to high:
GB/T8163 < GB3087 < GB9948 < GB5310 < GB6479
Selection: under normal circumstances, the GB/T8163 steel pipe is suitable for the design temperature is less than 350℃ and the pressure is less than 10.0Mpa of oil products, oil and gas and public media conditions. For oil products, oil and gas media, when the design temperature is more than 350℃ or the pressure is greater than 10.0MPa, it is appropriate to choose GB9948 or GB6479 steel pipes.
GB9948 or GB6479 should also be used for pipelines operating near hydrogen or in stress corrosion prone environments. GB6479 standard should be used at low temperature (less than -20℃) for carbon steel pipes. Only it stipulates the requirements of impact toughness of material low temperature.
GB3087 and GB5310 standards are specially set for steel pipes used in boilers. Boiler safety supervision regulations emphasized that all connected with the boiler pipes belong to the scope of supervision and the application of the material. The standard should comply with the rules of boiler safety. Therefore, GB3087 or standard GB5310 should be used (by the system supply) in boilers, power stations, heating and petrochemical production devices used in public steam pipes.
It is worth noting that the quality of the standard of steel pipes. The price of steel pipes is relatively high. For example, the price of GB9948 is 1/5 higher than that of GB8163. Therefore, in the selection of material standards of steel pipes, it should be based on the use of comprehensive consideration. It should be both reliable and economical. It should also be noted that steel pipes in accordance with GB/T20801 and TSGD0001, GB3087 and GB8163 should not be used for GC1 pipeline (unless one by one, with a quality of no less than L2.5. It can be used for design of GC1(1) pipeline with a pressure not greater than 4.0MPa).
(1) Carbon steel seamless pipes
Material grades: a total of 4 kinds: 10, 20, 09MnV, 16Mn
Standards:
GB8163 Seamless steel pipes for fluid conveying
GB/T9711 Technical conditions of delivery of pipes for oil and gas industry
GB6479 High pressure seamless steel pipes for fertilizer equipment
GB9948 Seamless steel pipes for petroleum cracking
GB3087 Seamless steel pipes for low and medium pressure boilers
GB/T5310 Seamless steel pipes for high pressure boilers
GB/T8163:
Material grades: 10, 20, Q345, etc
Scopes of applications: the design temperature is less than 350℃
The pressure is less than 10MPa oil products, oil and gas and public media.
GB6479:
Material grades: 10, 20G, 16Mn, etc.
Scopes of application: oil and gas with design temperature of -40 - 400℃ and design pressure of 10.0 - 32.0MPa
GB9948:
Material grades: 10, 20, etc.
Scopes of application: it is not suitable for the occasions of GB/T8163 steel pipes.
GB3087:
Material grades: 10, 20, etc.
Scopes of application: superheated steam, boiling water and others of low and medium pressure boilers.
GB5310:
Material grades: 20G, etc.
Scopes of application: superheated steam medium of high pressure boilers
Inspection: chemical composition analysis, tension test, flattening test and water pressure test must be carried out on the steel pipe used for general fluid transportation.
GB5310, GB6479, GB9948: these three kinds of steel pipes are required to carry out flaring tests and impact tests. What’s more, the fluid transport tube must be tested. The manufacturing inspection requirements of these three kinds of steel pipes are quite strict.
GB6479 standard also makes special requirements for low temperature impact toughness of materials.
GB3087 steel pipes: In addition to the general test requirements of fluid conveying steel pipe, it also requires a cold bending test.
GB/T8163 steel pipes: In addition to the general test requirements for the steel pipes of GB/T8163 standard, flared test and cold bending test should be carried out according to the agreement requirements. These two kinds of pipes are not as strict as the first three kinds of pipes.
Manufacturing: GB/T/8163 and GB3087 steel pipes: open hearth furnace or converter smelting are adopted and there are relatively more its impurity composition and internal defects. GB9948 is smelted by an electric furnace. Most of them have been refined outside the furnace, with relatively few components and internal defects. The GB6479 and GB5310 standards themselves define the requirements for off-furnace refining, which has the lowest impurity composition and internal defects and the highest material quality.
The above several steel pipes are manufactured in a standard quality grade order from low to high:
GB/T8163 < GB3087 < GB9948 < GB5310 < GB6479
Selection: under normal circumstances, the GB/T8163 steel pipe is suitable for the design temperature is less than 350℃ and the pressure is less than 10.0Mpa of oil products, oil and gas and public media conditions. For oil products, oil and gas media, when the design temperature is more than 350℃ or the pressure is greater than 10.0MPa, it is appropriate to choose GB9948 or GB6479 steel pipes.
GB9948 or GB6479 should also be used for pipelines operating near hydrogen or in stress corrosion prone environments. GB6479 standard should be used at low temperature (less than -20℃) for carbon steel pipes. Only it stipulates the requirements of impact toughness of material low temperature.
GB3087 and GB5310 standards are specially set for steel pipes used in boilers. Boiler safety supervision regulations emphasized that all connected with the boiler pipes belong to the scope of supervision and the application of the material. The standard should comply with the rules of boiler safety. Therefore, GB3087 or standard GB5310 should be used (by the system supply) in boilers, power stations, heating and petrochemical production devices used in public steam pipes.
It is worth noting that the quality of the standard of steel pipes. The price of steel pipes is relatively high. For example, the price of GB9948 is 1/5 higher than that of GB8163. Therefore, in the selection of material standards of steel pipes, it should be based on the use of comprehensive consideration. It should be both reliable and economical. It should also be noted that steel pipes in accordance with GB/T20801 and TSGD0001, GB3087 and GB8163 should not be used for GC1 pipeline (unless one by one, with a quality of no less than L2.5. It can be used for design of GC1(1) pipeline with a pressure not greater than 4.0MPa).
