Correct selection of seamless steel pipe
Seamless steel pipe is made without weld by hot working methods such as perforated hot rolling. If necessary, the hot-worked pipe can be further cold-worked to the desired shape, size and performance. At present, seamless steel pipe is the most used pipe in petrochemical production units.
(1) Carbon steel seamless steel pipe
Material grade: 10, 20, 09MnV, 16Mn 4 kinds in total
Standard: GB8163 “Seamless steel pipe for fluid transportation”
GB/T9711 “Oil and natural gas industry steel pipe delivery technical conditions”
GB6479 “High pressure seamless steel pipe for fertilizer equipment“
GB9948 “Seamless steel pipe for petroleum Cracking”
GB3087 “Seamless steel tubes for low and medium pressure boilers”
GB/T5310 “Seamless steel tubes for high pressure boilers“
GB/T8163:
Material grade: 10, 20, Q345, etc.
Scope of application: designed temperature is less than 350℃, pressure is less than 10MPa oil, oil and public medium
Material grade: 10, 20G, 16Mn, etc.
Scope of application: oil and gas with design temperature of -40 ~ 400℃ and design pressure of 10.0 ~ 32.0MPa
Material grade: 10, 20, etc.
Scope of application: not suitable for GB/T8163 steel pipe occasions.
Material grade: 10, 20, etc.
Scope of application: low and medium pressure boiler superheated steam, boiling water, etc.
Material grade: 20G, etc.
Scope of application: superheated steam medium of high pressure boiler
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 three kinds of standard steel pipe, in addition to the fluid transport tube must be tested, but also required to carry out flaring test and impact test; 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 standard steel pipe, in addition to the general test requirements for fluid transport steel pipe, but also requires cold bending test.
GB/T8163 standard steel pipe, in addition to the general test requirements for fluid transport steel pipe, according to the requirements of the agreement to carry out flaring test and cold bending test.The manufacturing requirements of these two kinds of pipes are not as strict as those of the first three kinds.
Manufacturing: GB/T/8163 and GB3087 standard steel pipe adopt open furnace or converter smelting, its impurities and internal defects are relatively more.
GB9948 electric furnace smelting. Most are added to the furnace refining process with relatively few ingredients and internal defects.
GB6479 and GB5310 standards themselves specify the requirements for refining outside the furnace, with the minimum impurities and internal defects and the highest material quality.
The above several steel pipe standards are manufactured in the order of quality from low to high:
GB/T8163＜ GB3087＜ GB9948＜ GB5310＜GB6479
Selection: under normal circumstances, GB/T8163 standard steel pipe is suitable for the design temperature is less than 350℃, pressure is less than 10.0mpa oil products, oil and gas and public medium conditions;
For oil products, oil and gas medium, when the design temperature is more than 350℃ or pressure is greater than 10.0mpa, it is appropriate to choose GB9948 or GB6479 standard steel pipe;
GB9948 or GB6479 standard should also be used for pipelines operated near hydrogen or in stress corrosion prone environments.
General low temperature (less than -20℃) using carbon steel pipe should be used GB6479 standard, only it specifies the requirements of low temperature impact toughness of materials.
GB3087 and GB5310 standards are specially set for boiler steel pipe standards. ”Boiler safety supervision regulations” emphasized that all connected with the boiler tubes are belongs to the scope of supervision, the application of the material and standard should comply with the rules of the boiler safety, therefore, boiler, power station, heating and petrochemical production device used in public steam pipe should be used (by the system supply) GB3087 or standard GB5310.
It is worth noting that the quality of good steel pipe standards, steel pipe prices are relatively high, such as GB9948 than GB8163 material price is nearly 1/5, therefore, in the selection of steel pipe material standards, should be considered according to the conditions of use, both reliable and economic. It should also be noted that steel tubes in accordance with GB/T20801 and TSGD0001, GB3087 and GB8163 shall not be used in GC1 piping (unless individually ultrasonic, quality not less than L2.5, can be used in GC1(1) piping design pressure not greater than 4.0Mpa).
(2) Low alloy steel seamless steel pipe
In petrochemical production facilities, the commonly used seamless steel pipe standards of chromium-molybdenum steel and chromium-molybdenum vanadium steel are
GB9948 “Seamless steel pipe for petroleum Cracking“
GB6479 “High pressure seamless steel pipe for fertilizer equipment“
GB/T5310 “Seamless steel tubes for high pressure boilers“
GB9948 contains chromium molybdenum steel grades: 12CrMo, 15CrMo, 1Cr2Mo, 1Cr5Mo and so on.
GB6479 contains chromium molybdenum steel grade: 12CrMo, 15CrMo, 1Cr5Mo and so on.
GB/T5310 contains chromium-molybdenum steel and chromium-molybdenum vanadium steel material grades: 15MoG, 20MoG, 12CrMoG, 15CrMoG, 12Cr2MoG, 12Cr1MoVG, etc.
Among them, GB9948 is more commonly used.
