Line pipe, tubing and casing of the main technical requireme
Line pipe, tubing and casing of the main technical requirements
A standard currently used by the oil and gas transmission pipe is widely used at home and abroad
The current standard widely used in domestic and international oil and gas transmission steel pipe:
(1) American Petroleum Institute API SPE (: 5L "line pipe specification;
(2) International standard Is0 3183-1,2,3 "oil and natural gas steel pipe Technical delivery conditions;
(3) For some of the important long-distance pipeline, according to the specific use of the environment has its own supplementary procurement technical conditions.
B in API oil and gas transport pipe standard steel pipe classification and its main distinction
Steel pipe for two products divided into PLsl and PLs2 level, in accordance with the requirements of API SPEC: 5L, these provisions of the two types of products
The different technical conditions. The main difference is: relative PLSl, PLS2 level of carbon equivalent, fracture toughness, maximum yield
The strength and maximum tensile strength requirements of the strength requirements. More stringent control of sulfur, phosphorus and other harmful elements. Seamless pipe lossless
The test became mandatory. Traceability must fill out the warranty book and after completion of the test to become mandatory.
c IS () of oil and gas transport steel pipe steel pipe standard classification and its main difference
: [SO 3183 standard in the oil and gas transmission steel pipe, steel pipe according to the difference between the quality requirements, is divided into A, B, c three
Stars, also known as A, B, c three requirements. The main difference is: lA IsO 3183 standard requirements developed
API SPE (: 5L provisions considerable basic quality requirements, quality requirements are generic; IsO 3183-2B level
In addition to the basic requirements in the standard requirements attached to the toughness and non-destructive testing requirements; There are some special purpose, such as
Acidic environment, marine conditions and low temperature conditions has very strict requirements for the quality and testing of the steel pipe, and these are mainly reflected in
Level standard requirements of ISO 3183-3C.
D oil and gas pipeline steel performance requirements
The main performance of the oil and gas pipeline steel requirements include:
(1) The general strength of the oil and gas pipelines are under the steel yield strength design. Using the higher yield strength
Steel tube, pipe working pressure can improve, get better value for money. Therefore, the yield strength of the pipe steel has changed from the most
Early gradual development of carbon steel, 1940s X42 ~ X52 steel grade X60 ~ X70 steel grade in the late 1960s.
Is now officially the production and official use of the yield strength has reached the higher grades of steel X80 ~ x100.
(2) The toughness of the 1950s and 1960s, in many parts of the world have taken place in the oil and gas pipeline rupture accident through
Over-analysis of these accidents, and contributed greatly to the awareness of the people of the pipe toughness. API 5L regulations, in addition to conventional mechanical
Can test, the factory should produce SR5 and SR6 supplement the requirements of the V-notch Charpy impact test and drop weight tear test
(Ie DWITr), the strict yuan loss test should be carried out before the steel pipe factory. Nevertheless, for long-distance pipeline to completely avoid
Rupture is difficult, you must also look to prevent unstable propagation of the crack. Studies show that the approach can be used to control the value of I) WTT reached
To crack arrest. For this reason, many countries of the world the pipeline steel provides for the fracture shear DwITr test area percentage of the minimum value.
(3) weldability as a result of the harsh field conditions caused by the field of laying pipe, butt-welded steel pipe
is required when a good weldability.
Poor welding steel pipe welding easy weld cracks and cause increased welds and heat affected zone hardness, toughness decreases
Increase the likelihood of rupture of the pipeline. Steel weldability design principles and hardened martensitic transformation point control. According to the alloying elements
Hormone on the martensitic transformation point and practical experience to determine the carbon equivalent formula, can be used to assess steel weldability. Commonly adopted
Carbon equivalent formula:
c mine) + China +
c. . Usually should be controlled at less than 0.40%. In fact, most of the steel are controlled to 0.35% or less.
(4) ductility if the ductility is insufficient, cause the steel sheet of the cold-formed forming process splitting or during the welding process to produce the layered tear
Crack. Guided bend test pipes welded pipe, API standards are in addition to the provisions of the flattening test requirements. Improve extended
The sexual key to the morphology and distribution of the reduction in steel, non-metallic inclusions and inclusions.
(5) corrosion resistance when the transporting sulfur-containing hydrocarbon, the inner wall of the conduit in contact with hydrogen sulfide and carbon dioxide, which leads to hydrogen embrittlement and should
Force corrosion cracking. Generally used to reduce the sulfur content of the steel, to control the sulfide form, improving the toughness of along the thickness direction of the other measures. Its
Is characterized by the micro-alloying and the controlled rolling in the hot-rolled state for high strength, high ductility, high toughness and good may
Put out I born. In addition to the tight alloy design performance requirements in order to fully meet the oil and gas pipeline steel, sulfur, phosphorus
Very strict control and other harmful elements. Usually sulfur controls 0.0:10% or less, in order to improve the ductility, toughness, Laid
Do not transverse toughness.
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