A 20ft steel (20ФА)
|Designation GOST Cyrillic||20Ф|
|Designation GOST Latin||20F|
|By chemical elements||20V|
|Designation GOST Cyrillic||20ФА|
|Designation GOST Latin||20FA|
|By chemical elements||20V|
A 20ft steel is used: for the manufacture of billets and pipes seamless hot-deformed oil and gas increased corrosion resistance and cold-resistance, designed for use in systems transporting gas, systems, oil and gas pipelines, technological pipelines, transporting oil and oil products, as well as in the systems of reservoir pressure maintenance in the Northern climatic zones at ambient temperatures from -60°C to +40°C, temperature of the transported media from +5°C to +40°C and operating pressure up to 7.4 MPa; seamless hot-deformed pipes with improved corrosion and cold-resistance (article 20ФА) with an outer diameter from 89 to 426 mm, strength class not less than K48, infield pipelines, transporting products of oil wells (low pressure water pipelines produced water at pressures up to 2 MPa in the system reservoir flooding); pipes with diameter from 57 to 168 mm for use in the system of gas pipelines, oil and gas pipelines, technological pipelines, transporting oil and oil products, as well as in the systems of reservoir pressure maintenance in terms of climatic zones with temperature of the transported medium from +5° C to +40° C.
Structural micro-alloyed steel of higher corrosion resistance and cold-resistance. Pipe oil and gas differ from conventional pipes according to GOST 8731, GOST 8732, high cold resistance, high resistance to General and pitting corrosion, resistance to sulfide corrosion cracking and hydrogen cracking.
|Blanks. Of the workpiece. Slabs||В31||OST 14-21-77, TU 14-1-4944-90|
|Steel pipes and fittings to them||В62||TU 1383-010-48124013-03, TU 1317-214-0147016-02, TU 1317-006.1-593377520-2003, TU 1308-269-0147016-2003, TU 1380-281-00147016-2004, TU 1380-282-00147016-2004, TU 14-158-101-97, TU 14-3-1654-89, TU 1308-226-0147016-02, TU 1303-007-12281990-2015, TU 14-161-180-99|
According to TU 1383-010-48124013-03, to ensure fine-grainedness and nitrogen binding to nitrides and carbonitrides, the introduction of titanium and niobium is allowed not more than 0.030% and 0.040%, respectively. For globularization of nonmetallic inclusions, steel is deoxidized by silicocalcium or cerium. The total content of Nb + V + Ni ≤ 0.15%.
According to TU 1317-006.1-593377520-2003 the chemical composition is given for steel grade 20FA. The mass fraction of hydrogen in the steel in the metal of the pipe should not exceed 1.0 ppm (2.0 ppm in the ladle sample, niobium and titanium can be added from the calculation of the mass fraction to 0.030% and 0.010%, respectively.) In the deoxidized steel for the globularization of sulfide inclusions enter calcium (silicocalcium) or cerium from the calculation of the mass fraction of 0.050%.
According to TU 1308-226-0147016-02 the chemical composition is given for steel grade 20F. Pipes should be made of steel that has been modified by calcium and its alloys. Permissible deviations in the content of chemical elements in finished rolled products in accordance with GOST 4543. The content of metallurgical hydrogen in steel is not more than 2 ppm.
According to TU 14-158-101-97 the chemical composition is given for steel grade 20FA. Deviations in chemical composition are allowed: by carbon ± 0.020%, by aluminum ± 0.010%, by manganese +0.15%, by sulfur and phosphorus +0.0050% each. Deviations in chemical composition in the finished metal are allowed in accordance with GOST 1050, except for carbon and manganese.
|Section, mm||sT|s0,2, MPa||σU, MPa||d5, %||KCU, kJ/m2||HRB|
|Pipe the seamless hot-deformed heat-treated in the delivery condition on the other 1308-226-0147016-02 (provided the toughness of the Charpy specimens at -60 °C, the proportion of a viscous component at -60 °C ≥70%)|
|Pipe the seamless hot-deformed oil and gas increased corrosion resistance and cold-resistance on the other 1317-214-0147016-02. In the state of delivery (specified marsvolta metal pipes and KCV-60 °C)|
|Pipe the seamless hot-deformed oil and gas increased corrosion resistance and cold-resistance on the other 1383-010-48124013-03. In the state of delivery (specified marsvolta metal pipes and KCV-40 °C)|
|Pipe the seamless hot-deformed heat-treated in the delivery condition on the other 14-158-101-97. In the graph given the values of KCU KCV longitudinal samples at different temperatures test KCV+20°C/KCV-40°C/KCV-50°C/|
|Seamless tubes gas & oil heat-treated in the delivery condition on the other 1317-006.1-593377520-2003 (samples in the delivery condition specified strength class, in the column the value is KCU KCV-50 °C)|
Description mechanical marks
|sT|s0,2||Yield strength or limit of proportionality with a tolerance for residual deformation of 0.2%|
|σU||Limit short-term strength|
|d5||Elongation after rupture|
|HRB||Rockwell hardness (indenter steel, spherical)|
|Corrosion resistance||In the medium H2S: speed General corrosion ≤ 0.5 mm/year; resistance to hydrogen cracking in the CLR ≤ 3 % CTR ≤ 6 %; resistance to sulfide corrosion cracking with voltage ≥ 75 % of σ0,2.|