Steel 20ЮЧА (20YUCH)
|Designation GOST Cyrillic||20ЮЧА|
|Designation GOST Latin||20JuChA|
|By chemical elements||20AlZr|
|Designation GOST Cyrillic||20ЮЧ|
|Designation GOST Latin||20JuCh|
|By chemical elements||20AlZr|
20ЮЧА steel is used: for the manufacture of pipes, enclosures, ends, flat flanges and other parts operating in environments containing hydrogen sulfide and carbon dioxide at temperatures from -40 °C to +475 °C; details of pipeline valves by conducting the heat treatment; welded vessels, gas and petrochemical industry; seamless hot-deformed oil and gas pipes with improved corrosion and cold-resistance, designed for use in systems of oil and gas pipelines, technological pipelines, transporting oil and oil products, as well as in the systems of reservoir pressure maintenance in terms of oil companies operated in environments containing hydrogen sulphide and carbon dioxide.
Steel resistant to stress corrosion cracking.
|Thermal and thermochemical treatment of metals||В04||ST ЦКБА 026-2005|
|Bars and shapes||В32||TU 14-1-3332-82|
|Sheets and strips||В23||TU 14-1-3333-82|
|Blanks. Of the workpiece. Slabs||В31||TU 14-1-4179-86, TU 14-1-3345-82|
|Sheets and strips||В33||TU 14-1-4853-90|
|Steel pipes and fittings to them||В62||TU 14-3-1652-89, TU 14-3-1600-89, TU 14-157-54-97, TU 14-162-14-96, TU 14-162-20-97, TU 14-3-463-2005, TU 14-3Р-54-2001, TU 14-3-1745-90|
|Processing of metals by pressure. Forgings||В03||TU 26-0303-1532-84|
According to TU 14-1-4853-90, TU 14-3-1652-89 and TU 14-1-4179-86 the chemical composition is given for steel 20YuCH. In the deoxidized steel for the purpose of globularization of sulphide nonmetallic inclusions, REM (titanium, calcium, zirconium) is introduced at the rate of 0.7 kg / t. The content of the REM in steel is not a delivery indicator, but is controlled and entered in the quality document. In the steel, a technological additive silicocalcium is added from the calculation of 0.001-0.010% calcium in the finished rolled product.
According to TU 14-3-1652-89 and TU 14-1-4179-86 the content of the remaining elements is according to GOST 1050.
According to TU 14-162-14-96, the chemical composition is given for 20JUCH steel. Variations in the carbon content (-0,020%), aluminum (± 0,010%), manganese (+0,15%), sulfur (+0,005%), phosphorus (+0,005%) are allowed in the steel. In the deoxidized steel for the purpose of globulating sulfide nonmetallic inclusions, cerium is introduced with a cerium content of 0.050% in steel, the content of which is not controlled, and the calculated value is entered in the certificate. In order to increase the strength properties, it is allowed to introduce into the steel vanadium in an amount up to 0.050%.
According to TU 14-3-1745-90, TU 14-3R-54-2001 the chemical composition is given for steel 20YuCH. The residual content of the remaining elements in accordance with GOST 1050. The deviation from the carbon content is -0,020%, aluminum +0,010%, other elements in accordance with GOST 1050. In the deoxidized steel for the purpose of globularization of sulphide nonmetallic inclusions, one or more modifiers from the group: REM, titanium, zirconium in an amount of up to 0.07% each. The content of these elements in steel is not a delivery indicator, but is entered in the quality document.
According to TU 14-1-3332-82, the chemical composition is given for steel 20UCH. In steel, the deviation from the normalized chemical composition by carbon is -0.020%, in aluminum ± 0.010%, and by the content of the remaining elements and residuals - according to GOST 1050. The RZM (cerium group) is introduced into the deoxidized steel at a rate of not less than 1 kg per ton and the production of cerium in the metal in an amount of 0.015-0.030%. The content of cerium is not a delivery indicator, but is controlled and entered in the certificate.
|Section, mm||sT|s0,2, MPa||σU, MPa||d5, %||KCU, kJ/m2||HB, MPa||HRB|
|Pipe the seamless hot-deformed heat-treated in the delivery condition on the other 14-162-14-96|
|The billet according to TU 14-1-4179-86 (heat-treated longitudinal samples)|
|Blank pieces of pipe fittings according to ST CKBA 026-2005. Annealing in air from 900-920 °C (exposure for 2.5-4.0 hours depending on the thickness and weight of the workpiece). (KCU-40°C)|
|Long products hot-rolled steel on the other 14-1-3332-82. Normalization at 900-920 °C. specified KCU at -40°C (KCU-40°C)|
|Rolled plates (10-160 mm) as supplied (normalization or thermolysine, KCU-40°C)|
|Cold-rolled tubes DH=25-89 and seamless hot deformed tubes in the delivery condition (normalized) on the other 14-3-1745-90, TU 14-3R-54-2001. Heat-treated in the delivery condition (KCU-40°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|
|HB||Brinell hardness number|
|HRB||Rockwell hardness (indenter steel, spherical)|
|Macrostructure and pollution||On the other 14-1-3332-82 nonmetallic inclusions should have a globular form and score no more than 4.0 "b" scale "SN" according to GOST 1778. Allowed the presence of certain sulphides elongated shape with a ratio of maximum size to minimum more than 3, balescu no more than 1 "b" dial "C" according to GOST 1778. Contamination of metal non-metallic inclusions should not exceed average score of 2.5; the maximum is 3.0.|
|Microstructure||On the other 14-3-1745-90, TU 14-3R-54-2001 banding of ferritic-pearlitic structure g/d pipes shall not exceed 4.0 points according to GOST 5640. Grain size of the metal tubes in the delivery condition must not be larger than 7 points, allowed individual grains 6 points.|
|Corrosion resistance||On the other 14-3-1745-90 threshold value of hydrogen sulfide corrosion cracking must be at least 147 MPa (15 kgf/mm2). Steel resistant to stress corrosion cracking.|