Steel 20ЮЧА (20YUCH)
Designation
| Name |
The value |
| Designation GOST Cyrillic |
20ЮЧА |
| Designation GOST Latin |
20JuChA |
| Transliteration |
20YuChA |
| The chemical elements |
20AlZr |
| Name |
The value |
| Designation GOST Cyrillic |
20ЮЧ |
| Designation GOST Latin |
20JuCh |
| Transliteration |
20YuCh |
| The chemical elements |
20AlZr |
Description
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.
Note
Steel resistant to stress corrosion cracking.
Standards
| Name |
Code |
Standards |
| Thermal and thermochemical treatment of metals |
В04 |
ST ЦКБА 026-2005 |
| Sectional and shaped rolling |
В32 |
TU 14-1-3332-82 |
| Sheets and stripes |
В23 |
TU 14-1-3333-82 |
| Bulls. Blanks. Slabs |
В31 |
TU 14-1-4179-86, TU 14-1-3345-82 |
| Sheets and stripes |
В33 |
TU 14-1-4853-90 |
| Pipes steel and connecting parts 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 |
| Metal forming. Forgings |
В03 |
TU 26-0303-1532-84 |
Mechanical characteristics
| Section, mm |
sT|s0,2, MPa |
σB, MPa |
d5, % |
kJ/m2, кДж/м2 |
Brinell hardness number, MPa |
HRB |
| Pipe the seamless hot-deformed heat-treated in the delivery condition on the other 14-162-14-96 |
|
338-470 |
502-627 |
≥25 |
- |
- |
≤92 |
| The billet according to TU 14-1-4179-86 (heat-treated longitudinal samples) |
| - |
≥235 |
≥410 |
≥23 |
≥490 |
≤190 |
- |
| 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) |
| ≤180 |
≥235 |
≥412 |
≥23 |
≥490 |
≤190 |
- |
| 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) |
| Образец 15х15 |
≥235 |
≥412 |
≥23 |
≥490 |
- |
- |
| Rolled plates (10-160 mm) as supplied (normalization or thermolysine, KCU-40°C) |
|
≥235 |
≥410 |
≥23 |
≥480 |
- |
- |
| 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) |
|
245-382 |
≥412 |
≥23 |
≥490 |
≤190 |
- |
Description mechanical marks
| Name |
Description |
| Section |
Section |
| sT|s0,2 |
Yield strength or limit of proportionality with a tolerance for residual deformation of 0.2% |
| σB |
Limit short-term strength |
| d5 |
Elongation after rupture |
| kJ/m2 |
Toughness |
| HRB |
Rockwell hardness (indenter steel, spherical) |
Technological properties
| Name |
The value |
| Macrostructure and contamination |
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. |
