ASTM A333 Gr. 8 specification covers seamless steel pipe for Ultra-low temperature service.
As the results of the experimental data, our factory successfully completed the grade of steel for Gr8 specifications for cryogenic Φ 355.6 x 50.8 mm pipe heat treatment.
The test results of tensile, impact work, hardness and flattening all meet the requirements of ASTM A333.
The Gr8(commonly known as 9%Ni) steel pipe is mainly used for the storage and transportation of liquefied natural gas, and is one of the most technologically advanced, difficult and value-added products in civil steel products.Because of its flammability and ultra-low temperature, the ultra-low temperature steel used for storage and transportation of liquefied natural gas must have the comprehensive characteristics of strength, thermal stress and strain, welding performance and corrosion resistance.Therefore, whether such products can be produced is an important symbol representing the overall technical level of a steel enterprise.The successful production of Gr8 cryogenic tube effectively expands the variety range of 720 units and lays a foundation for further development of the market.
A333 Gr8 cryogenic pipe is a brand in American ASTM standard, which is mainly used for storage and transportation of liquefied natural gas. It is one of the products with the highest technical level, difficulty and added value in civil steel products.Whether this kind of products can be produced successfully represents the overall technical level of an enterprise.In order to ensure this kind of steel pipe material requirement, valingheng steel has designed the steelmaking and smelting process in its own innovation.The test results of the steel pipe developed and produced show that the performance data of the steel pipe obtained by the heat treatment process are up to standard.
The Grade 8 steel involved is similar to AISI 4032 low alloy steel. ASTM A333 Grade 8 pipe shall be made by the seamless or welding process with the addition of no filler metal in the welding operation.
Packing:
Bare packing/bundle packing/crate packing/wooden protection at the both sides of tubes and suitably protected for sea-worthly delivery or as requested.Inspection and Test: Chemical Composition Inspection, Mechanical Properties Test(Tensile Strength,Yield Strength, Elongation, Flaring, Flattening, Bending, Hardness, Impact Test), Surface and Dimension Test,No-destructive Test, Hydrostatic Test.
Surface treatment: Oil-dip, Varnish, Passivation, Phosphating, Shot Blasting.
Both ends of each crate will indicate the order no., heat no., dimensions, weight and bundles or as requested.
Chemical Compositions(%)
| Compositions | Data |
| Carbon(max.) | 0.13 |
| Manganese | 0.90 max |
| Phosphorus(max.) | 0.025 |
| Sulfur(max.) | 0.025 |
| Silicon | 0.13-0.32 |
| Nickel | 8.40-9.60 |
| Chromium | … |
| Other Elements | … |
Mechanical properties
| Properties | PSI (Longitudinal) | MPa(Transverse) |
| Tensile strength, min, (MPa) | 100 000 | 690 |
| Yield strength, min, (MPa) | 75 000 | 515 |
| Basic minimum elongation for walls 5/16 in. [8mm] and over in thickness, strip tests, and for all small sizes tested in full section. | 22 | -- |
| When standard round 2-in, or 50-mm gage length or proportionally smaller size test specimen with the gage length equal to 4D (4 times the diameter) is used | 16 | -- |
| For strip tests, a deduction for each 1/32 in [0.8 mm] decrease in wall thickness below 5/16 in [8 mm] from the basic minimum elongation of the following percentage | 1.25 | -- |
Elongation in 2 in or 50 mm, min, %:
Wall Thickness
|
Grade 8
| ||
in
|
mm
|
Longitudinal
|
Transverse
|
| 5/16 (0.312) | 8 | 22 | -- |
| 9/32 (0.281) | 7.2 | 21 | -- |
| 1/4 (0.250) | 6.4 | 20 | -- |
| 7/32 (0.219) | 5.6 | 18 | -- |
| 3/16 (0.188) | 4.8 | 17 | -- |
| 5/32 (0.156) | 4 | 16 | -- |
| 1/8 (0.125) | 3.2 | 15 | -- |
| 3/32 (0.094) | 2.4 | 13 | -- |
| 1/16 (0.062) | 1.6 | 12 | -- |
IMPACT REQUIREMENTS
| Size of Specimen |
Minimum Average Notched Bar Impact Value of Each Set of Three Specimen
|
Minimum Notched Bar Impact Value of One Specimen only a Set
| ||
ft-lbf
|
J
|
ft-lbf
|
J
| |
| 10 by 10 | 13 | 18 | 10 | 14 |
| 10 by 7.5 | 10 | 14 | 8 | 11 |
| 10 by 6.67 | 9 | 12 | 7 | 9 |
| 10 by 5 | 7 | 9 | 5 | 7 |
| 10 by 3.33 | 5 | 7 | 3 | 4 |
| 10 by 2.5 | 4 | 5 | 3 | 4 |
| Straight line interpolation for intermediate values is permitted. | ||||
the notched-bar impact properties of each set of three impact specimens, when tested at temperature specified shall be not less than the values prescribed.
IMPACT TEMPERATURE
Grade
|
Minimum Impact Test Temperature
| |
°F
|
°C
| |
8
|
-320
|
-195
|
MECHANICAL TESTING
Transverse or Longitudinal Tension Test and Flattening Test, Hardness Test, or Bend Test For material heat treated in a batch-type furnace, tests shall be made on 5% of the pipe from each treated lot. For small lots, at least one pipe shall be tested. For material heat treated by the continuous process, tests shall be made on a sufficient number of pipe to constitute 5% of the lot, but in no case less than 2 pipe. Hydrostatic Test Impact Test One notched bar impact test, consisting of breaking three specimens shall be made from each heat represtented in a heat-treatment load on specimens taken from the finished pipe.
HEAT TREATMENT REQUIREMENTS
All seamless and welded pipe shall be treated to control their microstructure by the following methods: Normalizing per A 333/A 333M-05 section 4.2.1.1; section 4.2.1.2 or section 4.2.1.3 Quenched and Tempered per A 333/A 333M – 05 section 4.2.2.1 Double Normalized and Tempered per A 333/A 333M – 05 section 4.2.2.2
IMPACT TEMPERATURE REDUCTION
Specimen Width Along Notch or Actual Material Thickness
|
Temperature Reduction , Degrees Colder
| ||
in
|
mm
|
°F
|
°C
|
| 0.394 | 10 (standard size) | 0 | 0 |
| 0.354 | 9 | 0 | 0 |
| 0.315 | 8 | 0 | 0 |
| 0.295 | 7.5 (3/4 std. size) | 5 | 3 |
| 0.276 | 7 | 8 | 4 |
| 0.262 | 6.67 (2/3 std. size) | 10 | 5 |
| 0.236 | 6 | 15 | 8 |
| 0.197 | 5 (1/2 std. size) | 20 | 11 |
| 0.158 | 4 | 30 | 17 |
| 0.131 | 3.33 (1/3 std. size.) | 35 | 19 |
| 0.118 | 3 | 40 | 22 |
| 0.099 | 2.5 (1/4 std. size) | 50 | 28 |
| Straight line interpolation for intermediate values is permitted. | |||
Referenced Documents
- ASTM A 370 Test Methods and Definitions for Mechanical testing of Steel Products
- ASTM A999/A 999M Specification for General requirements for Alloy and Stainless Steel Pipe.
- ASTM A 671 Specification for General requirements for Alloy and Stainless Steel Pipe
- ASTM E 23 Test Methods for Notched bar Impact testing of Metallic Materials
