ASTM A333 Grade 8 Tubing
Dec 05, 2025
ASTM A333 Grade 8 LTCS Tubing Description
A333 GR8 is a low-temperature seamless steel pipe under the ASTM standard, specifically designed for extreme cryogenic environments as low as -196°C. It belongs to the 3.5% nickel series of low-temperature alloy steels. Its "low carbon, high nickel" composition (carbon ≤0.19%, nickel ~3.5%) combined with strict normalizing heat treatment ensures exceptional toughness and resistance to brittle fracture at ultra-low temperatures.
Key mechanical properties include: tensile strength ≥415 MPa, yield strength ≥240 MPa, elongation ≥30%, and Charpy impact energy ≥20J at -46°C. It is widely used in LNG transportation, cryogenic petrochemical equipment, and polar engineering applications.
Chemical Compositions(%) of ASTM A333 Grade 8
| 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 of ASTM A333 Grade 8
| 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 | -- |
A333 GR8 V.S API 5L
| Comparison Item | ASTM A333 GR8 | API 5L |
|---|---|---|
| Standard Type | Material Standard (specifies chemical composition, mechanical properties) | Product Standard (specifies dimensions, manufacturing, inspection of line pipe) |
| Primary Purpose | Extremely low-temperature environments (e.g., -196°C LNG storage) | Oil and gas transportation pipelines |
| Core Requirements | Low-temperature toughness (e.g., impact energy at -195°C) | Strength, toughness, weldability, corrosion resistance |
| Typical Materials | A333 Grade 8 (~3.5% nickel) | X42, X52, X70, etc. (carbon-manganese steels) |
| Manufacturing Process | Requires normalizing treatment to refine grain structure | Hot rolling, cold rolling, heat treatment, etc. |
| Application Scenarios | LNG storage tanks, cryogenic piping, polar engineering | Onshore/offshore oil and gas transmission pipelines |
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.
Packaging and shipping
