ASTM A333 Grade 6 seamless steel tubing is a low-alloy steel pipe produced in accordance with standards established by the American Society for Testing and Materials (ASTM). Its primary characteristic lies in its excellent low-temperature toughness. This steel pipe undergoes specific heat treatment processes to ensure it maintains sufficient strength and toughness at extremely low temperatures (typically -45°C and below), effectively preventing fracture risks caused by low-temperature brittleness.
- Charpy Impact Energy (Low-Temperature Toughness Indicator)
Standard Requirements:
Charpy V-notch impact test: At -46°C (-50°F)
Average impact energy of three specimens ≥20J
Minimum individual specimen value ≥16J
Actual Performance:
Produced using fine-grained killed steel technology, actual impact energy typically reaches 40–60J (-46°C), significantly exceeding requirements.
Nickel addition maintains high toughness down to -100°C (impact energy ≈30J).
Influencing Factors:
Grain size: Controlled by aluminum deoxidation (ASTM grain size ≥5), enhancing toughness.
Heat treatment: Normalizing or normalizing + tempering relieves stress and refines microstructure.
- Low-Temperature Performance Parameters
Ductile-to-Brittle Transition Temperature (DBTT):
A333 Grade 6: ≈-70°C to -80°C (varies with composition and heat treatment). Below this temperature, fracture mode shifts from ductile to brittle.
Allowable Stress:
ASME BPVC Section II Part D specifies 138MPa at -46°C (similar to room temperature), indicating no significant strength loss at low temperatures.
Thermal Expansion Coefficient:
≈11.2×10⁻⁶/°C (20–100°C)-comparable to carbon steel, ensuring thermal compatibility in low-temperature piping systems.
- Application Scenarios
General low-temperature pipelines
Mild low-temperature environments
Chemical industry low-temperature equipment
Liquefied natural gas (LNG) storage
Typical Applications
Oil & Gas Industry:
LNG transport pipelines (-162°C requires 9Ni steel for compatibility).
Arctic/Siberian oil/gas extraction equipment.
Chemical Industry:
Support structures for liquid hydrogen (-253°C) and liquid oxygen (-183°C) storage tanks.
Low-temperature reactor vessels and heat exchanger piping.
Other Fields:
Cold-region infrastructure (bridges, towers).
Freezing equipment (-50°C cold storage).
Specification
Wall Thickness : 2.0mm-60mm
Grade: ASTM A333 Gr. 1,Gr. 3,Gr. 6...
Single Random: 17′ ~ 24′ lengths
Double Random: 36′ ~ 44′ lengths
Schedules: SS 5, S 10, S 20, S 40, S 60, S XS, S 80, S 100, S 120, S 140, S 160, S XXS
Chemical Composition
| Chemical Composition (%) | |||||||||||
| A333 PIPE | C | Si | Mn | P | S | Cr | Ni | Cu | Mo | V | Al |
| Grade 6 | ≤0.30 | ≥0.10 | 0.29-1.06 | ≤0.025 | ≤0.025 |
| A333 PIPE | Tensile Strength (Mpa) | Yield Strength (Mpa) |
Elongation Y | Elongation X |
| Grade 6 | ≥415 | ≥240 | ≥30 | ≥16.5 |
GNEE A333 GR6 low temperature pipe for sale
