Sichuan Liaofu Special Steel Company is one of the most experienced manufacturers and suppliers of astm a333 grade 6 seamless pipe in China. With over 20 years' experience, our factory offer high quality products made in China with competitive price. Welcome to contact us for wholesale service.
Standard Compliance
ASTM A333 is a standard developed by the American Society for Testing and Materials (ASTM) for seamless and welded steel pipes used in low-temperature applications, suitable for environments ranging from -45°C to 345°C (e.g., liquefied natural gas, chemical, and cryogenic pipeline systems).
Grade 6 is one of the most commonly used grades in this standard, belonging to low-carbon manganese steel, which exhibits excellent low-temperature impact toughness and resistance to brittle fracture.
Material Composition
| Element | Content Range (%) |
|---|---|
| Carbon (C) | ≤0.30 |
| Manganese (Mn) | 0.29–1.06 |
| Phosphorus (P) | ≤0.025 |
| Sulfur (S) | ≤0.025 |
| Silicon (Si) | 0.10–0.40 |
Mechanical Properties
| Property Index | Requirement |
|---|---|
| Tensile Strength (σb) | ≥415 MPa |
| Yield Strength (σ0.2) | ≥241 MPa |
| Elongation (δ) | ≥30% (OD ≤168.3mm) |
| Low-Temperature Impact Toughness | -45°C Impact Energy ≥41 J |
Key Features
Excellent Low-Temperature Performance:
Can be used long-term at -45°C, with strict impact testing (e.g., Charpy V-notch test) to ensure anti-brittle fracture capability.
Good Weldability:
Low carbon content reduces welding crack risk, supporting processes like GTAW and SMAW; preheating is unnecessary for thin-walled pipes.
Corrosion Resistance and Workability:
Corrosion resistance is similar to ordinary carbon steel, requiring anti-corrosion treatment (e.g., coating); good cold/hot workability, but annealing is recommended after cold working to relieve stress.
Production Flow
Billet Preparation: High-quality low-carbon manganese steel round bars (e.g., killed steel with higher manganese content) are used to ensure uniform composition.
Piercing and Rolling: Hollow shells are formed by piercing machines, then wall thickness is reduced and sized via hot rolling or cold drawing for high dimensional accuracy.
Heat Treatment: Typically normalized (heated to 880–940°C and air-cooled) to refine grain structure and optimize impact toughness.
Surface Treatment and Inspection: Scale removal, followed by visual, dimensional, and non-destructive testing (UT/MT).
Size Range
Outer Diameter: 1/8 inch (3.35mm) to 24 inches (609.6mm)
Wall Thickness: Follows SCH 10 to SCH 160 grades or ASME B36.10 standards for customization.
Application Fields
Cryogenic Industry:
LNG transportation pipelines, cryogenic storage tank connections, liquid nitrogen/oxygen systems.
Chemical and Petrochemical Industry:
Low-temperature reactor pipelines, refrigerant transportation, low-temperature medium pipelines in petrochemical plants.
Energy Industry:
Refinery low-temperature pipelines, offshore platform cryogenic systems, preliminary hydrogen storage and transportation facilities (hydrogen embrittlement risk should be noted).
Structural Engineering:
Structural pipes in cold regions (e.g., polar facilities, high-latitude bridge supports).
Routine Inspection Items
Chemical Composition Analysis: Ensures C, Mn, P, S, etc., comply with ASTM A333 standards.
Mechanical Property Testing: Tensile testing, flattening test (verifies workability), and -45°C impact test (mandatory).
Non-Destructive Testing:
Ultrasonic Testing (UT): Detects internal defects (e.g., cracks, inclusions).
Magnetic Particle Testing (MT): Checks for surface and near-surface defects.
Hydrostatic Test: Each pipe must withstand specified pressure (typically ≥2000 psi or as designed) to ensure tightness.
Special Requirements
Optional tests include grain size detection, radiographic testing (RT) for welds, or high-temperature performance testing (for applications near the upper temperature limit).
Comparison with Other Materials
| Material | Main Differences | Typical Application Scenarios |
|---|---|---|
| A333 Grade 6 | Low-carbon manganese steel, -45°C impact ≥41 J, moderate cost | Conventional low-temperature pipelines (e.g., LNG, liquid nitrogen) |
| A333 Grade 3 | Nickel steel (3.5% Ni), superior impact toughness at -101°C | Ultra-low-temperature environments (e.g., liquid hydrogen, cryogenic processes) |
| A333 Grade 8 | Stainless steel (304L/316L), corrosion-resistant + low-temperature performance | Corrosive low-temperature environments (e.g., chemical media) |
| ASTM A106 Gr B | High-temperature carbon steel, no low-temperature impact requirements | High-temperature steam pipelines (non-cryogenic scenarios) |
Temperature Limitations:
Minimum service temperature is -45°C; not suitable for lower temperatures (e.g., liquid hydrogen, require Grade 3 or stainless steel).
Anti-Corrosion Treatment:
Galvanizing, epoxy coating, or PE lining is required in outdoor or humid environments to prevent rust.
Hydrogen Environment Applications:
Evaluate hydrogen embrittlement risk for hydrogen transportation; recommend limiting hydrogen pressure or selecting higher-grade materials (e.g., hydrogen-resistant steel).
Welding Considerations:
Preheat thick-walled pipes (wall thickness >20mm) to 70–100°C before welding; stress-relief annealing (600–650°C holding) may be performed after welding.
Hot Tags: astm a333 grade 6 seamless pipe, China, manufacturers, suppliers, factory, 316 Stainless Steel Tube, 316L Stainless Steel Tube, , 304 Stainless Steel Seamless Tube price per kg, TP304 stainless steel hollow bars