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ASTM A333 Pipe Specification |
What is ASTM A333 material?
ASTM A333 standard specification includes seamless and welded carbon and alloy steel pipes of nominal (average) wall thickness, intended for use at low temperatures and in applications where notch resistance is required.
ASTM A333 low temperatures carbon steel (LTCS) is used in industries such as oil and gas, chemical and power generation. The steel is designed to resist brittle fracture and has excellent impact resistance, making it ideal for use in cold environments. For applications of ASTM A33 pipe material below -45°C, impact resistance tests are required. Generally, ASTM A333 pipes are manufactured in a size range from NPS 1/2 to NPS 24.
Various grades of ferritic steel are obtainable, but some sizes may not be available under this specification, as heavier wall thicknesses have an adverse effect on impact properties at low temperatures.
Chemical composition
of 8 Grades
| Element | Gr.1 | Gr.3 | Gr.4 | Gr.6 | Gr.8 | Gr.9 | Gr.10 | Gr.11 |
| Carbon max. |
0.3 | 0.19 | 0.12 | 0.3 | 0.13 | 0.2 | 0.2 | 0.1 |
| Manganese | 0.40 - 1.06a |
0.31 - 0.64 |
0.50 - 1.05 |
0.29 - 1.06a |
0.90 max. |
0.40 - 1.06 |
1.15 - 1.50 |
0.60 max. |
| Phosphorus max. |
0.025 | 0.025 | 0.025 | 0.025 | 0.025 | 0.025 | 0.035 | 0.025 |
| Sulfur max. |
0.025 | 0.025 | 0.025 | 0.025 | 0.025 | 0.025 | 0.015 | 0.025 |
| Silicon | ... | 0.18 - 0.37 |
0.08 - 0.37 |
0.10 min |
0.13 - 0.32 |
... | 0.10 - 0.35 |
0.35 max. |
| Nickel | ... | 3.18 - 3.82 |
0.47 - 0.98 |
0.40 max. |
8.40 - 9.60 |
1.60 - 2.24 |
0.25 max. |
35.0 - 37.0 |
| Chromium | ... | ... | 0.44 - 1.01 |
0.30 max. |
... | ... | 0.15 max. |
0.50 max. |
| Copper | ... | ... | 0.40 - 0.75 |
0.40 max. |
... | 0.75 - 1.25 |
0.15 max. |
... |
| Aluminum | ... | ... | 0.04 - 0.30 |
... | ... | ... | 0.06 max. |
... |
| Vanadium max. |
... | ... | ... | 0.08 | ... | ... | 0.12 | ... |
| Niobium c max. |
... | ... | ... | 0.02b | ... | ... | 0.05 | ... |
| Molybdenum | ... | ... | ... | 0.12 | ... | ... | 0.05 | 0.50 max. |
| Cobalt | ... | ... | ... | ... | ... | ... | ... | 0.50 max. |
a For each reduction of 0.01 % carbon below 0.30 %, an increase of 0.05 % manganese above 1.06 % would be permitted to a maximum of 1.35 % manganese. b By agreement between the manufacturer and the purchaser, the limit for niobium may be increased up to 0.05 % on heat analysis and 0.06 % on product analysis. c The terms Niobium (Nb) and Columbium (Cb) are alternate names for the same element. |
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Mechanical properties
| | Tensile Strength min. |
Yield Strength min. |
Elongation % min. |
|||
| Grade | psi | MPa | psi | MPa | Longit. | Trans. |
| Gr.1 | 55 000 | 380 | 30 000 | 205 | 35 | 25 |
| Gr.3 | 65 000 | 450 | 35 000 | 240 | 30 | 20 |
| Gr.4 | 60 000 | 415 | 35 000 | 240 | 30 | 16.5 |
| Gr.6 | 60 000 | 415 | 35 000 | 240 | 30 | 16.5 |
| Gr.8 | 100 000 | 690 | 75 000 | 515 | 22 | ... |
| Gr.9 | 63 000 | 435 | 46 000 | 315 | 28 | ... |
| Gr.10 | 80 000 | 550 | 65 000 | 450 | 22 | ... |
| Gr.11 | 65 000 | 450 | 35 000 | 240 | 18 | ... |
| Longit = Longitudinal / Trans = Transverse | ||||||
Heat treatment
All seamless and welded pipes manufactured to ASTM A333, other than Grades 8 and 11, shall be heat treated to control their microstructure in accordance with one of the following methods:
- Normalize by heating to a uniform temperature of not less than 1500°F (815°C) and cool in air or in the cooling chamber of an atmosphere controlled furnace. Or normalize as above-mentioned, and, at the discretion of the manufacturer, reheat to a suitable tempering temperature.
- For the seamless process only, reheat and control hot working and the temperature of the hot-finishing operation to a finishing temperature range from 1550 to 1750°F (845 to 945°C) and cool in air or in a controlled atmosphere furnace from an initial temperature of not less than 1550°F [845°C]. Or treat as above-mentioned, and, at the discretion of the manufacturer, reheat to a suitable tempering temperature.
- Seamless pipe of Grades 1, 6, and 10 may be heat treated by heating to a uniform temperature of not less than 1500°F (815°C), followed by quenching in liquid and reheating to a suitable tempering temperature.
- ASTM A333 Grade 8 pipe shall be heat treated by the manufacturer by either of the following methods: quenched + tempered; double normalized + tempered. When required, Grade 11 shall be annealed and then normalized in the range of 1400 to 1600°F (760 to 870°C).
Referenced Documents
ASTM Standards
- A999/A999M Specification for General Requirements for Alloy and Stainless Steel Pipe
- A671/A671M Specification for Electric-Fusion-Welded Steel Pipe for Atmospheric and Lower Temperatures
- E23 Test Methods for Notched Bar Impact Testing of Metallic Materials
- E165/E165M Practice for Liquid Penetrant Examination for General Industry
- E709 Guide for Magnetic Particle Testing
ASME Standards
ASME Boiler and Pressure Vessel Code
- Section VIII
- Section IX
Frequently used ASTM Grades
| Material | Pipes | Fittings | Flanges | Valves | Bolts & Nuts |
| Carbon Steel Alloy Low-Temp |
A333 Gr.6 |
A420 Gr.WPL6 |
A350 Gr.LF2 |
A352 Gr.LCB |
A320 Gr.L7 A194 Gr.7 |
| A333 Gr.3 |
A420 Gr.WPL3 |
A350 Gr.LF3 |
A352 Gr.LC3 |
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