ASTM A333 Grade 3 Grade 6 Grade 8 Grade 9 Alloy Steel Pipe Seamless
Welded Pipe
1. A333 PIPE SPECIFICATIONS
A/SA333 NPS 1/4″ – 42″
Schedules 10 through 160, STD, XH and XXH
2. Scope
ASTM A333 covers nominal (average) wall seamless and welded carbon
and alloy steel pipe intended for use at low temperatures. Several
grades of ferritic steel are included. Some product sizes may not
be available under this specification because heavier wall
thicknesses have an adverse affect on low-temperature impact
properties.
3. Material & Manufacture
The pipe shall be made by the seamless or welding process with the
addition of no filler metal in the welding operation.
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 4.3.1.1; section 4.3.1.2 or section 4.3.1.3
Quenched and Tempered per A 333/A 333M – 05 section 4.3.2.1 Double
Normalized and Tempered per A 333/A 333M – 05 section 4.3.2.2
4. Chemical Requirements
| | Composition, % | |
Element | Grade 1 | Grade 3 | Grade 6 |
Carbon, max | 0.30 | 0.19 | 0.30 |
Manganese | 0.40 – 1.06 | 0.31 – 0.64 | 0.29 – 1.06 |
Phosphorous, max | 0.025 | 0.025 | 0.025 |
Sulfur, max | 0.025 | 0.025 | 0.025 |
Silicon | 0.18 -0.37 | 0.10 min |
Nickel | 3.18 – 3.82 | |
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. When Grade 6 is ordered under this specification,
supplying an alloy grade that specifically requires the addition of
any element other than those listed for the ordered grade is not
permitted. However, the addition of elements required for the
deoxidation of the steel is permitted.
5. Tensile Requirements
The material shall conform to the requirements as proscribed:
| | Grade 1 | Grade 3 | Grade 6 |
| | psi | MPa | psi | MPa | psi | MPa |
Tensile Strength, min | 55,000 | 380 | 65,000 | 450 | 60,000 | 415 |
Yield Strength, min | 30,000 | 205 | 35,000 | 240 | 35,000 | 240 |
| | Longitudinal | Transverse | Longitudinal | Transverse | Longitudinal | Transverse |
Elongation in 2 in. or 50 mm, (or 4D), min, %: | | | |
Basic minimum elongation for walls 5/16 in. [8 mm] and over in
thickness, strip tests, and for all small sizes tested in full
section | 35 | 25 | 30 | 20 | 30 | 16.5 |
When the 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 | 28 | 20 | 22 | 14 | 22 | 12 |
For strip tests, a deduction for each 1/32in. [0.8 mm] decrease in
wall thickness below 5/16 in. [8 mm] from the basic minimum
elongation of the following percentage | 1.75 | 1.25 | 1.50 | 1.00 | 1.50 | 1.00 |
| | | | | | | |
| Elongation in 2 in. or 50 mm, min, %: |
Wall Thickness | Grade 1 | Grade 3 | Grade 6 |
in. | mm | Longitudinal | Transverse | Longitudinal | Transverse | Longitudinal | Transverse |
5/16 (0.312) | 8 | 35 | 25 | 30 | 20 | 30 | 16 |
9/32 (.281) | 7.2 | 33 | 24 | 28 | 19 | 28 | 15 |
1/4 (.250) | 6.4 | 32 | 23 | 27 | 18 | 27 | 15 |
7/32 (.219) | 5.6 | 30 | | 26 | | 26 | |
3/16 (.188) | 4.8 | 28 | | 24 | | 24 | |
5/32 (.156) | 4 | 26 | | 22 | | 22 | |
1/8 (.125) | 3.2 | 25 | | 21 | | 21 | |
3/32 (.094) | 2.4 | 23 | | 20 | | 20 | |
1/16 (.063) | 1.6 | 21 | | 18 | | 18 |