ASTM A106/A106M is a standard specification for seamless carbon steel pipes intended for high-temperature applications, with pipe sizes ranging from NPS 1/8 to NPS 48 (DN 6 to DN 1200) and nominal wall thicknesses that comply with, but are not limited to, the ASME B36.10M standard. This specification covers the chemical composition, mechanical properties, hydrostatic testing, dimensions, tolerances, and other requirements for Grade A, Grade B, and Grade C steel pipes. We supply seamless carbon steel pipes for high-temperature applications that comply with the ASTM A106 specification.
1. Basic Information
| Parameter | Specification |
|---|---|
| Standard | ASTM A106/A106M |
| Standard Name | Seamless Carbon Steel Pipe for High-Temperature Service |
| Pipe Type | Seamless Carbon Steel Pipe |
| Steel Grade | Grade A, Grade B, Grade C |
| Outer Diameter (NPS) | NPS 1/8 - NPS 48 (DN 6 - DN 1200) |
| Wall Thickness (Schedules) | Sch 10 - 160, STD, XS, XXS |
| Outer Diameter Tolerance | ±1% OD |
| Wall Thickness Tolerance | Not more than 12.5% below nominal thickness |
| Manufacturing Method | Hot-rolled forming, cold-drawn forming |
| Main Applications | High-temperature, high-pressure pipelines and process lines |
| Connection Methods | Welding, flanged connections, threaded connections, etc. |
| Dimensional Standards | Typically based on ASME B36.10M ( ASME B36.10M Pipe Schedule Chart ) |
| Primary Tests | Tensile, bending, flattening, hydraulic, or non-destructive electrical tests, etc. |
2. Chemical Composition
| Chemical Element | A106 Grade A | A106 Grade B | A106 Grade C |
|---|---|---|---|
| Carbon (C) max | 0.25% | 0.30% | 0.35% |
| Manganese (Mn) | 0.27% - 0.93% | 0.29% - 1.06% | 0.29% - 1.06% |
| Phosphorus (P) max | 0.035% | 0.035% | 0.035% |
| Sulfur (S) max | 0.035% | 0.035% | 0.035% |
| Silicon (Si) min | 0.10% | 0.10% | 0.10% |
| Chromium (Cr) max | 0.40% | 0.40% | 0.40% |
| Copper (Cu) max | 0.40% | 0.40% | 0.40% |
| Molybdenum (Mo) max | 0.15% | 0.15% | 0.15% |
| Nickel (Ni) max | 0.40% | 0.40% | 0.40% |
| Vanadium (V) max | 0.08% | 0.08% | 0.08% |
3. Mechanical Properties
| Mechanical Property | A106 Grade A | A106 Grade B | A106 Grade C |
|---|---|---|---|
| Yield Strength (min) | 205 MPa [30,000 psi] | 240 MPa [35,000 psi] | 275 MPa [40,000 psi] |
| Tensile Strength (min) | 330 MPa [48,000 psi] | 415 MPa [48,000 psi] | 485 MPa [48,000 psi] |
| Elongation (min) | Longitudinal: 35% / Transverse: 25% | Longitudinal: 30% / Transverse: 16.5% | Longitudinal: 30% / Transverse: 16.5% |
| Characteristics | High ductility, easy to bend | Balanced strength, widely used | Highest strength, lower toughness and weldability |
4. Manufacturing Process
ASTM A106 steel pipes are seamless steel pipes. The steel can be produced via ingot casting or continuous casting; the seamless pipes are then formed through processes such as hot working, piercing, and rolling.
4.1 Typical production process:
Steelmaking → Continuous Casting/Ingot → Billet Heating → Piercing → Hot Rolling/Hot Working → Sizing → Heat Treatment → Straightening → Cutting → Inspection → Marking → Packaging
4.2 For cold-drawn pipes, the following steps may be added:
Hot-rolled pipe → Pickling/Surface Treatment → Cold Drawing → Heat Treatment → Straightening → Finishing
5. Heat Treatment
5.1 Hot-finished pipe need not be heat treated. When hot-finished pipe is heat treated, it shall be heat treated at a temperature of 1200 °F [650 °C] or higher.
5.2 Cold-drawn pipe shall be heat treated after the final cold-drawing pass at a temperature of 650 °C [1200 °F] or higher.
6. Dimensions and Wall Thickness
ASTM A106 covers: NPS 1/8 – NPS 48 (DN 6 – DN 1200)
The standard permits the use of other sizes, provided they meet the other technical requirements of A106; the conventional sizing system is typically used in conjunction with ASME B36.10M.
Common specifications are expressed as follows:
NPS 1/2 × SCH 40
NPS 1 × SCH 40
NPS 2 × SCH 40
NPS 4 × SCH 40
NPS 6 × SCH 40
NPS 8 × SCH 40
NPS 10 × SCH 40
NPS 12 × SCH 40
The following notation may also be used:
Outer Diameter × Wall Thickness (OD × WT)
For example:
Ø168.3 × 8.0 mm
Specific outer diameters, wall thicknesses, weights, and dimensional tolerances shall be determined in accordance with the applicable dimensional standards and purchase orders.
7. Inspection and Testing
ASTM A106 requires that steel pipes undergo appropriate mechanical property and quality inspections, primarily including:
7.1 Tensile Test
Used to verify the tensile strength, yield strength, and elongation of the steel pipe.
7.2 Bending Test
Used to evaluate the plasticity and surface quality of the steel pipe during the bending process.
7.3 Flattening Test
Used to check for defects such as cracks or fractures in the steel pipe during the flattening process.
7.4 Hydraulic Test
Used to verify the pressure resistance and sealing performance of the steel pipe.
7.5 Non-Destructive Electrical Tests
ASTM A106 specifies that the mechanical testing system includes requirements for hydraulic testing and non-destructive electrical testing; the specific method to be used and the relevant acceptance criteria shall be carried out in accordance with the standard and order requirements.
8. Surface Quality
The surface of A106 seamless steel pipes shall meet the requirements of the standard and shall not contain serious defects that affect service performance, such as cracks, folds, delamination, excessive pitting, severe mechanical damage, or other defects that affect the performance of the steel pipes.
Steel pipes are also typically subject to inspections for appearance, dimensions, wall thickness, and straightness.
9. Delivery Conditions
ASTM A106 steel pipes may be supplied in delivery conditions corresponding to their manufacturing processes. Common forms found in actual products include:
Hot-Finished
Cold-Drawn
Among these, hot-finished steel pipes are the most common form of A106 supply.