basic information
ASTM A106 SEAMLESS PIPES
STANDARD: ASTM A106/A106M
GRADE: GR.A, GR.B, GR.C
Outside Diameter:
Ranging from NPS 1/8 to NPS 48 (DN 6 to DN 1200)
Wall Thickness:
Nominal (average) wall thickness as specified in ASME B36.10M.
Length:Commonly used 5.8M, 6M, 12M, but we can also produces depends on client's requirement.
Test: Hydrostatic testing, Non-destructive electrical testing, and Mechanical testing
Applications: Oil and gas sector, Construction industry, Power industry.
Chemical Requirements
| Chemical Requirements | |||
| Composition,% | |||
| Grade A | Grade B | Grade C | |
| Carbon,max | 0.25A | 0.3B | 0.35B |
| Manganese | 0.27-0.93 | 0.29-1.06 | 0.29-1.06 |
| Phosphorus,max | 0.035 | 0.035 | 0.035 |
| Sulfur,max | 0.035 | 0.035 | 0.035 |
| Silicon,min | 0.10 | 0.10 | 0.10 |
| Chromium,maxC | 0.40 | 0.40 | 0.40 |
| Copper,maxC | 0.40 | 0.40 | 0.40 |
| Molybdenum,maxC | 0.15 | 0.15 | 0.15 |
| Nickel,maxC | 0.40 | 0.40 | 0.40 |
| Vanadium,maxC | 0.08 | 0.08 | 0.08 |
| A For each reduction of 0.01% below the specified carbon maximum,an increase of 0.06% manganese above the specified maximum will be permitted up to a maximum of 1.35%. B Unless otherwise specified by the purchaser,for each reductionof 0.01% below the specified carbon maximum,an increase of 0.06% manganese above the specified maximum will be permitted up to a maximum of 1.65%. C These fiveelements combined shall not exceed 1%. |
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Grade A: It has a maximum carbon content of 0.25%. The manganese content ranges from 0.60% to 1.35%. Phosphorus is limited to a maximum of 0.040%, and sulfur is controlled at a maximum of 0.045%. The relatively low carbon content helps maintain good ductility for fabrication processes.
Grade B: The carbon content is slightly higher, up to a maximum of 0.30%. Manganese content is between 0.65% and 1.60%. Phosphorus and sulfur limits are stricter, at a maximum of 0.035% each. This grade offers a balance between strength and ductility.
Grade C: It shares the same maximum carbon content of 0.30% with Grade B. Manganese content is also in the range of 0.65% to 1.60%. Phosphorus and sulfur are limited to a maximum of 0.035% each, similar to Grade B. Grade C is designed for higher strength applications.
Tensile Requirements
| Tensile Requirements | |||||||
| Grade A | Grade B | GradeC | |||||
| Tensilestrength,min,psi [MPa] | 48000 [330] | 60000 [415] | 70000 [485] | ||||
| Yield strength,min,psi[MPa] | 30000 [205] | 35000 [240] | 40000 [275] | ||||
| Elongationin 2 in.[50 mm],min,%: | Longitudinal | Transverse | Longitudinal | Transverse | Longitudinal | Transverse | |
| Basic minimum elongation transverse strip tests,and for all small sizes tested in full section | 35 | 25 | 30 | 16.5 | 30 | 16.5 | |
| When standard round2-in.[50-mm]gauge length test specimen isused | 28 | 20 | 22 | 12 | 20 | 12 | |
| For longitudinal strip tests | A | A | A | ||||
| For transverse strip tests,a deduction for each 1/32-in.[0.8-mm] decrease in wall thickness below 5/16 in.[7.9 mm]from the basic minimum elongation of the following percentage shall be made | 1.25 | 1.00 | 1.00 | ||||
| A The minimum elongation in 2 in.[50 mm]shall be determinedby the following equation: e=625000A0.2/U0.9 for inch-pound units,and e=1940A0.2/U0.9 |
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| for SI units, where: e =minimum elongation in 2 in.[50 mm],%,rounded to the nearest 0.5%, A=cros-sectional area of the tension test specimen,in²(mm²),based upon specified outside diameter or nominal specimen width and specified wall thickness,rounded to the nearest 0.01 in²[1 mm²].(if the area thus calculated is equal to or greater than 0.75 in.2 500 mm²,then the vaue 0.75in2 [500 mm²]shall be used.),and U =specified tensile strength,psi [MPa]. |
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Grade A: It has a minimum yield strength of 30,000 psi (205 MPa) and a minimum tensile strength of 48,000 psi (330 MPa). Grade A is designed for general purpose applications where moderate strength is required.
Grade B: With a minimum yield strength of 35,000 psi (240 MPa) and the same minimum tensile strength of 48,000 psi (330 MPa) as Grade A, Grade B offers higher strength than Grade A. Grade B is suitable for more demanding applications that require greater strength.
Grade C: This grade has the highest strength among the three, with a minimum yield strength of 40,000 psi (275 MPa) and a minimum tensile strength of 52,000 psi (360 MPa). Grade C is ideal for applications with the most severe loading conditions.
Manufacturing
Seamless Pipe Production
Billet Preparation: High-quality steel billets are selected based on the chemical composition requirements of the specific grade. The billets are heated to a suitable temperature, usually around 2200 - 2400°F (1200 - 1300°C), to make the steel more ductile.
Piercing Process: The heated billet is pierced through the center by a piercing mill, forming a hollow shell. This process requires precise control of the piercing angle and speed to ensure uniform wall thickness.
Rolling and Reducing: The hollow shell is then rolled and reduced in diameter through a series of rolling mills. The mills gradually shape the pipe to the desired size and wall thickness. During this process, the pipe is continuously cooled to maintain its structural integrity.
Heat Treatment: After rolling, the pipe may undergo heat treatment such as normalizing or tempering. Normalizing involves heating the pipe to a specific temperature and then cooling it in air, which refines the grain structure and improves mechanical properties. Tempering is used to relieve internal stresses and enhance toughness.
Applications
Grade A
Low-Pressure Fluid Transportation: It is commonly used for transporting fluids such as water, oil, and natural gas in low-pressure systems. For example, in municipal water supply pipelines where the pressure is relatively low, Grade A pipes can provide reliable service.
Structural Applications: Due to its moderate strength and good ductility, it can be used in structural applications like scaffolding, handrails, and simple support structures. Its ability to withstand moderate loads and resist deformation makes it suitable for these purposes.
Grade B
Medium-Pressure Pipeline Systems: It is ideal for medium-pressure fluid transportation, such as in oil and gas pipelines that operate at pressures between low and high levels. The higher strength compared to Grade A allows it to handle increased pressure loads.
Industrial Piping: In industrial facilities, Grade B pipes are used for conveying various chemicals, steam, and other process fluids. They can withstand the operating conditions of many industrial processes, including moderate temperatures and pressures.
Grade C
High-Pressure Applications: Grade C pipes are used in high-pressure pipeline systems, such as those in the oil and gas industry for transporting natural gas at high pressures over long distances. The high strength ensures that the pipes can safely contain the high-pressure fluids.
Heavy-Duty Structural Components: In demanding structural applications where high strength is required, such as in bridge construction or large-scale industrial equipment supports, Grade C pipes can be utilized. They can bear heavy loads and resist deformation under significant stress.
Advantages
Strength and Ductility Balance: Each grade offers a good balance of strength and ductility.
- Grade A provides moderate strength and ductility, suitable for general applications.
- Grade B has higher strength while maintaining acceptable ductility, making it versatile for a wide range of applications.
- Grade C has the highest strength, which is crucial for high-pressure and heavy-load applications, and its ductility ensures that it can withstand some degree of deformation without fracturing.
Corrosion Resistance: ASTM A106 pipes have relatively good corrosion resistance, especially when used in environments with mild corrosive conditions. The steel composition and surface treatment options such as painting or coating can further enhance their resistance to corrosion, extending their service life.
Weldability: These pipes are known for their excellent weldability. The steel composition is designed to allow for easy welding with common welding processes. This makes them convenient to fabricate into complex piping systems and structures, reducing installation time and costs.
Availability and Cost-Effectiveness: ASTM A106 pipes are widely available in the market. They are produced in large quantities, which helps to keep the cost relatively low. For many applications, especially in the construction and fluid transportation industries, they offer a cost-effective solution that provides the required performance.
