ASME SA106 Carbon Seamless Steel Tubes are widely used in industrial settings, especially in scenarios where high - temperature and high - pressure fluid or gas transportation is required. These tubes are specified by the American Society of Mechanical Engineers (ASME) standard SA106, which is equivalent to ASTM A106.
1. Chemical Composition
ASME SA106 carbon seamless steel tubes are made from killed steel. The primary melting processes include open - hearth, basic - oxygen, or electric - furnace methods, which may be combined with separate degassing or refining.
The standard covers three grades: A, B, and C. In terms of chemical composition, for Grade A, the carbon content is ≤0.25%, manganese is in the range of 0.27 - 0.93%, and the maximum sulfur and phosphorus content is ≤0.035% each. Grade B has a carbon content of ≤0.30%, manganese from 0.29 - 1.06%, and the same sulfur and phosphorus limits as Grade A. Grade C has a slightly higher carbon limit of ≤0.35%, with manganese in the 0.29 - 1.06% range and sulfur and phosphorus ≤0.035%. Additionally, in all grades, the sum of Cu, Ni, Cr, Mo, and V elements should not exceed 1.00%.
2. Mechanical Properties
Grade A has a minimum tensile strength of 330 MPa, a minimum yield strength of 205 MPa, and an elongation of 20% in the annealed condition.
Grade B offers a minimum tensile strength of 415 MPa, a minimum yield strength of 240 MPa, and also has an elongation of 20% when annealed.
Grade C has the highest strength among the three grades, with a minimum tensile strength of 485 MPa, a minimum yield strength of 275 MPa, and an elongation of 20% in the annealed state. These mechanical properties make SA106 tubes suitable for applications where the pipes need to withstand significant stress.
3. Manufacturing Process
SA106 tubes can be produced through either hot - rolling or cold - drawing processes. Generally, for outer diameters (OD) greater than 325 mm, the cold - drawing method is used, while for OD less than 325 mm, hot - rolling is the preferred choice. After production, cold - drawn finish pipes usually require a normalizing heat treatment at around 900 °C to optimize their microstructure and mechanical properties.
The dimensional specifications of SA106 tubes follow ANSI B36.10/ASME B36.10 standards. The outer diameter can range from as small as 6.00 mm up to 914.4 mm, and various wall - thickness options are available to meet different application requirements.
4. Testing Requirements
Hydrostatic test: This is a crucial test to ensure the integrity of the tubes. The test pressure is set to produce a stress on the pipe wall equal to 60% of the specified minimum yield strength (SMYS) at room temperature. For NPS 3 and below, the maximum pressure must not exceed 2500 psi, and for larger sizes, it should not exceed 2800 psi. The pressure is maintained for no less than 5 seconds.
Tensile test: For NPS 8 and above, either transverse or longitudinal tests are acceptable, while for sizes less than NPS 8, only longitudinal tests are carried out.
Flattening test: This test is conducted on tubes with NPS 2 and above, and for NPS 2 and below, a bend test (cold) is performed. Additionally, non - destructive electrical tests, ultrasonic tests, eddy - current tests, and magnetic flux leakage tests may also be carried out as per customer requirements.
5. Applications
Oil and Gas Refineries: SA106 tubes are used for transporting various fluids such as crude oil, refined products, and gases within the refinery complex. Their ability to withstand high - temperature and high - pressure conditions makes them ideal for pipelines in processes like distillation, cracking, and reforming.
Power Plants: In power generation facilities, especially in boilers, SA106 tubes are used to transport high - pressure steam. The high - temperature resistance of these tubes ensures the safe and efficient operation of the boiler system.
Petrochemical Plants: They are used to convey a wide range of chemicals and petrochemical products. Their corrosion - resistance properties, combined with high - temperature and pressure resistance, make them suitable for use in reactors, heat exchangers, and pipelines within petrochemical plants.
Shipbuilding: SA106 carbon seamless steel tubes are used in shipboard systems for applications such as engine cooling water lines, steam lines, and fuel lines. Their durability and reliability are essential for the long - term operation of ships in harsh marine environments.
