Definition and Standards
ASTM A106 Grade B is a standard for high-temperature carbon steel seamless pipes developed by the American Society for Testing and Materials (ASTM). It belongs to the ASTM A106/A106M standard system and is applicable to pipeline systems in the petroleum, natural gas, chemical and other industries. It regulates the manufacturing, chemical composition, mechanical properties and testing process of steel pipes to ensure the reliability of materials under complex working conditions.
Chemical Composition
The chemical composition requirements of ASTM A106 Grade B are strict, mainly including (if the carbon content is reduced, the manganese content can be appropriately increased (up to 1.35%) to balance the mechanical properties)
|
Element |
content |
|
C |
≤0.30%(Low carbon content improves welding performance) |
|
manganese |
0.29%~1.06%(Increase strength and toughness) |
|
sulfur |
≤0.035%(Reduce the impact of impurities on corrosion resistance) |
|
phosphorus |
≤0.035%（Reduce the impact of impurities on corrosion resistance） |
|
chromium |
≤0.40% |
|
copper |
≤0.40% |
|
molybdenum |
≤0.15% |
Mechanical Properties
ASTM A106 Grade B has excellent mechanical properties:
|
tensile strength |
≥415 MPa； |
|
Yield Strength |
≥240 MPa； |
|
Elongation |
≥22% |
Quality Control and Testing System
Process testing
Smelting analysis: Use spectroscopy to detect the content of key elements (accuracy of ±0.001%) to ensure compliance with the requirements of ASTM A106 standard. If deviations are found, use the pre-furnace adjustment rack alloy fine-tuning to ensure that the final steelmaking water meets the low sulfur and phosphorus control requirements of Grade B.
Finished product analysis: Take samples for tensile testing (GB/T 228.1), measure the tensile strength, yield strength and elongation, and control the error to ≤2%. Use Brinell hardness tester (HBW) or Rockwell hardness tester (HRB).
Nondestructive testing
Ultrasonic flaw detection (UT): Use the automatic ultrasonic testing system (AUT) to fully scan the pipe body, and mark and remove the unqualified pipe sections.
Magnetic particle testing: Fluorescent magnetic particle testing is performed on the surface and near the surface of the steel pipe. Steel pipes with cracks or folding defects can be detected.
Nondestructive testing
Complies with ASME B36.10M dimensional specifications and NACE MR0175 corrosion resistance standards.
