Analysis of ASME SA106Gr.B High-Temperature Carbon Steel Seamless Pipe

First, Core Standards and Definitions of SA106Gr.B High-Temperature Carbon Steel Seamless Pipe

ASME SA106Gr.B seamless pipe is a Grade B carbon steel seamless pipe for high-temperature service, produced in accordance with the American Society of Mechanical Engineers (ASME) standard SA-106/SA-106M. This standard is fully equivalent to the ASTM A106 seamless pipe standard, both specifying the chemical composition, mechanical properties, and manufacturing process for carbon steel seamless pipes for high-temperature and high-pressure environments.

Second, Chemical Composition and Properties of SA106Gr.B High-Temperature Carbon Steel Seamless Pipe

1. Chemical Composition

Carbon: ≤0.30% (controlled to 0.18%-0.25% in some applications), ensuring a balance between weldability and toughness.

Manganese: 0.29%-1.06% (typically 0.60%-0.90%), strengthening the ferrite matrix and improving strength and impact resistance. Phosphorus/Sulfur: ≤0.035%, strictly limited to prevent inclusion formation and ensure material purity.

Silicon: 0.10%-0.50%, deoxidizes and enhances steel strength.

Alloying Elements: Trace amounts of chromium, molybdenum, and other elements may be added to improve corrosion resistance and high-temperature strength.

2. Mechanical Properties

Tensile Strength: ≥415 MPa (≥485 MPa required in some applications), capable of withstanding the tensile forces of high-pressure fluids.

Yield Strength: ≥240 MPa, ensuring only moderate plastic deformation under pressure.

Elongation: ≥22% (≥30% in some applications), imparting exceptional toughness to the material and buffering impact energy.

Low-Temperature Toughness: Verified through impact testing, suitable for use in extreme environments ranging from -29°C to 565°C.

Third, Manufacturing Process and Quality Control of SA106Gr.B High-Temperature Carbon Steel Seamless Pipe

1. Production Process

Hot Rolling Process: Heating the tube billet → Piercing → Three-roll cross-rolling → Sizing → Cooling → Straightening → Hydrostatic Testing.

Cold Drawing Process: Heating the tube billet → Piercing → Annealing → Pickling → Multi-pass cold drawing → Heat treatment → Straightening → NDT.

Key Parameters: Rolling temperature, deformation, and cooling rate must be strictly controlled to ensure grain refinement and microstructure uniformity.

3. Quality Inspection

Nondestructive Testing: Ultrasonic and radiographic testing are used to detect internal defects (such as cracks and inclusions).

Physical and Chemical Property Testing: Regular sampling of chemical composition, tensile testing, and impact testing are performed to ensure compliance with standards.

Dimensional Tolerances: Dimensional deviations, such as outer diameter, wall thickness, and length, must be kept within standard ranges to ensure interchangeability.

Fourth, Application Scenarios and Advantages of SA106Gr.B High-Temperature Carbon Steel Seamless Pipe

1. Petrochemical Industry

High-Temperature and High-Pressure Pipes: Transport crude oil, natural gas, and chemical raw materials (such as acidic media), with corrosion resistance and high-temperature strength to meet complex operating conditions.

Refining Equipment: Used in reactors, heat exchangers, distillation towers, etc., to withstand high-temperature cracking and corrosive media.

2. Power Industry

Boiler Systems: Used as main steam pipes, superheater, and reheater tubes, withstanding high-temperature steam pressure (such as 600°C steam in supercritical units).

3. Other Industries

Metallurgical Industry: Blast furnace gas pipelines and hot blast furnace piping.

Shipbuilding Industry: Ship boilers and steam turbine piping.

4. Advantages:

High-Temperature Stability: Maintains stable physical and chemical properties even at 565°C.

Weldability: Low carbon content reduces weld hardening, resulting in excellent weld toughness.

Economical: Lower cost and shorter lead times compared to alloy steel pipes.

Fifth, SA106Gr.B High-Temperature Carbon Steel Seamless Pipe Selection and Procurement Recommendations

1. Supplier Qualifications: Prioritize suppliers certified by API 5L and API 5CT to ensure product compliance with international petrochemical industry standards.

2. Customization Requirements: If hydrogen sulfide corrosion resistance is required (such as in H₂S-containing oil and gas fields), compliance with NACE MR0175 standards and HIC/SSCC testing may be required.

3. For low-temperature applications (below -29°C), the Mn content should be increased to 0.8%-1.2% to improve low-temperature toughness.