Seamless cold drawn low-carbon steel pipes for ASME SA179 heat exchangers and condensers

1、 Standards and Scope of Application

Standard specifications:

ASME SA179/SA-179M is a seamless cold drawn low-carbon steel pipe standard designed specifically for heat transfer equipment such as heat exchangers and condensers, suitable for pipes with outer diameters ranging from 1/8 inch to 3 inches (3.2-76.2mm).

Note: Pipes with an outer diameter or wall thickness smaller than the standard range are applicable, but the mechanical properties do not apply to pipes with an outer diameter<3.2mm or wall thickness<0.4mm.

Measurement unit:

Supports inch pound units (such as M units) and SI millimeter kilogram units, but must be clearly specified in the order and cannot be mixed.

2、 Chemical composition and material properties

Low carbon design:

Carbon content of 0.06-0.18% ensures good toughness and welding performance.

Manganese content ranges from 0.27% to 0.93%, and the strength is enhanced by 56% through solid solution strengthening.

Strictly limit impurities such as phosphorus (≤ 0.035%) and sulfur (≤ 0.035%) to reduce brittleness and corrosion tendency.

Special environmental adaptability:

The SA-179 (H2S) version is designed for corrosive environments containing hydrogen sulfide, such as the petroleum and natural gas industries, and enhances corrosion resistance through component optimization.

3、 Mechanical properties

Tensile strength: 360-480MPa, meeting the pressure change requirements of heat exchange medium 56.

Yield strength: ≥ 205MPa, preventing a 56% decrease in heat transfer efficiency caused by plastic deformation.

Elongation rate: ≥ 35%, suitable for thermal stress impact and deformation under complex working conditions of 56.

4、 Manufacturing process and quality control

Cold drawing process:

At room temperature, through mold drawing, the dimensional accuracy (outer diameter tolerance ± 0.10mm) and surface smoothness (roughness Ra ≤ 0.8 μ m) are improved, while the grain size is refined to enhance strength by 16.

Testing requirements:

Conduct a water pressure test one by one to ensure no leakage.

Dimensional tolerances and surface defects (such as cracks and folds) are strictly controlled according to standards.

5、 Typical application areas

Heat exchange equipment: heat transfer pipes 13 in shell and tube heat exchangers, condensers, and evaporators.

Industrial scenario:

Heat exchange of high-temperature media (such as steam and oil) in chemical plants.

Boiler feedwater preheating system 6 in the power industry.

6、 Selection precautions

Size matching: Select the outer diameter and wall thickness based on the aperture of the heat exchanger tube plate to avoid interference or excessive clearances.

Media compatibility: SA-179 (H2S) material 5 should be selected for environments containing H ₂ S.

Welding process: Low carbon design can reduce preheating requirements, but heat input needs to be controlled to avoid intergranular corrosion.