What Is ASTM A179?
ASTM A179 cold-drawn seamless steel pipe is essentially a seamless steel pipe primarily made of low-carbon steel. Its manufacturing process employs cold drawing, which produces a high degree of surface finish on both the inner and outer surfaces together with good wall thickness uniformity. Due to its low-carbon characteristics, A179 steel pipe exhibits good performance during welding, being less prone to defects such as cracks. It possesses excellent thermal conductivity, which is crucial for its application in heat exchange equipment. It should be noted that this type of steel pipe is generally not suitable for extreme high-temperature and high-pressure conditions, but its performance is stable and reliable within its designed temperature and pressure range.
Chemical Composition and Mechanical Properties
The chemical composition of A179 is tightly controlled to keep the steel soft, ductile and easy to form into thin-walled heat exchanger tubes.
| Element | ASTM A179 |
|---|---|
| Carbon (C) | 0.06 - 0.18% |
| Manganese (Mn) | 0.27 - 0.63% |
| Phosphorus (P), max | 0.035% |
| Sulfur (S), max | 0.035% |
| Mechanical Property | Value |
|---|---|
| Tensile strength, min | 47 ksi (325 MPa) |
| Yield strength, min | 26 ksi (180 MPa) |
| Elongation in 2 in or 50 mm, min | 35% |
Equivalent Grades
A179 has well-established equivalents in the major international standards, as summarised below. These grades share a similar low-carbon chemistry and are commonly interchanged in heat exchanger construction.
| Standard | Equivalent Grade |
|---|---|
| ASME | ASME SA179 |
| DIN | DIN 17175 St35.8 |
| EN | EN 10216-1 P235TR1 |
| JIS | JIS G 3461 STB340 |
A106 vs A179
Standard positioning and design temperature. A106 is a seamless carbon steel pipe for high-temperature service, designed for environments such as steam, high-temperature water and high-temperature gas pipelines where design temperatures can reach hundreds of degrees Celsius. A179 is a cold-drawn seamless low-carbon steel pipe with minimum wall thickness for low-temperature applications, particularly heat exchangers, condensers and other equipment requiring efficient heat transfer at temperatures close to or below room temperature.
Chemical composition and performance focus. A106 prioritises strength: by adjusting carbon and manganese content it ensures tensile strength and pressure resistance at high temperatures. A179 prioritises toughness: its low carbon content, with a maximum of 0.18% carbon, and strict control of sulfur and phosphorus ensure toughness at low or room temperatures and prevent brittle fracture. The cold-drawing process also gives A179 high dimensional accuracy and a smooth surface, suitable for the precise heat transfer needs of heat exchangers.
Manufacturing process. A106 is produced by hot rolling or hot expanding, which is cost-effective and efficient for large-diameter, thick-walled pipes. A179 is produced by cold drawing through dies at room temperature, requiring multiple passes of cold working and annealing. The process is more complex and costly, but achieves tighter tolerances and higher surface quality.
Applications, Testing and Packaging
A179 tubes are used in heat exchange equipment such as power plant boiler economizers, condensers, evaporators and heat exchanger tube bundles in chemical plants, as well as refrigerant pipes in air conditioning systems and precision pipelines in industrial cooling water systems. Tubes are subject to standard inspection including dimensional checks, hydrostatic or non-destructive testing and surface examination, and are packed in wooden boxes or bundles protected with plastic paper and suitably protected for sea-worthy delivery or as requested.
Frequently Asked Questions
What is A179 steel pipe used for?
A179 is used for heat transfer tubes in heat exchangers, condensers, boiler economizers, evaporators and similar equipment operating at low or ambient temperatures.
Is A179 the same as A106?
No. A106 is a carbon steel pipe for high-temperature service produced by hot rolling, while A179 is a cold-drawn low-carbon tube for heat exchange service at low or ambient temperatures.
Can A179 be welded?
Yes. The low carbon content of A179 gives it good weldability with a low risk of cracking defects.
What is the tensile strength of A179?
The minimum tensile strength is 47 ksi (325 MPa), with a minimum yield strength of 26 ksi (180 MPa) and a minimum elongation of 35%.
What is SA179?
SA179 is the ASME designation of the same cold-drawn seamless low-carbon steel tube covered by ASTM A179.