ASME SA179 ASTM A179 Carbon Steel Seamless U Tube for Heat Exchanger and Condenser

ASME SA179 / ASTM A179 seamless U tube is a low-carbon steel heat exchanger tube manufactured from seamless cold-drawn tubing and subsequently bent into a U-shaped configuration.

The product is designed for shell and tube heat exchangers, condensers, coolers, and similar heat transfer equipment. Compared with straight tubes, the U-shaped design allows thermal expansion to be accommodated through the tube geometry and enables the tube bundle to operate without requiring a separate floating head structure.

The finished U tube is manufactured with controlled outside diameter, wall thickness, straight leg length, bend radius, and leg spacing according to the heat exchanger drawing and applicable specification.

Material and Standard

ASME SA179 / ASTM A179

Material Standard: ASME SA179 / ASTM A179
Material Grade: SA179 / A179
Material Type: Low Carbon Steel
Product Type: Seamless U Tube
Manufacturing Process: Cold Drawn Seamless Tube + U Bending

ASTM A179 / ASME SA179 covers seamless cold-drawn low-carbon steel tubes for tubular heat exchangers, condensers, and similar heat-transfer equipment.

The standard defines requirements for chemical composition, mechanical properties, dimensions, heat treatment, and testing applicable to the finished seamless tube.

U Tube Design

U-Bend Configuration

The straight SA179 seamless tube is bent into the specified U shape according to the equipment design.

Key dimensional parameters include:

• Tube outside diameter
• Wall thickness
• Straight leg length
• U-bend radius
• Center-to-center distance
• Overall U tube length

The bending dimensions are determined according to the heat exchanger drawing and tube bundle design.

Thermal Expansion Considerations

In a U-tube heat exchanger, the curved section of the tube provides geometric flexibility for differential thermal expansion between the tube bundle and shell.

The suitability of the U-bend radius and tube dimensions should be determined according to the operating temperature range, pressure conditions, tube material, and equipment design.

Manufacturing Process

Seamless Tube Production

SA179 seamless tubes are produced by cold drawing to obtain the specified tube outside diameter and wall thickness.

Heat Treatment

The tube is heat treated according to the applicable ASTM A179 / ASME SA179 requirements.

U Bending

The straight seamless tube is bent into a U shape using controlled bending equipment.

The bend radius and center-to-center dimensions are manufactured according to the heat exchanger drawing.

Post-Bending Inspection

The U-bend section can be inspected for:

• Outside diameter
• Wall thickness
• Bend radius
• Ovality
• Straight leg alignment
• Surface condition

Additional testing can be performed according to project requirements.

Product Specifications

Available Dimensions

The U tube dimensions are normally customized according to the heat exchanger design.

U-Bend Inspection

Depending on the project specification, inspection may include:

• Dimensional inspection
• Wall thickness measurement
• Bend radius verification
• Ovality measurement
• Visual surface inspection
• Eddy Current Testing
• Hydrostatic Testing
• Pneumatic Testing
• PMI when specified

The actual inspection scope should follow the applicable product specification and purchase order requirements.

Applications

Shell and Tube Heat Exchangers

SA179 seamless U tubes are commonly used in U-tube shell and tube heat exchangers where carbon steel tubing is specified.

Condensers

The tubes can also be used in condenser equipment for industrial heat transfer systems.

Industrial Cooling Equipment

Applications may include:

• Process coolers
• Heat recovery equipment
• Industrial condensers
• Thermal process systems

The final material selection should be based on the design temperature, pressure, process fluid, water chemistry, and corrosion conditions.

Quality Control

Material Traceability

Each production batch can be identified and documented through:

• Heat number
• Material certificate
• Inspection records

Dimensional Inspection

Typical inspection parameters include:

• Tube OD
• Wall thickness
• Straight leg length
• Bend radius
• Center distance
• U-bend geometry

Additional Testing

According to customer requirements:

• Eddy Current Testing
• Hydrostatic Testing
• Air Underwater Testing
• Third-Party Inspection