ASTM A179 Extruded Finned Tube With AL1060 Fins For Air Cooled Heat Exchangers

ASTM A179 Extruded Finned Tube With AL1060 Fins is a high-performance heat exchanger tube specifically engineered to maximize heat transfer efficiency in various industrial applications. It combines the superior pressure containment and corrosion resistance of a carbon steel core tube with the excellent thermal conductivity and lightweight properties of aluminum fins.

Breakdown of Components:

1. Core Tube: ASTM A179

Material: This is a low-carbon steel tube, specifically known as "seamless cold-drawn low-carbon steel heat-exchanger tube."

(1). Chemical Composition

The chemical composition requirements for ASTM A179 are very specific, emphasizing low carbon and manganese content to ensure good weldability and formability.

Key Notes on Chemistry:

• Low Carbon: The limited carbon content range provides excellent ductility and weldability, making the tubes easy to form and weld to tubesheets and headers.
• Residual Elements: Unless otherwise specified, the standard allows for residual chromium, nickel, and molybdenum content up to 0.25%, 0.10%, and 0.15%, respectively, from the manufacturing process.
• Copper Content Requirements: Notes on copper are important. For applications where atmospheric corrosion resistance is critical (such as certain condenser applications), a minimum copper content of 0.20% is often specified on the purchase order to enhance corrosion resistance.

(2). Mechanical Properties

The mechanical properties are based on tension tests performed on the finished tube. The cold-drawing process significantly increases the tube's strength and hardness compared to hot-finished products.

2. Fins: AL1060 Aluminum

Material: AL1060 is a commercially pure aluminum alloy (99.6% aluminum minimum).

Key Features:

• Excellent Thermal Conductivity: Aluminum is an excellent conductor of heat. AL1060 has a thermal conductivity of approximately 229 W/m·K, significantly higher than carbon steel (approximately 54 W/m·K). This allows heat to dissipate quickly from the core tube to the fins and then to the surrounding air or gas.
• Lightweight: Aluminum has a density approximately one-third that of steel, reducing the overall weight of the heat exchanger.
• Corrosion Resistance (External): Aluminum forms a protective oxide layer, providing excellent resistance to atmospheric corrosion. This makes it an ideal choice for exposed fin surfaces in air-cooled applications.
• Economical and Efficient: AL1060 is one of the most economical aluminum alloys.

3. The "Extruded" Process

This is the critical manufacturing step that bonds the fin to the tube. It is not a mechanical fit; it is a metallurgical bond.

Processing Procedure:

• An aluminum sleeve/tube (the future fin) is mounted over the cleaned steel tube.
• The assembly is passed through a machine that uses a set of precision rollers.
• The rollers apply extreme pressure, forcing the aluminum to flow plastically.
• This pressure and flow create a strong, continuous, and seamless metallurgical bond between the aluminum fin and the steel tube.
• The process simultaneously forms the fin shape from the aluminum sleeve.

Key Advantages and Benefits:

• This finned tube design delivers superior heat transfer by pairing a durable steel core for internal pressure with highly conductive aluminum fins for external air cooling.
• Its exceptional performance is ideal for high-temperature differentials.
• The extruded fin bond guarantees lifelong reliability by preventing loosening, all while providing a more economical alternative to all-copper or stainless-steel tubes.

Typical Applications:

This tube is a workhorse in industries where reliable heat rejection is critical:

• Air Cooled Heat Exchangers (ACHEs): Cooling process fluids, water, oil, or steam in refineries, chemical plants, and power stations.
• Heat Recovery Steam Generators (HRSGs): Recovering waste heat from gas turbine exhaust.
• Air Conditioning and Refrigeration Systems: As condenser and evaporator coils.
• Deaerators and Pre-heaters in power generation cycles.
• Various OEM Equipment: Used by manufacturers of industrial air compressors, hydraulic systems, and other machinery that requires efficient cooling.