H Type Finned Tubes Economizer

H-type finned tubes are high-efficiency heat exchange elements widely used in industrial boilers, waste heat recovery systems, and chemical equipment. Their core structure consists of a base tube (usually a seamless steel pipe) and welded or rolled fins on the outside, significantly improving heat transfer efficiency by increasing surface area.

H-Type Finned Tube Manufacturing Process

High-frequency welding: High weld fusion rate, high tensile strength, and good thermal conductivity.

Material selection: Commonly used are ND steel, stainless steel, or aluminized steel to withstand high pressure, high temperature, and corrosive environments.

The manufacturing process of H-type finned tubes mainly includes two core aspects: high-frequency welding and material selection. The production process can be further divided into the following steps:

I. H-Type Finned Tube Raw Material Selection and Pretreatment

Base tube material: Typically, low-carbon seamless steel pipes or welded steel pipes such as Q235 and Q345 are selected, with a diameter range of DN20-DN150 and a wall thickness of 2-5mm. Good thermal conductivity and mechanical strength are required.

Fin Material: Cold-rolled carbon steel strip (e.g., 08Al, SPCC), thickness 0.3-1.5mm, width 10-50mm. Stainless steel or aluminum can also be used for special applications.

Pretreatment:

The base tube needs straightening (straightness ≤1mm/m) and sandblasting/acid pickling to remove rust (surface roughness Ra≥12.5μm).

The steel strip needs leveling (deviation ≤0.5mm/m) and annealing (600-650℃) to improve plasticity.

II. Core Process of High-Frequency Welding for H-Type Finned Tubes

Welding Principle: Utilizing the skin effect of high-frequency current (200-400kHz), the contact surface between the steel strip and the base tube is instantly heated to a molten state of 1200-1400℃, and then a forging pressure of 0.8-1.5MPa is applied to achieve metallurgical bonding.

H-type finned tube parameter control:

Power: 80-200kW (typical parameters for φ32mm tube are 120kW/15m/min).

Cooling: Atomized water cooling (5-8L/min) gradient cooling.

Quality inspection: Weld continuity must be inspected by X-ray or ultrasonic testing; tensile strength must be ≥90% of the base material strength.

III. Post-treatment and surface corrosion protection of H-type finned tubes

Stress relief: Tempering at 580-620℃ (≥30min) to relieve welding stress.

Surface treatment:

Hot-dip galvanizing (80-120μm thickness) or aluminizing treatment.

Stainless steel materials require passivation treatment.

Air tightness test: 3.5MPa water pressure holding test; leakage rate <0.01%.

Core Advantages of H-Type Finned Tubes

High Heat Transfer Efficiency: The heating area of ​​H-type finned tubes is 7-8 times that of plain tubes and 2-3 times that of spiral finned tubes, effectively improving heat recovery.

Wear Resistance and Rigidity: Its rigidity is 3-5 times higher than a single-piece finned tube, offering excellent wear resistance and a long service life.

Reduced Dust Accumulation: The unique serrated structure and straight channel design ensure consistent airflow direction, reducing dust accumulation and facilitating cleaning with soot blowers.

Significant Energy Saving: For example, after a power plant upgraded its system, the flue gas temperature dropped from 180℃ to 120℃, and coal consumption per ton of steam decreased from 135kg to 98kg, resulting in considerable annual cost savings.

Application Scenarios of H-Type Finned Tubes:

Industrial Boilers: Used in economizers, superheaters, and other critical components, reducing equipment size and energy consumption.

Waste heat recovery: In flue gas coolers, the flue gas temperature can be reduced from 150℃ to 120℃ or lower, fully absorbing waste heat.

Chemical and metallurgical applications: High temperature resistant (up to 600℃ and above), corrosion resistant, suitable for complex industrial environments.

Welded H Type Boiler Finned Tube Welding Machine Manufacturer and Suppliers in China Factory