Stainless Steel 304 Helical Laser Welding Finned Tube
Stainless steel 304 helical laser welded finned tube is a heat exchange element with helical fins attached to the surface of 304 stainless steel base tube by laser welding process, which is specially designed for high temperature and high pressure scenes such as boilers.
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What is stainless steel 304 helical laser welding finned tube?
⚙️ I. Structure & Material Composition
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Base Tube Material
Made of 304 stainless steel (austenitic structure), offering excellent corrosion resistance (tolerates pH 2-12 media), high-temperature resistance (long-term operating temperature ≤800°C), and non-magnetic properties. Ideal for corrosive environments in chemical, power, and other industries19. Typical base tube wall thickness ranges from 0.8-2.5mm, ensured defect-free by eddy current testing. -
Fin Design
- Shape: Spiral wound structure (mainstream design), enhancing fluid turbulence and heat transfer coefficient.
- Parameters: Fin height 5-20mm, thickness 0.3-1.0mm, pitch 2-10mm (customizable based on conditions). Heat exchange area per unit length can reach 5-12 times that of a bare tube.
- Material: 304 stainless steel matching the base tube or special alloys (e.g., copper-nickel alloy) to ensure compatible thermal expansion coefficients.
🔥 II. Core Process: Laser Welding Technology
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Technical Advantages
- High-Strength Bond: Laser instantly melts the fin root and base tube, forming a metallurgical bond. Weld tensile strength ≥ 90% of base material, burst pressure >20MPa.
- Precision Control: Heat-affected zone [HAZ] <0.1mm, penetration depth 0.2-1.5mm, preventing intergranular corrosion].
- Zero Contact Thermal Resistance: Compared to high-frequency welding, heat transfer efficiency increases by >30%, with no weld oxidation issues].
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Process Flow
Base tube and fins undergo electrolytic polishing (Ra≤0.8μm) and plasma cleaning. Pulse laser welding is employed with ER308/ER316 filler wire to ensure weld corrosion resistance matches the base material].
III. Performance Advantages
- High-Efficiency Heat Transfer
Finned extended surface increases convective heat transfer coefficient by 3-8 times. Boiler flue gas temperature can be reduced by 30-50°C, improving thermal efficiency by 5%-15%. - Superior Environmental Resistance
304 stainless steel’s chromium oxide passivation film offers self-healing properties. Passes 48hr salt spray test without corrosion, with annual corrosion rate <0.01mm. Service life extended by 3-5 times compared to carbon steel tube. - Excellent Fatigue Resistance
Pulse laser welding minimizes residual stress, enabling resistance to thermal stress shock during frequent boiler start-stop cycles].
IV. Application Areas
- Energy Equipment
Boiler economizers, waste heat recovery systems—reducing energy consumption and meeting “dual carbon” emission targets]. - Chemical & Petroleum
Used in heat exchangers, condensers—resisting acid/alkali corrosion and suitable for high-pressure environments (e.g., base tube thickening required for >6 MPa operation)]. - Special Scenarios
- High-Dust Environments: Use 4-6mm fin pitch to prevent clogging];
- Cryogenic Environments: Custom S30409 base tube + Al-Mg alloy fins maintains toughness at -196°C].
️ V. Selection & Technical Recommendations
- Material Upgrade
For high chloride ion environments, recommend 316L stainless steel (molybdenum-containing). For temperatures >500°C, consider 310S or nickel-based alloys. - Structural Optimization
- Anti-Dust Accumulation Design: Avoid overly dense fin spacing in flue gas applications; implement regular soot blowing];
- Stress Analysis: Conduct FEM simulation for critical pressure/temperature differential applications (>15MPa or ΔT>250°C) for safety].
Core structure of stainless steel laser welding finned tube
Using 304 stainless steel as the base tube material (strong corrosion resistance and good processing performance), the spiral fins are firmly attached to the surface of the tube body through laser welding technology to form an efficient heat exchange structure. The fin thickness is usually 0.5-3mm, the height is 5-20mm, the weld depth is controllable (0.2-1.5mm), and the heat affected zone is less than 0.1mm.
Performance characteristics of stainless steel laser welded finned tube
Corrosion resistance: The annual corrosion rate of 304 stainless steel in the pH range of 2-12 is less than 0.01mm, and the salt spray test life is 3-5 times longer than that of ordinary carbon steel high-frequency welded tubes.
Heat exchange efficiency: The heat exchange area per unit length can reach 5-12 times that of the light tube, the exhaust temperature can be reduced by 30-50℃, and the thermal efficiency can be increased by 5%-15%.
Impact resistance: The bursting pressure is greater than 20MPa, which can adapt to the stress impact of frequent boiler start-up and shutdown.
Applicable scenarios for stainless steel laser welded fin tubes
Mainly used in industrial boilers, wall-mounted boilers and other environments that require high temperature (up to 800℃), high pressure and easy corrosion, to solve the problems of dust accumulation and rapid corrosion of traditional heat exchange tubes.