Whether the stainless steel heat exchange tube can be repaired depends on the degree of damage! The specific repair plan is as follows.
If it is mild or localized damage, welding repair or polymer repair agents can be used. Welding repair is suitable for scenarios with crack length ≤ 30% of pipe diameter or pitting corrosion pits (depth ＜ 1mm). TIG argon arc welding is preferred, combined with ER309L stainless steel welding wire to reduce the risk of intergranular corrosion in the heat affected zone. After welding, acid pickling and passivation treatment are required; Polymer repair agents are suitable for emergency repair of low-pressure heat exchange systems with medium temperatures ≤ 150 ℃. Temperature resistant steel repair agents (such as 8112 model) are used to fill small cracks or corrosion holes. The operation process includes surface acetone cleaning → repair agent application → 24-hour room temperature curing.
If the damage is moderate or even severe, mechanical reinforcement repair or replacement welding method can be used. The double expansion ring fitting technology is suitable for heat exchange tubes with axial cracks or circumferential tears (length ≤ 1/3 of the pipe circumference) and pipe diameter ≥ DN80. Stainless steel rings (material needs to match the original pipe) are installed in the damaged section, and a sealed structure is formed by hydraulic expansion, which can bear a pressure of ≤ 1.6MPa; Replacement welding involves inserting a short pipe of the same material after cutting off the damaged pipe section. High precision centering fixtures are used to ensure that the weld seam gap is ≤ 0.5mm. After welding, radiographic testing and pressure testing are required.
The repaired stainless steel heat exchange tubes should also undergo non-destructive testing, pressure testing, and anti-corrosion testing!