Views: 0 Author: Kath Publish Time: 2025-03-20 Origin: Site
Introduction
In the stainless steel welding process, preventing oxidation is crucial to ensure the quality and corrosion resistance of butt weld pipe fittings. Here are some effective ways to achieve this as below.
1. Use Shielding Gas
(1) Argon Shielding: Argon, an inert gas, effectively isolates the welding area from atmospheric oxygen, preventing oxidation. Typically, 99.99% pure argon is used as the shielding gas.
(2) Mixed Gas Shielding: In certain applications, a mixed gas (e.g., 5% hydrogen + 95% argon) can be used for back shielding. The chemical reaction between hydrogen and oxygen helps further reduce the oxygen content in the pipeline.
2. Control Welding Parameters
(1) Low Heat Input: Opt for low current, low voltage, and fast welding parameters to minimize heat input. This approach reduces the time the weld and heat-affected zone spend at high temperatures.
(2) Interlayer Temperature Control: For austenitic stainless steel, keep the welding temperature below 350°C and the interlayer temperature between 150-250°C.
3. Protective Measures During Welding
(1) Pre-Gas Supply and Delayed Gas Stop: Utilize a welding machine with pre-gas supply and delayed gas stop functions. This ensures continuous protection before and after welding, preventing the weld from exposure to air at high temperatures.
(2) Sealing Measures: Seal the inside of the pipe weld using tin foil tape or plugging plates. This prevents air from entering the welding area, maintaining a well-sealed environment.
4. Post-Welding Treatment
(1) Pickling and Passivation: After welding, perform pickling and passivation on the weld. This process removes oxide scale and forms a dense oxide film, enhancing corrosion resistance.
(2) Cooling Measures: Wrap the weld with circulating water cooling copper tubes or damp cotton cloth to accelerate cooling. This reduces the high-temperature dwell time and prevents oxidation.
Implementing these measures can significantly reduce oxidation during stainless steel welding, thereby ensuring high-quality welds and maintaining the material's corrosion resistance.
