Desoldering of Iron Pipes in Office Chairs

Welding repair can be used for desoldering of iron pipes in office chairs. For thin pipe joints, CO₂ gas shielded arc welding is a safer option. The specific steps are as follows:

Prepare Tools and Materials

• Core Equipment: Welding machine (a CO₂ gas shielded arc welding machine is recommended), matching welding wire (such as ER50 - 6), shielding gas (CO₂).
• Auxiliary Tools: Angle grinder or sandpaper, pliers or clamps, screwdriver (if the desoldered part needs to be disassembled), gloves, safety goggles.
• Required Materials: Welding rods, welding flux (if a non-CO₂ gas shielded arc welding machine is used).
• Safety Equipment: Welding protective mask, welding gloves, flame-retardant protective clothing.

Disassemble the Desoldered Part (if necessary)

Turn the chair upside down so that the desoldered part faces upwards. Use a screwdriver and other tools to carefully disassemble the desoldered area for subsequent welding operations.

Pre-welding Treatment

• Grinding and Rust Removal: Use an angle grinder or sandpaper to grind the fracture and an area of at least 20 millimeters around it to remove rust, old paint, and oil stains until the metal luster is exposed.
• Surface Cleaning: Wipe the metal dust generated by grinding with a clean cloth to ensure the welding area is clean. If a non-CO₂ gas shielded arc welding machine is used, apply welding flux after grinding to improve thermal conductivity.

Positioning and Fixing

Align the broken chair leg precisely with the main body, restore the original angle and position, temporarily fix it with clamps, and then perform "tack welding". Weld short welds of 10 - 20 millimeters at key positions to initially fix the fracture.

Welding Operation

• Parameter Setting: According to the wall thickness of the iron pipe (usually 1 - 2 millimeters), set the welding current to 120 - 200 amperes, the voltage to 18 - 24 volts, and the shielding gas flow rate to 15 - 25 liters per minute.
• Welding Skills: Start the arc at the tack welding position, use short-arc welding, keep the welding torch at an appropriate angle to the workpiece and move it evenly, observe the state of the molten pool, and avoid burning through the pipe wall. If a non-CO₂ gas shielded arc welding machine is used, heat the welding rod and press it tightly against the welding area, adjusting the angle and position appropriately.

Post-welding Treatment

• Cooling and Grinding: After welding is completed, let it cool naturally to room temperature. Use sandpaper to grind the welded area to remove excess welding material and uneven parts.
• Rust Prevention Treatment: Apply anti-rust primer to the weld and the surrounding area to lay the foundation for subsequent overall painting.

Reinstall the Chair

Turn the chair upside down, reinstall the disassembled parts, and tighten the screws with a screwdriver to ensure the chair structure is firm. If there are a large number of office chairs (such as 7 - 8), you can contact Weiodin (Tianjin) Welding Technology Co., Ltd. or Tianjin Yingyuan Welding Company for repair negotiations. If you do not have professional skills or experience, it is advisable to seek the help of professional maintenance personnel to ensure welding quality and safety. When operating, be sure to comply with safety regulations and operating procedures.