Office Chair Repair Welding
Office chair repair welding requires selecting the appropriate process based on the material and part, and strictly following operational specifications to ensure safety and quality.
Welding Process Selection
Office chairs commonly use Q235 cold-rolled steel plates (1.5-3mm thick) and 20 seamless steel pipes (wall thickness 1.2-2.5mm), both of which are low-carbon steels. The core process recommended is Metal Active Gas (MAG) welding: Using an 80% Ar + 20% COโ mixed gas shield, it provides moderate penetration (2-4mm), high deposition efficiency (5-8kg per hour), uniform weld formation, and a comprehensive cost that is more than 30% lower than Tungsten Inert Gas (TIG) welding, making it suitable for welding the main structures such as chair frames. As an auxiliary process, TIG welding can be selected: It offers excellent argon shielding and pure welds, but has low deposition efficiency (about 2kg per hour), making it only suitable for precision welding of ultra-thin parts (0.8-2mm, such as local repairs of exposed decorative parts).
Key Points for Welding Operations (Taking Square Tube Frames as an Example)
Preliminary Material Preparation
- Material Selection: Prioritize using galvanized square tubes or ordinary carbon steel square tubes with a thickness of โฅ1.5mm. For chair legs, select 20ร40mm tubes; for seat frames, use 30ร50mm tubes; and adjust the backrest frame according to needs.
- Tool Preparation: 220V household welding machines, angle grinders, E4303 welding electrodes (suitable for carbon steel), tape measures, marking pens, wire brushes, protective masks, insulating gloves, and non-slip welding tables.
- Cutting and Blanking: Cut the square tubes according to the design dimensions. The chair legs should be 40-45cm long, the seat frame should be 35-40cm long and 30-35cm wide, and the backrest frame can be made with a tilted arc and marked cutting points.
Frame Assembly and Positioning
- Seat Base: Weld four short square tubes into a rectangular frame and add 2-3 horizontal reinforcing ribs inside to enhance load-bearing capacity.
- Chair Leg Installation: Weld the chair legs vertically at the four corners of the seat frame and use a square ruler to calibrate the perpendicularity, ensuring that all four legs are of the same height.
- Backrest Welding: Bend the backrest square tube into an arc (or install a straight square tube at an angle) and weld it to the rear side of the seat frame, reserving a 10-15cm tilt angle to improve comfort.
Welding Operations
- Surface Treatment: Use a wire brush to clean rust and oil stains from the welding areas to ensure a flat contact surface.
- Welding Parameters: For flat welding positions, set the current to 80-120A (adjust according to the thickness of the square tube) and maintain a 30-45 degree angle between the electrode and the welding surface.
- Quality Inspection: The welds should be continuous and full, avoiding slag inclusions and porosity. After welding, gently tap the weld slag to inspect the quality, and always wear a protective mask and insulating gloves throughout the process.
Precautions for Welding Special Parts
If the weld point of an office chair wheel breaks:
- Remove the wheel: Use a wrench to take off the wheel and use pliers to clean dust and debris around the weld point.
- Welding repair: Use a welding torch to melt the welding wire and apply it to the weld point. After cooling, install the wheel and test whether it rotates smoothly and whether the weld point is firm.
Risks of Non-Professional Welding
After the base of a computer chair is welded open, non-professional repairs pose serious safety hazards: The high temperature of electric welding can burn the seal at the top of the gas spring, causing the plastic control switch to fail due to heat (such as automatically retracting when sat on), and even triggering an explosion of the gas spring, causing injury. It is recommended to contact professional repair personnel to replace the parts rather than attempting to weld them yourself.
