Office Chair Welding

Office chair welding requires a combination of process selection, operational specifications, and quality standards. The key points are as follows:

I. Common Welding Processes

1. Metal Active Gas Welding (MAG): Suitable for complex-structured office chairs, such as combinations of thin-walled steel tubes and thick connecting plates. Its advantages include moderate penetration, high deposition efficiency, uniform weld formation, and relatively low overall cost, gradually replacing traditional manual arc welding.
2. Arc Welding: Connects materials by melting the base metal with arc heat. It features simple equipment and flexible operation, suitable for metals like iron, steel, and stainless steel. However, it is prone to burning through thin walls or poor weld formation, requiring strict parameter control.
3. Gas Tungsten Arc Welding (TIG): Used for local repairs of exposed decorative parts, offering high weld purity but low deposition efficiency, suitable for precision welding of ultra-thin parts (e.g., below 0.5mm).

II. Material and Equipment Selection

1. Materials: The main structure commonly uses Q235 cold-rolled steel plates (thickness 1.5-3mm) and 20 seamless steel tubes (wall thickness 1.2-2.5mm), both low-carbon steels with stable welding performance.
2. Equipment: A digitally controlled MAG welding machine is recommended for the main welder, with auxiliary tools including angle grinders (for weld cleaning), E4303 welding electrodes (suitable for low-carbon steel), tape measures (for dimension measurement), and marking pens (for marking cutting points).

III. Welding Operation Key Points

1. Parameter Control: Adjust the current according to material thickness, such as 80-120A for square tube welding, ensuring continuous and full welds while avoiding defects like slag inclusions and porosity.
2. Safety Specifications: Clean rust and oil stains before welding, keeping the welding surface flat; wear protective masks and insulating gloves during operation, and work in a well-ventilated environment to prevent inhalation of harmful gases.
3. Quality Standards: The tensile strength of key load-bearing welds must be ≥380MPa; exposed welds should meet a "mirror-grade" standard, i.e., no undercut, no porosity, with a reinforcement height of 0.8-1.2mm and a width deviation of ≤0.5mm.

IV. Specific Steps (Taking Square Tube Welding as an Example)

1. Material Preparation: Select square tubes with a thickness of ≥1.5mm, cut and mark the cutting points after blanking.
2. Frame Assembly: Build the seat base, install chair legs, weld the backrest, and calibrate the perpendicularity and inclination angle.
3. Welding Fixation: Adopt a flat welding position, keep the electrode at a 30-45 degree angle to the welding surface, and lightly tap the weld slag after welding to check quality.
4. Post-Processing: Grind the weld protrusions and burrs, check the firmness of the welding points, and perform surface treatment as needed (such as applying anti-rust paint or spraying plastic).

V. Precautions

1. Avoid welding on wet ground to prevent electric shock; wait for the weld to cool completely before touching the finished product after welding.
2. Traditional manual arc welding is gradually being replaced by MAG welding due to its susceptibility to defects. New processes need to be combined with digital equipment to improve efficiency.