Office Chair Welding

The welding of office chairs involves various processes and precautions, as detailed below:

Welding of some office chair support rods and bottom rods: In modern office chair design, the bottom support rods need to be welded to the bottom rods to ensure the stability of the seat cushion. During welding, the support rods should first be spread apart to both sides, utilizing their flexibility to facilitate the welding of the bottom rods. This process usually requires two people to cooperate, with one person spreading the support rods and the other welding the bottom rods. If the support rods are difficult to spread apart, auxiliary tools such as clamps or rod spreaders can be used. During the welding process, heat and harmful gases are generated, so workers must wear protective equipment such as gloves and goggles and ensure good ventilation in the welding environment.

Welding of bench chairs:

• Material and heat effects: The metal frames of bench chairs are mostly made of low-carbon steel or stainless steel. During welding, the local high temperature can reach over 1500 degrees Celsius, which can change the internal lattice arrangement of the metal and form a "heat-affected zone". If the heat-affected zone is too large, stress concentration is likely to occur near the weld, leading to cracks.
• Process parameters: The welding current intensity and speed determine the "heat input" value. Excessive heat input can result in excessive weld penetration, metal overheating, and deformation after cooling; insufficient heat input can lead to incomplete fusion, potentially forming unfused areas or pores. Bench chair welding usually adopts medium heat input, combined with multi-layer and multi-pass welding to control heat accumulation.
• Weld leg size: The connection between the chair legs and the crossbeam is mostly a fillet weld, and the weld leg size needs to be determined according to stress calculations. A size that is too small lacks sufficient strength, while a size that is too large increases heat input and the risk of deformation. The standard practice is to take 0.7 to 1.0 times the thickness of the thinner plate as the weld leg height.
• Welding sequence: The frames of bench chairs are mostly symmetrical structures. Welding should be carried out symmetrically from the middle to both ends or using the skip welding method to make the deformation uniform. Some factories also perform overall heat treatment (annealing) after welding to eliminate residual stress and restore metal toughness.
• Surface treatment: After welding, the weld slag and spatter on the weld surface need to be cleaned; otherwise, they can damage the coating adhesion and lead to rust. The welded area usually needs to be ground to a surface roughness of Ra3.2 micrometers or less before applying an anti-corrosion coating.