Cause Analysis of Welding Deformation

Cause Analysis of Welding Deformation

During the welding process, the steel melts due to heat, and thermal expansion and contraction causes uneven shrinkage as the steel cools and contracts.

There are many factors that affect welding deformation, which can be summarized into three main categories: materials, structure, and process.

1. material 

This is primarily due to the physical properties of the material itself, particularly its thermal expansion coefficient, yield strength, and elastic modulus. Materials with a higher thermal expansion coefficient exhibit greater weld deformation, while an increase in elastic modulus reduces weld deformation. Conversely, materials with a higher yield strength result in higher residual stresses, leading to increased deformation. Stainless steel has a higher thermal expansion coefficient than carbon steel, so under the same thickness, stainless steel exhibits a greater tendency for weld deformation than carbon steel.

2. structure

The design of welded structures has the most significant impact on welding deformation. The general principle is that as restraint increases, residual welding stress increases, and welding deformation decreases accordingly.

3. welding process

The main influencing factors are welding methods, welding heat input (current and voltage), component positioning or fixing methods, welding sequence, and the use of welding fixtures. The most influential factor is the welding sequence.