Gap misalignment
Gap misalignment is an uneven gap width in a weld joint, leading to uncontrolled penetration and varying heat input. Makes it difficult to maintain constant weld properties.
Physicochemical mechanism of action
Gap misalignment occurs due to uneven pressure distribution or thermal expansion during the welding process. This leads to varying joint thickness and thus variable penetration rates and heat input.
Metallurgical relevance & welding risks
Gap misalignment can lead to uneven cooling of the weld, resulting in different microstructure and hardness distribution. This increases the susceptibility to cracking and reduces the toughness of the weld. Additionally, it can cause uncontrolled penetration and thus uneven material loss.
Shop practice & procedures
To minimize gap misalignment, the following measures should be taken:
• Pressure control: Ensure that the pressure is evenly distributed over the entire weld length.
• Thermal control: Use a controlled cooling procedure to minimize thermal expansion differences.
• Material selection: Choose materials with low coefficients of thermal expansion or use backing materials that reduce the thermal stress pattern.