Lack of side wall fusion
Lack of fusion at the weld toe (lack of sidewall fusion) occurs when the base material isn't melted enough at the weld toe, caused by too low heat input or wrong torch handling. This significantly reduces the effective cross-section.
Physical-chemical mechanism
Lack of sidewall fusion happens when the base material doesn't melt completely at the weld toe. This can be caused by too low heat input or wrong torch handling. The unmelted metal forms a thin layer on the toe, which weakens the mechanical bond between the parts.
Metallurgical relevance & welding risks
Lack of sidewall fusion significantly reduces the load-bearing cross-section and can lead to cracks or fractures. It also causes poor mechanical bonding between the parts, affecting the overall strength of the weld. In severe cases, it can lead to total failure of the component.
Workshop practice & actions to take
To avoid lack of sidewall fusion, make sure you use enough heat input and correct torch handling. Set the heat input so the base material melts completely. A hot torch and a short arc can help improve melting. Also, make sure the workpiece is properly positioned and there are no obstacles interfering with the melting.