Wetting Contact Angle

Physical-Chemical Mechanism of Action

The wetting angle is the geometric relationship between the molten solder and the base metal. It indicates how well the solder spreads toward the workpiece.

Metallurgical Relevance & Risks in Welding

A small wetting angle (less than 10°) means the solder penetrates well into the base metal, creating a homogeneous joint. A large angle (more than 20°) can lead to incomplete wetting, resulting in porosity and low strength.

Workshop Practice & Action Instructions

To achieve an optimal wetting angle of 10° to 20°, ensure correct solder feeding direction and proper solder flow. For finer materials or difficult-to-wet alloys, use a slower feeding speed and increase the heat input.