Orbital MAG Narrow Gap Welding

In practice, you can usually forget about magnetic fields – they don't really affect the weld. What matters is the joint cross-section: too narrow, and you get stress and cracks; too wide, and you dump in too much heat and material, the grain coarsens, and the weld becomes weak. Stick to the usual guidelines for joint preparation and adjust the heat input to the material. If you're unsure, make a test weld and check the structure.