Weld Solidification Interval

The solidification interval is the range between liquidus and solidus temperature, where the material is still partly liquid and partly solid during cooling. Depending on how wide or narrow this interval is, the structure can turn out differently. If the interval is too long, it promotes segregation and makes the weld metal susceptible to hot cracking. In practice, it's important that the weld metal doesn't cool too quickly. You have to control the heat dissipation so that the structure can build up evenly and no critical stresses arise. If you control the cooling, you avoid typical cracks and get a clean, durable weld.