Solidification cracks:
Causes:
- Large depth/width ratio of weld bead
- High arc energy and/or preheat
- Sulphur, phosphorus or niobium pick-up from parent metal

Fig 1: Butt joint

Fig 2: Fillet joint
Solidification cracks:
Causes:

Fig 1: Butt joint

Fig 2: Fillet joint