Within the Heat Affected Zone (HAZ) in a fusion welding

Within the Heat Affected Zone (HAZ) in a fusion welding process, the work material undergoes

1. micro structural changes but does not melt
2. neither melting nor micro structural changes
3. both melting and micro structural changes after solidification
4. melting and retains the original micro structure after solidification

Temperature is above the Recrystalization temperature due to which micro structural changes takes place