Fusion welding processes -- Heat flow in welding -- Chemical reactions in welding -- Fluid flow and metal evaporation in welding -- Residual stresses, distortion, and fatigue -- Basic solidification concepts -- Weld metal solidification I: grain structure -- Weld metal solidification II: microstructure within grains -- Post-solidification phase transformations -- Weld metal chemical inhomogeneities -- Weld metal solidification cracking -- Formation of the partially melted zone -- Difficulties associated with the partially melted zone -- Work-hardened materials -- Precipitation-hardening materials I: aluminum alloys -- Precipitation-hardening materials II: nickel-base alloys -- Transformation-hardening materials: carbon and alloy steels -- Corrosion-resistant materials: stainless steels