The method of optimizing performance of a weld includes determining a set of specified mechanical properties, such as hardness or toughness for the weld, selecting a base metal material, selecting a welding process and welding process conditions, and selecting a weld metal material. The weld metal material and/or the base metal material may be selected by determining a characterization of the weld or base metal material, the characterization including performing a thermal-mechanical simulation of the metal materials and determining the properties of the metals produced by the thermal-mechanical simulation, and subsequently correlating the characterization of the metal materials with the set of specified mechanical properties and the welding process conditions. The method may also include producing said weld having said set of mechanical properties.