The printed and heat-treated 1.2363 tool steel is effectively equivalent in hardness to the forge-hardened 1.2363 tool steel and can be heat-treated to increase hardness and durability. Markforged recommends heat-treating 1.2363 tool steel to optimize material properties, although it can also be used in the as-sintered state. Heat the 1.2363 tool steel part in a standard (non-vacuum) furnace to 970°C (1780°F). Hold the part at this temperature for 30-45 minutes. Then quench the part in air to below 65°C (150°F). Double-hardened 1.2363 tool steel part in a standard furnace. For each tempering, the part is heated to 150-550°C (302-1022°F) and tempered for 2 hours, or 1 hour per inch of thickness. Allow the part to cool to room temperature between heating cycles.