Calor curatio A105 Fittings ASTM non est amet postulationem. Although there is an exception for flanges that have an ASTM A105 Fitting Pressure Rating above Class 300. These are flanges of special design, wherein both the design pressure or the design temperature are not known as well as for items over 4 inches NPS and above Class 300. Heat treatment is required, when methods such as normalizing, annealing, normalize and temper, normalize and quench and tempering must be applied.