UV 421 TT is an agglomerated fluoride basic flux for submerged arc welding of unalloyed and low alloyed steel grades. It has a high basicity and neutral metallurgical behaviour and is designed for medium and high strength fine grained structural steels. This flux finds its main application in welding shops as the multi-purpose flux to cover the widest range of applications in as welded and PWHT applications. It can be combined with many wire-grades types (solid and cored), supported by the widest collection of approvals. Suited for very good toughness properties and CTOD values in as welded condition and PWHT-condition. In general the flux gives a very nice bead appearance with very good slag release, even in narrow weld preparations.