Spatial Distribution of Manganese, Silicon, Chromium and Oxygen in Submerged-Arc Weld Deposits

摘要

Submerged-arc deposits prepared under acid types of fluxes were examined with regard to their content of silicon, manganese, oxygen and nitrogen. It was found that silicon and oxygen are transferred from the slag to the metal, the amounts picked up depending on the welding conditions. The final concentrations of Si and O are related to the contents of FeO and SiO2 in the slag in a manner corresponding to chemical equilibrium at temperatures between 1850 and 2050C. In the tested combination of unalloyed flux and a wire containing 2% Mn this element was transferred to the slag. This reaction did not proceed to the state of pseudoequilibrium as those involving silicon and oxygen. Incompleteness of reaction in the high-temperature stage was believed to be mainly responsible for lowered manganese contents in a zone 0.5 to 1.5 mm from the bead surface. A similar gradient of opposite sign was observed when chromium was being transferred to the metal phase from an alloyed flux. It was concluded that the amount of matter transferred across the metal/slag phase boundary was the main controlling factor both with regard to the concentrations established in the high-temperature stage and in the subsequent formation of concentration gradients at the metal/slag interface. (Author)