Masahiko Hamada

Modeling of the deoxidization process on submerged arc weld metals

AbstractFixed welding tests were performed to investigate deoxidization during submerged arc welding and to develop a model for it. For all the chemical compositions of the fluxes used, the oxygen content of the weld metal decreased with increasing arcing time in the initial stage of welding. The oxygen content of the weld metal eventually became constant; this is assumed to be a quasi-equilibrium state. Both the rate of reduction of the weld metal oxygen content and the oxygen content of the quasi-equilibrium condition depend on the chemical composition of flux. The weld metal oxygen content in the quasi-equilibrium condition can be estimated thermodynamically. In addition, the rate of reduction of the weld metal oxygen content satisfies the following equation.1O=exp−k⋅t+lnOi−Oe+Oe

Bend pipe and process for producing the same

\left[O\right]= \exp \left[-k\cdot t+ \ln \left({\left[\mathrm{O}\right]}_{\mathrm{i}}-{\left[\mathrm{O}\right]}_{\mathrm{e}}\right)\right]+{\left[\mathrm{O}\right]}_e

DUPLEX STAINLESS STEEL AND PRODUCTION METHOD THEREFOR

Where [O] is the weld metal oxygen content at arcing time t, [O]e is the oxygen content in the quasi-equilibrium state, [O]i is the oxygen content immediately after starting welding, and t is the arcing time. We found that the coefficient k decreases with increasing viscosity of the molten slag, which mainly depends on the chemical composition of the flux. Based on these results, we found that deoxidization in weld metal during submerged arc welding can be predicted by estimating [O]e and k and briefly determining [O]i.