Study on applicability of temper bead repair welding in bottom-mounted instrumentation using bead formation - temperature field - hardness prediction model

Abstract

To rationalize the evaluation process of temper bead repair welding, a numerical model that can predict hardness during repair welding was developed by combining a coupled bead shape-heat conduction analysis model with a hardness prediction model based on many experimental results. To confirm the usefulness of the developed model, bead-on-plate welding was performed experimentally and numerically to compare the measured and calculated distribution of hardness. As a result, measured and calculated hardness were in good agreement. In addition, the developed model was applied to temper bead repair process for a bottom-mounted instrumentation, and the appropriate welding conditions for reducing the hardness of the repair welded zone were discussed. Numerical results revealed buttering and small heat input could be effective to reduction of hardness for temper bead welding. Since these results was consistent with previous findings, the developed model was found to be applicable to the temper bead welding and it enables quantitative evaluation of hardness according to temper bead repair welding conditions.