炭素鋼圧接継手の組織とその機械的性質について

Abstract

It is previously known that the original weld interface of carbon steel pressure weld made in air or vacuum is apt to consist with the austenite grain boundaries at 1200°C and that this phenomenon is probably resulted from existence of micro-cavities on the original weld interface. It is the purpose of this study to clear the effect of microscopic causes in the weld interface, which constitute of the ununiform structure in pressure weld, on the mechanical properties of the pressure welded joints in carbon steel. The following results were obtained.1. The microscopic causes which impede the migration of austenite grain boundaries could not to be removal from the pressure weld by annealing. The cyclic-heat treatment between 1200°C and 500°C is a successful method for elimination of the ununiform micro-structure in pressure weld.2. It was found that the mechanical properties of the annealed joints of S1OC and S45C carbon steel pressure welds made at 1200°C for 5 min were just the same to those of parent metals, respectively. Therefore the microscopic causes on the weld interface, which retard the migration of grain boundary, does not always deteriorate on the mechanical properties of carbon steel pressure welded joints at room temperature.