Effect of aging treatment on mechanical properties in ENiCrFe-7 weld overlay cladding materials

Effect of aging treatment (as-weld, 615 degrees C/16 h and 615 degrees C/64 h) on mechanical properties in Alloy ENiCrFe-7 weld overlay cladding materials was investigated. The estimation the relationship between small punch and tensile was carried out. The result indicated that more and more intergranular precipitates (Nb5Si3, Cr23C6, Cr3C2 and Cr7C3) and interdedritic precipitates (NbC) were found with increasing aging time. There was the highest ultimate tensile strength (sigma(ut)) or punch maximum load (F-max) for 615 degrees C/48 h Alloy, which resulted from the most intergranular precipitates and interdendritic precipitates. Residual stress played a major role on sigma(ut) or F-max transformation into those precipitates with increasing aging time. On the other hand, the tensile elongation (A) or the punch maximum displacement (d(m)) consistently increased with increasing aging time. The precipitation of NbC precipitates and the better homogeneity of chemical composition in the interdendritic region after aging treatment played a dominating role on the increase of elongation. The relationship between results of small punch and tensile test were ascertained as follows by the least-squares method: