Study on constitutive equation of alloy In718 in hammer forging process

Abstract

Effect of hot-deformation parameters of alloy In718 on the flow stress in the hammer forming process was analyzed in detail via axial compression testing of cylindrical specimens. All tests were conducted at a constant strain rate of 10s-1. The total strain of 0.7 was obtained by three consecutive passes or five. The deformation temperature ranged from 960°C to 1040°C. The interval time was 5s between any two consecutive passes. The complex multi-pass true stress-strain curves in the hammer forging process were reasonably simplified according to the unloading point of every pass, and the continuous stress-strain curves were obtained. The continuous simplified stress-strain curves approximately reflected the changing trends of multi-pass stress-strain curves. These continuous and simplified curves were described quantitatively in mathematics, and then constitutive equation reflecting the relationship between the flow stress and hot-deformation parameters was set up successfully.