Evaluation of microstructure change and hot workability of high nickel high strength steel using wedge test

In the present paper, a new method is introduced for establishing the suitable hot working condition in order to attain desired microstructure without fracture by combination of simulation results and outcomes of limited forged wedge specimens. Two high nickel high strength steel grades were chosen for demonstrating the ability of new proposed technique even for high alloy materials. Numerical simulations and experimental hot forging of wedge specimens had been carried out at 950, 1100 and 1200 °C. At these temperatures, it became possible to relate the microstructural changes to deformation behavior by using combination of simulations and experimental results and as an example, critical strains for beginning of dynamic recrystallization had been defined. The plastic strains before appearance of surface fractures were also determined at temperatures of 1100 and 1200 °C. Comparison of strain at fracture position for hot deformed wedge specimens and tensile specimens at 1100 °C shows similarity of tensile strains at fracture.