Nature Inspired Thermomechanical Treatment to Investigate the Mechanical Properties of AISI 1040

Abstract

Strengthening of metals as a function of metal working and thermal treatment is being utilized effectively in steel structures. Effect on strength beyond thermomechanical treatment has been the focus of this research by imprinting a nature inspired pattern on one side of the sheet metal. Pangolin scale pattern overlapped on AISI 1040 sheet metal while preserving its base treatment. Microstructure, impact toughness, hardness, and tensile strength with notch opposite to worked side was investigated after forging and post forging heat-treatment. After heating at 800°C, overlapping patterned forging was done on one side of two plates and then subsequently cooled in two ways, air cooled, and water quenched. To analyze the effect of forging and heat treatment, Charpy impact, UTS, hardness tests, and metallography were carried out on the heat treated (forged + quenched), untreated (forged + air cooled) and base (as received) specimens. The Room temperature Charpy test showed that the untreated specimen has the highest impact toughness of 120 J as that of the base and heat-treated specimen, 44 J and 60 J respectively. The heat-treated specimen showed an increase in macro and micro hardness than for the base and untreated specimens. Whereas the UTS has dropped in untreated and heat-treated specimens as compared to the base specimen, because in tensile test load is applied uniformly throughout the specimen so the stress concentrations in the unforged side of the metal higher than the side which is forged with overlapping patterns.