Effect of warm deformation parameters on hardness and microstructure of AISI 1020 low carbon steel for near-net shape forging

Abstract

This research aims to present a concept for altering a metal manufacturing process from cold to warm forging thereby reducing unnecessary steps and energy consumption. This will lower costs and increase production profits. The study explores the impact of warm forging process parameters on the hardness and microstructure of low-carbon steel for near-net-shape forging in more than two continuous stages. The material used in this experiment is annealed AISI 1020 carbon steel with chemical additions of 0.01% Ni, 0.03% Cr, and 0.044% Al. The study procedure involves: (i) heating slugs with a height-to-diameter ratio (ho/do) of 2.07 to a temperature range of 200–700  and soaking them for 1 hour. The grain size noticeably increases at temperatures above 500 °C. (ii) The materials were forged at six different temperatures from 200 to 700  with both hardness and microstructure examined at each stage. This was done to determine the recrystallization temperature. The experimental results showed that recrystallization begins at 500  in a warm forging process and becomes more pronounced at 600 to 700 °C. The lowest average hardness value in the transverse direction (TD) occurs at 500 to 700 °C. This suggests that the suitable warm working temperature range should be below 500 °C, as the primary microstructure in the forging process has not yet undergone recrystallization. Our research provides valuable insights for manufacturers aiming to transition from cold to warm forging, emphasizing the importance of precise control over deformation parameters to achieve desired material properties.