Influence of cryogenic treatment on AISI H13 hot work die steels has been studied to correlate carbide density with surface roughness and dry sliding wear. This work includes hardening of AISI H13 specimens at 1020°C, oil quenching followed by double tempering at 500°C and then cryogenic treatment at −185°C for different cryosoaking periods from 8 to 32 h, followed by soft tempering at 100°C. The dry sliding wear behaviour on pin-on-disc has been studied for a load of 40 N at a speed of 3 m s −1 for the sliding distance of 6000 m. A model has been proposed to elaborate upon the effect of tertiary carbide precipitation on the improvement of surface roughness, followed by establishing quasi-stable wear mechanism and the interpretation obtained from the Avrami equation of kinetics. A logical correlation has been established between carbide density and surface roughness.

Cryogenic treatment could be useful in preventing AISI H13 steel forging dies from the premature failure that is continuously under the action of mechanical stresses and temperature. This work involves heating H13 steel specimens to 1020°C, quenching in oil followed by double tempering at 520°C for 2 h subsequently undergoing cryogenic treatment at minus185°C for cryosoaking periods starting from 8 to 32 h. Dry sliding wear tests were performed at room temperature on pin-on-disc wear testing machine at 40 N load, 3 m s -1 speed and 6000 m sliding distance. The hardness, carbide density, particle size measurements, and microstructural analysis were carried out. It has been established that reduced carbide particle size due to cryogenic treatment assists in minimizing material flow which was corroborated by decrease in the wear coefficient for H13 steel by 51% as compared to conventional treatment. This outcome was supported by the application of the equation of phase transformation.

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AISI H13 die steel specimens were subjected to heating at 1020 °C followed by oil quenching and double tempering at 520 °C. Subsequently, these specimens were subjected to deep cryogenic treatment at −185 °C in liquid nitrogen environment for 16 h and then subjected to soft tempering at 100 °C once the specimens attained room temperature. Thereafter, the specimens were subjected to scanning electron microscopy (SEM) analysis and electron backscatter diffraction (EBSD) analysis. The electrochemical corrosion activity was investigated in 3.5% NaCl at 23 ± 0.5 °C by evaluating the evolution of open circuit potential over time and potentiodynamic curves, and electrochemical impedance spectroscopy study was also carried out. The heat-treated specimens exhibited better resistance to corrosion through more electropositive values of open circuit potential. This could be attributed to lower grain boundary area in heat-treated specimens as compared to 16 h cryogenically treated specimen as higher grain boundary areas behave as an anode in an electrochemical cell, thereby enhancing the rate of corrosion. According to electrochemical tests, the cryogenically treated surface is more resistant to corrosion, followed by heated alloy. However, both surface modification treatments improved the corrosion behavior of the untreated alloy.

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