• EFFECT OF CASE HARDENING PROCESS PARAMETERS OF ALLOY STEELS ON THEIR WEAR CHARACTERISTICS

    • EL-Hebeary, M.R.
    • EL-Sawy, E.E.T.
    • EL-Bahloul,A.M.M.
    Materials Science. Non-Equilibrium Phase Transformations., Vol. 4 (2018), Issue 2, pg(s) 59-62

    Cane chains are very important transmission elements which are carefully designed according to fatigue strength and wear resistance. To increase the life of cane chains, the resistance of the surface failure should be increased. In this investigation, experiments were carried out to evaluate the wear resistance using wear test rig designed and manufactured for this purpose. Three types of steels were used, namely 16MnCr5, 17CrNiMo6, and 18MnCrB5. Discs manufactured from these steels were carburized for different periods of time (6, 10, and 12 hours). Tempering process was carried out at different temperatures to obtain hardness values of 48, 52, and 56 HRC. The accumulated weight loss was measured and the wear rates were determined for each case hardened steel at the constant normal test load of 800 N. The accumulated weight loss was measured as a function of the number of revolutions. Wear rate was calculated and presented with case hardened depth and hardness for all steels. The hardness distribution and carbon content of carburized layer was presented as a function of the distance from the surface. Carburized layer microstructure and carbide percentage were presented and measured. From test results, it was concluded that the wear rate for all steels under investigation decreases with the increase of their case hardness. Minimum wear rate was obtained at hardness 56 HRC. Wear rate for all steels decreases with the increase of carburizing time tending to reach a minimum at carburizing time 10 hours. Wear rate for steel 16MnCr5 is less than that of the wear rate for 17CrNiMo6 and 18MnCrB5 by about 15℅ and 45℅ respectively under the same testing conditions. Carburized layer, carbon content and case depth increase with the increase of carburizing time.

  • STUDY OF PHASE TRANSFORMATIONS IN THE ROLLS OF ALLOY STEELS DURING QUENCHING BASED ON FINITE-ELEMENT MODEL

    Materials Science. Non-Equilibrium Phase Transformations., Vol. 3 (2017), Issue 4, pg(s) 154-157

    The studies are represented of phase and structure transformations during the process of multi-stage heat treatment of large-scale rolls. Adapted analytical models are introduced and applied to the calculation of phase transformations together with the finiteelement models of rolls. The results show phase components distribution over the hardened layer of rolls of the special alloy steels 50CrMnMoV and 45Cr3MnNiMoV at different stages of the manufacturing process.