• 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.

  • METALLOGRAPHIC INVESTIGATION OF INDUCTION HARDENED PART TWO-SIDE LEVER

    Materials Science. Non-Equilibrium Phase Transformations., Vol. 1 (2015), Issue 2, pg(s) 17-21

    Basic idea in this metallographic investigation is checking the effect of induction (surface) quenching of produced part, two-side lever made of 42CrMo4 steel. This part is build in railway wagon. According its production assignation it has to be surface hardened just in some positions. Formerly surface hardness of this part was realized by chemical-heat treatment i.e. case hardening of 16MnCr5 steel. But because of specific form of the part and increased britlness which appear in the thinnest parts of lever (between the rounded opening and the surface) and idea was obtained to change the case hardening with induction quenching. Efficiency of performed induction quenching i.e. hardness values and depth of quenched layer was controlled by optical microscopy and hardness measurement.