Effects Of Morphology, Structure And Material Coupling Elements On Rolling Contact Fatigue Wear Of Alloy Steel

Alloy steel rolling components, such as machine tool rolling tracks and train rails, appear surface stress concentration due to high frequency and repeated pressure under rolling contact condition. And it results in the pitting damage, which is attached to rolling contact fatigue wear.The failure of alloy steel components is complex problem caused by multi-factors. The studies of creature optimized properties and structures have shown that optimization of biology functions depends on the coupling of multiple elements. In this paper, the effects of morphology, structure and material coupling elements and their characteristics on rolling contact fatigue wear of alloy steel were discussed.By laser remelting processing, bionic units prepared on the surface of train rails alloy steel appeared grain refinement and greater dislocation density. The microhardness was enhanced significantly.Punctate, striation and grid units prepared on the surface of specimen by laser remelting processing. Cracks initiation could be delayed and propagation of cracks could be blocked, deflected and even stopped.Units prepared with a certain spacing distribution could be influenced on molding by neighboring units.Bionic units in different degrees were distributed on the surface of materials. The greater effective length support rate() of contact line mapped area, the more significant supporting role was played by units. It leads to a better fatigue wear resistance.Units in different depth sizes illustrated different maximum stress location. Within a certain range, the greater depths’ difference of units combination attributes to the more dispersed stress distribution when units in different depths are assembled on the surface of specimen alternatively. So that a better rolling contact fatigue wear resistance could be achieved. An oversized difference results in an unbalance bearing on one of adjacent units, which turn out to be an opposite effect.The surface strengthening treatment was applied for machine tool rolling tracks alloy steel and train rails alloy steel by laser remelting processing. Obvious improvements could both be performed on microhardness and rolling contact fatigue resistance.Laser carburized units were prepared on the surface of materials with carbon coating. Compared with remelted units, carburized units appeared a higher microhardness.The addition of bionic units could enhance yield strength and tensile strength. By the method, the time of crack initiation could be delayed, the working life was prolonged and the fatigue wear resistance was enhanced.The biomimetic coupling wearable model and the anti-wear mechanism were proposed. The model is constructed by “hard” unit and “soft” matrix, so that alternated hardness surface results in the uneven stress distribution. More stress was distributed on the units, while less stress was distributed in the matrix. Thus, wear resistance of material surface was enhanced.