Influence Of Laser Alloying Bionic Unit With WC/Cr On Fatigue Wear Resistance Of Gray Iron

The machine is widely used in industry today.The machine guide way suffered major rolling fatigue wearing in the course of wearing and tearing. Rolling fatigue wear is defined as A reciprocating by the cycle contact stress acting on the surface of the material produced a failure mode in rolling contact fatigue conditions.Thus, anti-fatigue and wear properties of fatigue life in contact with the surface of machine guide way related.during machine guide way services, because of fatigue defects in the process of wearing and fatigue which affects machining precision and will scrap devices. Inconspicuous fatigue cracks will beproduce inside the machine and expand in fatigue wear processing, which will have a huge safety risk.Using inlaid steel rails way to solve this problem traditionally, Inlaid steel rails as in gray cast iron bed inlaid steel as work contact surface. The advantage is having good mechanical damping performance while reducing the surface fatigue defects.Inlaid steel rails improve the service life of gray cast iron of machine guide way, while the effect of improving their resistance to fatigue and wear performance is limited.Previous studies showed that the surface treatment for Gray cast iron machine bed can be very effective way to enhance the wear resistance of the material.However, machine guide way in this manner has poor binding effect between the strengthening layer and the substrate, and can not be solved due to the presence of graphite adverse effects caused by the formation of fatigue defects.Therefore, the need for a new approach to improve the gray cast iron machine guide at the contact conditions in service of rolling fatigue fatigue fatigue and wear properties and to understand the mechanism of defect formation,which guide the production and processing of safety is important.The study found that the nature of the biological evolution through natural,can be well adapted to the natural environment.This indicates that there is good biological resistance and ability to adapt to the natural environment.Based on this thinking, selecting nature biological prototype of a good anti-wear,On this basis, the use of bionic coupling principle.Using laser alloying and laser remelting technology, gray cast iron WC or Cr added Fe-based treatment, study its anti-fatigue properties.The following conclusions:(1)Add a single WC or Cr alloy elements can improve the fatigue strength and wear resistance, While its hardness,toughness and tensile properties were significantly improved. at the same time adding two elements can improve the effectiveness of its maximum.(2)It reveals the strengthening mechanism for adding different alloying elements formed:Cr presence of crystals(Ar, α-Fe) and have a skeleton network structure strengthening effect, but only the W skeleton network structure from strengthening.Laser alloying WC + Cr + Fe alloy powder when the material has the highest tensile strength, because the W element on the basis of Cr element and the crystal grain boundary strengthening, and further strengthening of the grain boundaries.By stretching the sample understand laser treatment is effective to improve the toughness and tensile strength of the material.(3)By comparing samples of different wear results found:Compared to the untreated sample, treated samples(base and unit body) fatigue defects produced significantly lighter.Bionic laser treated samples of strengthening mechanism of initiation and propagation of cracks restrictions:Due to the presence of dissolved graphite regions, crack initiation limit; due to the presence of the unit body,it is causing the pressure to reduce the matrix, thus increasing the crack initiation cycle and improving the wear resistance.First, crack propagation is extended hybrid mode of intergranular and transgranular. Because grain refinement and cracks frequently shift, this leads to reduced driving energy, limiting crackpropagation.Secondly, since the surface of the unit body is divided into several regions, the unit body will hinder cracks appear in the various regions, and connecting the longer cracks formed In macroscopic.Making more serious surface damage is suppressed.(4)Laser processing technique described bionic specimen fatigue wear failure modes and mechanisms. Failure mainly in the form of crack initiation and propagation,peeling formation of pits, pitting and big black pit.Analysis of crack initiation and propagation mechanism, the mechanism of pits, pitting and big black hole generated analysis.It pointed out that the pits, pitting and big black hole formed in the process of rolling fatigue wear was impacted by hardening,adhesion phenomena and the second phase of the existence.It noted pits, pitting the big black hole produced on different mechanisms.