The Research Of U75V Rail Surface Laser Strengthening

Railway transportation to its convenient and quick, efficient low-cost advantage hasbecome the most important one of the mode of transportation. With the development ofhigh-speed railway and freight railway load’s unceasing increase, Rail damage becomesmore and more serious and directly affect the safety of railway transportation, Soincreasing the hardness of the surface of the rail, and improve the service life of the rail tobecome the railway’s main research topics.Based on ANSYS software to U75V rail surface laser hardening numerical simulation,draw the following conclusion:1. In simulation of circular spot laser hardening, the spot radius, speed the sameconditions, the spot power substrate temperature is higher, the more uniform stressdistribution; In the spot radius, power under the same conditions, the faster the spot of thesubstrate temperature is lower, stress distribution is not uniform;2. In the simulation of multiple round spot and a rectangular spot reinforcement, itwas found that the rectangular spot reinforcement, matrix temperature field and stressfield of the distribution more uniform, so rectangular spot is the most ideal laser hardeninglight source;3. To rail for models to rectangular spot have lap and no lap two ways to simulate,calculate the substrate temperature field, stress field, found a lap of the spot than nooverlap of the spot that substrate temperature higher, the greater the stress influence area,high power without overlap of rectangular spot for U75V rail surface strengthening ideallight source.In order to validate the correctness of the theoretical analysis of U75V rail steel wascarried on by laser hardening experiment, in the laser hardening of the test, in spot speed,the radius of the same circumstances, the six different strengthening power has beenconducted, and found hardening layer surface melting zone, central phase transition zoneand matrix adjacent transition zone three part of the internal organization of small, allappeared acicular martensite, strengthen the hardness after for matrix3times of theoriginal hardness, hardening layer depth in1000μ m~1100μ m between, but in powerincreases to3000w later, with the rise of power hardening layer hardness presented downtrend. Experimental research surface, in the circular spot radius of2mm, speed of15mm/s, power is3000w, strengthen the best effect.