The Experimental Study About Laser Surface Strengthening Of M2High Speed Steel Gear Cutter

Laser quenching is a new technology which is researched earliest, most, progress the fastestand is used the most widely in laser heat treatment, and it is a major means of high energy surfacestrengthening technology. what’s more it is suitable for most materials and different position of thedifferent shape of parts, can increase wear resistance and fatigue strength of parts. Some foreignindustry officials consider this technology as a way to guarantee the quality of the product.However, in terms of gear cutting tools the achievements about laser surface heat treatment rarelybeen reported, different researchers hold different views about high speed steel’s laser quenchingmechanism, and even contradictory. So, the application research of laser surface strengthening forgear cutting tools and improveing the wear resistance and service life of high speed steel gearcutting tools have important theoretical significance and great practical value.This research use the W6Mo5Cr4V2gear shaper cutter which has been collapse edge or islimit to resharpening, finger gear milling cutter, involute spline broach, cylindrical milling cutterand commercially available white steel knife made into the sample to conduct laser scanning fusedquenching with a variety of different power, scanning speed and first tempering in570℃. Throughstudying the fused laser quenching process parameters influence the surface quality ofW6Mo5Cr4V2steel, forming quality, surface roughness and the influence of surface roughness toscreen and optimize a reasonable laser melting quenching process parameters. Studying withsingle-channel fused laser quenching influence on W6Mo5Cr4V2steel surface’s rockwell hardness,so as to determine the effect of surface strengthening.under different laser quenching processparameters Using microhardness meter measuring steel of W6Mo5Cr4V2surface laser heatinglayer’s microhardness, fitting hardness curve, and establishing the mathematical model haveprovided reliable basis for fine grinding allowance of all kinds of gear cutting tools. Using SEM andEDS of attachment to analysis of sample heating layer and explore the formation and changing ruleof microstructure of the layers in the process of fused laser quenching and tempering treatment.Specific results are as follows: (1) Through carrying laser melting quenching with different process parameters onW6Mo5Cr4V2steel getting different surface hardness, The secondary hardening effecthappened after a tempering and the sample surface rockwell hardness increased obviously thanthe original hardness Starting from the strengthening effect and process stability, we advise notonly with laser hardening to achieve the goal of strengthening(2) Under the reasonable laser process parameters, the sample surface roughness value Rystable between18~25, surface roughness parameter value Ra stable between1.7~2.9,It ishelpful to control the fine grinding allowance.(3)(3) The microstructure of the laser hardening and The secondary hardening M2highspeed steel of laser heating layer can be divided into five regions from outside to inside, namelythe fusion region, microfusion region, phase transformation hardening region, tempering softbelt, and inadequacy tempering region, And Each region present roughly concentric ringdistribution. From outside to inside five regions contain isometric crystal and dendrites, coarseisometric crystal and fine isometric crystal, Martensite and retained austenite and unmeltedcarbide, tempered sorbite, and slightly softening matrix organization after short tempering, andit has good corresponding relation with microhardness.(4)(4) The W2C, MoC, Cr23C6, Fe3W3C Fe4W2C carbide which come fromW6Mo5Cr4V2alloy steel’s Cr, W, Mo, V and carbon have high hardness, which separating outsporadically during tempering and producing the secondary hardening effect The fine-grainstrengthening effect is apparent in twigs crystal parts of top level fusion zone, Many carbide andoxide of Cr, Mo, W, V, which are generated in situ dispersively distributed and appearedmicrohardness peak, the ideal gear cutter blade should be located in this region.(5)(5) The reasonable fused quenching surface of gear cutter knife should be the rear faceand the lientang knife surface. The gear shaper cutter should adopt offset technology and controlgear shaper cutter rotating angular velocity when it suffer laser fused quenching, the gear hobadopt appropriately points beam spiral scanning This paper have corrected the offset of gearshaper cutter when it is suffering laser fused quenching.