The analysis of layer of metamorphism of surface of the mould in line cut treatment
Mould of treatment of cut of electric spark line already was made in the mould in get applied extensively. However, certain and negative effect also can be caused to mould surface when line cut is machined, below the fast and cooling action of the instantaneous high temperature of online cut and working fluid, mould surface can form degenerative layer after longitudinal cut, make exterior hardness drops, arise show the malady such as micro-crack, affect the production quality of the mould and service life badly, should cause enough take seriously.
The formation of one metamorphism layer
Cut of electric spark line is the fuel factor that uses spark energy, make workpiece material fused, the treatment method that evaporate develops to ask to dimension. Because the working fluid of line cut collects appliance to have the liquid of interpose report effect more, it is certain to because this is in treatment process,return companion to have electroanalysis action. The fuel factor when cut and electroanalysis action, make machine the surface to produce the degenerative layer of certain ply normally, if surface layer hardness is reduced, appear show micro-crack to wait, the mould that causes line cut treatment is easy happen inchoate wear away, immediate impact mould dies easily to the maintenance that reduces gap and mould point blade, shortened the service life of the mould.
To carbolic steel, the fused layer of workpiece surface (degenerative layer affects a composition by fused and caky layer and heat) white appears on metallographic photograph, have become white layer. It and base metal differ completely, be one kind quench dendriticly coin an organization, the union with lining is very not firm also. It is main by martensite, many grain extremely fine leftover austenite and certain carbide are comprised.
The influencing factor of 2 metamorphism layer
1, the metallographic organization of workpiece material and elemental component because the discharge action of electric spark, make the metallographic organization of layer of workpiece material surface produced apparent change, form discontinuous. The degenerative layer with inhomogenous ply. Power source of it and workpiece material, electrode silk material, pulse and working fluid when parameter is concerned. Classics metallographic organizes an analysis, big austenite remained in degenerative layer. When silk of electrode of use molybdenum silk and fluid of the job that contain carbon, detect via spectral analysis and electronic bougie, inside degenerative layer, the content of molybdenum and carbolic element increases substantially; And silk of electrode of use copper silk and go when the working fluid of ionic water, discover content of element of the copper coin inside degenerative layer to increase, and without cementite phenomenon.
2, the ply of degenerative layer normally, the ply of degenerative layer along with the accretion of pulse energy thickening. Because of the random sex of process of electric spark discharge, in same treatment the condition falls, the ply of degenerative layer often is inhomogenous, the data of the degenerative layer thickness that measures from place of concerned test specimen makes clear, rule of line cut phone allows to have apparent effect to degenerative layer ply. For example: Electrode silk is brass silk, low speed walks along silk (0.6m/s) treatment voltage 60V, voltaic 5.5A, maximum of degenerative layer ply is 20 μ M, add on average for 13.8 μ M.
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