COBEM99

S19 Usinagem dos Materiais

Title:

THE ANALYSE OF THE MICROSTRUCTURE OF MATERIALS GROUNDED USING CBN WHEELS

Summary :

THE CBN GRINDING WHEELS ARE SUPERABRASIVE TOOLS, WITH HIGHER CUTTING ABILITY THAN THE CONVENTIONAL ONES, SPECIALLY USED IN GRINDING OF DTG MATERIALS. DUE TO THE HIGHER HARDNESS AND THERMAL CONDUCTIVITY OF THE CBN SUPERABRASIVE S GRAINS, WHEN COMPARED WITH CONVENTIONAL ABRASIVE ONES, THE USE OF CBN TOOLS REDUCE THE GRINDING TEMPERATURES AND DECREASING THE PROBABILITY OF WORKIPECE S THERMAL DAMAGE. THESE PROPRIETIES OF CBN S GRAINS PERMIT LOWERING THE ENERGY PARTITION BECAUSE, LESS HEAT IS GENERATE DURING GRINDING AND MUCH MORE HEAT IS DISSIPATED THROUGH THE GRINDING WHEEL, INSTEAD OF THE WORKPIECE. THIS PAPER SHOWS A RESEARCH ABOUT THE MICROSTRUCTURAL CHANGES IN THE SUBSURFACE GROUNDED AND THE DIFFERENCES IN THE SUPERFICIAL INTEGRITY WHEN USING TWO TYPES OF SUPERABRASIVE GRINDING WHEELS, MANUFACTURED WITH VITRIFIED AND RESIN BONDS, ANALYZED IN DIFFERENT CUTTING CONDITIONS. THE MATERIAL GROUNDED WAS THE VC 131 STEEL, QUENCHED. IT WAS NOT OBSERVED MICROSTRUCTURAL CHANGES IN THE SUBSURFACE GROUNDED WITH THE TWO TYPES OF TOOLS, NEITHER BETWEEN THEM. AS A RESULT, THE USE OF DIFFERENT TYPES OF THE BOND DO NOT AFFECT THE SURFACE INTEGRITY NEITHER RESULTED IN MICROSTRUCTURAL CHANGES, BECAUSE THE MAXIMUM TEMPERATURES MEASURED IN THE GRINDING ZONE WERE LOWER THAN 125ºC, MUCH LESS THAN THE REQUIRED ONES TO MICROSTRUCTURAL CHANGES. KEY WORDS: MICROSTRUCTURE, CBN GRINDING WHEEL, RESIN BOND, VITRIFIED BOND, VC131 STEEL

Author :

Bianchi, Eduardo Carlos
Daré Neto, Luiz 0
Silva, Eraldo J. da
Valarelli, Ivan De Domenic

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