There is serious adhesion of the grinding wheel during the grinding process of titanium rods, the grinding force and the grinding temperature are very high, so grinding burns and cracks occur briefly. When grinding titanium rods with ordinary abrasives, even if the grinding depth is small, grinding burns and cracks will occur on the grinding surface. It is roughly represented by yellow-brown spots and hairline cracks. Its direction is straight with the grinding direction. With large grinding amounts, there will be fish scale-like wrinkles and plastic deformation of metal deposits on the surface. What kind of substance is this? Let’s take a look at the grinding of titanium rods with silicon carbide abrasive particles to make the chemical reaction formula: SiC+Ti→TiC+Si. , And then look at the oxidation reaction of silicon carbide abrasive particles at a certain atmospheric temperature: SiC+2O2→SiO2+CO2.
Titanium rods have been widely used in domestic and foreign aerospace industries for their outstanding heat and corrosion resistance and particularly high specific strength. To align the grinding burn problems that are very simple in the grinding process of the titanium rod, select the leading test method to grind the grinding force, grinding temperature, workpiece surface roughness and surface tracing, surface layer metallography during the grinding process Arrangements and micro hardness changes were analyzed and discussed. The research results show that the TC6 titanium rod burns when the grinding temperature exceeds 600℃. Surface tracing gradually deteriorates with the increase of grinding temperature. When severe burns occur, cracks occur on the surface of the workpiece, and its direction is roughly straight with the grinding direction. When the workpiece is burned, the metallographic arrangement of the surface layer of the material changes, and the α-phase particles are significantly coarse, which reduces the physical and mechanical properties of the titanium rod. The research results provide theoretical and experimental basis for seeking an optimized, efficient and high-precision titanium rod grinding process.
During this period, part of the carbon atoms will be scattered towards the surface of the workpiece to be ground. Under the effect of sliding shear force, the SiO2 oxide film is peeled off, which constitutes the SiC abrasive wear and oxidation, and the surface of the workpiece leaves a scattered layer of oxygen and carbon elements The loss of carbon weakening layer occurs on the surface of the abrasive grains, the hardness of the SiC abrasive grains decreases, the grinding force increases, the grinding wheel wear increases, and the grinding temperature rise is inevitable. From the microscopic general, the process of abrasive particles and adhesion is that the cutting edge first appears small area of ​​adhesion and gradually large area of ​​adhesion, the abrasive particles are finely broken, then the abrasive particles are broken down and the plastic deformation occurs in the grinding area of ​​the titanium rod. The abrasive particles and the workpiece are bonded to each other, which has both physical and chemical adsorption effects. With the addition of relatively slipping shear forces, the processed material is transferred to the abrasive particles, which is the entire process of grinding wheel adhesion.
The adhesion of the grinding wheel is very simple to form a blockage, which raises the temperature of the grinding area, and the distributed grinding burns along the workpiece layer of the grinding surface, accompanied by the decay layer and residual stress. During the grinding cooling process, when the grinding depth is large, the density of the oxide film on the grinding surface reaches the critical temperature, and the temperature in the grinding arc area will rise sharply due to the film formation of the grinding fluid. The cooling effect Get worse. When the elevated temperature exceeds the limit of the usual abrasive, the abrasive particles will fall due to softening damage. Therefore, it is necessary to select a new type of super hard grinding wheel to further increase the high temperature tolerance of the grinding arc area.