Carbide Burr Low Temperature Aging Treatment To Improve Toughness
Carbide Burr In order to improve the performance of the mold, many manufacturers will be its mold for proper processing, mold processing refers to the molding and blanking tool processing, in addition to shear and die cutting die, but in many cases, Will also reflect the processing of defects, resulting in decreased mold performance, how to build mold processing defects? The following seven measures can be built mold defects.
1, a reasonable choice and dressing wheel
The use of white corundum wheel is better, its performance is hard and brittle, and easy to produce a new cutting edge, so the cutting force is small, grinding heat is small, the use of medium size particle size, such as 46 to 60 mesh better Grinding wheel hardness in the use of soft and soft (ZR1, ZR2 and R1, R2), that is coarse-grained, low hardness of the wheel, self-excitation can reduce the cutting heat. Fine grinding when the appropriate choice of grinding wheel is very important for high-molybdenum steel molybdenum high molybdenum situation, the choice of GD single crystal corundum grinding wheel is more suitable, when processing carbide,Carbide Burr quenching high hardness of the material, the preferred organic binder diamond Grinding wheel, organic binder grinding wheel self-grinding, grinding out the workpiece roughness up to Ra0.2μm, in recent years, with the application of new materials, CBN (cubic boron nitride) grinding wheel shows a very good processing effect, In the NC molding grinder, coordinate grinding machine, CNC internal and external grinder finishing, the effect is better than other types of grinding wheel. In the grinding process, we should pay attention to the timely repair of grinding wheel, to maintain the sharp wheel, when the wheel passivation, the workpiece surface will be wiped, squeeze, resulting in surface burns, strength reduction.
2, the rational use of cooling lubricants
Play the cooling, washing, lubrication of the three major role, keep the cooling lubrication clean, so as to control the grinding heat within the allowable range to prevent the workpiece thermal deformation. Improve the grinding conditions when grinding, such as the use of oil-immersed grinding wheel or internal cooling wheel and other measures. The cutting fluid into the center of the grinding wheel,Carbide Burr cutting fluid can be directly into the grinding area, play an effective cooling effect, to prevent the workpiece surface burns.
3, the heat treatment after the quenching stress to a minimum
Because of the quenching stress, the microstructure of the carbonized structure under the action of the grinding force, the organization produces a phase change which makes the workpiece crack easily. For high-precision molds in order to eliminate the residual stress of grinding, after grinding should be low-temperature aging treatment to improve toughness.
4, to eliminate the grinding stress
Mold can also be in the 260 ~ 315 ℃ salt bath for 1.5 min, and then cooled in 30 ℃ oil,Carbide Burr so that the hardness can be reduced 1HRC, residual stress decreased by 40% to 65%.
5, constant temperature grinding
For precision grinding of precision molds with dimensional tolerances within 0.01 mm, attention should be paid to the effects of ambient temperature, requiring constant temperature grinding. It can be seen from the calculation that 300mm long steel parts, the temperature difference of 3 ℃,Carbide Burr the material has about 10.8μm change, (10.8 = 1.2 × 3 × 3, per 100mm deformation of 1.2μm / ℃), the finishing process must be fully considered The influence of this factor.
6, the use of electrolytic grinding
Improve mold manufacturing accuracy and surface quality. Electrolytic grinding, the grinding wheel scrape off the oxide film: rather than grinding metal, grinding force is small, grinding heat is also small, will not produce grinding burr, cracks, burns and other phenomena,Carbide Burr the general surface roughness can be better than Ra0 .16μm; In addition, the grinding wheel grinding is small, such as grinding carbide, silicon carbide grinding wheel wear is about 400% to 600% of the weight of the cemented carbide grinding, grinding with grinding, grinding wheel wear Only the carbide grinding amount of 50% to 100%.
7, a reasonable choice of grinding
The use of radial feed less grinding method even fine grinding. Such as appropriate to reduce the radial feed and wheel speed, increase the axial feed,Carbide Burr so that the contact area between the wheel and the workpiece to reduce the cooling conditions are improved, so as to effectively control the surface temperature.