Formation And Control Of The Burr Formed In Grind-hardening Machine

The grind-hardening is a new technology utilizing heat and mechanical composite effect toinduce martensitic phase transformation during grinding to quench the surface of steel directlywith a fast cooling. It is a green manufacturing and clean production mode which can replace theinduction quenching, the flame quenching, and the laser-quenching integrating surface heattreatment with surface finishing, and reducing the manufacturing procedures, the input of specialfacilities as well as workers of heat treatment and pollution resulted from heating treatment.With the surface grinding-hardening experiment as base and combined with grindingprinciple, this paper studied on the formation and control of the burr formed in grind-hardeningof65Mn steel and the main work and innovation points as follows:Firstly, it adopted single factor experiment, and studied on the morphology types of the burrand variation of the burr’size that formed on the both side of the specimen along the lengthdirection. The result shows that: there are four morphology types of burr under this experimentalcondition; the burr’size increased from the cut in region to cut out region in one pass grindingwith different grinding parameter, and it also gradually increased with the increasing of thedepth of cut or the decreasing of the table speed. The burr’size along the direction of length wasbasic same in two-passes grinding or three-passed grinding, but it increased with the increasingof grinding path number.Secondly, effects of depth of cut、table speed and grinding method on the burr’size alone thelength direction were studied with orthogonal test. The result shows that: in all factors whichaffect the burr’size, the depth of cut and grinding method are significant factors, but the tablespeed is non-significant factor. The sequence of significance is as follows: the depth of cut>grinding method>table speed. In this experiment, the minimum burr’size can be acquired whilethe depth of cut is0.2mm; the table speed is0.6m/min; the grinding method is one-pass downgrinding.Thirdly, effects of chamfering size on the burr’size that formed in grind-hardening werestudied with single factor and orthogonal test. The result shows that: with the increasing of thechamfering height or raising of the chamfering degree, the burr’size decrased accordingly.Meanwhile, the grinding parmeter、chamfering height are significant factors, and the chamferingdegree is non-significant factor. The sequence of significance is as follows: grinding parmeter> chamfering height> chamfering degree.Finally, in practical applications, the level combination should be chosen reasonableaccording to the requriment of grind-hardened layer’depth.