Study On The Impact Of Dressing Process On The Ground Surface Integrity Of 18CrNiMo7-6 Steel

Since the"Made in China 2025"was put forward,research on the extreme fatigue life of key components of high-end equipment has received extensive attention.Surface integrity is an evaluation standard proposed to weigh the surface and surface layer quality of the workpiece after processing,which has a profound impact on the anti-fatigue ability of the parts.Appropriate grinding process can obtain good surface integrity of the parts,extending the fatigue life of the part.However,during the process of grinding,the surface of the grinding wheel is prone to block and wear,which makes it lose grinding capacity and greatly reduces the integrity of the grinding surface.So,it is necessary to dress the grinding wheel timely.Studying the effect of wheel dressing on the integrity of the grinding surface is of great value for improving the extreme fatigue life of key parts.18Cr Ni Mo7-6 gear steel is widely used in manufacturing fields such as mining machinery and reducer gears due to its good mechanical properties and machinability.In order to make full use of the advantages of 18Cr Ni Mo7-6 gear steel and control its grinding surface integrity,three kinds of dressing tools are used to dress the grinding wheel,and the cylindrical grinding test is carried out to explore the effect of the dressing method and dressing parameters on the integrity of the grinding surface.The main contents of this project are as follows:Designing a diamond roller dressing device suitable for MKA1320 CNC cylindrical grinder;By the single-factor test,the effect of dressing parameter changes of sintered diamond rollers,electroplated diamond rollers,single-particle diamond pen on the grounding surface integrity?mainly three-dimensional surface roughness,residual stress,residual stress distribution?were studied;According to the differences in the manufacturing process and the dressing mechanism of the two kinds of diamond rollers,the differences in grinding quality were analyzed;By the three-factor four-level orthogonal experiments,the primary and secondary dressing parameters that affecting the residual stress were studied,and the optimal dressing parameter combination was obtained.The research results show that:?1?When using diamond roller to dress the grinding wheel,as the increase of dressing depth,axial feed rate,dressing speed ratio,the grinding capacity of the grinding wheel is enhanced,and it is easier to get larger residual compressive stress.Three-dimensional roughness parameters S_a,S_q,S_kuincrease,S_sk decreases,and the surface quality deteriorates.?2?When using single-particle diamond pen to dress the grinding wheel,as dressing depth increases,S_a,S_q,S_ku decrease first and then increase,S_sk increases first and then decreases;As axial feed rate increases,S_a,S_q,S_ku gradually increase,S_sk increases first and then decreases;With the increase of dressing depth and axial feed rate,the residual tensile stress on the surface decreases and gradually converts to compressive stress.?3?Compared with sintered diamond roller,the grinding wheel dressing by electroplated diamond roller have stronger grinding ability,and it is easier to form residual compressive stress on the grinding surface,but the grinding surface roughness value is also higher.?4?When using the sintered diamond roller to dress the grinding wheel and the optimization goal is to obtain the maximum residual compressive stress,the best dressing parameter combination is:dressing depth 0.006 mm,axial feed rate 0.6m/min,dressing speed ratio 0.8.At this time,the circumferential residual compressive stress value reached-310 MPa.