Based on laser-scanned measuring technology, a met ho d of on-line dynamic non-contact measurement and feedback control of processin g dimension, i.e. the double edges laser-scanned large diameter on-line dynami c mea...Based on laser-scanned measuring technology, a met ho d of on-line dynamic non-contact measurement and feedback control of processin g dimension, i.e. the double edges laser-scanned large diameter on-line dynami c measurement and control system is presented, which can be used to measure diam eter in large-scale machine part processing. In this paper, the working princip le, overall structure and microcomputer real-time control and data processing s ystem of the system are discussed in detail, the method of double edges scanned large diameter dimension measurement and control is theoretically analyzed, its possibility has been verified by experiments of lathing large diameters machine parts by a vertical lathe. The system adopts the measuring scheme of double edge s laser-scanned combined with grating displacement measurement. The two edges c haracteristic information of the measured diameter is given by the double edges laser-scanned measuring system, the non-contact measurement of large diameter dimension is realized to combine with the grating displacement measuring systems . The main controller gives out feedback control signal by means of measured res ults, and controls advance and retreat of lathe tool by the servo-control syste m of a vertical lathe to realize on-line dynamic non-contact measurement and c ontrol in processing.展开更多
The Mg-2Zn-1.5Mn alloy(ZM21)sheets were hot-rolled in a single pass at 150℃with different reductions through on-line heating rolling.Microstructures and edge cracking behavior of the rolled sheets were investigated.T...The Mg-2Zn-1.5Mn alloy(ZM21)sheets were hot-rolled in a single pass at 150℃with different reductions through on-line heating rolling.Microstructures and edge cracking behavior of the rolled sheets were investigated.The in-situ tensile tests at 150℃were also carried out,the crack initiation and propagation were compared with the edge cracking behavior of ZM21 sheets prepared by on-line heating rolling.The results reveal that the edge cracks are most likely to originate in the rolling direction and normal direction(RD-ND)plane due to the secondary tensile stress along RD.Edge cracking becomes more severe with an increasing reduction.The edge cracks mainly initiate and propagate in the fine recrystallized grain areas and the junction of recrystallized grains and sub-grains with hard orientation.The in-situ tensile test indicates that micro-cracks mainly initiate at the triple junction of grain boundaries where grains have hard orientation with low basal Schmid factor(SF).Meanwhile,those cracks are more likely to propagate along the grain boundaries with maximum difference in basal Schmid factor.Besides,the crack initiation and propagation during the in-situ tensile deformation at 150℃are found not to be associated with the recrystallization.展开更多
文摘Based on laser-scanned measuring technology, a met ho d of on-line dynamic non-contact measurement and feedback control of processin g dimension, i.e. the double edges laser-scanned large diameter on-line dynami c measurement and control system is presented, which can be used to measure diam eter in large-scale machine part processing. In this paper, the working princip le, overall structure and microcomputer real-time control and data processing s ystem of the system are discussed in detail, the method of double edges scanned large diameter dimension measurement and control is theoretically analyzed, its possibility has been verified by experiments of lathing large diameters machine parts by a vertical lathe. The system adopts the measuring scheme of double edge s laser-scanned combined with grating displacement measurement. The two edges c haracteristic information of the measured diameter is given by the double edges laser-scanned measuring system, the non-contact measurement of large diameter dimension is realized to combine with the grating displacement measuring systems . The main controller gives out feedback control signal by means of measured res ults, and controls advance and retreat of lathe tool by the servo-control syste m of a vertical lathe to realize on-line dynamic non-contact measurement and c ontrol in processing.
基金financially supported by the National Natural Science Foundation of China(No.52071036,U2037601)the Fundamental Research Funds for the Central Universities Project(2020CDJQY-A002,2021CDJCGJ009)。
文摘The Mg-2Zn-1.5Mn alloy(ZM21)sheets were hot-rolled in a single pass at 150℃with different reductions through on-line heating rolling.Microstructures and edge cracking behavior of the rolled sheets were investigated.The in-situ tensile tests at 150℃were also carried out,the crack initiation and propagation were compared with the edge cracking behavior of ZM21 sheets prepared by on-line heating rolling.The results reveal that the edge cracks are most likely to originate in the rolling direction and normal direction(RD-ND)plane due to the secondary tensile stress along RD.Edge cracking becomes more severe with an increasing reduction.The edge cracks mainly initiate and propagate in the fine recrystallized grain areas and the junction of recrystallized grains and sub-grains with hard orientation.The in-situ tensile test indicates that micro-cracks mainly initiate at the triple junction of grain boundaries where grains have hard orientation with low basal Schmid factor(SF).Meanwhile,those cracks are more likely to propagate along the grain boundaries with maximum difference in basal Schmid factor.Besides,the crack initiation and propagation during the in-situ tensile deformation at 150℃are found not to be associated with the recrystallization.
