Research On The Preparation And Performance Of Coated Oblique Guillotine Tool

The application fields of metal sheet products are becoming more and more extensive,and increasingly stringent requirements have been put forward for the processing precision and material utilization of sheet metal products.The tool performance has a decisive influence on the quality of the metal sheet during the shearing process.In order to improve the friction and wear performance of the oblique guillotine tool and improve the wear-resistance,a coating treatment process scheme was proposed.The oblique guillotine tool were prepared and their shear properties were studied in depth.This paper reviews the performance characteristics and wear patterns of carbide shearing tools,and theoretically analyzes the stress of the oblique guillotine tool shears during the shearing process and the contact relationship with the sheets.On this basis,the coating structure of the oblique guillotine tool shears was designed.Two types of coated tools were prepared by using PVD arc ion plating process,and it use two coating materials of AlTiN and CrAlSiN.Scanning electron microscopy?SEM?,energy dispersive spectroscopy?EDS?and X-ray diffractometer?XRD?were used to observe and measure the structure and composition of the coating.Vickers microhardness tester and nanoindentation tester were used to test hardness of the coating.The micro-hardness and nano-hardness of the layer,and the use of scratch test to study the micro-mechanical properties of the coating and the bonding force with the substrate.The results show that AlTiN and CrAlSiN coatings can adhere well to the cemented carbide substrate,and the coating thickness reaches 3.32?m and 3.56?m,respectively.After coating,the hardness and toughness of the coating were significantly improved.The hardness of the AlTiN and CrAlSiN coatings reached 33.207 GPa and 30.631 GPa,respectively,which were 1.49 and1.37 times the hardness of the substrate.The bonding between the AlTiN coating and the substrate was very good,with a binding force of 57.38 N,while the CrAlSiN coating had a lower binding force of only 18.35 N.Three kinds of oblique guillotine tools shears?uncoated,Al TiN coating,CrAlSi N coating?were used to test the electrical steel sheet.The shear properties of the three kinds of oblique guillotine tools shears were compared.The results show that with the increase of the number of shearing,the shearing edge wear of the tool is gradually intensified.The shear quality of the electrical steel sheet becomes worse,the work hardening was increased,and the tool edge radius and the shear force gradually become larger,among which the AlTi N coated tool.The best wear resistance and shearing quality.When the shearing to 12000 times,the burr on the cross section of the electrical steel sheet sheared by the uncoated tool reaches26.65?m,while the burr on the sheared section of the AlTiN coating and CrAlSi N coated tool is 15.64?m and 18.11?m,respectively.The layer tools are 41.3%smaller and 32.1%smaller.The surface of the electrical steel sheet sheared by the uncoated tool is also the largest in work hardening.The maximum hardened value of the uncoated tool for the electrical steel sheets reached 321.15 HV_0.05,which is 8.4%greater than the 296.29HV_0.05.05 of the AlTiN coated tool,compared to 311.12HV_0.05.05 of the CrAlSiN coated tool is also 3.2%larger.The tribological performance test of the coated specimens was performed on a ball-disk friction wear tester,and the wear mechanism of the coated oblique guillotine tool was studied in-depth.The results show that the CrAlSiN coating shows a more wear-resistant state in the friction and wear test.However,due to the weak bonding force with the matrix,the CrAlSiN coating is prone to severe exfoliation during actual shearing.The uncoated oblique guillotine tool sheared to 12000 times and serious cobalt and oxidative wear occurred.The AlTiN coated tool effectively avoids the oxidative wear of the carbide substrate,with only a small amount of abrasive wear and wear resistance.The wear resistance of AlTiN coated tools has been greatly improved and the service life has been greatly extended.