| With the vigorous development of nuclear power in China,in order to ensure the stable and sustainable development of nuclear power,it is not only necessary to cut and sample nuclear fuel rods or metal parts of nuclear facilities in the hot cell,but also necessary to cut them in the process of dismantling nuclear power decommissioning and smelting radioactive scrap metal.In order to reduce the workload of replacing the circular saw blade used for horizontal milling machines by remote operation in the hot cell,reduce the cost of cleaning and controlling scrapped tools,and reduce the impact of the cutting process of metal smelting on the environment,it is urgent to increase the cutting of radioactive polluted metal tools life.The tests of laser transformation hardening+560?tempering and melting quenching+560?tempering with different power were carried out on one side of high-speed steel circular saw blade,The results show that laser melting quenching can increase the surface hardness of high-speed steel circular saw blades,laser transformation hardening will reduce its surface hardness,and 560?tempering will reduce the surface hardness of laser processing circular saw blades.Based on the single-sided laser tests,double-sided laser melting quenching circular saw blades were prepared,and its microstructure was studied using scanning electron microscope?SEM?and energy disperse spectroscopy?EDS?.The surface hardness of the hardened circular saw blade with 140w laser power is the highest,which can reach 69.7HRC after grinding;The laser melting quenching layer can be divided into melting zone,micro-melting zone,transformation hardening zone and tempered soft zone,among which the transformation hardening zone has the highest microhardness.Dry cut 316L stainless steel pipe test on W6Mo5Cr4V2?M2?ordinary circular saw blade,TiN-coated circular saw blade,nitrided circular saw blade and self-made laser melting quenching circular saw blade with spindle speed 190r/min and longitudinal feed 160mm/min.As a result,the durability of the nitrided circular saw blade is the best,followed by the TiN-coated circular saw blade,although the surface hardness of laser melting quenching circular saw blades increases,the cutting performance decreases.Through SEM and EDS,the cross-sectional morphology and element composition of the circular saw blade before and after wear were compared and analyzed,and the dry cutting wear mechanism of TiN coated circular saw blade,nitrided circular saw blade and laser melting quenching circular saw blade was expounded.The paper discusses the adaptability of four kinds of circular saw blades for high speed dry cutting 316L stainless steel,and explains the reason why the hot cell is not suitable for the use of carbide tool and diamond wheel as dry cutting tools.Based on the three-factor three-level orthogonal test,the cutting parameters of the nitriding circular saw blade for dry cutting 316L stainless steel are optimized.Through the inspection of tool surface wear and workpiece surface roughness,the results show that the cutting parameters with the highest tool durability are:cutting speed 55.6m/min,feed speed 95mm/min,milling cutter thickness 1.5mm.Based on the multiple linear regression theory,the durability formula of the nitriding circular saw blade is calculated,which provides a reference for the recycling industry of nuclear contaminated metal. |
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