The Study On Plastic Deformation Technology And Microstructure And Mechanical Properties Of High-carbon Wire And It Product

In this paper,the drawing and spheroidize annealing processes of SWRH57EK SWRH72B SWRH82B high-carbon wire rod was studied.The deforming mechanism of pearlite and spheroidize annealing mechanism of pearlite at low temperature was deeply analyzed.The effect of chemical composition,deforming degree,heating temperature and holding time on cementite sphericity was investigated.The results of experimental shown that the cementite lamellae were deformed and thinned to a fibrous shape then the tensile strength of all the drawn wires increases continuously with increasing strain.Under the present experimental conditions,by control annealing parameters,good obtain annealing quality of wire was obtained.Fine and uniform cementite with spherical appearance distribute on the crystal boundary of equiaxed ferrite crystals.The size of spherical cementite particle is about 1 μ m and the size of ferrite grain is about 3 μ m.By annealing in non-oxidizing atmosphere cover anneal furnace,no oxideo-decarbonisation combining was observed on the surface of wire,which ensures the good mechanicalproperty of wire.The wire rolling proceeding and analyzing the deforming mechanism in rollinghigh-precision metal strip bar were studied. The experiential formula of width calculationwas regressed,which is It can be applied to practicalrolling of high-precision metal strip bar.On the basis of analyzing the microstructure, property and producing craftwork of oversea advanced card wires,SWRH72B and 70NbV high-carbon wire were choosed toproduce card wires. The result shows that the microstructure of the radular of SWRH72B card wire is fine needle-shape martemper and a few cementite particles(<3%) and the microstructure of root is spherical pearlite.The quenching microstructure of radular is evaluated as level 1 ,which is 765 HV;The microstructure of the radular of 70NbV card wire is also fine needle-shape martemper and a few cementite particles (10%)and the microstructure of root is spherical pearlite.But the micro-hardness of the radular of 70NbV card wire is 849HV,the microstructure as well as property is better than that of SWRH72B card wire.In addition,the microstructure and property of 70NbV card wire is as good as that of overseas,therefore,70NbVcard wire can be used as substitute for overseas advanced card wires.