Development Of C-Nb-Ni-Ti-B Reinforced Hardfacing Flux Cored Wire And Metal Coating Properties

It is an important means to improve the service life and recycle the old parts by surfacing welding technology,which can effectively avoid a considerable part of the economic losses caused by wear and tear,and it is more and more widely used in various fields of industry.The current domestic production of strong resistance to abrasive wear iron-based hardfacing flux-cored wire,mostly adopts surfacing metal alloy containing Cr type organization,its abrasion mechanism mainly through deposited metal of surfacing Cr3C2,Cr7C3,Cr23C6 chromium carbide organization and MC type carbide alloy compounds to improve wear resistance,because its matrix organization,especially in the organization a carbide organization bulky,the problem of welding wear-resisting layer is easy to crack,flake shock resistance is poor,easy to produce.In this paper,the research of the flux cored wire is carried out in the direction of the demand of wear resistance and impact resistance,and the type of filler metal powder of the flux cored wire is selected through the study of experimental materials.The flux-cored wire slag system of micro slag type was determined by the study and trial welding of various slag combinations.Using L16(45)orthogonal test design scheme,the filler metal powder of flux-cored wire was studied,and the gas-shielded wear-resistant surfacing wire with good performance was developed.Meanwhile,the influence of arc analysis on process performance was analyzed,and the standard parameters suitable for this kind of surfacing wire were developed.The developed gas protective surfacing flux cored wire is mainly used in wear resistant surfacing repair.It has the advantages of thin surfacing layer(surfacing layer 1-2 can achieve good performance),good wear resistance,impact resistance,long service life and so on.The developed gas-shielded wire has good surfacing property,thin slag on the weld bead,no slag removal is needed in the surfacing process,easy to use and good generality.The influence of powder composition and content on the performance of welding wire was obtained by orthogonal experiment.The results show that the impact resistance of wire will be reduced when the amount of graphite in filler metal powder of flux-cored wire exceeds 1%.The impact resistance of the surfacing metal is the best and it can meet the hardness requirement when the adding amount of niobium is 10%.The impact resistance of surfacing metal can be improved by adding more nickel powder.The content of boron carbide has the greatest influence on the impact resistance of the welding wire cladding metal.When the amount of boron carbide is 5%,the properties of the welding wire surfacing metal are more suitable.Developed wire amount accounts for 26.3%of the wire weight of alloy powder,design the micro Tony is suitable for welding wire,slag content is 5.2%,welding wire filling coefficient was 31.5%,wire diameter ?1.6 mm;The arc analysis test shows that the arc stability is better when the welding parameter(26-30)V/(260-320)A is welding with rich argon.When welding parameters(24-26)V/(230-250)A are used,the stability of arc parameters(U and I)has little difference when CO2 gas protection or argon rich protection is used.By welding wire cladding metal alloy analysis,it was determined that the surfacing alloy was C-Nb-NI-Ti-B series,and the alloy content was C:1.24,Nb:6.3,Ni:1.45,Ti:0.45,B:3.7.Development of flux cored wire cladding metal has a good application performance,test results show that the developed welding wire cladding of a layer of surfacing metal hardness HRC61.4,second cladding metal hardness HRC64.76,five floor cladding metal HRC68.0 hardness,the drug core wires cladding of same thickness of surfacing metal hardness than C-Cr-B strengthening flux-cored wire cladding metal high hardness;The wear resistance of the developed flux cored wire cladding metal cladding layer is 3.51 times that of the same specification C-Cr-B strengthened flux cored wire cladding metal cladding layer,and the impact resistance is 2 times that of the same specification C-Cr-B strengthened flux cored wire cladding metal cladding layer.The welding wire developed has been applied to the surfacing repair of the tool head of shield tunneling machine,and good results have been obtained.