Study On The Composite Strengthening Of Flux Cored Wire Of Austenitic Stainless Steel By Boride And Nitride

Due to the rapid development of modern industry,manufacturing industry ushers in the era of industry 4.0,and more and more energy is consumed due to wear and corrosion.In order to achieve the goal of environmental protection and energy saving,new and excellent surfacing materials have received extensive attention.By adding nitride and boride to stainless steel flux cored wire,a new type of wear-resistant and corrosion-resistant surfacing material is prepared,and the stainless steel surfacing alloy is prepared by metal inert gas welding,so that its performance can reach the performance of Fe1 alloy powder,which is of great significance to improve the repair efficiency of valves and other parts.By testing the microstructure,properties and phase evolution of surfacing layer of stainless steel flux cored wire with different boride and nitride additions,the action mechanism of boron and nitrogen was clarified(1)Whether boron or nitrogen is added,the matrix of cladding metal is austenite,but the second phase is different.When boron is added,the surfacing layer contains M₂B(M=Fe,Cr)and Fe₃(C,B)borides with rod,dendrite or a small amount of flake morphology;when nitrogen is added,BN and Cr N hard phases appear in the surfacing layer,showing network,dendrite or fishbone distribution.(2)When the boron content is 2%,the performance of the surfacing layer reaches the best state.At this time,the Rockwell hardness reaches the maximum value of 43.5HRC,which is 2.4 times that of the surfacing layer without boron,and the minimum wear amount is 0.0141g,which is 5.8 times that of the surfacing layer without boron.When the nitrogen content is 1%,the maximum hardness is 44HRC and the minimum wear is 0.0139g.At room temperature,the wear morphology is mainly furrow and exfoliation layer,and the wear mechanism is mainly abrasive wear with a small amount of adhesive wear;the increase of wear temperature leads to the decrease of wear resistance,the increase of wear amount and the increase of friction coefficient,and the wear mechanism is mainly adhesive wear.(3)The results show that the corrosion resistance of surfacing alloy increases with the increase of boron content.When the boron content is 2%,the corrosion potential reaches the maximum of-0.254V,the self corrosion current density is the minimum,the capacitive resistance radius is the maximum,the RF value is the maximum,the obvious passivation zone appears,and the corrosion resistance is the best.When the addition amount is 1%,the maximum corrosion potential is-0.318V,the minimum self corrosion current density,the maximum capacitive reactance radius,the maximum equivalent circuit Rf value,the obvious passivation range,and the best corrosion resistance.