Study On The Influence Of Oxide Scale Defects On The Surface Quality Of Axle Plates

Axle plate is the main load-bearing material of truck,its surface quality directly affects the effect of anti-corrosion paint,thus affecting the stability of truck in the whole service cycle.In this paper,the defects of iron oxide scale on the axle plate of truck are studied,and the phase composition of the defects is determined through laboratory analysis.According to the analysis results,the corresponding process links are found,and through targeted tests,the range of process parameters is further defined,and the mass production of the axle plate without oxide scale defects is realized.According to the analysis of metallography,SEM and XRD,the thickness of iron oxide scale is 20?m and the proportion of Fe₂O₃ is 10%.In the defect state,the thickness of iron oxide scale can reach 150?m,and the proportion of Fe₂O₃ is as high as 30%.This defect is pressed into the surface of the steel plate,resulting in uneven thickness of the surface of the axle plate.Si was found in the defects,which was beyond the matrix content.It was found that it was caused by the unclean descaling of the axle plate in the production process.Cr element was found in the defects.It was found that the excessive wear of the roll was brought in during the rolling process.Through the special test,in the system with the lowest descaling pressure of 21MPa,the upper limit of Si content in axle plate is 0.4%.However,the silicon element is closely combined with the axle plate matrix.When the descaling nozzle is worn and the descaling method is abnormal,it will lead to the unclean removal of primary oxide scale and defects.The optimum working condition of roller is in the period of 200⁴000 tons.The field test shows that the reduction rate and rolling speed have no effect on the oxide scale defects on the surface of axle plate.The rolling temperature of finishing mill is increased by 60?,and the surface quality of steel plate is obviously improved.Through the research,it is found that the defects of iron oxide scale have superposition effect.Different influencing factors can lead to oxide scale defects.These influencing factors are superimposed on each other.With the fluctuation of field production process,the oxide scale defects on the surface appear different forms,which makes the solution of defects become extremely complex.Through the improvement on the spot,the mass production of axle plate without oxide scale defect is realized..