| In the hot rolling process of steel plate surface will form a layer of dense scale,commonly known as "scale skin".Scales may have adverse effects on subsequent processing and need to be removed.At present,the large-scale descaling of steel mill enterprises mainly adopts the pickling method,and the special chemical properties of acid will pose a great threat to the surrounding environment and workers' health.Therefore,it has become an urgent problem to seek an alternative to environmental protection.In recent years,researchers have developed a variety of descaling technologies one after another.Among them,abrasive slurry jet technology USES high-speed abrasive particles to carry out erosion on the metal surface,and water as the medium carrying solid particles is a new green descaling technology without pollution.However,the application of abrasive slurry jet descaling still faces great challenges.On the one hand,the theory of material removal mechanism is not perfect in the descaling process;on the other hand,the removal form of metal surface materials is not clear with different process parameters.The surface quality of the plate after descaling cannot meet the requirements of subsequent processing.Therefore,it is particularly important to master the removal mechanism of materials and realize the flexible control of process parameters on the surface quality of steel plates.In this paper,pickling Q235 strip steel is selected as the research object.Through theoretical analysis,software simulation and experiment,relevant process parameters of abrasive slurry jet descaling are analyzed,and the self-developed abrasive slurry jet descaling system is improved.The main research contents include:(1)Based on the erosion wear theory,the removal modes and volume model of single particle abrasive were studied.The velocity and kinetic energy distribution in jet flow are studied based on the theory of plane turbulent impingement jet.By analyzing the force of abrasive particles in jet flow,the force of abrasive particles in jet flow is obtained.It provides the theoretical basis for the subsequent result analysis.(2)Aiming at the problem of unclear material removal form in the abrasive slurry jet,the influence of abrasive type,particle size and impact Angle on the surface microstructure of the plate was studied by means of ultra-depth of field microscope.Using ABAQUS software analysis sheet of the abrasive velocity,impact Angle and particle size of width,length and depth of the pit,and the influence of the height,of the simulated pit width and the same experimental conditions including the scratch width of comparative study,found that simulated pit width scratch width range is consistent with the experiment,it is concluded that single diamond abrasive is mainly impact wear,impact was90 ° 90 ° impact is mainly in micro cutting.(3)The influence of abrasive type,particle size,injection Angle,distance and pressure on material removal at the center and edge of the jet was studied through the abrasive slurry jet experiment.At the same time,it was found that there were fine transparent crystals on the anti-oxidation film through the observation of ultra-depth of field microscope,and the energy spectrum analysis on the surface of the sheet after descaling by sem verified that descaling by abrasive slurry jet would leave scattered abrasive on the surface of the sheet.Through experimental research and numerical simulation,the influence of abrasive slurry jet process parameters on the surface microstructure and material removal form is further mastered in this paper.It provides theoretical and technical support for replacing acid pickling descaling with abrasive slurry jet technology as soon as possible. |
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