Study On Laser Dry Cleaning Effect And Surface Performance Of Typical Structural Steel

This paper briefly summarizes the traditional cleaning technology,and finds that the current traditional cleaning technology has some limitations,which cannot achieve high precision cleaning.And laser cleaning technology cleaning can clean some traditional cleaning technology can not complete the task.Although at present,laser cleaning can not replace the traditional cleaning technology,but in the near future laser cleaning will become an efficient cleaning technology in various fields.As a kind of green cleaning technology,laser cleaning has not been studied for its specific influence on the important parameters of the cleaning process.This paper explores the important parameters(power,frequency and scanning speed)of laser cleaning process through experiments:The influence of different power on laser cleaning effect and surface performance after cleaning were investigated.The cleaning effect of 60W-120 W cleaning power on the oxidized layer of Q235 surface was analyzed by experiment and simulation.The results showed that the cleaning power of 70 W makes the surface performance after cleaning of the samples relatively optimized.The best cleaning power is 90 W.The sample surface of 100 W is the smoothest,but it causes slight damage to the matrix.The cleaning power of 120 W has the maximum friction coefficient but it has the maximum damage to the matrix.In order to explore the cleaning effect,cleaning mechanism and surface performance under different scanning speed,by combining simulation analysis with experimental verification,the surface oxide of Q235 structural steel was taken as an example for laser cleaning.The results show that when the scanning speed is 7000mm/s,the cleaning effect is the best,and the roughness of the cleaning surface is the lowest at 3.173 m.When the scanning speed is reduced to 6000mm/s,slight oxidation occur on the cleaning surface.When the scanning velocity is 5000mm/s,the surface is seriously oxidized,the laser strengthening effect is the strongest,and the friction coefficient reaches the highest of 0.4205.The vertical and horizontal distribution of the cleaned texture also has a certain influence on the friction coefficient,and the friction coefficient of the transverse texture is higher.The cleaning surface produced tensile stress,and the residual stress decreases with the increase of scanning velocity.The cleaning mechanism of laser cleaning Q235 surface oxide layer is a variety of coupling mechanisms,mainly based on ablation mechanism and supplemented by sputtering mechanism.The ablation effect is enhanced with the reduction of scanning velocity.To sum up,in the laser dry cleaning,scanning speed as an important parameter has a significant impact on the cleaning effect,cleaning mechanism and surface performance.The cleaning effect,cleaning mechanism and surface performance under different frequencies were investigated.The optimal frequency can be obtained by theoretical calculation.Solid fiber laser was used in the experiment.The cleaning frequency single factor parameter was controlled.Take the surface oxide layer of Q235 low carbon structural steel as an example for cleaning experiment.The results show that the surface of the sample is the best after being cleaned at 350 k Hz frequency.When the frequency is 250 k Hz,the surface roughness of the sample reaches the minimum value of 2.572 m,and the matrix is slightly damaged.When the frequency is 150 k Hz,the friction coefficient of the sample reaches the maximum value of 0.3905 and the matrix damage is the maximum.The surface oxide layer cleaning mechanism of Q235 is ablative and sputtering.With the increase of frequency,ablative effect decreases gradually and sputtering effect increases gradually.When the frequency is 550 k Hz,the lowest proportion of ablation is 68%.When the frequency is 150 k Hz,the sample surface is secondary oxidized.The matrix surface is seriously damaged,and the surface roughness is the largest.In the range of 250-550 k Hz,the surface roughness of the sample increases with the increase of frequency.With the increase of frequency,the overall tendency of the surface friction coefficient decreases after the laser dry cleaning.When the frequency is 150 k Hz,the laser energy density is the highest and the laser enhancement is the most obvious.The residual stress of sample cleaning surface decreases with increasing frequency.After the laser with 350 k Hz,the electrochemical corrosion performance of the surface is the best.If it is higher or lower than this frequency,the electrochemical corrosion performance of the surface will decrease after the cleaning.In laser dry cleaning,frequency as an important parameter has a significant influence on the cleaning effect,cleaning mechanism and surface performance.Through the exploration of the important parameters of laser cleaning process(power,frequency,scanning speed),the influence rules of laser cleaning parameters on cleaning quality and surface properties were summarized,and the theory and method of the integration of substrate,adsorption-cleaning process-cleaning quality were formed.