Experimental Study On Derusting Using Abrasive Water Jet Technology

With the extensive application of engineering materials in the industrial production, the requirement of the surface quality increases. When the engineering materials are operated or stored for a long time, the surface will be corroded due to the dust, grease and other impurities.If the condition is not handled properly, the corrosion will reduce the equipment life and result in the hidden security danger. For the corrosion problem, many scholars try to adopt various derusting technologies. However, the traditional derusting work exists several proplem, such as serious pollution and uncomplete derusting. After analyzing traditional derusting method and their advantages and disadvantages, the AWJ technique is proposed to be applied to the derusting steel work.The AWJ technique is widely used in various fields, such as processing of ceramics,glass, carbide and other hard materials processing. Nowadays, there are 80% of the industrial cleaning using the AWJ technique abroad, however, the outdated chemical methods are still widely used in our country. Therefore, the study of the AWJ derusting technique is very important.This thesis uses the AWJ technique to derust the SPA-H corrosion steel plate. The mechanism and model of the AWJ derusting technique was analyzed. Then the two theoretical models of abrasive water jet derusting, i.e. the wear model and deformation model were compared. The characters of the AWJ derusting technique were analyzed, which focuses on the motion equation of the single abrasive particle crushing the material surface, impact energy and material crushing pressure and speed. Through the analysis of the physical model and incision model of abrasive water jet, the relationship between material parameters and the cutting depth, traverse speed, material cutting concrete are obtained, which provide the theoretical guidance for the research.In order to figure out the relationship of the process parameters and the cleaning efficiency and specific energy consumption, 20 groups of single test variable, i.e. target distance?S?, jet pressure?P?, traverse speed?V?, abrasive flow rate?M? were designed in this thesis. The derusting test using the AWJ technique shows that in a certain ranges of parameters, the jet pressure P and traverse speed V are proportional to the derusting efficiency,and inversely proportional to the specific energy consumption. The optimal value of jet pressure and traverse speed is the coincidence point of the derusting efficiency and specific energy consumption curve. What's more, with the increase of abrasive flow rate?M? or target?S?, the derusting efficiency is gradually increased at first, and then begins to decline after reaching the peak value. Since the trend of energy consumption and derusting efficiency is just opposite, the optimal value of the abrasive flow and the target distance must exist.In the experiments, 9 groups of the orthogonal tests for the AWJ derusting were designed.The range analysis method was used to process the experimental results. Furthermore, In the selected laboratory conditions, the primary and secondary order of the impact parameter was obtained, where the jet pressure has the most influence on cleaning efficiency, following by the target distance, the traverse speed and the abrasive flow rate. In the selected laboratory conditions, the optimal combination of process parameters to obtain the maximal derusting efficiency.To obtain the prediction model of the derusting efficiency, the orthogonal test data was analyzed based on MATLAB software. The predicting model between the process parameters and the cleaning efficiency was derived:?=0.0740S^0.4199P^0.5670V^0.4048M^-0.1474. To verify the reliability of the prediction model, this thesis designed 9 groups of random verification test.The maximum relative error of the obtained derusting efficiency model is 9.41%, which is lower than the allowable error range. Hence, In the selected laboratory conditions, this results can provide some guidance for the subsequent research of the AWJ derusting technique.