Development Of Aspartum Polyurea-based Welding Spatter Protection Composite Coatings

As a very important processing method in the manufacturing industry,welding plays a vital role in various manufacturing fields such as national defense and people’s livelihood.However,the existence of many factors can cause splashes in the welding process,splashing and bonding to the surface of the workpiece,which not only affects the surface quality of the workpiece,but also requires a certain labor and time cost.Therefore,the protection of welding splash is very necessary.This paper isolates welding spatter by means of a protective coating.The complete welding temperature field data is obtained by combining numerical simulation and actual measurement,and the welding spatter protective coating is designed and prepared by using this data to achieve the required heat-resistant temperature of the protective coating,and guide the construction of the protective coating.The complete temperature field data is formed through numerical calculation and multi-parameter measurement,and the temperature resistance of the protective coating is designed according to the obtained welding temperature field data,which is used to guide the test of its anti-spatter ability.The calculation and test found that the temperature at 20mm from the weld seam during the welding process can reach up to 182.94°C,and the duration is about 10-15s.Therefore,the temperature resistance design of the welding spatter protective coating should be stable in a temperature environment above about 200°C.Based on the requirements of spatter protection during welding,this article uses polyaspartate polyurea as the matrix,petroleum hydrocarbon as the stripping agent,and white corundum as the filler to prepare a welding spatter protection coating to make it resistant to welding during the welding operation.The high temperature of the heat source,the temperature diffusion in the welding plate and the impact of welding spatter isolate the welding spatter from the substrate,and the entire sheet can be manually peeled off when the welding operation is completed.This will not affect the workpiece itself,but also protect the substrate from damage.For bonding of welding spatter.This requires the protective coating to have certain peelability,tear resistance and thermal stability.Characterization tests have been performed on it.The test results show that the peel strength of the protective coating is negatively correlated with the content of petroleum hydrocarbons and positively correlated with the content of white corundum.But the thermal stability of the protective coating is positively correlated with white corundum.Therefore,the performance of the protective coating is comprehensively considered,and it is found that when 10%-60%petroleum hydrocarbons were added and the white corundum content was 120%,the average peel strength of the protective coating(σ_180°=0.2461k N·m^-1)is much smaller than its average tear strength(Ts=15.0388 k N·m^-1).It shows that the peelability and tear strength of the protective coating at this time are good,and the entire sheet can be peeled off manually.The glass transition temperature（Tg）of the protective coating has increased from 244.85°C to 286.24℃.T₅ and T₁₀ of the protective coating increased by 22.86℃and 54.06℃respectively.This shows the protective coating can be used stably under the environment of 286.24℃.The white corundum improves the thermal stability of the protective coating.The protective coating meets the required performance during welding spatter protection.According to the welding temperature field data and the temperature resistance of the protective coating,the splash protection ability of the protective coating with different thicknesses is tested within the predicted range.The test results show that when the protective coating is 25 mm/20 mm away from the weld and the thickness is greater than 200μm/300μm,it has good splash resistance.And the protective coating can be peeled off manually at the end of welding without tearing,and the protective coating has a remarkable anti-splash effect.The welding spatter protection coating is a high solid content system,which will not produce a large of organic volatiles such as smoke during the brushing and protection process,which is environmentally friendly and healthy.The research results of this paper have certain engineering significance,and can be applied to most welding operations,regardless of location,workpiece shape,etc.Tt is expected to be applied to manufacturing processes such as aerospace,water conservancy and hydropower,high-speed trains,and shipbuilding.