In order to improve the wear resistance of A588 weathering steel plate, it is necessary to carry out surface spraying on the steel surface to form a certain thickness of reinforcing layer.
In order to improve the wear resistance of the A588 weather-resistant steel plate, it is necessary to spray the surface of the steel to form a reinforcement layer with a certain thickness. The traditional spraying process is limited by the quality of the sprayed material, the sprayed particles and the precision of the process parameters. Cold spraying technology was applied to the preparation of reinforced layer of A588 weathering steel plate. The equipment and process parameters used in the cold spraying process are introduced, and the relationship between the process parameters and the performance of the pre-strengthened A588 weathering steel plate is studied, which provides a reference for the production of the A588 weathering steel plate.
Keywords: A588 weathering steel plate, cold spray technology, spray process parameters
1 Introduction
A588 weathering steel plate, also known as CORTEN A588, is a kind of high-strength low-alloy structural steel. It has the advantages of good corrosion resistance and toughness, and is widely used in various engineering structures due to its good comprehensive performance. However, the wear resistance of A588 weathering steel is poor. Therefore, the steel surface needs to be strengthened by composite technology to improve its comprehensive properties. Cold spraying technology is a new coating technology which has the advantages of simple process, easy to realize automation and low cost. This technology is adopted to prepare the reinforcing layer of A588 weathering steel plate.
2 The application of cold spraying process in A588 weathering steel plate
The equipment used in cold spraying involves a large number of components, including the gun head, the control system of the gun head, the gun body and the compressed gas control system (air, nitrogen, etc.). The process parameters include the feeding speed of feedstock, the pre-heating temperature of the coating, the material gas pressure, the gas flow rate and the atomic binding energy. The particle size of the feedstock particles is generally 10 - 100 μm, the relative density is 1.2 - 3 g/cm3, the spray distance is 10 - 20 mm, and the temperature of the preheating material is 500-400 ℃.
3 The influence of process parameters on A588 weathering steel plate
The mechanical properties of A588 weathering steel plate pre-strengthened by cold spraying process are affected by the process parameters. The tensile strength is affected by the particle size, the particle size of the feedstock and the preheating temperature. If the particle size is too large, the uniformity of the coating layer is poor, and the bonding strength between the substrate and the coating is reduced, resulting in a decrease of the tensile strength. The surface hardness is increased with the increasing of the particle size. When the particle size is bigger than 40 μm, the surface hardness of A588 weathering steel plate has little change. The preheating temperature has a great influence on the surface hardness of the sprayed layer. When the temperature is higher than 500℃, the surface hardness of plate will decrease. The morphology of the sprayed layer is affected by the atomization pressure and the gas flow rate. With the increase of the gas pressure and gas flow rate, the surface morphology of the sprayed the layer present a tendency of uniform size and distribution.
4 Conclusion
The treatment of surface strengthening layer of A588 weathering steel plate by cold spraying technology can significantly improve its surface hardness, wear resistance and fatigue life. The process parameters have a great influence on the quality of sprayed layer. Therefore, the selection of process parameters should be considered comprehensively, and the quality of A588-weathering steel plate should be strictly controlled during the entire process.
