Experimental Study On Influence Of Surface Integrity On Corrosion Resistance Of Reactor Materials

Hydrogen,as a high-energy and clean energy,has been widely used in many industries.However,in the process of preparing hydrogen,hydrogen production reactor contacts hydrogen atoms and corrosive substances for a long time,which leads to hydrogen damage and corrosion damage of materials.The corrosion resistance of the reactor can be effectively improved by improving the surface integrity of the reactor.In this paper,the influence laws of surface integrity on the corrosion resistance of reactor materials are studied.The influence laws of surface roughness and surface residual stress on the hydrogen and corrosion resistance of reactor materials are analyzed,and the surface integrity parameters with better corrosion resistance are determined.The main contents and results of this paper are as follows:(1)Tested on surface integrity parameters and properties of samples with different surface roughness and surface residual stress were carried out.Different surface roughness and residual stress were obtained by grinding and sand blasting respectively.Based on the data of surface roughness and residual stress obtained from the test,the variation laws of surface hardness,surface microstructure and tensile mechanical properties of the material were studied.The results show that with the decrease of surface roughness,the surface hardness decreases,the surface structure does not change,the tensile strength increases,and the elongation does not change.With the increase of residual compressive stress,the surface hardness increases,the surface structure fines,the tensile strength increases and the elongation decreases.(2)Based on the influence of surface roughness and residual stress on material properties,the hydrogen damage test of reactor material affected by surface integrity was designed and carried out.By means of electrochemical hydrogen charging device,samples with different surface roughness and residual stress were treated with hydrogen,the surface hardness,hydrogen brittleness and irreversible hydrogen damage of each sample after hydrogen charging were investigated,and the fracture forms of each sample were analyzed according to the morphology of tensile fracture.The results show that when the surface roughness is Ra0.17μm,the resistance to hydrogen is better,the susceptibility index to hydrogen brittleness is 20.963%and the irreversible susceptibility index to hydrogen brittleness is 10.57%.When the surface residual stress is-336 MPa,the resistance to hydrogen is better,the susceptibility index to hydrogen brittleness is 16.45% and the irreversible susceptibility index to hydrogen brittleness is 8.2%.(3)Based on the influence of surface roughness and residual stress on material properties,the damage test of surface integrity on uniform corrosion and electrolytic corrosion of reactor material was designed and carried out.Different surface roughness and residual stress samples were corroded by means of uniform corrosion tank and electrolytic corrosion device.The surface roughness,corrosion rate and tensile properties of each sample after corrosion were analyzed.The results show that when the surface roughness is Ra0.17μm,the corrosion resistance is better,the uniform corrosion and electrolytic corrosion rates are 10.882mm/a and119.264mm/a,and the tensile strength is 541.91 MPa and 527.84 MPa respectively.When the surface residual stress is-293 MPa,the corrosion resistance of uniform corrosion is better,the corrosion rate is 8.4mm/a and the tensile strength is 563.33 MPa.When the surface residual stress is-336 MPa,the corrosion resistance of electrolytic corrosion is better,the corrosion rate is 122.752mm/a and the tensile strength is 548.8MPa.In conclusion,this paper has a certain reference value for the implementation of processing technology of high integrity surface in the welding zone of hydrogen production reactor by exploring the influence of surface integrity on the corrosion resistance of hydrogen production reactor materials.