Experimental Investigation Of Stress Corrosion Characteristics For Pressure Vessel Commonly Used Steel In Carbonate Solution

The material demonstrated that, sevaral similar accidental explosions of urea synthesizers occurred in recent years on the world, which had caused the serious human damage and material loss. The analysis of accidents' cause had certain differences. The stress corrosion cracking(SCC) of alkalescence was one explanation,Which induced the outburst of vessel's body, and then the accidental explosions happened. In the industry of chemical and oil refining ,the SCC in the carbonate solution were often reported on the equipment and pipelines,which is one of the alkalescence solution. But the SCC of carbonate in the industry circumstance was just a qualitative analysis,and the industry circumstance always contain complex mediums,not just the carbonate. Because really few quantitative data of the SCC of the own pressure vessel commonly used steel in alkalescence solution were accumulated, hence the carbonate solution is choosed as the testing solution,in which the Stress corrosion cracking(SCC) of 16MnR steel and 15MnVR steel were studied by the method of stress corrosion test for pro-cracked wedge-open loading(WOL) specimens and slow strain rate testing (SSRT).The main research conclusions are as follows: 1 .SSRT indicated that the material has very low sensitivity of SCC in thechoosed carbonate solution.2.At different temperatures, the WOL specimens of two steel did not takeplace SCC in the Na₂CO₃ solution which were choosed in the testing, anddense film exists on the surface of specimens.3. At different temperatures, the WOL specimens of two steel did not takeplace SCC in the NaHCO₃ solution which were choosed in the testing,Corrosion pin holes exist on the surface of specimens,which could be thepossibility of SCC.