The nature of the solid erodent particles present in corrosive petroleum fluid can cause transporting pipeline to experience severe erosion and corrosion damages. The effect of erosion on corrosion behavior of API X12...The nature of the solid erodent particles present in corrosive petroleum fluid can cause transporting pipeline to experience severe erosion and corrosion damages. The effect of erosion on corrosion behavior of API X120 steel was investigated using aluminum oxide and silicon carbide particles with different sizes as erodent and 3.5wt.% NaCl aqueous solution saturated with carbon dioxide as a corrosive medium. The effect of the erodent particle size on the corrosion behavior of the steel material at different particle speeds and impact angles was investigated using weight loss, potentiodynamic polarization and surface analysis techniques. The erosion results confirmed that the material damage increased with increasing particle speed. It was observed that in carbon dioxide-saturated saline solution, deposition of protective iron carbonate film occurred on the steel surface. It was found that the corrosion film can provide better protection at lower particle speed than at higher speed. The ratio of total erosion-corrosion (S)/effect of erosion on corrosion (T) analysis confirmed that at higher S/T ratio, the particle speed and material removal rate are low and vice versa at lower S/T ratio. Lower S/T values for the combined erosion and corrosion tests performed with erodent silicon carbide particle compared to erodent aluminum oxide particle showed that erosion enhancement of corrosion is more evident in the test performed using aluminum oxide particle than using silicon carbide particle. The result also suggests that when subjected to larger size erodent particle, the damage to pipeline due to effect of erosion on corrosion process can be more significant compared to smaller size erodent particle.展开更多
In this paper,the product designs,mechanical properties and microstructure of ultra-high strength linepipe steel in grade X120 strip with a thickness of 16mm have been shown and analyzed systematically.The tensile tes...In this paper,the product designs,mechanical properties and microstructure of ultra-high strength linepipe steel in grade X120 strip with a thickness of 16mm have been shown and analyzed systematically.The tensile test results with different directions,including transverse,longitudinal and 30° to the rolling direction,showed that the yield strength and ultimate tensile strength reach and exceed 900MPa and 1000MPa respectively,which are far higher than requirements of X120,such as 827MPa and 931MPa.On the other hand,as shown from the test results of Charpy impact tests at different temperatures from 20 ℃ to-60 ℃,the absorbed energies and fracture shear area at-60℃ are about 200J and 100% respectively,which is very exciting and interesting.In order to clarify the strengthening mechanism and effect of X120 strip further,microstructure has been observed through metallography.Analysis of the metallography revealedthat the microstructure was composed of lower bainitewith a size of 1um and fine M/A components.The X120 strip was formed into 1420 mm diameter spiral welded pipe in Huabei pipe mill.Tested results showed that ultra-high strength and high toughness linepipe could be achieved through reasonable alloy composition design and optimized rolling processes.展开更多
文摘The nature of the solid erodent particles present in corrosive petroleum fluid can cause transporting pipeline to experience severe erosion and corrosion damages. The effect of erosion on corrosion behavior of API X120 steel was investigated using aluminum oxide and silicon carbide particles with different sizes as erodent and 3.5wt.% NaCl aqueous solution saturated with carbon dioxide as a corrosive medium. The effect of the erodent particle size on the corrosion behavior of the steel material at different particle speeds and impact angles was investigated using weight loss, potentiodynamic polarization and surface analysis techniques. The erosion results confirmed that the material damage increased with increasing particle speed. It was observed that in carbon dioxide-saturated saline solution, deposition of protective iron carbonate film occurred on the steel surface. It was found that the corrosion film can provide better protection at lower particle speed than at higher speed. The ratio of total erosion-corrosion (S)/effect of erosion on corrosion (T) analysis confirmed that at higher S/T ratio, the particle speed and material removal rate are low and vice versa at lower S/T ratio. Lower S/T values for the combined erosion and corrosion tests performed with erodent silicon carbide particle compared to erodent aluminum oxide particle showed that erosion enhancement of corrosion is more evident in the test performed using aluminum oxide particle than using silicon carbide particle. The result also suggests that when subjected to larger size erodent particle, the damage to pipeline due to effect of erosion on corrosion process can be more significant compared to smaller size erodent particle.
文摘In this paper,the product designs,mechanical properties and microstructure of ultra-high strength linepipe steel in grade X120 strip with a thickness of 16mm have been shown and analyzed systematically.The tensile test results with different directions,including transverse,longitudinal and 30° to the rolling direction,showed that the yield strength and ultimate tensile strength reach and exceed 900MPa and 1000MPa respectively,which are far higher than requirements of X120,such as 827MPa and 931MPa.On the other hand,as shown from the test results of Charpy impact tests at different temperatures from 20 ℃ to-60 ℃,the absorbed energies and fracture shear area at-60℃ are about 200J and 100% respectively,which is very exciting and interesting.In order to clarify the strengthening mechanism and effect of X120 strip further,microstructure has been observed through metallography.Analysis of the metallography revealedthat the microstructure was composed of lower bainitewith a size of 1um and fine M/A components.The X120 strip was formed into 1420 mm diameter spiral welded pipe in Huabei pipe mill.Tested results showed that ultra-high strength and high toughness linepipe could be achieved through reasonable alloy composition design and optimized rolling processes.
