Appropriate materials for injection pipelines and tubing for carbon dioxide geologic storage is fundamental to ensure asset integrity and save cost.This paper evaluates the corrosion behaviour of X65,1Cr,3Cr and 5Cr,w...Appropriate materials for injection pipelines and tubing for carbon dioxide geologic storage is fundamental to ensure asset integrity and save cost.This paper evaluates the corrosion behaviour of X65,1Cr,3Cr and 5Cr,which have the potential to be injection pipeline/tubing materials.The influence of steel Cr content on the general and localised corrosion behaviour was investigated at time periods from 6 to 192 h at 60℃and 100 bar.The evolution,morphology and chemistry of corrosion products on the surface of each material were evaluated using a combination of scanning electron microscopy,energy dispersive X-ray spectroscopy and X-ray diffraction and related to their overall corrosion protection.Results indicate that prior to the formation of protective films on the steel surfaces,the resistance of the materials to corrosion increase with increasing Cr content(Corrosion resistance:X65<1Cr<3Cr<5Cr).However,as corrosion products evolve,the protection afforded to the different steels significantly varies and decreases with increasing Cr content.×65 becomes the material with the lowest general corrosion rate by the end of the 192 h experiments and 5Cr exhibits the highest corrosion rate(ranking of corrosion resistance:X65>1Cr>3Cr>5Cr).In terms of the corrosion products on X65,both inner amorphous and outer crystalline corrosion layers consist of FeCO3.For the Cr-containing steels,the outer layer also comprises FeCO3,but the inner layer is enriched with Cr,and is predominantly amorphous Cr(OH)3.The extent of localised corrosion(determined using surface profilometry)is noticeably less for X65 compared to the Cr-containing steels.The paper raises questions about the benefits that low Cr steels offer towards extending component design life compared to carbon steel under the test conditions considered here.展开更多
Mn is a weak element for austenite formation and its effect on martensitic stainless steel is seldom researched. The microstructure and property of 13Cr martensitic stainless steel with varied Mn content and low carbo...Mn is a weak element for austenite formation and its effect on martensitic stainless steel is seldom researched. The microstructure and property of 13Cr martensitic stainless steel with varied Mn content and low carbon content were studied. The research demonstrates that Mn enlarges the austenitic zone at a high temperature and increases the strength and hardness of martensitic stainless steel. Following the addition of Mn,the corrosion resistance property of low carbon 13Cr stainless steel only decreases slightly. The strength and hardness of low carbon 13Cr stainless steel containing Mn is similar to that of high carbon 13Cr stainless steel.展开更多
1.25Cr-0.5Mo steels with different Ti-B or Al-B treatment were exposed in 18 MPa hydrogen atmosphere at 480℃ fo f 100, 500 and 1000 h respectively. Tensile and bend properties of steels before and after hydrogen chan...1.25Cr-0.5Mo steels with different Ti-B or Al-B treatment were exposed in 18 MPa hydrogen atmosphere at 480℃ fo f 100, 500 and 1000 h respectively. Tensile and bend properties of steels before and after hydrogen changing were tested. The results show that the different mechanical properties of the steels with different B content have different responses to high temperature high pressure hydrogen charging processes.After hydrogen changing, more loss of ductility can be found in the steel not treated with B than those in the steels treated with B. Metallographic analyses indicated that decarburization occurred in all the steels. Furthermore, many methane bubbles were found by SEM analysis in the surface decarburization layer in the steel without B,while only a few bubbles, the number and size of which decreased with increasing B content, were found in steels with B treatment. In addition, hydrogen determination results manifested that after being exposed in hydrogen atmosphere the steel containing no B had higher hydrogen content than that of steels containing B. All this suggests that B treatment improved the HA resistance of 1.25Cgr-0.5Mo steel, and the more B the steel contained the more perceptible the effect.展开更多
文摘Appropriate materials for injection pipelines and tubing for carbon dioxide geologic storage is fundamental to ensure asset integrity and save cost.This paper evaluates the corrosion behaviour of X65,1Cr,3Cr and 5Cr,which have the potential to be injection pipeline/tubing materials.The influence of steel Cr content on the general and localised corrosion behaviour was investigated at time periods from 6 to 192 h at 60℃and 100 bar.The evolution,morphology and chemistry of corrosion products on the surface of each material were evaluated using a combination of scanning electron microscopy,energy dispersive X-ray spectroscopy and X-ray diffraction and related to their overall corrosion protection.Results indicate that prior to the formation of protective films on the steel surfaces,the resistance of the materials to corrosion increase with increasing Cr content(Corrosion resistance:X65<1Cr<3Cr<5Cr).However,as corrosion products evolve,the protection afforded to the different steels significantly varies and decreases with increasing Cr content.×65 becomes the material with the lowest general corrosion rate by the end of the 192 h experiments and 5Cr exhibits the highest corrosion rate(ranking of corrosion resistance:X65>1Cr>3Cr>5Cr).In terms of the corrosion products on X65,both inner amorphous and outer crystalline corrosion layers consist of FeCO3.For the Cr-containing steels,the outer layer also comprises FeCO3,but the inner layer is enriched with Cr,and is predominantly amorphous Cr(OH)3.The extent of localised corrosion(determined using surface profilometry)is noticeably less for X65 compared to the Cr-containing steels.The paper raises questions about the benefits that low Cr steels offer towards extending component design life compared to carbon steel under the test conditions considered here.
文摘Mn is a weak element for austenite formation and its effect on martensitic stainless steel is seldom researched. The microstructure and property of 13Cr martensitic stainless steel with varied Mn content and low carbon content were studied. The research demonstrates that Mn enlarges the austenitic zone at a high temperature and increases the strength and hardness of martensitic stainless steel. Following the addition of Mn,the corrosion resistance property of low carbon 13Cr stainless steel only decreases slightly. The strength and hardness of low carbon 13Cr stainless steel containing Mn is similar to that of high carbon 13Cr stainless steel.
文摘1.25Cr-0.5Mo steels with different Ti-B or Al-B treatment were exposed in 18 MPa hydrogen atmosphere at 480℃ fo f 100, 500 and 1000 h respectively. Tensile and bend properties of steels before and after hydrogen changing were tested. The results show that the different mechanical properties of the steels with different B content have different responses to high temperature high pressure hydrogen charging processes.After hydrogen changing, more loss of ductility can be found in the steel not treated with B than those in the steels treated with B. Metallographic analyses indicated that decarburization occurred in all the steels. Furthermore, many methane bubbles were found by SEM analysis in the surface decarburization layer in the steel without B,while only a few bubbles, the number and size of which decreased with increasing B content, were found in steels with B treatment. In addition, hydrogen determination results manifested that after being exposed in hydrogen atmosphere the steel containing no B had higher hydrogen content than that of steels containing B. All this suggests that B treatment improved the HA resistance of 1.25Cgr-0.5Mo steel, and the more B the steel contained the more perceptible the effect.
