We investigated the effect of the 2-mercaptobenzothiazole concentration on the sour-corrosion behavior of API X60 pipeline steel in an environment containing H_(2)S at 25°C and in the presence of 0,2.5,5.0,7.5,an...We investigated the effect of the 2-mercaptobenzothiazole concentration on the sour-corrosion behavior of API X60 pipeline steel in an environment containing H_(2)S at 25°C and in the presence of 0,2.5,5.0,7.5,and 10.0 g/L of 2-mercaptobenzothiazole inhibitor.To examine this behavior,we conducted open-circuit potential(OCP),potentiodynamic polarization,and electrochemical impedance spectroscopy(EIS)tests.Energy dispersive spectroscopy and scanning electron microscopy were also used to analyze the corrosion products.The results of the OCP and potentiodynamic polarization tests revealed that 2-mercaptobenzothiazole reduces the speed of both the anodic and cathodic reactions.An assessment of the Gibbs free energy of the inhibitor(△G_(ads)^(■))indicated that its value was less than-20 kJ·mol^(-1)and greater than-40 k J·mol^(-1).Therefore,the adsorption of 2-mercaptobenzothiazole onto the surface of the API X60 pipeline steel occurs both physically and chemically,the latter of which is particularly intentional.In addition,as the△G_(ads)^(■)dsvalue was negative,we could conclude that the adsorption of 2-mercaptobenzothiazole onto the surface of the pipeline steel occurs spontaneously.The EIS results indicate that with the increase in the 2-mercaptobenzothiazole inhibitor concentration,the corrosion resistance of API X60 steel increases.An analysis of the corrosion products revealed that iron sulfide compounds form on the surface.In summary,the results showed that an increase in the inhibitor concentration results in a decrease in the corrosion rate and an increase in inhibitory efficiency.Additionally,we found that the 2-mercaptobenzothiazole adsorption process on the API X60 steel surfaces in an H2 S-containing environment follows the Langmuir adsorption isotherm and occurs spontaneously.展开更多
With rapid economic development in China, demand for energy and transportation is growing. Due to the limitations of factors such as terrain and traffic, a large number of buried oil and gas pipelines are parallel to ...With rapid economic development in China, demand for energy and transportation is growing. Due to the limitations of factors such as terrain and traffic, a large number of buried oil and gas pipelines are parallel to high- voltage transmission lines and electrified railways over long distances. Alternating pipelines is very serious in laboratory experiments were current （AC） corrosion of such cases. In this work, carried out with an electrochemical method in a simulated soil solution at various AC current densities from 0 to 200 A]m2 and AC frequencies from 10 to 200 Hz. Experimental results indicated that with an increase in the AC current density, the corrosion po- tential of an X60 steel electrode shifted negatively, the anodic current density increased significantly, and the corrosion rate increased. Moreover, with an increase in the AC frequency, the corrosion potential of the X60 electrode shifted positively and the anodic current density decreased, which led to a decrease in the corrosion rate. Furthermore, the morphology of X60 electrodes indicated that uniform corrosion occurred at a low AC current density; while corrosion pits were found on the X60 electrode surface at a high AC current density, and deep corrosion pits seriously damaged the pipelines and might lead to leakage.展开更多
The growth dynamics of austenite grains was investigated in 60CrMnMo steel with different RE elements. The results show that austenite grains of 60CrMnMo steel can be refined and their growth can be restrained by addi...The growth dynamics of austenite grains was investigated in 60CrMnMo steel with different RE elements. The results show that austenite grains of 60CrMnMo steel can be refined and their growth can be restrained by adding a certain amount of RE. From the experimental results, the values of n and Q were evaluated.展开更多
The effect of rare earth (RE) on cyclic softening of low frequency fatigue of the hot rolled steel 60CrMnMo at high temperature was investigated. The hardness of specimens before thermal fatigue test and being cycled ...The effect of rare earth (RE) on cyclic softening of low frequency fatigue of the hot rolled steel 60CrMnMo at high temperature was investigated. The hardness of specimens before thermal fatigue test and being cycled 180 times from room temperature to 650℃ was compared. The results show that by adding a certain amount of RE in steel 60CrMnMo, the cyclic softening during low frequency fatigue test at high temperature can be restrained considerly. The carbide particles were refined during tempering treatment and the agglomeration and growth of carbide particles can be obstructed during thermal cycle.展开更多
The effect of rare earth(RE) on tensile behavior of hot roller steel 60CrMnMo was investigated at the temperature when roll served The roll′s fatigue at 500 ℃ was estimated The results show that elongation δ ...The effect of rare earth(RE) on tensile behavior of hot roller steel 60CrMnMo was investigated at the temperature when roll served The roll′s fatigue at 500 ℃ was estimated The results show that elongation δ of hot roller steel 60CrMnMo can be increased by adding RE It is possible to estimate the fatigue life with tensile behavior of hot roller steel 60CrMnMo展开更多
Two-dimensional rigid-plastic finite element method (FEM) was used for simulation of the effect of process parameterson the static recrystallization of 60SiMnA spring steel using MARC/AutoForge 3.1 software. A thermo-...Two-dimensional rigid-plastic finite element method (FEM) was used for simulation of the effect of process parameterson the static recrystallization of 60SiMnA spring steel using MARC/AutoForge 3.1 software. A thermo-mechanicalcoupled analysis was conducted considering the heat transfer between the workpiece, the roll and the environment,and the heat generation due to plastic work. The static recrystallization laws under different processing conditionsand the predicted distribution of the static recrystallization volume fraction on the deformation cross section arepresented.展开更多
The effect of rare earth(RE) on low frequency high temperature fatigue strength of hot rolled steel 60CrMnMo was investigated. The results show that by adding a certain amount of RE in steel 60CrMnMo, its serviceable ...The effect of rare earth(RE) on low frequency high temperature fatigue strength of hot rolled steel 60CrMnMo was investigated. The results show that by adding a certain amount of RE in steel 60CrMnMo, its serviceable life during low frequency fatigue test at high temperature can be improved.The number of cycles for fracture was increased by 18.5%～28.8%. The number of large inclusion particleswas reduced and the composition of inclusions and their shape were changed as well. The strip distances on fatigue fracture surface were decreased. It is concluded that the optimum amount of RE addtion is about 0.05 wt%～0. 10 wt%.展开更多
The corrosion fatigue behavior of stainless steel 3RE60 in 3.5%NaCl solution was studied at different cyclic stress levels. The results showed that both intergranular corrosion cracking and transgranular corrosion cra...The corrosion fatigue behavior of stainless steel 3RE60 in 3.5%NaCl solution was studied at different cyclic stress levels. The results showed that both intergranular corrosion cracking and transgranular corrosion cracking initiated at the bottom of pits. The corrosion fatigue behavior of 3RE60 may be related to complex electrochemical and mechanical coupling effects between the three phases (austenite, ferrite and martensite), where martensite and ferrite were anodic in the corrosion cell and could be prone to crack under certain conditions.展开更多
The 3-D thermo-mechanical coupled elasto-plastic finite element method (FEM)was used for the simulation of the two-pass continuous hot rolling process of 60SiMnA spring steelbars and rods using MARC/AutoForge3.1 softw...The 3-D thermo-mechanical coupled elasto-plastic finite element method (FEM)was used for the simulation of the two-pass continuous hot rolling process of 60SiMnA spring steelbars and rods using MARC/AutoForge3.1 software. The simulated results visualize the metal flow andthe dynamic evolutions of the strain, stress and temperature during the continuous hot rolling,especially inside the work-piece. It is shown that the non-uniform distributions of the strain,stress and temperature on the longitudinal and transverse sections are a distinct characteristic ofthe continuous hot rolling, which can be used as basic data for improving the tool design,predicting and controlling the micro-structural evolution of a bar and rod.展开更多
文摘We investigated the effect of the 2-mercaptobenzothiazole concentration on the sour-corrosion behavior of API X60 pipeline steel in an environment containing H_(2)S at 25°C and in the presence of 0,2.5,5.0,7.5,and 10.0 g/L of 2-mercaptobenzothiazole inhibitor.To examine this behavior,we conducted open-circuit potential(OCP),potentiodynamic polarization,and electrochemical impedance spectroscopy(EIS)tests.Energy dispersive spectroscopy and scanning electron microscopy were also used to analyze the corrosion products.The results of the OCP and potentiodynamic polarization tests revealed that 2-mercaptobenzothiazole reduces the speed of both the anodic and cathodic reactions.An assessment of the Gibbs free energy of the inhibitor(△G_(ads)^(■))indicated that its value was less than-20 kJ·mol^(-1)and greater than-40 k J·mol^(-1).Therefore,the adsorption of 2-mercaptobenzothiazole onto the surface of the API X60 pipeline steel occurs both physically and chemically,the latter of which is particularly intentional.In addition,as the△G_(ads)^(■)dsvalue was negative,we could conclude that the adsorption of 2-mercaptobenzothiazole onto the surface of the pipeline steel occurs spontaneously.The EIS results indicate that with the increase in the 2-mercaptobenzothiazole inhibitor concentration,the corrosion resistance of API X60 steel increases.An analysis of the corrosion products revealed that iron sulfide compounds form on the surface.In summary,the results showed that an increase in the inhibitor concentration results in a decrease in the corrosion rate and an increase in inhibitory efficiency.Additionally,we found that the 2-mercaptobenzothiazole adsorption process on the API X60 steel surfaces in an H2 S-containing environment follows the Langmuir adsorption isotherm and occurs spontaneously.
基金sponsored by the Projects in the National Science & Technology Pillar Program during the Twelfth Five-year Plan Period(Grant No.2011BAK06B01)
文摘With rapid economic development in China, demand for energy and transportation is growing. Due to the limitations of factors such as terrain and traffic, a large number of buried oil and gas pipelines are parallel to high- voltage transmission lines and electrified railways over long distances. Alternating pipelines is very serious in laboratory experiments were current （AC） corrosion of such cases. In this work, carried out with an electrochemical method in a simulated soil solution at various AC current densities from 0 to 200 A]m2 and AC frequencies from 10 to 200 Hz. Experimental results indicated that with an increase in the AC current density, the corrosion po- tential of an X60 steel electrode shifted negatively, the anodic current density increased significantly, and the corrosion rate increased. Moreover, with an increase in the AC frequency, the corrosion potential of the X60 electrode shifted positively and the anodic current density decreased, which led to a decrease in the corrosion rate. Furthermore, the morphology of X60 electrodes indicated that uniform corrosion occurred at a low AC current density; while corrosion pits were found on the X60 electrode surface at a high AC current density, and deep corrosion pits seriously damaged the pipelines and might lead to leakage.
文摘The growth dynamics of austenite grains was investigated in 60CrMnMo steel with different RE elements. The results show that austenite grains of 60CrMnMo steel can be refined and their growth can be restrained by adding a certain amount of RE. From the experimental results, the values of n and Q were evaluated.
文摘The effect of rare earth (RE) on cyclic softening of low frequency fatigue of the hot rolled steel 60CrMnMo at high temperature was investigated. The hardness of specimens before thermal fatigue test and being cycled 180 times from room temperature to 650℃ was compared. The results show that by adding a certain amount of RE in steel 60CrMnMo, the cyclic softening during low frequency fatigue test at high temperature can be restrained considerly. The carbide particles were refined during tempering treatment and the agglomeration and growth of carbide particles can be obstructed during thermal cycle.
文摘The effect of rare earth(RE) on tensile behavior of hot roller steel 60CrMnMo was investigated at the temperature when roll served The roll′s fatigue at 500 ℃ was estimated The results show that elongation δ of hot roller steel 60CrMnMo can be increased by adding RE It is possible to estimate the fatigue life with tensile behavior of hot roller steel 60CrMnMo
文摘Two-dimensional rigid-plastic finite element method (FEM) was used for simulation of the effect of process parameterson the static recrystallization of 60SiMnA spring steel using MARC/AutoForge 3.1 software. A thermo-mechanicalcoupled analysis was conducted considering the heat transfer between the workpiece, the roll and the environment,and the heat generation due to plastic work. The static recrystallization laws under different processing conditionsand the predicted distribution of the static recrystallization volume fraction on the deformation cross section arepresented.
文摘The effect of rare earth(RE) on low frequency high temperature fatigue strength of hot rolled steel 60CrMnMo was investigated. The results show that by adding a certain amount of RE in steel 60CrMnMo, its serviceable life during low frequency fatigue test at high temperature can be improved.The number of cycles for fracture was increased by 18.5%～28.8%. The number of large inclusion particleswas reduced and the composition of inclusions and their shape were changed as well. The strip distances on fatigue fracture surface were decreased. It is concluded that the optimum amount of RE addtion is about 0.05 wt%～0. 10 wt%.
基金Colleges and Universities Doctoral Station Fund Project (No. 97000812).
文摘The corrosion fatigue behavior of stainless steel 3RE60 in 3.5%NaCl solution was studied at different cyclic stress levels. The results showed that both intergranular corrosion cracking and transgranular corrosion cracking initiated at the bottom of pits. The corrosion fatigue behavior of 3RE60 may be related to complex electrochemical and mechanical coupling effects between the three phases (austenite, ferrite and martensite), where martensite and ferrite were anodic in the corrosion cell and could be prone to crack under certain conditions.
文摘The 3-D thermo-mechanical coupled elasto-plastic finite element method (FEM)was used for the simulation of the two-pass continuous hot rolling process of 60SiMnA spring steelbars and rods using MARC/AutoForge3.1 software. The simulated results visualize the metal flow andthe dynamic evolutions of the strain, stress and temperature during the continuous hot rolling,especially inside the work-piece. It is shown that the non-uniform distributions of the strain,stress and temperature on the longitudinal and transverse sections are a distinct characteristic ofthe continuous hot rolling, which can be used as basic data for improving the tool design,predicting and controlling the micro-structural evolution of a bar and rod.
