An industrial plant trial for optimizing the process parameters in a round billet continuous casting mold with electromagnetic stirring （M-EMS） was performed, in which the influences of stirring parameters with M-EM...An industrial plant trial for optimizing the process parameters in a round billet continuous casting mold with electromagnetic stirring （M-EMS） was performed, in which the influences of stirring parameters with M-EMS on the solidification macrostructure of high carbon steel were investigated. The results show that the billet quality is not well controlled under the condition of working current and frequency with EMS, in which the subsurface crack of grade 1.0-2.0 ups to 38.09%, the central pipe of grade 1.0-1.5 reaches to 14.28%, and the central porosity of grade 1.5 is 14.29%. The parameters of current 260 A and frequency 8 Hz as the final optimum scheme has a remarkable effect for improving the macroscopic quality of billet, in which the subsurface crack, central pipe and skin blowhole are all disappeared, and the central porosity and carbon segregation are also well improved.展开更多
The formation mechanism of 'white band' and central carbon segregation of high-carbon Cr bearing steel concasting billets are discussed in this paper. The maximum oxygen content in the steel produced by concas...The formation mechanism of 'white band' and central carbon segregation of high-carbon Cr bearing steel concasting billets are discussed in this paper. The maximum oxygen content in the steel produced by concasting process was 13xl0^-6 with an average oxygen content of 9.3xl0^-6. Comparison of metallurgical quality and fatigue property between the concasting steel (CC) and ingot casting steel (IC) showed that the carbon segregation (C/C0) in former steel was 0.92～1.10 and its fatigue life was equal to that of the latter steel.展开更多
Ferritic stainless steel （FSS） for various applications was developed on the basis of Thermo-calc simulation. Alloy design, precipitate analysis and processing parameters optimization were carried out on the basis o...Ferritic stainless steel （FSS） for various applications was developed on the basis of Thermo-calc simulation. Alloy design, precipitate analysis and processing parameters optimization were carried out on the basis of the simulation results according to the technical requirements of the applications. These developed products have outstanding properties, such as mechanical strength, ductility, formability, weldability and corrosion resistance. Baosteel has formed a series of FSS products which will increase the profit of the company and enhance the product variety of stainless steel.展开更多
In consideration of the composition characteristics and quality requirements of sulphurous free-cutting gear steel, the rational measures of sulfur control, calcium treatment and key technologies of continuous casting...In consideration of the composition characteristics and quality requirements of sulphurous free-cutting gear steel, the rational measures of sulfur control, calcium treatment and key technologies of continuous casting process are applied in the development of a full-line operation of LD-Billet continuous casting on steelmaking with semi-steel, which suggests an economic production of the steel has been realized. Test results show that the average retrieval rate of sulphurous alloy in the process of RH treatment is 95.3% and sulfur content of products is stability. Otherwise, content of T[O] in casting billet is in the range of 11×10-6 ~ 18×10-6 with average value is 14.7×10-6.Based on this, the billets have good surface quality and internal quality.展开更多
The effect of ground steel-making slag on microstructure and composition of hydration products of ordinary Portland cement (OPC) was investigated by mercury intrusion porosimetry (MIP),X-ray diffraction (XRD) and diff...The effect of ground steel-making slag on microstructure and composition of hydration products of ordinary Portland cement (OPC) was investigated by mercury intrusion porosimetry (MIP),X-ray diffraction (XRD) and differential thermal analysis (DTA).Results show that ground steel-making slag is a kind of high activity mineral additives and it can raise the longer-age strength of OPC mortar.The total porosity and average pore diameter of OPC paste with ground steel-making slag increase with the increase of the amount of ground steel-making slag replacing OPC at various ages,while after 28 days most pores in OPC paste with ground steel-making slag do not influence the strength because the diameter of those pores is in the rang of 20 to 50nm.The hydration mechanism of ground steel-making slag is similar to that of OPC but different from that of fly ash and blast furnace slag.The hydration products of ground steel-making slag contain quite a lot of Ca(OH) 2 in long age.展开更多
To establish an adequate thermodynamic model for the mechanism of formation of hydrogen sulfide(H_2S) corrosion products,theoretical and experimental studies were combined in this work. The corrosion products of API X...To establish an adequate thermodynamic model for the mechanism of formation of hydrogen sulfide(H_2S) corrosion products,theoretical and experimental studies were combined in this work. The corrosion products of API X60 pipeline steel formed under different H_2S corrosion conditions were analyzed by scanning electron microscopy,energy-dispersive X-ray spectroscopy,and X-ray diffraction. A thermodynamic model was developed to clarify the environmental boundaries for the formation and transformation of different products. Presumably,a dividing line with a negative slope existed between mackinawite and pyrrhotite. Using experimental data presented in this study combined with previously published results,we validated the model to predict the formation of mackinawite and pyrrhotite on the basis of the laws of thermodynamics. The established relationship is expected to support the investigation of the H_2S corrosion mechanism in the oil and gas industry.展开更多
Nitrogen plays a vitally important role for improving properties for stainless steels in many aspects.In this paper,the physical metallurgy behavior and the beneficial effects of nitrogen on corrosion resistance and o...Nitrogen plays a vitally important role for improving properties for stainless steels in many aspects.In this paper,the physical metallurgy behavior and the beneficial effects of nitrogen on corrosion resistance and other mechanical properties of stainless steels were summarised.Based on nitrogen alloying,various stainless steel products,such as austenitic,duplex and martensitic staniless steels were developed with enhanced properties,such as corrosion resistance,mechanical strength and weldability,among other things.展开更多
Oxygen-reducing air flooding is a low-permeability reservoir recovery technology with safety and low-cost advantages.However,in the process of air injection and drive,carbon in the air is oxidized through the crude oi...Oxygen-reducing air flooding is a low-permeability reservoir recovery technology with safety and low-cost advantages.However,in the process of air injection and drive,carbon in the air is oxidized through the crude oil reservoir to generate CO_(2),and this can cause serious corrosion in the recovery well.In this study,experiments on the corrosion of J55 tubular steel in a fluid environment with coexisting O_(2)and CO_(2)in an autoclave are presented.In particular,a weight loss method and a 3D morphometer were used to determine the average and the local corrosion rate.The corrosion surface morphology and composition were also measured by means of scanning electron microscopy(SEM)and an X-ray diffractometer(XRD).The corrosion pattern and morphological characteristics of J55 steel were analyzed in the O2/CO_(2)environment for different degrees of oxygen-reduction.As made evident by the experimental results,the corrosion products were mainly ferrous carbonate and iron oxide.In general,air injection increases the degree of oxygen reduction,from oxygen corrosion characteristics to CO_(2)corrosion-based characteristics.As a result,the corrosion product film becomes denser,and the corrosion rate is lower.展开更多
基金supported by the Program for New Century Excellent Talents in University from the Ministry of Education of China (No.NCET-04-0285)
文摘An industrial plant trial for optimizing the process parameters in a round billet continuous casting mold with electromagnetic stirring （M-EMS） was performed, in which the influences of stirring parameters with M-EMS on the solidification macrostructure of high carbon steel were investigated. The results show that the billet quality is not well controlled under the condition of working current and frequency with EMS, in which the subsurface crack of grade 1.0-2.0 ups to 38.09%, the central pipe of grade 1.0-1.5 reaches to 14.28%, and the central porosity of grade 1.5 is 14.29%. The parameters of current 260 A and frequency 8 Hz as the final optimum scheme has a remarkable effect for improving the macroscopic quality of billet, in which the subsurface crack, central pipe and skin blowhole are all disappeared, and the central porosity and carbon segregation are also well improved.
文摘The formation mechanism of 'white band' and central carbon segregation of high-carbon Cr bearing steel concasting billets are discussed in this paper. The maximum oxygen content in the steel produced by concasting process was 13xl0^-6 with an average oxygen content of 9.3xl0^-6. Comparison of metallurgical quality and fatigue property between the concasting steel (CC) and ingot casting steel (IC) showed that the carbon segregation (C/C0) in former steel was 0.92～1.10 and its fatigue life was equal to that of the latter steel.
文摘Ferritic stainless steel （FSS） for various applications was developed on the basis of Thermo-calc simulation. Alloy design, precipitate analysis and processing parameters optimization were carried out on the basis of the simulation results according to the technical requirements of the applications. These developed products have outstanding properties, such as mechanical strength, ductility, formability, weldability and corrosion resistance. Baosteel has formed a series of FSS products which will increase the profit of the company and enhance the product variety of stainless steel.
文摘In consideration of the composition characteristics and quality requirements of sulphurous free-cutting gear steel, the rational measures of sulfur control, calcium treatment and key technologies of continuous casting process are applied in the development of a full-line operation of LD-Billet continuous casting on steelmaking with semi-steel, which suggests an economic production of the steel has been realized. Test results show that the average retrieval rate of sulphurous alloy in the process of RH treatment is 95.3% and sulfur content of products is stability. Otherwise, content of T[O] in casting billet is in the range of 11×10-6 ~ 18×10-6 with average value is 14.7×10-6.Based on this, the billets have good surface quality and internal quality.
文摘The effect of ground steel-making slag on microstructure and composition of hydration products of ordinary Portland cement (OPC) was investigated by mercury intrusion porosimetry (MIP),X-ray diffraction (XRD) and differential thermal analysis (DTA).Results show that ground steel-making slag is a kind of high activity mineral additives and it can raise the longer-age strength of OPC mortar.The total porosity and average pore diameter of OPC paste with ground steel-making slag increase with the increase of the amount of ground steel-making slag replacing OPC at various ages,while after 28 days most pores in OPC paste with ground steel-making slag do not influence the strength because the diameter of those pores is in the rang of 20 to 50nm.The hydration mechanism of ground steel-making slag is similar to that of OPC but different from that of fly ash and blast furnace slag.The hydration products of ground steel-making slag contain quite a lot of Ca(OH) 2 in long age.
基金financially supported by the National Natural Science Foundation of China(Nos.51271025 and 51171022)
文摘To establish an adequate thermodynamic model for the mechanism of formation of hydrogen sulfide(H_2S) corrosion products,theoretical and experimental studies were combined in this work. The corrosion products of API X60 pipeline steel formed under different H_2S corrosion conditions were analyzed by scanning electron microscopy,energy-dispersive X-ray spectroscopy,and X-ray diffraction. A thermodynamic model was developed to clarify the environmental boundaries for the formation and transformation of different products. Presumably,a dividing line with a negative slope existed between mackinawite and pyrrhotite. Using experimental data presented in this study combined with previously published results,we validated the model to predict the formation of mackinawite and pyrrhotite on the basis of the laws of thermodynamics. The established relationship is expected to support the investigation of the H_2S corrosion mechanism in the oil and gas industry.
文摘Nitrogen plays a vitally important role for improving properties for stainless steels in many aspects.In this paper,the physical metallurgy behavior and the beneficial effects of nitrogen on corrosion resistance and other mechanical properties of stainless steels were summarised.Based on nitrogen alloying,various stainless steel products,such as austenitic,duplex and martensitic staniless steels were developed with enhanced properties,such as corrosion resistance,mechanical strength and weldability,among other things.
基金Major national science and technology projects“Key Techniques for the Development of Low Abundance Tight Low Permeability Reservoirs”(2016ZX05048).
文摘Oxygen-reducing air flooding is a low-permeability reservoir recovery technology with safety and low-cost advantages.However,in the process of air injection and drive,carbon in the air is oxidized through the crude oil reservoir to generate CO_(2),and this can cause serious corrosion in the recovery well.In this study,experiments on the corrosion of J55 tubular steel in a fluid environment with coexisting O_(2)and CO_(2)in an autoclave are presented.In particular,a weight loss method and a 3D morphometer were used to determine the average and the local corrosion rate.The corrosion surface morphology and composition were also measured by means of scanning electron microscopy(SEM)and an X-ray diffractometer(XRD).The corrosion pattern and morphological characteristics of J55 steel were analyzed in the O2/CO_(2)environment for different degrees of oxygen-reduction.As made evident by the experimental results,the corrosion products were mainly ferrous carbonate and iron oxide.In general,air injection increases the degree of oxygen reduction,from oxygen corrosion characteristics to CO_(2)corrosion-based characteristics.As a result,the corrosion product film becomes denser,and the corrosion rate is lower.
