Based on the relevant phase diagrams of ternary system in MgO-CaO-ZrO2-SiO2 quarternary systems,the phase diagram of Fe-O system and the condensed phase stability area diagram of iron oxides,the corrosion resistance o...Based on the relevant phase diagrams of ternary system in MgO-CaO-ZrO2-SiO2 quarternary systems,the phase diagram of Fe-O system and the condensed phase stability area diagram of iron oxides,the corrosion resistance of MgO-CaO-ZrO2 refractories to silicate cement,and the forming conditions and preparing measures of hercynite are analyzed.展开更多
This paper attempts to clarify the systematic works of the refractories for the RH degassers and the ways of improving their lining life.It includes: (1) types of RH degassers; (2) the operating conditions of refining...This paper attempts to clarify the systematic works of the refractories for the RH degassers and the ways of improving their lining life.It includes: (1) types of RH degassers; (2) the operating conditions of refining and the severely damaged areas in RH degassers; (3) the reasons why side wall and bottom of lower vessel, throat and snorkels become the severe wear areas are analyzed, such as erosion and abrasion caused by the high circulation rate of treated molten steel, thermal and structural spalling by the violent temperature change, high corrosion by the Feoxides containing siliceous slag and CaF2riched desulfurization powders attack, degradation of texture by the vaporisation of refractory components in vacuum and in oxygen blowing; besides the above mentioned factors, what other reasons to make the snorkels become the most quick wear elements are also explained; (4) the studies of resistance to refining slags attack and slag penetration and its prevention; the evaluation of various refractory materials to withstand the attack of slags is based on the experimental results of rotating cylinder method, rotary drum test and induction furnace test, and the phase diagrams analyses; the measures to reduce the slag penetration are discussed, for example the deep of slag penetration can be decreased by reducing the size of brick pores; (5) suitable refractory materials selection and recent developments for the different severe wear areasin RH, and lining maintenance; (6) refractories for RH to refine silicon steel; (7) the ways of improving RH lining life.展开更多
The specimens were prepared using Cr2O3 micropowder, TiO2 micropowder and chromium powder as starting materials, PVA as binder, after spraying granulation and cold isostatic pressing, firing at 1 450 ℃ for 3 h in sta...The specimens were prepared using Cr2O3 micropowder, TiO2 micropowder and chromium powder as starting materials, PVA as binder, after spraying granulation and cold isostatic pressing, firing at 1 450 ℃ for 3 h in standard nitrogen and oxygen control atmosphere (oxygen partial pressure was 1 010 Pa and 10.1 Pa, respectively). Effects of chromium powder (mass percent were 0, 0.5%, 1.0%, 1.5% and 2.0%, respectively) on sintering behaviors of Cr2O3 materials were researched. The results show that: adding 0.5% chromium powder can obviously decrease the oxygen partial pressure in the specimens. Meanwhile, because the expansion caused by the oxidation reaction is small, Cr2O3 materials could realize the densification sintering under 1 010 Pa and 10.1 Pa of oxygen partial pressure. The chromium powder addition in Cr2O3 materials shouldn't be excessive, otherwise, the expansion reaction occupies a dominant position, which deteriorates the properties of the materials.展开更多
文摘Based on the relevant phase diagrams of ternary system in MgO-CaO-ZrO2-SiO2 quarternary systems,the phase diagram of Fe-O system and the condensed phase stability area diagram of iron oxides,the corrosion resistance of MgO-CaO-ZrO2 refractories to silicate cement,and the forming conditions and preparing measures of hercynite are analyzed.
文摘This paper attempts to clarify the systematic works of the refractories for the RH degassers and the ways of improving their lining life.It includes: (1) types of RH degassers; (2) the operating conditions of refining and the severely damaged areas in RH degassers; (3) the reasons why side wall and bottom of lower vessel, throat and snorkels become the severe wear areas are analyzed, such as erosion and abrasion caused by the high circulation rate of treated molten steel, thermal and structural spalling by the violent temperature change, high corrosion by the Feoxides containing siliceous slag and CaF2riched desulfurization powders attack, degradation of texture by the vaporisation of refractory components in vacuum and in oxygen blowing; besides the above mentioned factors, what other reasons to make the snorkels become the most quick wear elements are also explained; (4) the studies of resistance to refining slags attack and slag penetration and its prevention; the evaluation of various refractory materials to withstand the attack of slags is based on the experimental results of rotating cylinder method, rotary drum test and induction furnace test, and the phase diagrams analyses; the measures to reduce the slag penetration are discussed, for example the deep of slag penetration can be decreased by reducing the size of brick pores; (5) suitable refractory materials selection and recent developments for the different severe wear areasin RH, and lining maintenance; (6) refractories for RH to refine silicon steel; (7) the ways of improving RH lining life.
文摘The specimens were prepared using Cr2O3 micropowder, TiO2 micropowder and chromium powder as starting materials, PVA as binder, after spraying granulation and cold isostatic pressing, firing at 1 450 ℃ for 3 h in standard nitrogen and oxygen control atmosphere (oxygen partial pressure was 1 010 Pa and 10.1 Pa, respectively). Effects of chromium powder (mass percent were 0, 0.5%, 1.0%, 1.5% and 2.0%, respectively) on sintering behaviors of Cr2O3 materials were researched. The results show that: adding 0.5% chromium powder can obviously decrease the oxygen partial pressure in the specimens. Meanwhile, because the expansion caused by the oxidation reaction is small, Cr2O3 materials could realize the densification sintering under 1 010 Pa and 10.1 Pa of oxygen partial pressure. The chromium powder addition in Cr2O3 materials shouldn't be excessive, otherwise, the expansion reaction occupies a dominant position, which deteriorates the properties of the materials.
