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Optimizing loading path and die linetype of large length-to-diameter ratio metal stator screw lining hydroforming 被引量:2
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作者 祝效华 石昌帅 童华 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第1期224-231,共8页
In order to meet the high temperature environment requirement of deep and superdeep well exploitation, a technology of large length-to-diameter ratio metal stator screw lining meshing with rotor is presented. Based on... In order to meet the high temperature environment requirement of deep and superdeep well exploitation, a technology of large length-to-diameter ratio metal stator screw lining meshing with rotor is presented. Based on the elastic-plasticity theory, and under the consideration of the effect of tube size, material mechanical parameters, friction coefficient and loading paths, the external pressure plastic forming mechanical model of metal stator screw lining is established, to study the optimal loading path of metal stator lining tube hydroforming process. The results show that wall thickness reduction of the external pressure tube hydroforming(THF) is about 4%, and three evaluation criteria of metal stator screw lining forming quality are presented: fillet stick mold coefficient, thickness relative error and forming quality coefficient. The smaller the three criteria are, the better the forming quality is.Each indicator has a trend of increase with the loading rate reducing, and the adjustment laws of die arc transition zone equidistance profile curve are acquired for improving tube forming quality. Hence, the research results prove the feasibility of external pressure THF used for processing high-accuracy large length-to-diameter ratio metal stator screw lining, and provide theoretical basis for designing new kind of stator structure which has better performance and longer service life. 展开更多
关键词 tube hydroforming loading path large length-to-diameter ratio metal stator lining simulation
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Product/metal ratio (PMR):A novel criterion for the evaluation of electrolytes on micro-arc oxidation (MAO) of Mg and its alloys 被引量:6
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作者 SONG LaiWen SONG YingWei +2 位作者 SHAN DaYong ZHU GuoYi HAN EnHou 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第10期2795-2801,共7页
Product/metal ratio (PMR) was introduced as a novel criterion for the evaluation of electrolytes on micro-arc oxidation (MAO) of Mg and its alloys. The criterion initially sprang from Pilling-Bedworth ratio (PBR), foc... Product/metal ratio (PMR) was introduced as a novel criterion for the evaluation of electrolytes on micro-arc oxidation (MAO) of Mg and its alloys. The criterion initially sprang from Pilling-Bedworth ratio (PBR), focused on the roles of electrolytes for the compactness of the fabricated coatings, and took attention on properties of reactants/products during MAO. Meanwhile, based on our experiments as well as the results from literatures, the effects of electrolyte additives on morphologies and com-positions of the fabricated MAO coatings of Mg alloys were exploited for verification and supplement of the initial criterion. In combination of the initial PMR criterion and experimental verification, PMR could be represented by special mode (PMRs=Voxide products/Valloy substrates) and general mode (PMRg= PMRs+ PMRd). The ideal PMRs should be between 1 and 2, while PMRd is related to the coating deposition during MAO. PMRd is a supplement to PMRs when the effect of the overlaying prop-erty (O) of the coatings and the effective deposition (D) of electrolyte composites are considered (PMRd=f(O, D). O is related to the melting point (MP) and boiling point (BP) of the MAO products. D is related to the effective reactions between alloy substrates and electrolytes during MAO. 展开更多
关键词 micro-arc oxidation Mg alloys Pilling-Bedworth ratio product/metal ratio
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Effects of Na_(2)CO_(3)on reduction mechanism and kinetics of iron during deep reduction of ilmenite concentrate
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作者 Xiao-dong Lv You-ling Hou +2 位作者 Yun-tao Xin Wei Lv Xue-wei Lv 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2023年第3期419-428,共10页
High-quality upgraded titanium slag obtained through semi-molten reduction with the addition of Na_(2)CO_(3)is important for the fluidizing chlorination process to produce TiO_(2)pigments.The key is the effect of Na_(... High-quality upgraded titanium slag obtained through semi-molten reduction with the addition of Na_(2)CO_(3)is important for the fluidizing chlorination process to produce TiO_(2)pigments.The key is the effect of Na_(2)CO_(3)on the reduction behavior of iron.Therefore,the effects of Na_(2)CO_(3)on reduction mechanism and kinetics of iron during deep reduction of ilmenite concentrate were studied.The results indicated that the metallization ratio of the reduced sample increased with increasing temperature,time,and dose of Na_(2)CO_(3).The addition of Na_(2)CO_(3)significantly accelerated the reduction of iron in the ilmenite concentrate and promoted the growth of iron particles.However,the addition of Na_(2)CO_(3)produced sodium iron titanates;thus,the metallization ratio of the sample decreased with an increase in the temperature and time when the temperature was above 1200℃and the time was more than 30 min.When the doses of Na_(2)CO_(3)were 0,3,and 6 wt.%,the reduction of iron was controlled by the interfacial chemical reaction,both the interfacial chemical reaction and diffusion,and diffusion,respectively,and the apparent activation energies were 134.91,64.89,and 120.82 kJ/mol,respectively. 展开更多
关键词 Ilmenite concentrate Sodium carbonate metallization ratio Reduction mechanism KINETICS
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