液态金属的流动性是影响其充型能力的主要因素之一,采用U形铜模研究了不同工艺参数对Zr_(55)Cu_(30)Al_(10)Ni_(5)和Zr_(61)Ti_(20)Cu_(25)Al_(12)合金充型能力以及非晶形成能力的影响。结果表明:随吸铸功率和吸铸压力的升高,两种合金...液态金属的流动性是影响其充型能力的主要因素之一,采用U形铜模研究了不同工艺参数对Zr_(55)Cu_(30)Al_(10)Ni_(5)和Zr_(61)Ti_(20)Cu_(25)Al_(12)合金充型能力以及非晶形成能力的影响。结果表明:随吸铸功率和吸铸压力的升高,两种合金熔体的流动长度增加,充型能力逐渐增强。Zr_(55)Cu_(30)Al_(10)Ni_(5)在吸铸功率8 k W,吸铸压力0.02 MPa,Zr_(61)Ti_(20)Cu_(25)Al_(12)在吸铸功率7 k W、吸铸压力0.03 MPa时,充型能力强。采用X射线衍射(XRD)、差示扫描量热(DSC)分析结果表明不同铸造参数下的试样均为非晶态结构,且适当提高吸铸功率,有助于提升铸造合金非晶形成能力(GFA)。展开更多
Investigation was conducted on roasting properties of pellets with an iron concentrate of complex mineral composition. The results indicated that the pellets of complex mineral composition concentrate required higher ...Investigation was conducted on roasting properties of pellets with an iron concentrate of complex mineral composition. The results indicated that the pellets of complex mineral composition concentrate required higher pre- heating temperature and longer preheating time than that of single magnetite concentrate. Therefore, it is difficult for preheated pellets to withstand the mechanical collision in the roasting process in rotary kiln. It was found that after the iron concentrate being subjected to high pressure roll grinding, the specific surface area reached 2 029. i cm2/g. Consequently, the preheating and roasting temperature of pellets were decreased by 70 and 50 ℃ and preheating and roasting time were decreased by 2 and 4 min, respectively. Meanwhile, the compression strength of preheated and roasted pellets were increased by 200 N for a pellet and 220 N for a pellet, respectively. The mechanism lied in that the increase of specific surface area activated thermal reaction and promoted formation of inter-grain bridge.展开更多
The experiments were conducted on the changes of sintering performance of one kind of ultra fine-sized iron concentrate with or without being processed by high pressure roll grinding （HPRG）. The experimental results...The experiments were conducted on the changes of sintering performance of one kind of ultra fine-sized iron concentrate with or without being processed by high pressure roll grinding （HPRG）. The experimental results indi eate that the specific surface area increases from 1723.0 to 2 201.6 cm^2/g when the iron concentrate is processed by HPRG. The permeability of sintering mix increases and the iron concentrate becomes easy to react with CaO reagent at high temperature. The effect gets intensified when iron concentrate and lime are processed together By HPRG. The further studies indicate that compared with the base case, the sinter quality also gets improved, in which the yield of sinter increases from 67.24% to 69.52% and further to 71.68%, the tumble index （TI） increases from 60.38% to 62.13% and further to 64.45%, and the productivity increases from 1.42 to 1.57 t/（m^2 · h） and further to 1.62 t/（m^2 · h） when the iron concentrate is processed by HPRG or is processed with lime together. The metallurgical properties of sinter also get improved when the iron concentrate is pretreated by high pressure roll. The results indicate that it is conducive to the increase of sinter quality and productivity when the iron concentrates are processed by HPRG.展开更多
文摘液态金属的流动性是影响其充型能力的主要因素之一,采用U形铜模研究了不同工艺参数对Zr_(55)Cu_(30)Al_(10)Ni_(5)和Zr_(61)Ti_(20)Cu_(25)Al_(12)合金充型能力以及非晶形成能力的影响。结果表明:随吸铸功率和吸铸压力的升高,两种合金熔体的流动长度增加,充型能力逐渐增强。Zr_(55)Cu_(30)Al_(10)Ni_(5)在吸铸功率8 k W,吸铸压力0.02 MPa,Zr_(61)Ti_(20)Cu_(25)Al_(12)在吸铸功率7 k W、吸铸压力0.03 MPa时,充型能力强。采用X射线衍射(XRD)、差示扫描量热(DSC)分析结果表明不同铸造参数下的试样均为非晶态结构,且适当提高吸铸功率,有助于提升铸造合金非晶形成能力(GFA)。
基金Item Sponsored by National Natural Science Foundation of China(50725416)
文摘Investigation was conducted on roasting properties of pellets with an iron concentrate of complex mineral composition. The results indicated that the pellets of complex mineral composition concentrate required higher pre- heating temperature and longer preheating time than that of single magnetite concentrate. Therefore, it is difficult for preheated pellets to withstand the mechanical collision in the roasting process in rotary kiln. It was found that after the iron concentrate being subjected to high pressure roll grinding, the specific surface area reached 2 029. i cm2/g. Consequently, the preheating and roasting temperature of pellets were decreased by 70 and 50 ℃ and preheating and roasting time were decreased by 2 and 4 min, respectively. Meanwhile, the compression strength of preheated and roasted pellets were increased by 200 N for a pellet and 220 N for a pellet, respectively. The mechanism lied in that the increase of specific surface area activated thermal reaction and promoted formation of inter-grain bridge.
基金Sponsored by Program for New Century Talents in University of China(NCET-10-0834)
文摘The experiments were conducted on the changes of sintering performance of one kind of ultra fine-sized iron concentrate with or without being processed by high pressure roll grinding （HPRG）. The experimental results indi eate that the specific surface area increases from 1723.0 to 2 201.6 cm^2/g when the iron concentrate is processed by HPRG. The permeability of sintering mix increases and the iron concentrate becomes easy to react with CaO reagent at high temperature. The effect gets intensified when iron concentrate and lime are processed together By HPRG. The further studies indicate that compared with the base case, the sinter quality also gets improved, in which the yield of sinter increases from 67.24% to 69.52% and further to 71.68%, the tumble index （TI） increases from 60.38% to 62.13% and further to 64.45%, and the productivity increases from 1.42 to 1.57 t/（m^2 · h） and further to 1.62 t/（m^2 · h） when the iron concentrate is processed by HPRG or is processed with lime together. The metallurgical properties of sinter also get improved when the iron concentrate is pretreated by high pressure roll. The results indicate that it is conducive to the increase of sinter quality and productivity when the iron concentrates are processed by HPRG.
