In order to stabilize the sinter chemical composition,the expert system for composition control based on adaptive prediction has been developed on the basis of modern control theory and artificial intelligence.It has ...In order to stabilize the sinter chemical composition,the expert system for composition control based on adaptive prediction has been developed on the basis of modern control theory and artificial intelligence.It has been verified by using real data at No.3 Sintering Plant of Anshan Iron and Steel Co.,and satisfactory results have been obtained.展开更多
The mechanical properties of dual-phase steel (DP1000) over the strain rate range of 10^-3-10^3 s^-1 were studied using an electronic universal testing machine and a high-speed tensile testing machine.The plastic defo...The mechanical properties of dual-phase steel (DP1000) over the strain rate range of 10^-3-10^3 s^-1 were studied using an electronic universal testing machine and a high-speed tensile testing machine.The plastic deformation mechanism was investigated from the perspectives of the strain rate sensitivity index,activation volume and dynamic factors.The results show that the tensile strength and yield strength of DP1000 increase as the strain rate increases.The elongation increases without any change after fracture,and then decreased rapidly when the strain rate reaches 103 s^-1.The true strain curves of DP1000 show three stages:the point of instability decreases in the strain range of 10^-3-10^-1 s^-1;the instability point increases between 100-5×10^2 s^-1;above 5×10^2 s^-1,and the instability strain becomes smaller again.The plastic deformation mechanism of the DP was determined by the competitive contributions of work hardening (strain hardening,strain rate hardening) and softening effects due to the adiabatic temperature rise.展开更多
Corrosion behavior of Cu-P-Cr-Ni weathering steels with different nickel contents was studied by periodic immersion corrosion test for 72 h.The mass loss method was used to evaluate the weatherability of weathering st...Corrosion behavior of Cu-P-Cr-Ni weathering steels with different nickel contents was studied by periodic immersion corrosion test for 72 h.The mass loss method was used to evaluate the weatherability of weathering steel.The rust layers formed on weathering steel were characterized by scanning electron microscopy,X-ray diffraction,electron probe microanalysis,X-ray photoelectron spectroscopy,and electrochemical measurements.The results of periodic immersion corrosion test for 72 h showed that the mass loss rates of Cu-P-Cr-0.14Ni steel and Cu-P-Cr-0.04Ni steel were 1.57 and 1.61 g/(m^(2)h),respectively.According to the electrochemical experiment,the corrosion potentials of the two tested steels at the initial stage of corrosion were-0.6852 and-0.7037 V,respectively.With the corrosion time reaching 72 h,the corrosion potential difference between the two tested steels was gradually reduced.In the initial stage,NiO was formed in the rust layer and can dramatically promote the crystallization of corrosion products to improve the stability of the rust layer.After periodic immersion corrosion test for 72 h,Ni element had no obvious effect.At this time,it was mainly the enrichment of Cu and Cr elements in the form of CuO and Cr_(2)O_(3)in the rust layer that could further protect the matrix.展开更多
The microstructure and mechanical properties of a traditional Ti-microalloyed weathering steel were analyzed,and the strength was improved by proposing an optimized Ti content.The yield strength and elongation of the ...The microstructure and mechanical properties of a traditional Ti-microalloyed weathering steel were analyzed,and the strength was improved by proposing an optimized Ti content.The yield strength and elongation of the steel were 640 MPa and 25.5%,respectively.The microstructure was ferrite and pearlite,and the average grain size was 5.4μm.The precipitates were mainly TiC with the size below 20 nm,and the average diameter was 18.2 nm.The yield strength of the newly proposed weathering steel with Ti content of 0.018%higher than that of the traditional steel reached up to 709 MPa,and the elongation was 23.5%.The ferrite grain was refined to 3.8μm,the fraction of TiC under 10 nm was obviously increased,and the average diameter of particles was 9.8 nm.The increase in Ti also promoted the recrystallization process,thus leading to the reduction in dislocation density.The yield strength of the newly proposed weathering steel was increased to higher than 700 MPa by adjusting the Ti content mainly resulting from three aspects:grain refinement,precipitation and dislocation strengthening.The contributed values were 45,64 and–40 MPa,respectively.展开更多
Iron ore sintering is a pre-treatment technology by which orefines are converted into porous and permeable sin-ters,which are the used in blast furnaces.This process can be adversely affected by air leakage phenomena ...Iron ore sintering is a pre-treatment technology by which orefines are converted into porous and permeable sin-ters,which are the used in blast furnaces.This process can be adversely affected by air leakage phenomena of various types.As experimental measurements are relatively difficult and often scarcely reliable,here a theoretical model based on typicalfluid-dynamic concepts and relationships is elaborated.Through the analysis of two extreme cases,namely,those in which leakage is due to a small hole or a full rupture,a generalized hole-bed mod-el is introduced,which for thefirst time also includes a complete bed permeability equation and can deal with different leakage position conditions.The results show that the model can evaluate the influence of leakage on the system at one time and be used to calculate theflowrate and pressure drop.Notably,the obtained results are within a 15%deviation with respect to available experiment values,used for comparison.展开更多
提高高炉炉料结构中块矿配比对降低铁水生产成本具有重要作用,而天然块矿一般湿度较大,天然块矿在入高炉前有必要进行干燥。以块矿为研究对象,通过实验研究了干燥介质温度、流速和块矿粒度对块矿的干燥特性的影响。结果表明,升高干燥温...提高高炉炉料结构中块矿配比对降低铁水生产成本具有重要作用,而天然块矿一般湿度较大,天然块矿在入高炉前有必要进行干燥。以块矿为研究对象,通过实验研究了干燥介质温度、流速和块矿粒度对块矿的干燥特性的影响。结果表明,升高干燥温度、提高空气流速、减小块矿粒度可以有效缩短块矿干燥时间,提高干燥效率,适宜的干燥工艺条件为:干燥气体温度400℃,干燥气体流速12 m^(3)/h;在此基础上对块矿干燥进行了动力学分析,发现与Henderson and Pabis模型、Lewis模型相比,Page模型与实际干燥水分比MR-时间曲线吻合程度最高。同时得到了干燥介质温度T、流速V与干燥水分比MR的干燥动力学方程。发现干燥过程依次出现升速干燥、恒速干燥、第一降速干燥和第二降速干燥4个阶段,且升速干燥和恒速干燥过程时间相对较短,分别为干燥总时间的5%和10%。展开更多
基金Supported by the National Natural Science Foundation of ChinaKey Program of the 8th Five-Year Plan of China。
文摘In order to stabilize the sinter chemical composition,the expert system for composition control based on adaptive prediction has been developed on the basis of modern control theory and artificial intelligence.It has been verified by using real data at No.3 Sintering Plant of Anshan Iron and Steel Co.,and satisfactory results have been obtained.
基金Funded by the National Natural Science Foundation of China(No.52004122)the State Key Laboratory of Marine Equipment made of Metal Material and Application(No.SKLMEAUSTL-201906)+1 种基金the Guidance plan of Natural Science Foundation of Liaoning Province(No.2019-ZD-0025)the Key Project of Liaoning Education Department(No.2019FWDF03)。
文摘The mechanical properties of dual-phase steel (DP1000) over the strain rate range of 10^-3-10^3 s^-1 were studied using an electronic universal testing machine and a high-speed tensile testing machine.The plastic deformation mechanism was investigated from the perspectives of the strain rate sensitivity index,activation volume and dynamic factors.The results show that the tensile strength and yield strength of DP1000 increase as the strain rate increases.The elongation increases without any change after fracture,and then decreased rapidly when the strain rate reaches 103 s^-1.The true strain curves of DP1000 show three stages:the point of instability decreases in the strain range of 10^-3-10^-1 s^-1;the instability point increases between 100-5×10^2 s^-1;above 5×10^2 s^-1,and the instability strain becomes smaller again.The plastic deformation mechanism of the DP was determined by the competitive contributions of work hardening (strain hardening,strain rate hardening) and softening effects due to the adiabatic temperature rise.
基金The authors appreciate the financial support from Maanshan Iron&Steel Co,Ltd.and Student Research Training Program of University of Science and Technology Beijing.
文摘Corrosion behavior of Cu-P-Cr-Ni weathering steels with different nickel contents was studied by periodic immersion corrosion test for 72 h.The mass loss method was used to evaluate the weatherability of weathering steel.The rust layers formed on weathering steel were characterized by scanning electron microscopy,X-ray diffraction,electron probe microanalysis,X-ray photoelectron spectroscopy,and electrochemical measurements.The results of periodic immersion corrosion test for 72 h showed that the mass loss rates of Cu-P-Cr-0.14Ni steel and Cu-P-Cr-0.04Ni steel were 1.57 and 1.61 g/(m^(2)h),respectively.According to the electrochemical experiment,the corrosion potentials of the two tested steels at the initial stage of corrosion were-0.6852 and-0.7037 V,respectively.With the corrosion time reaching 72 h,the corrosion potential difference between the two tested steels was gradually reduced.In the initial stage,NiO was formed in the rust layer and can dramatically promote the crystallization of corrosion products to improve the stability of the rust layer.After periodic immersion corrosion test for 72 h,Ni element had no obvious effect.At this time,it was mainly the enrichment of Cu and Cr elements in the form of CuO and Cr_(2)O_(3)in the rust layer that could further protect the matrix.
基金support from Maanshan Iron&Steel Co.,Ltd.and student research training project of University of Science and Technology Beijing.
文摘The microstructure and mechanical properties of a traditional Ti-microalloyed weathering steel were analyzed,and the strength was improved by proposing an optimized Ti content.The yield strength and elongation of the steel were 640 MPa and 25.5%,respectively.The microstructure was ferrite and pearlite,and the average grain size was 5.4μm.The precipitates were mainly TiC with the size below 20 nm,and the average diameter was 18.2 nm.The yield strength of the newly proposed weathering steel with Ti content of 0.018%higher than that of the traditional steel reached up to 709 MPa,and the elongation was 23.5%.The ferrite grain was refined to 3.8μm,the fraction of TiC under 10 nm was obviously increased,and the average diameter of particles was 9.8 nm.The increase in Ti also promoted the recrystallization process,thus leading to the reduction in dislocation density.The yield strength of the newly proposed weathering steel was increased to higher than 700 MPa by adjusting the Ti content mainly resulting from three aspects:grain refinement,precipitation and dislocation strengthening.The contributed values were 45,64 and–40 MPa,respectively.
文摘Iron ore sintering is a pre-treatment technology by which orefines are converted into porous and permeable sin-ters,which are the used in blast furnaces.This process can be adversely affected by air leakage phenomena of various types.As experimental measurements are relatively difficult and often scarcely reliable,here a theoretical model based on typicalfluid-dynamic concepts and relationships is elaborated.Through the analysis of two extreme cases,namely,those in which leakage is due to a small hole or a full rupture,a generalized hole-bed mod-el is introduced,which for thefirst time also includes a complete bed permeability equation and can deal with different leakage position conditions.The results show that the model can evaluate the influence of leakage on the system at one time and be used to calculate theflowrate and pressure drop.Notably,the obtained results are within a 15%deviation with respect to available experiment values,used for comparison.
文摘提高高炉炉料结构中块矿配比对降低铁水生产成本具有重要作用,而天然块矿一般湿度较大,天然块矿在入高炉前有必要进行干燥。以块矿为研究对象,通过实验研究了干燥介质温度、流速和块矿粒度对块矿的干燥特性的影响。结果表明,升高干燥温度、提高空气流速、减小块矿粒度可以有效缩短块矿干燥时间,提高干燥效率,适宜的干燥工艺条件为:干燥气体温度400℃,干燥气体流速12 m^(3)/h;在此基础上对块矿干燥进行了动力学分析,发现与Henderson and Pabis模型、Lewis模型相比,Page模型与实际干燥水分比MR-时间曲线吻合程度最高。同时得到了干燥介质温度T、流速V与干燥水分比MR的干燥动力学方程。发现干燥过程依次出现升速干燥、恒速干燥、第一降速干燥和第二降速干燥4个阶段,且升速干燥和恒速干燥过程时间相对较短,分别为干燥总时间的5%和10%。
