结晶器电磁搅拌对方坯质量的影响

主要测定6机6流小方坯连铸机结晶器内磁感应强度的分布,分析铸坯的低倍检验结果。结果表明：电流和频率、浇注的钢种对结晶器电磁搅拌的使用效果有较大的影响。为了保证各流铸坯质量一致,必须对各流结晶器内的磁感应强度经常进行测定。     

电磁搅拌对板坯内部质量的影响

介绍板坯连铸电磁搅拌辊技术在马钢的应用实践,在使用该项技术之后,有效的增加了铸坯的等轴晶区,改善中心偏析和中心疏松,消除了中间裂纹,但铸坯也出现白亮带、等轴晶区致密度下降的缺陷。     

U74重轨大方坯开坯后中心碳偏析的演变分析

针对U74重轨钢大方坯进行了开坯前后中心碳偏析的演变分析,并进一步分析了电磁搅拌参数和连铸工艺参数对铸坯中心碳偏析的影响,采用回归分析探讨了电磁搅拌强度和连铸工艺参数过热度与铸坯中心碳偏析的关系.     

小方坯连铸结晶器电磁搅拌磁场和流场的耦合分析

借助有限元方法,对小方坯结晶器电磁搅拌过程进行了磁场和流场耦合数值分析,得出了不同频率下钢液内部磁感应强度和电磁体积力及搅拌速度的分布规律.结果表明,在结晶器电磁搅拌时,随着频率的增加,钢液内部磁感应强度降低,电磁体积力在钢液内部分布不均匀;在电流频率为3 Hz时,钢液搅拌速度最大.在现场对结晶器电磁搅拌器的磁场强度进行了冷态测试,实验值和模拟值基本相符.     

用M-IEMS改善重轨钢大方坯中心碳偏析和组织

以 2 8 0mm× 32 5mm重轨钢大方坯的试验数据为依据 ,分析了电磁搅拌参数和连铸工艺参数对铸坯中心碳偏析以及铸坯的低倍结构的影响 ,采用M IEMS以及与连铸工艺参数的合理匹配 ,能明显改善铸坯的中心碳偏析和铸坯的内部组织结构     

Preparation of CuCr alloys by thermit-reduction electromagnetic stirring

The influences of the additive CaF2, different molds, mold pre-heating temperature, electromagnetic stirring, and alloying elements on CuCr have been investigated respectively during the preparation of CuCr alloys by thermit-reduction electromagnetic stirring. The results indicate that the reasonable reactant mass ratio of CuO: Cr2O3: Al is 100:140:160; CaF2 can reduce the solidifica- tion point of slags to improve the metal separating efficiency from slags; the crystal particles become thinner because of the high cooling velocity in the metal mold; while casting in the graphite mold, the casting properties of CuCr improve with the increase of pre-heating temperature; the compact alloys are prepared at 500°C; electromagnetic stirring can prevent the growth of dendrite crys- tal into refine crystal particles, as well as homogenize Cu and Cr to improve the CuCr properties; the optimal stirring time is 7 min; when the alloying elements Ni and Co are added to the reactants, elements Cu and Cr can distribute evenly but the crystal particles become thick.     

Influence of electromagnetic stirring on microstructure of AZ91-0.8%Ce magnesium alloy

1 INTRODUCTION In recent years, magnesium alloys have been used in the automobile industry to save fuel and lower emission levels, and about 60 different types of components of magnesium alloys have been applied in automobile parts, in which AZ91magnesium alloy (Mg-Al system) approximately accounts for 90%[1?4]. It is well known that grain size has very important effect on material properties. According to Hall-Petch equation, when grain size decreases, the mechanical properties such as…     

Effect of electromagnetic stirring on the microstructure and wear behavior of iron-based composite coatings

The effect of electromagnetic stirring on the microstructure and wear behavior of coatings has been investigated. A series of iron-based coatings were fabricated by the plasma-transferred arc cladding process by applying different magnetic field currents. The microstructure and wear resistance of the composite coatings were characterized by scanning electron microscope (SEM), energy dispersive X-ray analysis (EDAX), X-ray diffraction (XRD), and wet sand rubber wheel abrasion tester. The experimental re- sults showed that the microstructure of the coatings was mainly the γ-Fe matrix and (Cr, Fe)7C3 carbide reinforced phase. The coatings were metallurgically bonded to the substrate. With increasing magnetic field current, the amount of the block-like (Cr, Fe)7C3 carbide reinforced phase increased at first, reached a local maximum, and then decreased sharply. When the magnetic field current reached 3 A, the block-like (Cr, Fe)7C3 carbides with high volume fraction were uniformly distributed in the matrix and the coating displayed a high microhardness and an excellent wear resistance under the wear test condition.     

Refinement role of electromagnetic stirring and calcium in AZ91 magnesium alloy

Effects of calcium addition and electromagnetic stirring on the microstructure of AZ91 magnesium alloy and refinement mechanism were investigated. The results show that calcium addition ranging from 0.1wt% to 0.3 wt% does not lead to formation of any new phases but cause the refinement of ascast microstructure.However, combined calcium alloying and electromagnetic stirring significantly decrease the grain size, change the morphologies of the β-Mg17Al12 phases,and reduce their volume percentage. The minimum grain size of AZ91 alloy is obtained in the case of the addition of 0.2 wt%Ca with exciting voltage of 100 V. The microstructural refinement is attributed to the increase of the degree of undercooling and nucleation temperature of primary α-Mg phases on the basis of DTA analysis results.     

Preparation of semisolid AlSi7Mg alloy slurry through weak traveling-wave electromagnetic stirring

The semisolid AlSi7Mg alloy slurry with large capacity was prepared by low superheat pouring and week traveling-wave electromagnetic stirring.The effects of electromagnetic stirring power and frequency on the shape and distribution of primary α-Al grains in the AlSi7Mg alloy slurry were discussed.The experimental results show that the AlSi7Mg alloy slurry with fine and spherical primary α-Al grains distributed homogeneously can be obtained.Under the condition of low superheat pouring and week traveling-wave...     

SiC_P/Al水平连铸电磁搅拌结晶器的设计

所设计的水平连铸电磁搅拌结晶器由电磁搅拌装置和结晶器两部分构成 .电磁搅拌装置安装在中间包和结晶器之间 ,可对碳化硅铝基复合材料液在结晶前和结晶过程中进行充分搅拌 .通过对水平连铸电磁搅拌结晶器基本参数计算 ,并结合实验研究 ,在理论上简要分析了水平连铸过程中金属液的形态和传热特征及其对所得到铸坯质量的影响