Research On Horizontal Continuous Casting Of Tube Blanks, Wire Rods And External Fields Modification

In recent years, with the development of industry and national economy, the needs of high quality condenser-tubes and bonding wires increase quickly. To meet the succedent procedure, tube blanks and wire rods free from defects are needed, which is the key to improve production efficiency and obtain high-quality tubes and bonding wires. Nowadays, external fields such as electromagnetic field and power ultrasonic field are successfully applied in metallurgy and material processing, which provides a chance to produce high quality tube blanks and wire rods.The purpose of the dissertation is to produce high quality copper-nickel, pure copper tube blanks and Al-l%Si wire rods. The research is mainly supported by two projects, one is "Basic Research on Electromagnetic continuous casting of tube blanks", which is supported by Iron and Steel Cooperation Research Foundation, co-sponsored by National Natural Science Fundation and Baosteel Group Corporation;and the other is "Research on the Effect of Electromagnetic Field on Copper Tubes During Horizontal Continuous Casting", cooperated with the Research Center of Precise Copper Tube of the Chinese Academic of Science.The main contents are as follows:Horizontal continuous casting systems of pilot scale were designed to produce tube blanks. The method of casting-rolling to produce BFe10-1-1 condenser tubes was investigated. According to the solidification character of BFe30-l-l tube blanks, numerical simulation computation model of temperature field was established for simulating heat transfer during continuous casting. The influence of parameters on solidification of BFe30-1-1 tube blanks was investigated, and the feasibility of horizontal continuous casting of BFe30-l-l tube blanks was studied. It showed that:(1) BFe10-1-1 condenser tubes can be produced by casting-rolling method. The tensile properties of BFe10-1-1 tube blanks at room temperature is perfect and the maximum rolling temperature is 600℃.(2) BFe30-l-1 tube blanks with smooth surface and dense solidification structure can be obtained by horizontal continuous casting. The microstructure of cast BFe30-1-1 tube blanks is typical dendritic segregation and the quality of BFe30-l-l tube blanks is severely influenced by casting parameters.Horizontal electromagnetic continuous casting of copper tube blanks was proposed. The distribution of electromagnetic field in the mold was calculated. The electromagnetic shaping systems were designed and horizontal electromagnetic continuous casting of copper tube blanks was carried. Effects of commercial frequency electromagnetic field on surface quality, solidification structure, and mechanical properties of copper tube blanks were investigated. The results showed that surface quality can be improved by the application of electromagnetic field during horizontal continuous casting;grains are refined and distribute more uniform in the circumferential direction;Moreover, the mechanical properties and final yield are enhancedA novel process of ultrasonic treatment was proposed to improve the quality of horizontal continuously cast Al-l%Si alloy. Experimental apparatus was designed and horizontal continuous casting of Al-l%Si wire rods was conducted to investigate the effects of ultrasonic field on the surface quality, solidification structures and mechanical properties of Al-l%Si alloy. The results show that the uniformity of melt temperature and surface quality of wire rods is enhanced with the application of ultrasonic field. Grains are refined and boundary segregation of Si element is suppressed. Moreover, the tensile properties of the alloy are evidently increased with the increase of ultrasonic power.