Another representative of the shuangliu casting method
Another representative of the shuangliu casting forming, is in the process of continuous casting process using the technique of electromagnetic brake, crystallization in applying a horizontal magnetic field, the bottom to prevent two metal liquid mixture, thereby formation interface of compound in the process of continuous casting billet [9]. Two different components of liquid metal at the same time through the long and short of the submerged nozzle into the mold, with the aid of in the crystallizer below the Level of the Magnetic Field LMF (Level Magnetic Field), and the upper metal gravity equal lorentz force large enough, make the mould in two areas. Liquid metal in the process of continuous casting, the upper area of the formation of the outer metal, and the lower area of the metal liquid into the inner metal core makes.
Using the electromagnetic field will be divided into two parts, on/under crystallizer, solved the problem of the two kinds of metal mixed molten, through precise control of magnetic field intensity, the throwing speed and two kinds of metal casting speed, can get stable microstructures and properties of the outer metal thickness and uniform, is a new type of advanced composite steel billet production methods. But, this kind of method of equipment manufacturing, technology level, operation skill and high requirement of automatic control, especially control of casting speed, the right to make two kinds of metal interface combined with good and stable more difficult. In addition, the combination of metals has also been a certain limit.
2 double metal composite material double mould casting process
2.1 the forming principle of double continuous casting crystallizer
Above all, it USES the preformed core material coated casting method, the process is complex, interface quality is difficult to control, especially in a continuous casting to ensure uniform interface quality, consistency, is usually very difficult; USES single mould of double metal continuous casting technology (shuangliu casting method), the main difficulty lies in the combination of two kinds of liquid metal is hard to control, easy to appear position instability, the interface layer thickness uneven phenomenon. By forcing the influence of electromagnetic field formed in the liquid metal in the mould layered approach, the pouring process, mold cooling characteristics, is very tall to the requirement of drawing speed control and so on, the combination of metal freedom have also been greatly restricted.
Based on the above reasons, the author put forward with double mold a casting method of double metal composite material [10], its basic principle is shown in figure 2. Mold casting solidification and forming the core materials of core material, the protection ring (air isolation ring) under the protection of, keep the surface state of no oxidation, no impurities, no oil, directly into the coating layer, mould hot continuous casting coated layer, can be omitted in the reverse way of solidification of the parent metal pretreatment and complex process, can be omitted, CPC method of coating layer in continuous casting process on the mandrel besmear to brush the anti oxidation coating process, it has a simple process, saving energy and reducing consumption, composite interface is good wait for an advantage. By controlling the core material mould cooling intensity and the temperature of the metal melt cladding layer the crystallizer, can not only realize cladding layer metal reverse coagulation, and can realize between the core material and the metal cladding layer diffusion or welding, eventually form a metallurgy combined with high quality double metal composite material interface.
With double continuous casting crystallizer production double metal composite materials, the control of the key process parameters are: two kinds of metal pouring temperature, mould cooling intensity, double the distance between the mould and casting speed, and the reasonable matching between the process parameters, etc.
The principle diagram of the double double metal mould casting process
2.2 bimetal composite casting forming simulation test
According to the principle of the process shown in figure 2, the design and manufacture of a double metal composite material double continuous casting crystallizer forming test model at a time. Experimental prototype of the basic structure is: the core material mold and mold adopts layer steel mould; Mold temperature by thermocouple and temperature control of metallic melts each control; Screw was adopted to realize continuous casting composite billet drawing.
An exploratory experiment, this paper USES the low melting point of Pb (Pb) and Pb - Sn eutectic alloy (38.1 Pb - Sn 38.1) as test materials, mainly discusses the feasibility of continuous casting forming, core material and the coating layer of metal casting temperature, casting speed, such as the influence of process parameters, and the reasonable matching problem between various process parameters.
