| Some parts such as sink roll used in hot dip aluminizing and tube used in squeeze castingare not only corroded by molten aluminum, but also worn by other contact materials. The partin such condition must be replaced after a certain time of use. Moreover, molten aluminumwill be contaminated because of dissolution of the part into molten aluminum, which willmake the capability of product made of aluminum worse, or even scrapped.In this paper, the corrosion–wear characteristics of metals in molten aluminum have beenidentified by a self-made high temperature test rig, design principle of corrosion–wearresistant materials in molten aluminum has been proposed, and a new alloy cast iron with highcorrosion-wear resistance in molten aluminum has been prepared and synthesized.Corrosion of QT350, HT300, high chromium cast iron, alloy grey cast iron, Q235, H13,Cr13, SKH51, W, Mo, Nb, Ta and Zr in molten aluminum have been investigated by750℃×24h static molten aluminum immersion test under the same experimental conditions. Theresults show that: Except Zr is completely dissolved in molten aluminum, other chosen metalsenable mutual diffuse with molten aluminum, and intermetallic layers are formed. For ironbased materials, C in form of graphite or carbides plays a role of barrier to molten aluminum.The corrosion resistance in molten aluminum of graphite is better than carbides. Moreover,the barrier effect of graphite to molten aluminum is related to its shape, size and distribution.As the gap between graphits or carbides is smaller, the corrosion resistance in moltenaluminum of iron based materials is better. The intermetallic compound layer formed betweenrefroctory metals and molten aluminum cannot play a role of barrier for poor bond strengthbetween intermetallic compound layer and refroctory metals, but the corrosion resistance inmolten aluminum of refroctory metals is excellent because of small solubility of refroctorymetals in molten aluminum.Since the existing high temperature test apparatus have a lot of deficiencies inperformance and structure, such as over consumption of molten metal, uncertaintyload and the lack of friction coefficient measurement, a self-made high temperature test righas been developed. The new device has characteristics such as less consumption of liquidmetal for the use of lift type heating furnace, accurate loading for the use of flexible wire rope hanging weight loading, accurate transmission and measurement of friction for the use ofspecial suspension mechanism. The device can accurately simulate corrosion-wear behave ofmetals in different molten metal, and can provide technical supporting for the research aboutcorrosion-wear mechanism of metals.Corrosion-wear characteristics of QT350, HT300, high chromium cast iron, Q235, H13,Cr13, SKH51, W and Mo in molten aluminum were investigated by self-made hightemperature test rig. The results show that: The intermetallic compound layer that formedbetween chosen metals and molten aluminum in the process of corrosion-wear is as same asthe layer formed in the process of corrosion. The intermetallic compound layer formedbetween metals and molten aluminum is cut from metal matrix and separated to abrasive toproduce plowing on the metal substrate. The wear mechanism of cast irons in moltenaluminum is mainly abrasive wear. The synergistic amounts between corrosion and wear ofmetals are more than95%and the synergistic effect between corrosion and wear leads torapidly increased weight loss of metals.On the basis of the research results about the corrosion-wear characteristics of metals inmolten aluminum, design principle of corrosion–wear resistant materials in molten aluminumhas been proposed: by adding carbide forming elements such as Cr and W, high hardnesscarbides with good corrosion resistance in molten aluminum are formed in cast iron matrix,and play a role of bearing in the process of corrosion-wear in molten aluminum. Moreover,other alloy elements such as Mo and V are added into cast iron matrix in order to obtainperfect organization and performance.On the basis of design principle of corrosion–wear resistant materials in moltenaluminum, a new alloy cast iron with high corrosion-wear resistance in molten aluminum hasbeen successfully developed by adding W, Cr, Mo, V alloying elements into high chromiumcast iron. The corrosion resistant in molten aluminum of new alloy cast iron is more than3times than H13steel, and the corrosion-wear resistant in molten aluminum of it is more than12times than H13steel.In order to prepare large size parts, new alloy cast iron and304stainless steel have beensuccessfully synthesized by transient liquid phase diffusion bonding technology. Underparameters as follows: bonding temperature1080℃, holding time6min and bonding pressure 6MPa, the tensile strength of joint is bigger than new alloy cast iron, and the shear strength ofjoint is317.5MPa. |
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