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Al-25%Si Alloy liners (hypereutectic Si-Al alloys) Instead of Conventional Casting Cylinder Sleeves
Tianjin Baienwei New Material Technology Co.,Ltd develops,produces and sells the silicon-aluminum(Al-Si) alloys with the outstanding physical and mechanical properties.We are now offering the expectional cylinder sleeves(tube billets) to our Europe commercial customers.It will be difficult to find the high reliable and trustworthy supplier which can delivery the leading edge aluminum alloys material and service for companies.Any other size also can be customized according to client’s requirement.
Hypereutectic Al-Si alloys are typically defined as those where the silicon content is equal or more than 17 wt %.As a versatile material,the hypereutectic Al-Si alloys have been commonly used in automobiles,motorcycles and tactical vehicles.Applications of the Al-Si alloys in the automotive industry,including engine blocks and parts of engines,particularly,cylinder liners.The following reason is why we introduce the aluminum alloys cylinder liner for the engine blocks. As we all known,fuel consumption is a serious problem exsiting in the operation of automobiles.More fuel consumption also means greater pollution emissions.The reduction in cylinder distortion (higher dimensional stability) that is possible with this alloy results in less noise and friction; engine-oil consumption and exhaust emissions are thus reduced, e.g 1kg hypereutectic Al-Si alloy can replacement 3kg casting alloy,the overall performance of automobiles can be enhanced.The hypereutectic Si-Al alloys material shows good wear-resistance combined with low coefficient of thermal expansion and have a high strength-weight-ratio.Hereby,it can remarkably improved the workability and ductility for the highest operation demands.Finally, the blanks are specially treated in an environmentally friendly process, aqueous exposure. The resulting smooth surface structure improves friction characteristics and cuts the engine's oil consumption and hydrocarbon-emissions levels.Thereby，curretly the use of cyliner liners made of hypereutectic aluminum alloys have been preferred and applied by many automobile manufacturers.
In the ALUSIL process ,the entire engine housing consists of a hypereutectic aluminum silicon alloy. The increased silicon content, which contains 17% silicon in the most frequently used ALUSIL alloy, is typical of such a hypereutectic alloy.Currently available and mature products in our company,e.g Al-25%Si alloy(AlSi25Cu4Mg) cylinder liners can instead of the casting AlSi17Cu4Mg alloy. The hypereutectic Al-Si alloys material are fabricated by our proprietary technology of Rapid Solidification at T6 condition(Solution heat treatment process)..Herein,the silicon content by the weight of 20%~35% in the alloy which features excellent wear-resistance,high temperature strength,heat stability as well as high abrasion resistance.The AlSi25 alloys are relatively easy to honing and grinding,both for bars billets and cylinder sleeves tubes.They are machinable to a very fine finish(0.5μm~5μm) with carbide or poly-crystalline diamond(PCD) tools.Due to these cylinder liners are produced by extrusion of billets,so the cost is higher than that of cast iron ones.The Al-25%Si alloy cylinder liner makes us an anttractive(and possible) only for top level cars.
Competitive advantages of using the Al-25Si alloys(also called DISPAL S260 Aluminum Alloy in foreign countries) for cylinder liner:
● A lightweight cylinder block can be achieved.
● In comparision of cast iron cylinder liner,the thermal conductivity and coefficient of thermal expansion is far higher and greater than that of cast iron ones,a good tight contact between the cylinder liner and cylinder block body can be achieved upon temperature elevation and, thus, an internal-combustion engine having a good heat-dissipation characteristic can be provided.
● In the condition of ultra-mild wear(UMW),the microstructure(SEM) shows the silicon particles of Al-25%Si alloy is effective maintaining a minimal surface damage,thus,improve the wear-resistance.
● As we mentioned earlier, the inner-wall temperature of Al-25Si alloy cylinder liner can be kept low and the life of the lubricating oil can be prolonged.
● By using the hypereutectic Al-25%Si alloy cylinder liners,thanks to the friction coefficient is low, the friction loss which occurs between the piston rings and the cylinder liner can be lessened and, thus, the mileage can be improved.