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Precision Casting Technology of Vermicular Graphite Cast Iron
2023-07-12

release unit:河北瑞丰科技有限公司

core technology:Vermicular graphite cast iron

project unit:Hebei Ruifeng Technology Co., Ltd

industry field:Equipment manufacturing

Project description

Hebei Ruifeng Technology Co., Ltd. is a listed company that manufactures gasoline, diesel engine cylinder blocks, cylinder heads, and new energy and vehicle lightweight products. Its main products include automotive engine cylinder blocks, cylinder heads, and new energy vehicle components. At present, it is supporting more than 20 automobile and engine factories, such as Jiangling Motors, BYD Auto Motor and Germany Deutz AG. It is a leading enterprise in the industrial cluster of Hebei Province.
The performance of vermicular graphite cast iron is between gray cast iron and nodular cast iron, and its wear resistance, density, and pressure fatigue performance are not only superior to ductile iron but also better than gray cast iron. Through the research and development of this brand of cast iron, the technical ability of the company is improved and broadened, closely following the development of Vanguard International Semiconductor Corporation advanced technology, and then expanding the company's product development and manufacturing capacity.
At present, V-type diesel engines plus those used in other Commercial vehicle, the number of diesel engines with vermicular cast iron as cylinder block and cylinder head will equal to 10% of the total number of vehicle engines in the world. It is estimated that there are more than 30 kinds of diesel engines with different designs, and more than 3 million cylinder blocks and cylinder heads will be produced. The production of cylinder blocks and cylinder heads for Commercial vehicle in China, Russia and India is growing. Each of the three major automobile manufacturing companies in the United States (General Motors, Ford and Chrysler) has announced that the V-shaped diesel engine cylinder block will be used in off-road vehicles (SUVs) and dual-use vehicles (pickups), and the vermicular cast iron cylinder block and cylinder head will have a broad market space. Therefore, the development and research of this grade of cast iron is imperative.
Intended countries: Germany and Spain 
mainly focus on researching how to stably obtain high creep rate during the treatment process of vermicular graphite cast iron, especially when there is a significant difference in wall thickness of cylinder castings, how to balance the performance of thick and thin parts? How to control the appropriate range of residual magnesium content during the treatment of vermicular graphite cast iron? We adopt a two-step method of (1) creep processing; (2) By spheroidizing the vermicular iron and reheating the molten iron to solve these problems, qualified vermicular graphite cast iron cylinder heads are produced.
The specific method is as follows: Step 1: The vermicular treatment adopts the flushing method, and the amount of vermicular agent added is calculated according to the idea of over spheroidization (vermicular iron biased towards spheroidization). About 2/3 bags of molten iron are added (measured with an electronic scale), and the Mg and rare earth contents of the molten iron are sampled and checked for rapid metallographic analysis. Step 2: Determine the amount of reheated iron based on the Mg content, rare earth content, and metallographic analysis results. After reheating the iron, take samples for spectral analysis and metallographic verification. After passing the inspection, proceed to pouring.

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