Study on Impact Wear Resistance of Vermicular Cast Iron at High Temperature
Vermicular cast iron is the main material for the cylinder head of high power density diesel engine combustion chamber.With the continuous increase of rotational speed,explosion pressure and power density,the frequent collision and impact between the valve and the compacted iron valve seat lead to the increase of impact wear.The impact wear test under different ambient temperature(room temperature,300 ℃,400 ℃,500 ℃)and different impact frequency(10 Hz,12 Hz,14 Hz)was carried out by using a self-made impact wear tester.The test results show that the wear amount of vermicular cast iron increases rapidly first and then tends to be slow with the increase of the number of impacts;however,with the increase of impact frequency and working temperature,the wear amount first increases slowly and then increases rapidly.The impact surface of the material has pits,furrows and material accumulation,and with the increase of impact times,the impact frequency and ambient temperature,many flake-like spalling layers and plastic deformation appear on the wear surface.The wear mechanism is mainly abrasive wear and contact fatigue wear,accompanied by slight adhesive wear and erosion wear.
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