Study on Dissolving Erosion Mechanism of Pre-embedded Main lubrication Oil Pipeline during Casting for Small-to-medium Sized Marine Diesel Engine Block
Author of the article:SUN Changfen
Author's Workplace：Comprehensive Technology Research Institute of Hudong Heavy Machinery Co.,Ltd.,Shanghai 200129,China
Key Words：pre-embedded pipe casting fluid eutectic line detaching
Abstract：
In the casting process of ductile iron,the heat temperature of the steel tubes embedded in the main lubricating oil of the small and medium-sized marine diesel engine block was too high,which main pipes will be melted easily at a high temperature.The corrosion mechanism of steel tubes without surface protection was discussed by measuring the temperature change of the steel tubes and the casting solution near the steel tubes during the filling process.The results show that when the temperature of the steel tube is above 600℃,carbon begins to permeate from the casting solution to the grain boundary of the steel tube,forming cementation Fe3C on the grain surface.When the temperature of the steel tube rises above 1150℃,the austenite surface cementite begins to melt and the grain begins to denudate,and the microstructure stops denudation when the solidification ends at 1020℃.It is proposed that the temperature and time above the eutectic line can effectively reduce or avoid the corrosion of steel tubes during the casting process,and the corresponding technological measures are put forward.
