In this paper

the welding repair method of oil filter of marine mainframes made of gray cast iron is studied. Through the analysis of gray cast iron and duplex stainless steel materials and their weldability

the technology of transition layer welding of heterogeneous metal is used to repair the fuel filter of the mainframes. Welding lengthens the nozzle on the broken side of the filter to ensure sufficient space for welding. It also formulated a reasonable welding process

conducted a simple welding test on metals of the same material as the fuel filter to verify the feasibility of the process

and then performed repair work on the main fuel filter

and adopted a series of measures to control the welding cracks of gray cast iron. The defects of the main engine fuel filter were eliminated

and the corresponding inspection was carried out after welding

so that the main engine fuel filter was repaired success-fully

and the system operated well

ensuring the transformation cycle of the XX ship.