Method for forming main lubricating oil passage of nodular cast iron diesel engine body and application

Abstract

The invention belongs to the technical field of cast iron casting, and discloses a method for forming a main lubricating oil passage of a nodular cast iron diesel engine body and application. A bottom-pouring open-type gating system with a filter device is adopted to purify molten iron, a feeding head is arranged at the thermal center part of the main lubricating oil passage, and cold iron is usedin cooperation to balance the temperature field of nodular cast iron; and the stokehold chemical composition, reasonable charging, multi-stage inoculation, duration control, good nodularization, thorough slagging-off and fast pouring parameters are determined according to the principles of high carbon equivalent and high carbon and low silicon, and internal compaction of the thick and large thermal center part is performed to eliminate shrinkage and slag inclusion inside the main lubricating oil passage of the engine body. The method is beneficial to realizing the basic balance of the temperature field of the nodular cast iron. The method guarantees the high quality of the molten iron, realizes the internal compaction of the thick and large thermal center part, eliminates the quality risks of shrinkage and slag inclusion defects inside the main lubricating oil passage of the engine body, and overcomes the shrinkage casting defect of the main lubricating oil passage of the complicatednodular cast iron diesel engine body.

Description

technical field [0001] The invention belongs to the technical field of cast iron casting, and in particular relates to a method and application for forming a main lubricating oil channel of a diesel engine body of nodular cast iron. Background technique [0002] At present, the body of the 8DK20 diesel engine is a complex ductile iron casting made of QT400-15. The main lubricating oil passage in the length direction of the body runs through the lower part of the camshaft cavity from the gear end to the flywheel end, and the main lubricating oil passage in the width direction of the body is located at the upper part of the gearbox end. From the camshaft side to the air chamber side, the main lubricating oil passages in two directions (cylindrical straps with a diameter of about φ90) are cross-connected at the lower part of the camshaft cavity at the gear end of the body. The entire main lubricating oil passage of the body is in the shape of "T". font". [0003] Compared with...

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Problems solved by technology

[0005] (1) The existing technology is prone to secondary oxidation slag inclusions in the molding process

In addition, there is no feeding riser at the hot joint of the main lubricating oil passage and the use of chilled iron, so the basic balance of the temperature field of ductile iron cannot be achieved.

[0006] (2) In terms of melting process: the chemical composition before the furnace is not determined according to the principle of high carbon equivalent, high carbon and low silicon, reasonable packaging, multi-stage inoculation, time control, good spheroidization, and thorough slag removal, and no full use of nodular cast iron The self-feeding caused by graphitization expansion can not realize the internal compactness of the thick and large hot joints, and cannot eliminate the risk of shrinkage and slag defects in the main lubricating oil passage of the machine body

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