Casting method of complex-structure ductile iron thin-wall casting of ship turbocharger

Abstract

The invention relates to the casting technology of complex-structure ductile iron thin-wall castings, such as a fuel feed case, which are important parts of a ship turbocharger, and in particular relates to a casting method of a complex-structure ductile iron thin-wall casting of the ship turbocharger. The casting method includes the steps of, in sequence, fabricating moulds, modeling, making a core, assembling the moulds, pouring and clearing the sand shakeout. The method is characterized in that a pouring system used in the pouring process consists of a riser runner, a chilling block, a live riser arranged on a bottom flange of the fuel feed case and a feeding head arranged at the lateral side of the bottom flange. A filter screen is arranged on the pouring system. With the casting method disclosed by the invention, the defect of shrinkage porosity of the bottom flange of the fuel feed case is solved, the conventional idea of changing the entire cast solidification sequence by increasing the number the chilling blocks is thoroughly changed, the problem of shrinkage porosity at the bottoms of the castings is completely improved by adopting the new feeding scheme, the percent of pass of the castings is improved, and regular batch production of the castings is ensured.

Description

technical field [0001] The invention relates to a casting and forming technology of a ductile iron, thin-walled, and complex-structured fuel-injected shell casting, that is, an important part of a marine turbocharger, in particular to a casting of a complex-structured thin-walled ductile iron marine turbocharger casting method. Background technique [0002] Thin-wall ductile iron marine turbocharger with complex structure, the main structure of this product is as follows: the casting shape is complex, the main body wall thickness is 9mm, and the skin thickness of some parts is only 8mm; the local core skin thickness is 12mm, the core iron is not easy to place, and the core is easy Deformation; the side transparent doors are not on the same surface, so it is difficult to choose the parting surface; the casting processing volume is small, and some parts cannot subsidize the processing volume due to the limitation of the casting structure. The combustion shell has a complex st...

AI Technical Summary

Problems solved by technology

[0002] Thin-wall ductile iron marine turbocharger with complex structure, the main structure of this product is as follows: the casting shape is complex, the main body wall thickness is 9mm, and the skin thickness of some parts is only 8mm; the partial core skin thickness is 12mm, the core iron is not easy to place, and the core is easy Deformation; the side transparent doors are not on the same surface, so it is difficult to choose the parting surface; the processing volume of the casting is small, and some parts cannot subsidize the processing volume due to the limitation of the casting structure

The combustion shell has a complex structure, including oil chambers, water chambers, and air chambers. At the same time, the mechanical properties of this type of casting material are required to be --- tensile strength: Lσ≥400MPa; yield strength: σ0.2≥250MPa; elongation: δ≥ 15%; Hardness (HB): 135-185, this type of product mainly has shrinkage defects of the bottom flange, so it cannot be mass-produced

[0003] Considering the complexity of manual packing of this type of casting, there is currently no method that can improve the pass rate of this type of casting and ensure that this type of casting can be mass-produced normally.