A Nodular Cast Iron Alloy and Its Application in Thin-walled Hydraulic Retarder Impeller

Abstract

The invention belongs to the technical field of nodular cast iron alloy, and particularly relates to the nodular cast iron alloy for a thin-wall type hydrodynamic retarder impeller and an application of the nodular cast iron alloy. The nodular cast iron alloy comprises the following components in percentage by weight: 3.0-3.5% of C, 2.5-2.9% of Si, 0.3-0.5% of Mn, 0.05-0.07% of Cr, 1.57-1.60% of Ni, 0.60-0.65% of Cu, 89-92% of Fe and the balance of trace elements. A preparation method of the nodular cast iron alloy for the thin-wall type hydrodynamic retarder impeller comprises the following steps: smelting base materials; adjusting chemical components; carrying out spheroidisation; carrying out inoculation; casting and molding; annealing and cooling. According to the technical scheme provided by the invention, the mobility of nodular cast iron is improved by alloying, so that the filling of a cavity is facilitated, the edge of the cast thin-wall type impeller is free of crevices and slag inclusion, and the defect that the impeller is easy to burst apart in operation is overcome.

Description

technical field [0001] The invention belongs to the technical field of nodular cast iron alloys, in particular to a nodular cast iron alloy and its application in thin-walled hydraulic retarder impellers. Background technique [0002] Since the impeller of the hydraulic retarder requires high strength and rigidity, alloy steel is mainly used for casting at present. In some high-end hydraulic retarder impeller designs used in heavy trucks, the edge thickness is only 1mm. Because alloy steel has poor fluidity when casting such thin-walled components, it is difficult to cast complex and precise castings. [0003] Although cast iron, especially nodular cast iron has ideal castability and reasonable price, its rigidity and strength are not enough, so it cannot be directly used for casting the impeller of hydraulic retarder. The alloy improvement method of nodular cast iron has a long history and has different formulas , the process is complicated, and different products have dif...

AI Technical Summary

Problems solved by technology

In the high-end hydraulic retarder impeller design used in some heavy trucks, the edge thickness is only 1mm, because alloy steel has poor fluidity when casting such thin-walled components, it is difficult to cast complex and precise castings

[0003] Although cast iron, especially nodular cast iron has ideal castability and reasonable price, its rigidity and strength are not enough, so it cannot be directly used for casting the impeller of hydraulic retarder. The alloy improvement method of nodular cast iron has a long history and has different formulas , the process is complicated, and different products have different performance requirements. Such thin-walled components cast by conventional nodular cast iron are prone to cracking and breaking under high torque and high speed of 3000-4000N.m, causing the entire body to be scrapped. There are no suitable ductile iron alloys to successfully cast thin-walled retarder impellers