High-toughness and heat-resistant nodular cast iron for exhaust manifolds and preparation technology of high-toughness and heat-resistant nodular cast iron

Abstract

The invention discloses high-toughness and heat-resistant nodular cast iron for exhaust manifolds and a preparation technology of the high-toughness and heat-resistant nodular cast iron. The nodular cast iron is prepared from chemical components including, by weight, 3.02%-3.28% of C, 3.85%-4.10% of Si, 0.38%-0.55% of Mn, 0.017%-0.019% of P, 0.0037%-0.0058% of S, 0.410%-0.46% of Cu, 0.40%-0.43% ofMo, 0.037%-0.058% of Mg and the balance Fe. The preparation method includes the following steps that step 1: raw materials are prepared; step 2: a spheroidizing ladle and a pouring ladle are prepared; step 3: sampling and detecting work is performed on molten iron after melting down; step 4: filling of a spheroidizing agent and a nucleating agent is performed, a dam of the spheroidizing ladle isfilled with the spheroidizing agent, the spheroidizing agent is covered with the nucleating agent, and then the nucleating agent is covered with a slag removal agent; step 5: after the molten iron ispoured into the spheroidizing ladle, the slag removal agent is scattered to the surface of the molten iron, and slagging-off and cleaning work is performed; step 6: after slagging-off of the molten iron, the molten iron is taken by a spectroscopy room for testing of components. The nodular cast iron has the excellent high-temperature shear resistance, high-temperature corrosion resistance and high-temperature toughness, the internal stress change of pipelines is small during repeated heating and cooling, and finally, the service life of the exhaust manifolds is prolonged.

Description

technical field [0001] The invention relates to the field of exhaust manifold preparation, more specifically, it relates to a high-toughness heat-resistant nodular cast iron used for the exhaust manifold and a preparation process thereof. Background technique [0002] The exhaust manifold is connected to the cylinder block of the engine, and the exhaust of each cylinder is collected and introduced into the exhaust manifold, with divergent pipelines. In the actual application process, when the automobile exhaust is too concentrated, there will be mutual interference between the cylinders, that is, when a certain cylinder exhausts, it happens to encounter the undischarged exhaust gas from other cylinders. In this way, the resistance of the exhaust will be increased, thereby reducing the output power of the engine. At the same time, the multi-directional force caused by the disorder of the multi-directional airflow will also affect the life of the exhaust manifold in a high-tem...

AI Technical Summary

Problems solved by technology

[0004] Early automobile engines had low power per unit weight, low fuel combustion efficiency, and the exhaust gas temperature did not exceed 500°C

Images