多元合金化SiMo球墨铸铁在汽车发动机排气歧管中的应用研究

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中图分类号：TG255 文献标志码：B DOI：10.19710/J.cnki.1003-8817.20250257

Abstract：Aloying is one of the keyapproaches to improve the mechanical properties and thermal resistance of SiMo ductileiron.This paperreviews theeffcts of aloying elements on the microstructureand propertiesof SiMo ductile ron.Asystematic studyon multi-element allyed SiMo ductile iron was carriedout targeting exhaust manifolds of high peak-pressure diesel engines and gas engines.The results show that when the massfractionof Mo increases from 0.9% to 1.46% ，thevolume fraction of carbides in the microstructure rises，leading to increases in the tensile strength，yield strengthand hardnessof SiMo ductileiron，while theelongation decreases by 5O%.Vanadiumallying elevatesthe tensile strength butreduces the elongationofSiMo ductileiron;thematerialachieves satisfactoryroomtemperature mechanical properties at a ∨ mass fraction of 0.4% .Theshort-term tensile strength at 8OO℃ increases with the rise of V content，yet no significant change is observed when the Vmass fraction exceeds 0.4% . Among the multi-elementalloyed SiMoductileirons，theV-Nballoyed SiMoductileironreachesahigh-temperature tensile strength of 59MPa，whiletheV-CrandV-Nb-Craloyed variants exhibit high-temperaturestrengthsof61～64MPa. Thesevaluesmeet the high-temperature tensile strengthrequirements for SiMo ductile ironapplied in exhaust manifolds of high peak-pressure diesel engines and gas engines.

Keywords：SiMoductile iron，Exhaustmanifold，Multi-elementaloying，Room-temperature strength， Hightemperature strength

1前言

的废气汇集排出车外的重要部件，工作时需承受高温气流的热循环冲击、高温氧化以及环境腐蚀等，因此，要求发动机排气歧管的材料具有良好的汽车发动机排气歧管是将发动机各气缸排出高温强度、热疲劳稳定性、抗氧化性、加工成形性。（剩余9859字）