Influence of V Content on Microstructure and Mechanical Properties of Gray Cast Iron for Super-Large Cylinder Liner

Abstract: The cylinder liner is regarded as the “ventricle” of the heart of the engine, and its performance plays a decisive role in the overall performance of the engine. V was added to improve the mechanical properties such as the strength and hardness of the super-large cylinder liner. Using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Brinell hardness tester universal testing machine, the effects of the addition of V for gray cast iron microstructure and mechanical properties were investigated. The results show that after the addition of V, VC compounds can be produced in the matrix structure, the graphite structure and the pearlite structure are refined, and the pearlite sheet spacing is also significantly reduced. Mechanical performance has been significantly improved. The best overall performance was achieved at the content of 0.21 wt.% V, and Brinell hardness, compressive strength and tensile strength values are 421 HB, 1699 MPa and 501 MPa, respectively, which were increased by 78.5%, 64.8% and 61.6%. This is mainly because the V plays a role in fine-grain strengthening and precipitation strengthening of the alloy. Graphical abstract: [Figure not available: see fulltext.].