The effects of vibration frequency and amplitude on graphite morphology, primary austenite and properties of vibration lost foam casting gray iron were studied. When the vibration frequency is 35Hz and the amplitude is 2mm, the flake graphite length of lost foam casting gray cast iron is small, the austenite dendrite arm is thick and evenly distributed, forming an effective network skeleton in gray cast iron, and its tensile strength is large.

When the amplitude is 3mm and the vibration frequency is increased from 0Hz to 35Hz, the length of flake graphite decreases, the austenite grain size becomes smaller due to obvious fracture of primary austenite dendrite arm, the mechanical properties of gray cast iron are improved, and the tensile strength is increased from 196.04mpa to 225.99mpa without vibration. The results of temperature field test showed that the vibration significantly increased the solidification undercooling of lost foam casting gray cast iron. When the vibration frequency increases from 35Hz to 50Hz, the tensile strength is close to that of the gray cast iron obtained at 35Hz because the graphite morphology and austenite structure characteristics are not different from that of the gray cast iron obtained at 35Hz. When the vibration frequency increases from 50Hz to 100Hz, the mechanical properties of gray cast iron decrease due to the increase of the length of flake graphite and the grain size of primary austenite.

Under the condition of vibration frequency of 35Hz, the effect of amplitude on the microstructure and properties of lost foam casting gray cast iron was studied. When the amplitude increases from 0.75mm to 2mm, as the length of flake graphite decreases, the austenite dendrite arms are coarse and evenly distributed, forming an effective network skeleton in gray cast iron, hindering the deformation of metal, and increasing the tensile strength of gray cast iron, which can reach 247.51mpa. Compared with the gray cast iron without vibration, it increased by 26.25%. When the amplitude increases from 2mm to 3mm, although the length of flake graphite decreases, the energy required for fracture decreases due to the thinning of austenite dendrite arm, which reduces the tensile strength of gray cast iron. When the amplitude increases from 3mm to 4mm, the properties of gray cast iron decrease because the austenite in gray cast iron is unevenly distributed and the austenite network skeleton is damaged by excessive vibration force.