Effect of isothermal quenching on the microstructure and properties of gray cast iron cylinder head
Isothermal quenching is widely used to improve the mechanical properties of ductile iron castings,while there are relatively few studies and applications in gray cast iron castings.In this paper,the gray cast iron cylinder head was quenched at an isothermal temperature,and its structure and prop-erties were analyzed by a series of equipment such as optical microscope,scanning electron microscope and tensile testing machine.The results showed that the matrix structure of gray cast iron was acicular ferrite,high-carbon austenite and a little pearlite after isothermal quenching at 300 ℃ × 2 h,and the morphology of flake graphite did not change.The tensile strength of the cylinder head body was in-creased from 300 MPa to 493 MPa,and the hardness was 270 HBW.Compared with the size of the cylinder head before heat treatment,the average deformation is 0.2159 mm,which meets the dimensional error requirements of subsequent machining.
Isothermal quenchingGrey cast iron cylinder headTensile strengthDeformation
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