Steel piston and preparation method thereof

Abstract

The invention provides a steel piston. The steel piston comprises the components of, by weight percent, 0.3-0.45 wt% of C, 0.5-1.0 wt% of Si, 0-0.025 wt% of P, 0.02-0.1 wt% of S, 1.2-2.0 wt% of Mn, 0.1-1.0 wt% of Cu, 0.01-0.05 wt% of N, 0.08-0.2 wt% of V, 0.01-0.03 wt% of Ti, 0.01-0.03 wt% of Al and the balance Fe; the hardness is 250-310 HBW; a matrix structure is composed of fine lamellar pearlite, ferrite, bainite, martensite and retained austenite, wherein the bainite, the martensite and the retained austenite are not larger than 10%, and the grain size of the network ferrite is larger than grade 4. By adjusting the proportions of all the components, the tensile strength and yield strength of the steel piston are improved, and the plasticity of the steel piston is improved; the interval between the lamellar pearlite is decreased by controlling the content of Mn, the cutting performance of the steel piston is improved by combining Mn with S, and the machining cost is reduced. The invention further provides a preparation method for the steel piston.

Description

technical field [0001] The invention relates to the technical field of engines, in particular to a steel piston and a preparation method thereof. Background technique [0002] With the continuous improvement of engine power and explosion pressure, higher requirements are put forward for the engine and its spare parts. As the key component of the A-level engine, the piston is used to bear the gas pressure and drive the crankshaft to rotate through the connecting rod through the piston pin. [0003] The top of the piston is an integral part of the combustion chamber. It bears alternating mechanical loads and thermal loads during work, and is exposed to high temperature, high pressure, high speed, and poor lubrication conditions for a long time. It is in direct contact with high temperature gas. The instantaneous temperature can reach above 2500K. The heat is severe, and the heat dissipation condition is very poor, so the temperature of the piston is very high when it is worki...

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Problems solved by technology

[0003] The top of the piston is an integral part of the combustion chamber. It bears alternating mechanical loads and thermal loads during work, and is exposed to high temperature, high pressure, high speed, and poor lubrication conditions for a long time. It is in direct contact with high temperature gas. The instantaneous temperature can reach above 2500K. The heat is severe and the heat dissipation conditions are poor, resulting in a high temperature when the piston is working, and its top is as high as 600-700K, and the temperature distribution is very uneven

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