A kind of rolling method of high-strength automobile spring steel wire rod

Abstract

The invention relates to the field of hot rolling of iron and steel wire rods, and relates to a rolling method of high-strength automotive spring steel wire rods, which includes the steps of heating a steel billet, controlling rolling, and controlling cooling. In the heating process, the heating temperature of the billet in a heating furnace is 1000 to 1080°C, the total heating time is 70-150min, and the residual oxygen in the heating furnace is ≤3.0%; the controlled rolling process, the wire rod entering and finishing rolling temperature is 850-980°C, and the spinning temperature is 850-950°C; the controlled cooling process , the wire rod is rapidly cooled to 780°C after spinning, and the cooling rate C1 is controlled to be 5.0-10.0°C / s, and the average cooling rate C2 of the wire rod is controlled to be 0.5-4.0°C / s from 780°C to 600°C; the obtained wire rod It is ferrite + pearlite + sorbite structure, and the surface layer is not fully decarburized.

Description

technical field [0001] The invention belongs to the field of hot rolling of steel wire rods, and relates to a rolling method of high-strength automotive spring steel wire rods. Background technique [0002] Spring steel hot-rolled wire rods are mainly used to manufacture automobile suspension springs, clutch springs, valve springs and die springs, mainly including 55SiCr, 55SiCrV, 60Si2Mn and other grades. High-strength spring steel has high requirements for surface decarburization. During the service process of suspension springs and valve springs, decarburization, especially full decarburization, has a great impact on fatigue life. At present, for the decarburization of spring steel, the total decarburization of wire rods is mainly reduced by controlling the heating temperature, heating time and furnace atmosphere in the billet heating process, but the total decarburization of spring steel wire rods cannot be effectively eliminated. [0003] The Chinese patent application...

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Problems solved by technology

[0005] The spring steel production methods disclosed in the above patents all control the rapid cooling of the wire rod to the phase transition temperature in the controlled cooling process to avoid the precipitation of pro-eutectoid ferrite, thereby avoiding the complete decarburization of the wire rod surface, but this process can only Control the full decarburization of the wire rod after spinning. The full decarburization in the rolling process cannot be eliminated and can only be left to the finished wire rod

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