Continuous casting method for eliminating near-surface layer dendrite banded segregation of alloy spring steel wire rod

Abstract

The invention discloses a continuous casting method for eliminating near-surface layer dendrite banded segregation of an alloy spring steel wire rod. The continuous casting method comprises the processes of continuous casting tundish molten steel superheat degree control, continuous casting billet withdrawal speed control, crystallizer electromagnetic stirring control, crystallizer water inlet flow control and vibration parameter control; the tundish molten steel superheat degree is controlled to be 15-25 DEG C through tundish electromagnetic induction heating equipment; a crystallizer electromagnetic stirring part is mounted on the middle lower part of a crystallizer, the electromagnetic stirring current intensity is 150-300 A, and the electromagnetic stirring frequency is 1.5-2.5 Hz; andhydraulic vibration is adopted, the amplitude is 2.3-2.7 mm, the frequency of vibration is 100-130 cpm, and liquid level fluctuation is controlled to be + / -2 mm. The alloy spring steel wire rod, produced through the continuous casting method, of phi 5.5-20 mm is free of near-surface layer dendrite banded segregation through dendrite corrosion detection, after heat treatment, metallographic structures on a surface layer are uniform and consistent, and thus spring early fatigue break caused by dendrite banded segregation is effectively prevented.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a continuous casting method for eliminating dendrite band segregation near the surface of an alloy spring steel wire rod. Background technique [0002] Alloy spring steel hot-rolled wire rod is mainly used to manufacture automobile suspension springs, clutch springs, valve springs and die springs, mainly including 55SiCr, 55SiCrV, 60Si2Mn and other grades. Spring steel hot-rolled wire rods must at least go through drawing, heat treatment, coiling and other processing processes before they can become final springs. If the wire rod has a certain degree of macrosegregation defects, it may cause the steel wire to break after drawing. The mechanical properties of the steel wire after heat treatment Unevenness, unstable dimensions of the rolled out spring, and even early fatigue fracture of the spring. [0003] Dendrite banded segregation of spring steel refers to the f...

AI Technical Summary

Problems solved by technology

This method is mainly used to solve the problem of product change caused by ingot shape segregation, and does not consider the problem of dendrite band segregation defects near the surface in the wire rod

[0005] Patent CN 108672666 A discloses a continuous casting method for improving the central segregation of round billet spring steel 60Si2CrVAT, and the tundish temperature, crystallizer water volume, secondary cooling zone water volume, electromagnetic stirring parameters, terminal electromagnetic stirring position, etc. of the round billet continuous casting process are disclosed. Control to reduce the central segregation of the continuous casting slab, reducing the plastic incompatibility problem caused by the central segregation, and also did not consider the problem of dendrite band segregation defects near the surface in the wire rod

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