Spring steel and surface decarbonization control process thereof

Abstract

The invention discloses spring steel which is prepared from the following components in percentage by weight: 0.56-0.64% of C, 1.5-2.0% of Si, 0.70-1.00% of Mn, less than or equal to 0.035% of P, less than or equal to 0.035% of S, 0.10-0.35% of Cr, 0.01-0.04% of Nb and the balance of Fe and impurity elements. High-end spring steel which is uniform in structure, stable in performance, high in strength, good in plasticity, and especially has excellent controlled performance of a surface decarburized layer can be developed by adopting a niobium micro-alloying method and integrating a proper clean steel smelting process, a continuously-cast blank surface defect control technology, a heating furnace fuel and in-furnace atmosphere optimization technology, and the problems such as a complex production process, high alloy cost and low production efficiency in an existing spring steel preparation method are effectively solved.

Description

technical field [0001] The invention belongs to the field of iron and steel metallurgical production, and in particular relates to a spring steel and a surface decarburization process thereof. Background technique [0002] Springs are very important mechanical parts, widely used in automobiles, railways, aviation, navigation, national defense and other fields. Due to the particularity of the service environment, the spring steel is required to have a high elastic limit, excellent elastic loss resistance and a high yield ratio. In order to prevent the fatigue fracture of the material under high-frequency alternating stress, the spring is required to have a relatively high High fatigue strength and sufficient ductility. 60Si2Mn is one of the most widely used spring steel varieties in China, and its consumption accounts for 50-60% of the total spring steel. Under the current industrial production conditions, for most spring steels, the problem of surface decarburization is in...

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Problems solved by technology

[0007] The purpose of the present invention is aimed at the complex production process, high alloy cost and low production efficiency of the current production method for producing spring steel, and the decarburization layer on the surface of the spring steel produced cannot meet the user's requirements (conforming to the standard and not applicable) and the steel structure is uniform In order to solve the problems of poor stability and performance stability, a high-strength and toughness spring steel and its decarburization control process are provided. The smelting components involved are simple, the control is stable, and the cost of smelting and rolling is low; the obtained steel has uniform structure, stable performance, high strength, Good plasticity, especially able to control the steel surface without a full decarburization layer, the thickness of the local decarburization layer does not exceed 1.5% H (H is the thickness of the spring flat steel) or 1.5% D (D is the diameter of the spring wire bar)

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