High annealing rate spring steel hot rolled strip

Abstract

The utility model discloses high annealing rate spring steel hot rolled steel strip, including steel band base body, the middle part of steel band base body upper and lower two sides are provided with the convex wedge and form the structure of middle high both sides low respectively, the upper and lower sides of steel band base body are provided with a plurality of heat dissipation grooves respectively, and the depth of heat dissation groove is 0.3mm, and the width is 1.2mm, and the left and right ends of steel band base body are provided with fillet respectively, and the outside of steel band base body is provided with an oxidation -resistant transition layer. The utility model discloses the structural design of symmetry wedge shape section, surface heat dissipation groove and arc transition chamfer, can significantly improve annealing uniformity, improve annealing efficiency greatly, significantly reduce residual stress, and effectively guarantee the follow -up processing performance and product pass rate.

Description

Technical Field

[0001] This utility model relates to the field of hot-rolled steel strip technology, and in particular to hot-rolled spring steel strip with high annealing rate. Background Technology

[0002] Hot-rolled spring steel strip is a core substrate for manufacturing critical components such as automotive suspension springs and mechanical valve springs. Its annealing quality directly determines the precision of subsequent cold forming, the mechanical properties of the product, and its fatigue life. This type of steel strip requires a spheroidizing annealing process to refine the grains and reduce hardness, providing good formability for subsequent processing. Simultaneously, it must ensure uniform microstructure and low residual stress after annealing to meet the high load and fatigue resistance requirements of spring components.

[0003] However, existing hot-rolled spring steel strips mostly adopt a flat, single structure without dedicated heat exchange optimization design on the surface, resulting in significant shortcomings in actual annealing processes: First, uneven heat conduction; the flat structure leads to large differences in heating rates between the upper and lower surfaces and the edges and center of the strip, forming a significant temperature gradient, which easily causes inconsistent spheroidization effects and poor microstructure uniformity, thus affecting the stability of subsequent processing; Second, low heat exchange efficiency; the limited surface area for heat radiation reception and dissipation on the flat surface makes it difficult for heat to quickly penetrate into the interior of the strip, requiring extended holding time to achieve a basic spheroidization effect, increasing production energy consumption and cycle time. Therefore, in response to the above situation, there is an urgent need to develop a high-annealing-rate hot-rolled spring steel strip with a symmetrical wedge-shaped cross-section, surface heat dissipation grooves, and arc-shaped transition chamfers. This design can significantly improve annealing uniformity, greatly increase annealing efficiency, significantly reduce residual stress, and effectively ensure subsequent processing performance and product qualification rate, thus overcoming the shortcomings in current practical applications and meeting current needs. Utility Model Content

[0004] The purpose of this invention is to provide hot-rolled spring steel strip with a high annealing rate to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: High-annealing-rate hot-rolled spring steel strip includes a steel strip substrate. The upper and lower sides of the middle part of the steel strip substrate are respectively provided with raised wedges to form a structure that is high in the middle and low on both sides. Multiple heat dissipation grooves are respectively provided on the upper and lower sides of the steel strip substrate. The depth of the heat dissipation grooves is 0.3 mm and the width is 1.2 mm. The left and right ends of the steel strip substrate are respectively provided with rounded corners. An anti-oxidation transition layer is provided on the outer side of the steel strip substrate.

[0006] Preferably, the protrusion height of the protruding wedge is 0.4~0.8mm.

[0007] Preferably, the distance between adjacent heat dissipation slots is 5~10mm.

[0008] Preferably, the two protruding wedges are arranged symmetrically, one above the other.

[0009] The beneficial effects of this invention are as follows: When used, the high-annealing-rate hot-rolled spring steel strip, through the raised wedge blocks, ensures a more balanced heat conduction path on the upper and lower surfaces of the strip matrix during annealing. Combined with the heat dissipation grooves, this expands the contact area for heat radiation reception and dissipation, accelerating heat penetration and thermal stress release, effectively reducing temperature gradients, and improving microstructure uniformity. The rounded corners prevent defects such as chipping and burrs during annealing and subsequent processing. In summary, this invention, through its symmetrical wedge-shaped cross-section, surface heat dissipation grooves, and arc-shaped transition chamfers, significantly improves annealing uniformity, greatly increases annealing efficiency, significantly reduces residual stress, and effectively ensures subsequent processing performance and product qualification rate. Attached Figure Description

[0010] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0011] Figure 2 This is a cross-sectional view of the present invention.

[0012] Legend: 1. Steel strip substrate; 2. Raised wedge block; 3. Heat dissipation groove; 4. Rounded corner; 5. Anti-oxidation transition layer. Detailed Implementation

[0013] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0014] Specific implementation examples are given below.

[0015] Example 1 See Figures 1-2In this embodiment of the present invention, the high annealing rate spring steel hot-rolled strip includes a steel strip substrate 1. The chemical composition (mass fraction) of the steel strip substrate 1 is: C: 0.60%, Si: 1.80%, Mn: 0.75%, Cr: 0.95%, V: 0.15%, with the remainder being Fe and unavoidable impurities. The steel strip substrate 1 has raised wedges 2 on its upper and lower sides in the middle, forming a structure that is high in the middle and low on both sides. The raised height of the raised wedges 2 is 0.4mm, and two raised wedges 2 are symmetrically arranged vertically. Multiple heat dissipation grooves 3 are provided on the upper and lower sides of the steel strip substrate 1. The depth of the heat dissipation grooves 3 is 0.3mm, the width is 1.2mm, and the adjacent spacing is 10mm. Rounded corners 4 are provided at both ends of the steel strip substrate 1 to prevent defects such as chipping and burrs during annealing and subsequent processing.

[0016] An anti-oxidation transition layer 5 is provided on the outer side of the steel strip substrate 1. The anti-oxidation transition layer 5 is a mixed coating of aluminum powder and silica sol with a thickness controlled at 5-10 μm. It is metallurgically bonded to the substrate to prevent oxidation and decarburization of the steel strip surface during annealing and to avoid structural defects.

[0017] Example 2 See Figures 1-2 The protrusion height of the protruding wedge 2 is 0.8mm, and the distance between adjacent heat dissipation grooves 3 is 5mm.

[0018] Working principle: When using this high-annealing-rate hot-rolled spring steel strip, the raised wedge block 2 makes the heat conduction path of the upper and lower surfaces of the steel strip substrate 1 more balanced during the annealing process. Combined with the heat dissipation groove 3, it expands the contact area for heat radiation reception and heat dissipation, accelerates heat penetration and heat stress release, effectively reduces temperature gradient, and improves the uniformity of the structure. The rounded corner 4 prevents defects such as edge chipping and burrs from occurring during annealing and subsequent processing.

[0019] Furthermore, it should be noted that, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0020] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A hot-rolled spring steel strip with a high annealing rate, characterized in that, The steel strip substrate (1) includes a steel strip base (1), with raised wedges (2) on the upper and lower sides of the middle part of the steel strip base (1) to form a structure that is high in the middle and low on both sides. Multiple heat dissipation grooves (3) are provided on the upper and lower sides of the steel strip base (1). The depth of the heat dissipation grooves (3) is 0.3 mm and the width is 1.2 mm. Rounded corners (4) are provided on the left and right ends of the steel strip base (1). An anti-oxidation transition layer (5) is provided on the outer side of the steel strip base (1).

2. The high annealing rate hot-rolled spring steel strip according to claim 1, characterized in that, The protrusion height of the protruding wedge (2) is 0.4~0.8mm.

3. The high annealing rate hot-rolled spring steel strip according to claim 1, characterized in that, The distance between adjacent heat dissipation slots (3) is 5~10mm.

4. The high annealing rate hot-rolled spring steel strip according to claim 1, characterized in that, The two protruding wedges (2) are arranged symmetrically on top of each other.

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