A straightening method capable of improving the distribution of residual stress of steel

Abstract

The present application relates to a kind of straightening method capable of improving the distribution of residual stress of steel material, comprising: controlling Ccn-2 to 0 or close to 0, controlling Cwn-1 to 1 or close to 1, to control Ccn-1 in target range;Wherein, n is the number of straightening roll put into straightening work in straightening machine, n is greater than 3;Cc is residual curvature ratio, Cw is reverse curvature ratio.The straightening method provided by the present application controls Ccn-2 to 0 or close to 0, controls Cwn-1 to 1 or close to 1, controls Ccn-1 in target range to achieve the purpose of steel straightening, while the reverse bending of n-1 roll Rn-1 can make the residual stress of the straightened steel material surface to be 0 or close to 0, effectively improve the performance of steel.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical production technology, and specifically relates to a straightening method that can improve the distribution of residual stress in steel. Background Technology

[0002] Steel straightening typically involves multiple rounds of bending and springback. The main purpose of straightening is to improve the bending radius of the raw material, achieving the target bending radius, and in most cases, leveling it, meaning the bending radius after straightening is infinitely large. With the development of materials technology and increasingly stringent requirements for the intrinsic properties of materials, the yield strength of materials is increasing, as is the residual stress within the materials themselves. This places higher demands on the residual stress state after straightening. Furthermore, residual stress on the material surface affects its corrosion resistance and fracture resistance. Therefore, it is generally required that the overall residual stress of the material should not exceed the standard value, but the lower the residual stress on the material surface, the better.

[0003] Currently, there are two main types of steel straightening processes: large deformation straightening and small deformation straightening. Both can achieve the purpose of steel straightening, but they cannot effectively control the residual stress on the steel surface. Summary of the Invention

[0004] This invention relates to a straightening method that can improve the distribution of residual stress in steel, and can at least solve some of the defects of the prior art.

[0005] This invention relates to a straightening method that can improve the distribution of residual stress in steel, comprising:

[0006] Control Ccn-2 to 0 or close to 0, and control Cwn-1 to 1 or close to 1, so as to keep Ccn-1 within the target range;

[0007] Where n is the number of straightening rollers put into straightening work in the straightening machine, and n is greater than 3;

[0008] Cc is the residual curvature ratio, and Cw is the reverse curvature ratio.

[0009] As one implementation method, among the straightening rollers used for straightening, Cw1 and Cwn are both 0, and the inverse bending ratios of the other straightening rollers decrease along the direction of steel travel.

[0010] As one implementation method, Cwn-1 > 1.

[0011] As one implementation method, when using a large deformation straightening process, Cw2 > 2.5.

[0012] As one implementation method, when using a small deformation straightening process, Cw2 < 2.5.

[0013] As one implementation method, Ccn-2 is controlled to be 0 to 0.1.

[0014] As one implementation method, Cwn-1 is controlled to be 1 to 1.1.

[0015] As one implementation method, when the final straightening of the steel can be achieved at the straightening roller na, based on the currently determined number of straightening rollers put into straightening work, a-2 straightening rollers are removed in the order of removal from the tail end to the head end; wherein, the removed straightening rollers are put into standby state.

[0016] The present invention has at least the following beneficial effects:

[0017] The straightening method provided by this invention controls Ccn-2 to 0 or close to 0 and Cwn-1 to 1 or close to 1. While controlling Ccn-1 within the target range to achieve the purpose of straightening the steel, the reverse bending of the n-1 roller Rn-1 can make the residual stress on the surface of the straightened steel 0 or close to 0, effectively improving the performance of the steel. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram showing the distribution of straightening rollers provided in an embodiment of the present invention. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] This invention provides a straightening method that can improve the distribution of residual stress in steel, comprising:

[0022] Control Ccn-2 to 0 or close to 0, and control Cwn-1 to 1 or close to 1, so as to keep Ccn-1 within the target range;

[0023] Where n is the number of straightening rollers put into straightening work in the straightening machine, and n is greater than 3;

[0024] Cc is the residual curvature ratio, and Cw is the reverse curvature ratio.

[0025] like Figure 1 The straightening rollers used in the straightening operation are, in order: roller 1 R1, roller 2 R2, roller 3 R3, ..., roller i Ri, ..., roller n-2 Rn-2, roller n-1 Rn-2, and roller n Rn.

[0026] Preferably, rollers R1 and Rn do not straighten the steel, meaning that Cw1 and Cwn are both 0. 。

[0027] In one embodiment, among the straightening rollers used for straightening, except for roller No. 1 R1 and roller No. n Rn, the inverse bending ratios of the other straightening rollers decrease along the direction of steel travel.

[0028] In one embodiment, Ccn-2 is controlled to be 0 to 0.1.

[0029] Preferably, Cwn-1 > 1. In one embodiment, Cwn-1 is controlled to be between 1 and 1.1.

[0030] Among them, Ccn-1 is controlled within the target range, preferably Ccn-1 = 0. In actual production, Ccn-1 can be controlled between 0 and 0.1.

[0031] The straightening method provided in this embodiment controls Ccn-2 to 0 or close to 0 and Cwn-1 to 1 or close to 1. While controlling Ccn-1 within the target range to achieve the purpose of steel straightening, the reverse bending of the n-1 roller Rn-1 can make the residual stress on the surface of the straightened steel 0 or close to 0, effectively improving the performance of the steel.

[0032] Specifically, at roller n-1 Rn-1, the steel is reverse-bent. After the reverse bending, the steel will spring back. After the spring back, the steel is still in a flattened state, but the residual stress on the surface of the steel can be reduced.

[0033] In one embodiment, when using a large deformation straightening process, the inverse bending rate corresponding to roller 2 R2 is generally larger than that of steel. In this embodiment, preferably, Cw2 > 2.5. This method is particularly suitable for steel with severe original bending.

[0034] In one embodiment, when a small deformation straightening process is used, Cw2 < 2.5; this method is particularly suitable for steel with a relatively light original degree of curvature.

[0035] Preferably, Ccn-3 ≠ 0, meaning that final straightening cannot be achieved at roller n-3 (Rn-3). Otherwise, one straightening roller can be reduced accordingly. Similarly, if straightening can be achieved at roller n-4 (Rn-4), another straightening roller can be reduced. In other words, when final straightening of the steel can be achieved at roller na, based on the currently determined number of straightening rollers in operation, a-2 straightening rollers are removed, in the order of removal from the tail end to the head end; these removed straightening rollers are then placed in standby mode. Based on this method, Ccn-2 is controlled to be 0 or close to 0. Thus, after the reverse bending of roller n-1 (Rn-1), the residual stress on the surface of the straightened steel can be reduced to 0 or close to 0.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A straightening method capable of improving the distribution of residual stress in steel, characterized by, Comprise: Ccn-2 is controlled to 0~0.1, Cwn-1 is controlled to 1~1.1, and Ccn-1 is controlled in the target range; Wherein, n is the number of straightening rollers put into the straightening work in the straightening machine, and n is greater than 3; Cc is the residual curvature ratio, and Cw is the reverse bending curvature ratio; When the final straightening of the steel material can be achieved at the n-a number straightening roller, on the basis of the number of straightening rollers currently determined to be put into the straightening work, a-2 straightening rollers are removed in the order of being removed from the tail end to the head end; wherein, the removed straightening rollers are in standby state.

2. Straightening method according to claim 1, characterized in that: In the straightening rollers put into the straightening work, Cw1 and Cwn are both 0, and the reverse bending curvature ratios corresponding to the remaining straightening rollers decrease along the running direction of the steel material.

3. The straightening method of claim 1, wherein: When the large deformation straightening process is adopted, Cw2>2.

5.

4. The straightening method of claim 1, wherein: When the small deformation straightening process is adopted, Cw2<2.5.

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