Method for judging realization effect under heavy pressure

Abstract

The invention provides a method for judging a realization effect under heavy pressure, which belongs to the technical field of continuous casting and comprises the following steps of: acquiring cross sections of the same casting blank before and after being pressed as a cross section of an unpressed casting blank and a cross section of a pressed casting blank respectively; according to the cross section of the unpressed casting blank and the broadsiding shape of the cross section of the pressed casting blank, or according to the change of the core edge broadsiding ratio of the cross section of the unpressed casting blank and the cross section of the pressed casting blank, the pressed casting blank is subjected to heavy pressing to achieve effect judgment; wherein the core edge broadsiding ratio refers to the average value obtained by dividing the core width of the cross section of the casting blank by the width of the upper edge of the cross section of the casting blank and the width of the lower edge of the cross section of the casting blank. The problems that in the prior art, whether the casting blank achieves the process effect under heavy pressure or not is judged through a quantitative density measurement method, time and labor are wasted, the working difficulty is large, and the measurement precision is low can be solved.

Description

Technical Field

[0001] This invention relates to the field of continuous casting technology, and more specifically, to a method for determining the effect achieved under heavy pressure. Background Technology

[0002] The end-of-solidification reduction technology in continuous casting is an effective technical means to improve the core defects of the billet. It has been widely studied and applied in various billet types. In the last ten years or so, although the light reduction technology at the end of solidification is still being studied and applied, it has gradually developed into heavy reduction (or large reduction) technology in order to obtain better core quality of the billet and improve the final product performance.

[0003] Currently, there are different understandings and applications of heavy reduction technology. From the perspective of guiding theory and practical application, heavy reduction technology can be roughly divided into three categories: The first category is single-roll heavy reduction, which is to apply heavy reduction as an independent technology; the second category is to increase the total reduction on the basis of light reduction; the third category is a combination of light and heavy reduction, in which light reduction is used to improve segregation in the front and heavy reduction is used in the back to "weld" shrinkage cavities and improve the density of the billet.

[0004] From the current practical applications, there is no discussion or explanation of what heavy pressure is, or what the difference is between heavy pressure technology and light pressure technology. It is simply regarded as a compensation or optimization of light pressure, which seriously affects the development of heavy pressure and the realization of the advantages brought by heavy pressure technology, and completely deviates from the original intention of the development of heavy pressure technology.

[0005] In practical terms, the essential difference between heavy and light reduction lies in whether it increases the density of the central region of the billet. Light reduction technology only compensates for shrinkage and does not increase the density of the central region of the billet. Heavy reduction, on the other hand, uses the large deformation of a single roll to transfer strain to the central region of the billet, thereby increasing the central density and bringing process effects that light reduction cannot achieve. For example, heavy reduction can improve the density of the core of thick plate billets, thus meeting the flaw detection requirements even when the rolling ratio is reduced. Studies have shown that by increasing the core density of thick plates through heavy reduction, the rolling ratio can be reduced from the traditional 3.0 or higher to below 2.0, greatly increasing the thickness of the rolled material. Conversely, this can reduce the thickness of continuously cast billets, thereby improving production efficiency and reducing production costs. Therefore, only by quantifying the effect of heavy reduction can we quantify the heavy reduction process and clearly define the amount of reduction required to achieve the effect of heavy reduction, thus moving away from the vague concept that a large total reduction is equivalent to heavy reduction.

[0006] To quantify the improvement in the density of the billet center, most current methods involve quantitatively weighing the density of the central area of ​​the billet. Generally, a 20×20×20mm billet block from the center is taken and its density is accurately measured. For example, a significant increase in density indicates that the central density has improved. After weighing the density, the PCCS (Process Calculation Control System) uses "porosity" to quantitatively describe the effect under heavy pressure. When the porosity is less than 1.0, it means that the central area of ​​the billet has achieved density, that is, the billet has achieved the process effect under heavy pressure, and the rolling ratio can be reduced in subsequent steel rolling.

[0007] However, the aforementioned method of determining whether the cast billet has achieved the desired process effect under heavy pressure by measuring density is very time-consuming and labor-intensive, requiring specialized and precise equipment. Furthermore, the measurement process is highly sensitive to environmental conditions, such as the absence of vibration, as even slight vibration can affect the results. In general, any method for measuring density or compactness involves significant time and labor costs, strict operational procedures, and a substantial workload.

[0008] In summary, current methods for determining whether a billet has achieved the desired high-pressure process effect through quantitative density measurement are time-consuming, labor-intensive, difficult to implement, and have low measurement accuracy.

[0009] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0010] In view of the above problems, the purpose of this invention is to provide a method for determining the effect of heavy pressure, so as to solve the problems of time-consuming, labor-intensive, difficult and low measurement accuracy in the prior art, which uses quantitative density measurement to determine whether the billet has achieved the process effect of heavy pressure.

[0011] This invention provides a method for determining the effect achieved under heavy pressure, comprising the following steps: Obtain the cross-sections of the same billet before and after pressing, and use them as the cross-sections of the unpressed billet and the pressed billet, respectively. The effect of heavy pressing on the pressed billet is determined based on the cross-section of the unpressed billet and the width and shape of the cross-section of the pressed billet, or based on the change in the core-edge width-to-width ratio of the cross-section of the unpressed billet and the cross-section of the pressed billet. The core-edge width ratio refers to the core width of the billet cross-section divided by the average of the width of the upper edge of the billet cross-section and the width of the lower edge of the billet cross-section.

[0012] Furthermore, a preferred embodiment is to obtain the cross-section of the unpressed billet, including: A sample was taken transversely from the unpressed billet and used as the first billet transverse sample. The cross-section of the first casting billet is pre-treated to make the cross-section of the first casting billet cross-section smooth and flat, and the cross-section of the first casting billet cross-section is used as the cross-section of the unpressed casting billet.

[0013] Furthermore, a preferred embodiment is to obtain the cross-section of the pressed-down billet, including: A sample is cut transversely from the pressed-down billet to serve as a second billet transverse sample. The cross-section of the second billet is pre-treated to make it smooth and flat, and the cross-section of the second billet is used as the cross-section of the pressed billet.

[0014] Furthermore, a preferred approach is to determine the effectiveness of the re-pressing process on the unpressed billet based on the cross-section of the unpressed billet and the width and shape of the cross-section of the pressed billet, including: If the cross-sectional shape of the unpressed billet is a regular straight-edge shape, and the cross-sectional shape of the pressed billet is a concave shape on both sides, it is determined that the pressed billet has not achieved the effect of heavy pressing. If the cross-sectional shape of the unpressed billet is a regular straight-edge shape, and the cross-sectional shape of the pressed billet is still a regular straight-edge shape or a shape with outward convex sides, it is determined that the pressed billet has achieved the effect of heavy pressing.

[0015] Furthermore, a preferred approach is to determine the effectiveness of the re-pressing of the pressed-down billet based on the changes in the core-edge width-to-width ratio of the cross-section of the unpressed billet and the cross-section of the pressed-down billet, including: If the cross-section of the unpressed billet is a regular straight-edge shape, the core edge width-to-width ratio of the cross-section of the unpressed billet is set to 1. If the core-edge width-to-expansion ratio of the cross-section of the pressed-down billet is less than 1, it is determined that the pressed-down billet has not achieved the effect of heavy pressing; if the core-edge width-to-expansion ratio of the cross-section of the pressed-down billet is greater than or equal to 1, it is determined that the pressed-down billet has achieved the effect of heavy pressing.

[0016] Furthermore, a preferred approach is to determine the effectiveness of the re-pressing of the pressed-down billet based on the changes in the core-edge width-to-width ratio of the cross-section of the unpressed billet and the cross-section of the pressed-down billet, including: If the cross-section of the unpressed billet is an irregular straight edge shape on both sides, the core edge width ratio of the cross-section of the unpressed billet is equivalent to 1, and the core edge width ratio of the cross-section of the pressed billet is taken as the equivalent core edge width ratio. If the equivalent core edge width ratio is less than 1, it is determined that the pressed-down billet has not achieved the effect of heavy pressing; if the equivalent core edge width ratio is greater than or equal to 1, it is determined that the pressed-down billet has achieved the effect of heavy pressing.

[0017] Furthermore, a preferred approach is to determine the effectiveness of the re-pressing of the pressed-down billet based on the changes in the core-edge width-to-width ratio of the cross-section of the unpressed billet and the cross-section of the pressed-down billet, including: If the cross-section of the unpressed billet is an irregular straight edge shape on both sides, the core edge width ratio of the cross-section of the unpressed billet is used as the reference core edge width ratio. According to the preset core edge width ratio calculation formula, calculate the core edge width ratio of the reference and the core edge width ratio of the cross section of the pressed-down billet respectively; If the core-edge width-to-expansion ratio of the cross-section of the pressed-down billet is greater than or equal to the core-edge width-to-expansion ratio of the reference, it is determined that the pressed-down billet has achieved the effect of heavy pressing; if the core-edge width-to-expansion ratio of the cross-section of the pressed-down billet is less than the core-edge width-to-expansion ratio of the reference, it is determined that the pressed-down billet has not achieved the effect of heavy pressing.

[0018] Furthermore, a preferred embodiment is that the step of calculating the core edge width ratio of the reference and the core edge width ratio of the cross section of the pressed-down billet according to the preset core edge width ratio calculation formula includes: Obtain the upper edge width, core width, and lower edge width of the cross-section of the unpressed billet; and obtain the upper edge width, core width, and lower edge width of the cross-section of the pressed billet; The core width, core width, and bottom edge width of the cross-section of the unpressed billet are substituted into the preset core width ratio calculation formula to calculate the core width ratio of the reference; and the core width ratio of the cross-section of the pressed billet is calculated by substituting the core width, core width, and bottom edge width of the cross-section of the pressed billet into the preset core width ratio calculation formula.

[0019] Furthermore, in a preferred embodiment, the formula for calculating the preset core edge width ratio is: P = M / [(A+B) / 2]; where P is the core-edge width ratio, A is the width of the upper edge, B is the width of the lower edge, and M is the core width.

[0020] Furthermore, in a preferred embodiment, the method for determining the effect under heavy pressure is used to determine the effect of the billet under heavy pressure.

[0021] As can be seen from the above technical solution, the method for determining the effect of heavy pressing provided by this invention, based on the mechanism and practical results, judges the effect of heavy pressing on the billet according to the width and shape of the cross-section of the unpressed billet and the cross-section of the pressed billet, or according to the change in the core-edge width ratio of the cross-section of the unpressed billet and the cross-section of the pressed billet. Since the maximum deformation area during the pressing deformation process moves towards the core of the billet as the single-roll pressing amount increases, and the maximum deformation is located in the core of the billet after a certain pressing amount is reached, the effect of making the core of the billet denser is achieved. This is accompanied by a difference in the width and shape of the billet. Therefore, by quantitatively measuring and analyzing the shape and size of the cross-section of the billet before and after pressing, it is possible to quickly and concisely understand whether the billet after pressing has achieved the effect of improving the density of the billet core under heavy pressing. Therefore, this invention has the advantages of being able to quickly and simply determine whether the billet has achieved the effect of heavy pressure reduction, and is not affected by vibration during operation, thus ensuring the accuracy of the results. It can study the relative effective amount of heavy pressure reduction technology for different steel grades, different casting speeds, and different billet shapes, thereby effectively eliminating the ambiguous practical effects of existing heavy pressure reduction, and is conducive to standardizing and promoting the development of heavy pressure reduction technology.

[0022] To achieve the foregoing and related objectives, and in accordance with one or more aspects of the invention, the features described in detail below are included. Certain exemplary aspects of the invention are illustrated in detail below with reference to the accompanying drawings. However, these aspects indicate only a few of the various ways in which the principles of the invention can be used. Furthermore, the invention is intended to encompass all such aspects and their equivalents. Attached Figure Description

[0023] Other objects and results of the invention will become more apparent and readily understood with reference to the following description taken in conjunction with the accompanying drawings, and with a more complete understanding of the invention.

[0024] Figure 1 A flowchart illustrating a method for determining the effect under heavy pressure according to an embodiment of the present invention; Figure 2 A schematic diagram showing the cross-sectional shape of the billet according to an embodiment of the present invention as a regular straight-edge shape; Figure 3 This is a schematic diagram of the cross-sectional shape of a cast billet according to an embodiment of the present invention, which is an irregular straight edge shape with concave sides. Figure 4 This is a schematic diagram of the cross-sectional shape of a cast billet according to an embodiment of the present invention, which is an irregular straight edge shape with outward convexity on both sides; Figure 5 This is a schematic diagram of a low-magnification cross-section of a cast billet under light pressure according to Embodiment 1 of the present invention; Figure 6 This is a schematic diagram of a low-magnification cross-section of a cast billet under single-roll heavy pressure according to Embodiment 1 of the present invention. Detailed Implementation

[0025] In the following description, numerous specific details are set forth for illustrative purposes and to provide a thorough understanding of one or more embodiments. However, it will be apparent that these embodiments may also be implemented without these specific details.

[0026] In view of the aforementioned existing technologies, the method of determining whether the billet has achieved the process effect under heavy pressure by quantitatively measuring density has problems such as being time-consuming, labor-intensive, difficult to work, and having low measurement accuracy. This invention proposes a method for determining the effect achieved under heavy pressure.

[0027] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0028] To illustrate the method for determining the effectiveness under heavy pressure provided by this invention, Figure 1 The flowchart of a method for determining the effect under heavy pressure according to an embodiment of the present invention is shown; Figure 2 The cross-sectional shape of the billet according to an embodiment of the present invention is shown to be a regular straight-edge shape; Figure 3 The cross-sectional shape of the billet according to an embodiment of the present invention is shown to be an irregular straight edge shape with concave sides; Figure 4 The cross-sectional shape of the billet according to an embodiment of the present invention is shown to be an irregular straight edge shape with outward convex sides; Figure 5 A low-magnification cross-section of a cast billet under light pressure according to Embodiment 1 of the present invention is shown; Figure 6 A low-magnification cross-section of a cast billet under single-roll heavy pressure according to Embodiment 1 of the present invention is shown.

[0029] like Figures 1 to 4 As shown in the figure, the method for determining the effect under heavy pressure provided by the present invention mainly includes the following steps: Step S1: Obtain the cross-sections of the same billet before and after pressing, and use them as the cross-sections of the unpressed billet and the pressed billet, respectively.

[0030] Specifically, the same billet refers to a billet produced under similar operating conditions such as casting speed and secondary cooling process. Cross sections before and after pressing are obtained from the same billet to serve as the cross sections of the unpressed billet and the pressed billet, respectively. The cross section can be the end of the billet or the cross section of a sample cut from the middle of the billet. This invention does not make any special limitation on this.

[0031] As a preferred embodiment of the present invention, obtaining the cross-section of the unpressurized billet includes: A sample was taken transversely from the unpressed billet and used as the first billet transverse sample. The cross-section of the first casting billet is pre-treated to make it smooth and flat, and the cross-section of the first casting billet is used as the cross-section of the unpressed casting billet.

[0032] Specifically, in order to obtain a cross-section of the unpressed billet with more accurate shape and size, it is preferable to take a sample transversely from the unpressed billet as the first billet cross-section, i.e., the unpressed billet cross-section. Then, the first billet cross-section is pre-treated by grinding and other methods to ensure that the cut surface of the first billet cross-section is smooth and flat, without any cutting residue, so as to ensure the accuracy of dimensional measurement, thereby obtaining the cross-section of the unpressed billet. Basically, the sample cut on site is sufficient.

[0033] As a preferred embodiment of the present invention, obtaining the cross-section of the pressed-down billet includes: A sample is cut transversely from the pressed-down billet to serve as a second billet transverse sample. The cross-section of the second billet is pre-treated to make it smooth and flat, and the cross-section of the second billet is used as the cross section of the pressed billet.

[0034] Specifically, in order to obtain a cross-section of the pressed billet with more accurate shape and size, it is preferable to cut a sample transversely from the pressed billet as a second billet cross-section, i.e., the pressed billet cross-section. Then, the second billet cross-section is pre-treated by grinding or other methods to ensure that the cut surface of the second billet cross-section is smooth and flat, without any cutting residue, so as to ensure the accuracy of dimensional measurement, thereby obtaining the cross-section of the pressed billet. Basically, the sample cut on site is sufficient.

[0035] Step S2: Determine the effect of heavy pressing on the uncrushed billet based on the width and shape of the cross-section of the uncrushed billet and the cross-section of the pressed billet, or based on the change in the core-edge width ratio of the cross-section of the uncrushed billet and the cross-section of the pressed billet.

[0036] The core-edge width ratio refers to the core width of the billet cross-section divided by the average of the width of the upper edge of the billet cross-section and the width of the lower edge of the billet cross-section.

[0037] Specifically, the width and shape of the cross-section of the cast billet refers to the geometric shape of the cross-section, formed by the top edge, the transverse centerline of the core, the bottom edge, and the two side edges, such as... Figure 2-4 As shown. Ideally, the cross-sectional shape of an unpressed billet is a regular straight-edge shape, meaning the width of the top edge, the core width (the width of the billet from its height towards the center in the cross-section), and the bottom edge width are equal, i.e., the core-edge width ratio is 1. Generally, the cross-sectional shape of the pressed billet becomes irregular, such as... Figure 3 and Figure 4 ,in, Figure 3The cross-sectional shape of the billet shown changes from a wide, broad shape to a concave shape on both sides. At this time, the core-edge width ratio of the billet cross-section is less than 1. Figure 4 The cross-sectional shape of the billet shown changes from a wide, broad shape to a convex shape on both sides. At this point, the core-edge width-to-width ratio of the billet cross-section is greater than 1. The effect of the heavy-pressing process can be determined by observing the changes in the shape or size of the billet cross-section before and after pressing. Specifically, the effect of heavy-pressing can be judged based on the wide, broad shape of the cross-sections of the unpressed and pressed billets, or based on the changes in the core-edge width-to-width ratio of the cross-sections of the unpressed and pressed billets.

[0038] As a preferred embodiment of the present invention, the effect of heavy pressing on the pressed billet is determined based on the cross-section of the unpressed billet and the wide shape of the cross-section of the pressed billet, including: If the cross-sectional shape of the unpressed billet is a regular straight-edge shape, and the cross-sectional shape of the pressed billet is a concave shape on both sides, it is determined that the pressing billet has not achieved the effect of heavy pressing. If the cross-sectional shape of the unpressed billet is a regular straight-edge shape, and the cross-sectional shape of the pressed billet is still a regular straight-edge shape or a shape with outward convex sides, it is determined that the pressed billet has achieved the effect of heavy pressing.

[0039] Specifically, without quantitative research, the cross-sectional shape (breadth and spread) of the billet before and after pressing can generally be used to determine whether the heavy pressing process has been achieved. That is, the effectiveness of heavy pressing is judged by the breadth and spread of the cross-section of the unpressed and pressed billets. For example... Figure 3 and Figure 4 The width and shape of the cross-section of the billet shown are all the width and shape of the cross-section of the pressed billet; Figure 2 The cross-sectional shape of the billet shown is the same as the cross-sectional shape of the unpressed billet. Therefore, Figure 3 The width and shape of the cross-section of the billet shown are similar to Figure 2 The width and shape of the cross-section of the billet shown are compared. Figure 3 The cross-section of the billet is wide and concave on both sides, indicating that the deformation during pressing did not reach the center of the billet. Therefore, it is determined that the pressing of the billet did not achieve the desired effect of heavy pressing. Figure 4 The width and shape of the cross section of the billet Figure 2 The width and shape of the cross-section of the cast billet were compared. Figure 4 The cross-section of the pressed billet has a wide, convex shape on both sides, indicating that the pressing deformation is transmitted to the central area of ​​the billet. Therefore, it is determined that the pressed billet achieves the effect of heavy pressing.

[0040] As a preferred embodiment of the present invention, the effect of re-pressing the billet is determined based on the change in the core edge width ratio of the cross-section of the unpressed billet and the cross-section of the pressed billet, including: If the cross-section of the unpressed billet is a regular straight-edge shape, set the core edge width ratio of the cross-section of the unpressed billet to 1; If the core-edge width-to-width ratio of the cross-section of the pressed-down billet is less than 1, it is determined that the pressed-down billet has not achieved the effect of heavy pressing; if the core-edge width-to-width ratio of the cross-section of the pressed-down billet is greater than or equal to 1, it is determined that the pressed-down billet has achieved the effect of heavy pressing.

[0041] Specifically, if quantitative research is required, the change in the cross-sectional dimensions of the billet before and after pressing (core-edge width-to-expansion ratio) is used to determine whether the heavy pressing effect has been achieved. If the cross-section of the unpressed billet is a regular straight-edge shape, that is, the core-edge width-to-expansion ratio of the unpressed billet cross-section is equal to 1, and the core-edge width-to-expansion ratio of the pressed billet cross-section is less than 1, it means that the pressing deformation has not been transmitted to the central area of ​​the billet, and it is determined that the pressing billet has not achieved the heavy pressing effect; if the core-edge width-to-expansion ratio of the pressed billet cross-section is greater than or equal to 1, it means that the pressing deformation has been transmitted to the central area of ​​the billet, and it is determined that the pressing billet has achieved the heavy pressing effect.

[0042] As a preferred embodiment of the present invention, the effect of re-pressing the billet is determined based on the change in the core edge width ratio of the cross-section of the unpressed billet and the cross-section of the pressed billet, including: If the cross-section of the unpressed billet is irregularly straight-edged on both sides, the core edge width ratio of the cross-section of the unpressed billet is equivalent to 1, and the core edge width ratio of the cross-section of the pressed billet is taken as the equivalent core edge width ratio. If the equivalent core edge width ratio is less than 1, the pressed billet is determined to have failed to achieve the effect of heavy pressing; if the equivalent core edge width ratio is greater than or equal to 1, the pressed billet is determined to have achieved the effect of heavy pressing.

[0043] Specifically, assuming that, Figures 2-4 middle, Figure 2 The width of the unpressed billet's cross-section is relatively regular, meaning the core width, top edge width, and bottom edge width are equal, i.e., the core-edge width-to-width ratio is 1. Figure 3 and Figure 4 Both represent the broad shape of the cross-section of the pressed-down billet. Based on this, Figure 3 The core edge width ratio of the cross section of the pressed billet is compared to Figure 2 The cross-section of the unpressed billet has a small core-edge width ratio, i.e. Figure 3 The core edge width-to-width ratio of the cross-section of the pressed billet is less than 1; while Figure 4 The core edge width ratio of the cross section of the pressed billet is compared to Figure 2 The cross-section of the unpressed billet has a large core-edge width ratio, that is... Figure 4 The cross-sectional core edge width-to-width ratio of the pressed-down billet is greater than 1, which indicates that... Figure 3 The reduced billet did not achieve the effect of heavy reduction; while Figure 4 The pressure-reducing of the billet achieves the effect of heavy pressure reduction.

[0044] The above comparison method is based on the relatively regular cross-sectional shape of the unpressed billet. However, in actual execution, due to uneven cooling, localized stress, insufficient roll alignment, etc., the shape of the unpressed billet may not be regular. Low casting speeds or large-sized billets may result in a cross-sectional shape of the unpressed billet that is... Figure 3 As shown, the core has an inward concave shape, and under high drawing speeds, this causes the cross-section of the unpressed billet to tend towards... Figure 4 As shown, the core protrudes outwards in a bulging shape, which means that in reality, there are cases where the core edge width ratio of the unpressed billet cross section is not equal to 1.

[0045] At this point, it can be determined whether the cross-section of the unpressed billet is an irregular straight-edge shape. If the cross-section of the unpressed billet is an irregular straight-edge shape on both sides, the core edge width ratio of the cross-section of the unpressed billet is equivalent to 1, and the core edge width ratio of the cross-section of the pressed billet is taken as the equivalent core edge width ratio. When the equivalent core edge width ratio is less than 1, it is determined that the pressed billet has not achieved the effect of heavy pressing. When the equivalent core edge width ratio is greater than or equal to 1, it is determined that the pressed billet has achieved the effect of heavy pressing.

[0046] As a preferred embodiment of the present invention, the effect of re-pressing the billet is determined based on the change in the core edge width ratio of the cross-section of the unpressed billet and the cross-section of the pressed billet, including: If the cross-section of the unpressed billet has an irregular straight edge shape on both sides, the core edge width ratio of the cross-section of the unpressed billet is used as the reference core edge width ratio. Based on the preset core edge width ratio calculation formula, calculate the core edge width ratio of the reference and the core edge width ratio of the cross section of the pressed-down billet respectively; If the core-edge width-to-width ratio of the cross-section of the pressed-down billet is greater than or equal to the reference core-edge width-to-width ratio, the pressed-down billet is deemed to have achieved the effect of heavy pressing; if the core-edge width-to-width ratio of the cross-section of the pressed-down billet is less than the reference core-edge width-to-width ratio, the pressed-down billet is deemed to have failed to achieve the effect of heavy pressing.

[0047] Specifically, if the cross-section of the unpressed billet has irregular straight edges on both sides, the following approach can be adopted: the core edge width-to-width ratio of the unpressed billet's cross-section is used as the reference core edge width-to-width ratio; according to the preset core edge width-to-width ratio calculation formula, the values ​​of the reference core edge width-to-width ratio and the core edge width-to-width ratio of the pressed billet's cross-section are calculated respectively; if the value of the core edge width-to-width ratio of the pressed billet's cross-section is greater than or equal to the value of the reference core edge width-to-width ratio, it is determined that the pressed billet has achieved the effect of heavy pressing; if the value of the core edge width-to-width ratio of the pressed billet's cross-section is less than the value of the reference core edge width-to-width ratio, it is determined that the pressed billet has not achieved the effect of heavy pressing.

[0048] As a preferred embodiment of the present invention, the core edge width ratio of the reference and the core edge width ratio of the cross section of the pressed-down billet are calculated according to a preset core edge width ratio calculation formula, including: Obtain the top edge width, core width, and bottom edge width of the cross section of the unpressed billet; and obtain the top edge width, core width, and bottom edge width of the cross section of the pressed billet. Substituting the upper edge width, core width, and lower edge width of the unpressed billet cross section into the preset core edge width ratio calculation formula, the reference core edge width ratio value is calculated; and substituting the upper edge width, core width, and lower edge width of the pressed billet cross section into the preset core edge width ratio calculation formula, the core edge width ratio value of the pressed billet cross section is calculated.

[0049] The formula for calculating the core edge width ratio is as follows: P = M / [(A+B) / 2]; where P is the core-edge width ratio, A is the width of the upper edge, B is the width of the lower edge, and M is the core width.

[0050] As a preferred embodiment of the present invention, the method for determining the effect under heavy pressure provided by the present invention is preferably, but not limited to, used for determining the effect under heavy pressure on billets.

[0051] Based on the mechanism and practical results, the effect of heavy pressing on the billet is judged according to the width and shape of the cross-section of the unpressed billet and the pressed billet, or according to the change in the core-edge width ratio of the cross-sections of the unpressed billet and the pressed billet. As the single-roll pressing amount increases, the maximum deformation area during the pressing deformation process will move towards the core of the billet. When a certain pressing amount is reached, the maximum deformation will be located in the core of the billet, thereby achieving the effect of making the core of the billet dense. At the same time, there is a difference in the width and shape of the billet. Therefore, by quantitatively measuring and analyzing the shape and size of the cross-section of the billet before and after pressing, it is possible to quickly and simply understand whether the pressed billet has achieved the effect of improving the core density of the billet under heavy pressing. Therefore, this invention has the advantages of being able to quickly and simply determine whether the billet has achieved the effect of heavy pressure reduction, and is not affected by vibration during operation, thus ensuring the accuracy of the results. It can study the relative effective amount of heavy pressure reduction technology for different steel grades, different casting speeds, and different billet shapes, thereby effectively eliminating the ambiguous practical effects of existing heavy pressure reduction, and is conducive to standardizing and promoting the development of heavy pressure reduction technology.

[0052] To better illustrate the application of the method for determining the effect under heavy pressure provided by this invention, the following specific embodiments are provided: Example 1 Taking a 165×165mm square billet from a steel plant as an example, the steel grade produced is GCr15. The low-magnification cross-section of the billet under light pressing and the low-magnification cross-section under single-roll heavy pressing are as follows: Figure 5 and Figure 6 As shown, the low-magnification cross-section of the billet produced by the light-pressure process is clearly as follows: Figure 5 As shown, its broad shape is concave on both sides, while the low-magnification cross-section of the billet cast under heavy pressure is as follows: Figure 6 As shown, its wide shape is a bulging shape with both sides bulging outwards. The shape of the cross-section of the billet can be used to preliminarily determine whether the pressing of the billet has achieved the effect of heavy pressing. However, due to the influence of the shape of the cross-section of the unpressed billet, a quantitative evaluation method is more accurate. The example data of the corresponding core edge width ratio are shown in Table 1. Table 1 As can be seen from Table 1, this casting machine is a large billet casting machine with many straightening machines and large cylinder diameters, which results in a relatively large controllable pressure when producing 165×165mm small billets. This is equivalent to having a light pressing effect. Therefore, when no pressing is performed, the core edge width ratio of the billet cross section is less than 1.

[0053] Table 1 clearly quantifies that when the light pressing process is applied, the core-edge width ratio of the billet cross-section is 0.991, which is less than the core-edge width ratio of the unpressed billet cross-section (0.997). However, when the single-roll heavy pressing process is applied, the core-edge width ratios of the billet cross-section are 1.017 and 1.049, respectively, which are obviously greater than the core-edge width ratio of the unpressed billet cross-section (0.997). Therefore, by using the method for determining the effect of heavy pressing provided by this invention, and through the quantitative study of the core-edge width ratio of the billet cross-section, it is possible to quantitatively demonstrate and study whether the pressed billet has achieved the effect of the heavy pressing process.

[0054] As can be seen from Table 1, since the core edge width ratio of the unpressed billet cross section is not 1, the core edge width ratio of all processes can be equivalent to the case where 1 is the scale by using the equivalent core edge width ratio method. That is, all core edge width ratios are divided by the core edge width ratio of the unpressed billet. Obviously, the conclusion of whether the heavy pressing process effect is achieved is consistent. It's just that when evaluating, the comparison is based on the relative core edge width ratio of the unpressed billet cross section, or on 1 after equivalence.

[0055] The method provided by this invention demonstrates that with increasing casting speed, the core-to-edge width ratio of the billet cross-section tends to increase from 1.017 to 1.049 for the same single-roll reduction. This indicates that as the casting speed increases, the overall temperature of the billet rises, making the billet softer, and more deformation is transmitted to the center of the billet under the same reduction. Using the method provided by this invention, the inventors also studied the reduction effects of different steel grades under different reduction amounts. They found that for softer steel grades, a relatively small reduction amount can achieve the effect of heavy reduction. For example, for a 160×160mm square billet, if it is No. 70 steel, a single roll reduction of about 7mm is sufficient to achieve a core-to-edge width ratio greater than or equal to 1, while for GCr15, a single roll reduction of about 15mm is required to achieve the same core-to-edge width ratio. Furthermore, the larger the billet size, the greater the single-roll reduction is required to achieve a core-to-edge width ratio greater than or equal to 1 in the billet cross-section. Therefore, this invention can provide a quantitative evaluation for studying effective heavy reduction processes.

[0056] As can be seen from the above specific embodiments, the method for determining the effect of heavy pressing provided by the present invention, based on the mechanism and practical results, judges the effect of heavy pressing on the billet according to the width and shape of the cross-section of the unpressed billet and the cross-section of the pressed billet, or according to the change in the core-edge width ratio of the cross-section of the unpressed billet and the cross-section of the pressed billet. Since the maximum deformation area during the pressing deformation process moves towards the core of the billet as the single-roll pressing amount increases, and the maximum deformation is located in the core of the billet after a certain pressing amount is reached, the effect of making the core of the billet denser is achieved. This is accompanied by a difference in the width and shape of the billet. Therefore, by quantitatively measuring and analyzing the shape and size of the cross-section of the billet before and after pressing, it is possible to quickly and simply understand whether the billet after pressing has achieved the effect of improving the density of the billet core under heavy pressing. Therefore, this invention has the advantages of being able to quickly and simply determine whether the billet has achieved the effect of heavy pressure reduction, and is not affected by vibration during operation, thus ensuring the accuracy of the results. It can study the relative effective amount of heavy pressure reduction technology for different steel grades, different casting speeds, and different billet shapes, thereby effectively eliminating the ambiguous practical effects of existing heavy pressure reduction, and is conducive to standardizing and promoting the development of heavy pressure reduction technology.

[0057] The method for determining the effect under heavy pressure according to the present invention has been described above by way of example with reference to the accompanying drawings. However, those skilled in the art should understand that various modifications can be made to the method for determining the effect under heavy pressure proposed by the present invention without departing from the scope of the invention. Therefore, the scope of protection of the present invention should be determined by the contents of the appended claims.

Claims

1. A method of determining an effect under heavy pressing, characterized by, The method comprises the following steps: Obtaining the cross sections of the same casting blank before and after pressing down, respectively as the cross section of the non-pressed-down casting blank and the cross section of the pressed-down casting blank; According to the spread shape of the cross section of the non-pressed-down casting blank and the cross section of the pressed-down casting blank, or according to the change of the core edge spread ratio of the cross section of the non-pressed-down casting blank and the cross section of the pressed-down casting blank, the pressed-down casting blank is subjected to the effect judgment of re-pressing down; The core edge spread ratio refers to the core width of the cross section of the casting blank divided by the average of the upper edge width of the cross section of the casting blank and the lower edge width of the cross section of the casting blank.

2. The method of claim 1, wherein The cross section of the non-pressed-down casting blank is obtained, comprising: Transversely cutting a sample from the non-pressed-down casting blank as a first casting sample; The cutting surface of the first casting sample is pretreated to make the cutting surface of the first casting sample smooth and flat, and the cutting surface of the first casting sample is taken as the cross section of the non-pressed-down casting blank.

3. The method of claim 1, wherein The cross section of the pressed-down casting blank is obtained, comprising: Transversely cutting a sample from the pressed-down casting blank as a second casting sample; The cutting surface of the second casting sample is pretreated to make the cutting surface of the second casting sample smooth and flat, and the cutting surface of the second casting sample is taken as the cross section of the pressed-down casting blank.

4. The method of claim 1, wherein According to the spread shape of the cross section of the non-pressed-down casting blank and the cross section of the pressed-down casting blank, the pressed-down casting blank is subjected to the effect judgment of re-pressing down, comprising: If the spread shape of the cross section of the non-pressed-down casting blank is a regular straight edge shape, and the spread shape of the cross section of the pressed-down casting blank is a concave shape on both sides, it is judged that the pressed-down casting blank does not achieve the effect of re-pressing down; If the spread shape of the cross section of the non-pressed-down casting blank is a regular straight edge shape, and the spread shape of the cross section of the pressed-down casting blank is still a regular straight edge shape or a convex shape on both sides, it is judged that the pressed-down casting blank achieves the effect of re-pressing down.

5. The method of claim 1, wherein According to the change of the core edge spread ratio of the cross section of the non-pressed-down casting blank and the cross section of the pressed-down casting blank, the pressed-down casting blank is subjected to the effect judgment of re-pressing down, comprising: If the cross section of the non-pressed-down casting blank is a regular straight edge shape, the core edge spread ratio of the cross section of the non-pressed-down casting blank is set to 1; If the core edge spread ratio of the cross section of the pressed-down casting blank is less than 1, it is judged that the pressed-down casting blank does not achieve the effect of re-pressing down; if the core edge spread ratio of the cross section of the pressed-down casting blank is greater than or equal to 1, it is judged that the pressed-down casting blank achieves the effect of re-pressing down.

6. The method of claim 1, wherein According to the change of the core edge spread ratio of the cross section of the non-pressed-down casting blank and the cross section of the pressed-down casting blank, the pressed-down casting blank is subjected to the effect judgment of re-pressing down, comprising: If the cross section of the non-pressed-down casting blank is a non-regular straight edge shape on both sides, the core edge spread ratio of the cross section of the non-pressed-down casting blank is equivalent to 1, and the core edge spread ratio of the cross section of the pressed-down casting blank is taken as an equivalent core edge spread ratio; If the equivalent core edge spread ratio is less than 1, it is judged that the pressed-down casting blank does not achieve the effect of re-pressing down; if the equivalent core edge spread ratio is greater than or equal to 1, it is judged that the pressed-down casting blank achieves the effect of re-pressing down.

7. The method of claim 1, wherein According to the change of the core edge spread ratio of the cross section of the non-pressed-down casting blank and the cross section of the pressed-down casting blank, the pressed-down casting blank is subjected to the effect judgment of re-pressing down, comprising: If the cross section of the non-pressed down casting blank is a shape of two sides irregular straight side, the core side width spread ratio of the cross section of the non-pressed down casting blank is taken as a reference core side width spread ratio; According to a preset core side width spread ratio calculation formula, the value of the reference core side width spread ratio and the value of the core side width spread ratio of the cross section of the pressed down casting blank are calculated respectively; If the value of the core side width spread ratio of the cross section of the pressed down casting blank is greater than or equal to the value of the reference core side width spread ratio, it is determined that the pressed down casting blank realizes the effect of re-pressing down; if the value of the core side width spread ratio of the cross section of the pressed down casting blank is less than the value of the reference core side width spread ratio, it is determined that the pressed down casting blank does not realize the effect of re-pressing down.

8. The method of claim 7, wherein According to the preset core side width spread ratio calculation formula, the value of the reference core side width spread ratio and the value of the core side width spread ratio of the cross section of the pressed down casting blank are calculated respectively, including: The upper edge width, core width and lower edge width of the cross section of the non-pressed down casting blank are obtained, and the upper edge width, core width and lower edge width of the cross section of the pressed down casting blank are obtained; The upper edge width, core width and lower edge width of the cross section of the non-pressed down casting blank are substituted into the preset core side width spread ratio calculation formula to obtain the value of the reference core side width spread ratio, and the upper edge width, core width and lower edge width of the cross section of the pressed down casting blank are substituted into the preset core side width spread ratio calculation formula to obtain the value of the core side width spread ratio of the cross section of the pressed down casting blank.

9. The method of claim 8, wherein The preset core side width spread ratio calculation formula is: P=M / [(A+B) / 2]; wherein P is the value of the core side width spread ratio, A is the upper edge width, B is the lower edge width, and M is the core width.

10. The method of claim 1, wherein The determination method of the effect of re-pressing down is used for determining the effect of re-pressing down of a casting blank.

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