A method for rolling rails of different standards using the same roll pass of a BD2 rolling mill
By sharing the roll pass of the BD2 rolling mill, the rolling parameters of different standard rails were integrated and optimized, solving the problem of long roll pass design cycle in rail production, achieving on-time delivery and cost savings, and improving production efficiency and product quality.
Patent Information
- Application Number
- CN202510136293.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-07
- Publication Date
- 2025-10-28
- Estimated Expiration
- 2045-02-07
AI Technical Summary
In the existing technology, rail production requires the design of roll pass patterns for different standards in different countries, which results in a long development cycle, makes it impossible to guarantee on-time delivery, and increases roll costs and production costs.
By adopting the method of using the common BD2 rolling mill roll pass, and by integrating and optimizing the rolling parameters of different standard rails, a series of common BD2 roll passes were developed. Finite element software was used to calculate the standard cross-sectional area of each part of the rail, ensuring that the difference in cross-sectional area of each part is within the allowable range, thus realizing the common rolling of rails of different standards.
This significantly shortened the rail development cycle, ensured on-time delivery, saved on rolling mill costs, reduced production costs, and improved the product's market competitiveness. The rail specifications met the standards and had good straightness.
Smart Images
Figure CN119839044B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of rail rolling technology, and in particular to a method for rolling rails of different standards using the same BD2 rolling mill roll pass. Background Art
[0002] Steel rails belong to the category of shaped steel sections. Their main function is to guide the movement of rail vehicles and bear the weight of vehicles and goods, as well as the pressure of the wheels. Steel rails are classified into three types according to their weight per meter: crane rails, light rails, and heavy rails. The cross-section of a steel rail is I-shaped, consisting of three parts: the rail head (1), the rail web (2), and the rail base (3). Figure 1 (As shown). The rail head is the part of the rail that contacts the wheel, and the contact surface is called the rail surface; the rail web is the connecting part between the rail head and the rail base, and the rail base is the main load-bearing part of the rail, with a large width and bottom area.
[0003] Currently, the mainstream rolling method for heavy rails is universal rolling mill. The main frame of a universal rolling mill consists of a pair of main rolls and a pair of horizontal rolls. The axes of the four rolls are in a plane, with the horizontal rolls being the driving rolls and the vertical rolls being the driven rolls, allowing for simultaneous processing of all four sides of the rolled material. When rolling heavy rails using the universal rolling method, the roughing process uses two stand-up billet mills. The basic production process is as follows: (1) After heating and descaling the rectangular continuous casting billet, it is rolled by the first stand-up billet mill (i.e., BD1 mill, usually a two-roll reversible billet mill); (2) The first stand-up billet mill rolls the casting billet into a hat-shaped piece and then sends it to the second stand-up billet mill (i.e., BD2 mill, usually a two-roll reversible billet mill) for rolling; Since the metal content of the rail head, rail web and rail bottom of the finished rail is different, there will inevitably be uneven deformation during the billet rolling process. In the billet stage, the BD pass system is used to gradually roll the rectangular billet into the basic shape of the rail through trapezoidal holes, rail profile deep cutting holes, rail profile extension holes and pilot holes; In order to reduce uneven deformation during the billet process, 3-5 hat-shaped holes are generally used; (3) Figure 2 As shown, the second roughing mill rolls the cap-shaped workpiece into the prototype of a rail, and after descaling, it is sent to the universal mill for rolling; (4) after rolling and descaling in the universal roughing mill, it is sent to the universal intermediate mill for rolling. After rolling, the cross-sectional dimensions and shape of the workpiece are close to those of the finished rail; (5) after rolling in the universal intermediate mill, it is sent to the universal finishing mill for rolling, thus completing the rail rolling process. The waist of the workpiece with the initial rail shape bears the action of horizontal upper and lower rolls in the universal pass of the universal mill. The rail head and rail bottom sides are processed by vertical rolls in the vertical rolling pass of the edge rolling mill, thereby ensuring that the width of the rail head and rail bottom and the geometry of the sides meet the requirements, and ensuring the uniformity and symmetry of the rail deformation during the rolling process.
[0004] With economic globalization and the continuous development of my country's foreign trade exports, rail production involves different standards from different countries. For example, the production standards for symmetrical cross-section rails include American Standard, European Standard, Chinese Railway Standard, Japanese Standard, and Russian Standard. Rail models are usually named according to their weight per meter. American Standard rails include 115RE (56.7 kg / m) and 136RE (68 kg / m); European Standard rails include 54E1 (54 kg / m) and 60E1 (60.8 kg / m); Chinese Railway Standard rails include 50 kg / m, 60 kg / m, and 75 kg / m; and Russian Standard rails include P65 (65 kg / m), among other models. Normally, each different rail model requires the separate development of corresponding roll die patterns, resulting in a relatively long development cycle, including design and procurement. Moreover, the design of the rail rolls involves the BD1 rolling mill, the BD2 rolling mill, and the universal rolling mill. Compared with the universal rolling mill, the BD2 rolling mill takes nearly two months longer to design and manufacture the roll rolls, which seriously affects the smooth production of the rails and even makes it impossible to guarantee on-time delivery. Summary of the Invention
[0005] This invention provides a method for rolling rails of different standards using the same BD2 rolling mill roll pass. For rails with similar specifications, using the same BD2 rolling mill roll pass significantly shortens the rail development cycle, ensures on-time delivery, saves on roll costs, and reduces production costs.
[0006] To achieve the above objectives, the present invention employs the following technical solution:
[0007] A method for rolling rails of different standards using the same roll pass of a BD2 rolling mill, applicable to rails with symmetrical cross-sections; details are as follows:
[0008] Method 1: To produce other standard rails using the BD2 die pattern of Chinese standard rails, the following conditions must be met:
[0009] (1) The difference in single weight between other standard steel rails and Chinese standard steel rails is within 5 kg / m.
[0010] (2) Compared with the corresponding Chinese railway standard rail that meets the conditions (1), the difference in the proportion of the rail head cross-sectional area, rail web cross-sectional area, and rail bottom cross-sectional area to the total cross-sectional area of the rail is within 5% for other standard rails that are pre-rolled.
[0011] Method 2: Utilizing the BD2 shared die pattern to produce rails of the same specification, specifically including the following steps:
[0012] (1) Collect typical BD2 pass patterns used when rolling different standard rails on the BD2 mill;
[0013] (2) Parameterize the typical BD2 hole types collected in step (1) and classify the hole types according to the similarity of their cross-sectional areas;
[0014] (3) Based on step (2), the secondary development function of the finite element software is used to integrate and optimize the same type of BD2 hole type, and a series of BD2 common hole types are developed.
[0015] (4) For the series of BD2 common hole patterns obtained in step (3), calculate the cross-sectional area of the BD2 common hole pattern respectively using the curve integral method, and calculate the standard cross-sectional area of each part of the corresponding rail, including the standard cross-sectional area of the rail head, the standard cross-sectional area of the rail web and the standard cross-sectional area of the rail bottom, and set the maximum cross-sectional area difference of each part of the corresponding rail.
[0016] (5) When producing rails of different standards, first select the corresponding BD2 common die according to the cross-sectional area of the rail; then calculate the cross-sectional area of the rail head, the cross-sectional area of the rail web and the cross-sectional area of the rail bottom respectively. When the difference between the cross-sectional area of each part and the corresponding standard cross-sectional area is not greater than the difference of the corresponding maximum cross-sectional area, the selected BD2 common die is used for rolling.
[0017] Furthermore, the rails are rolled using a universal rolling mill method, and the rolling production line includes a BD1 rolling mill, a BD2 rolling mill, and a universal rolling mill.
[0018] Furthermore, the other standard rails mentioned include American standard rails, European standard rails, Japanese standard rails, and Russian standard rails.
[0019] Compared with the prior art, the present invention has the following beneficial effects:
[0020] 1) For rails with similar specifications, the method of using the same BD2 rolling mill roll pass is adopted, which greatly shortens the rail development cycle and ensures on-time product delivery.
[0021] 2) It saves on rolling mill costs, reduces production costs, and improves the market competitiveness of products;
[0022] 3) Practice has verified that the method described in this invention is feasible, the rail specifications meet the standard requirements, and the straightness is good, which meets the technical agreement requirements of the customer. Attached Figure Description
[0023] Figure 1 This is a cross-sectional view of the rail.
[0024] Figure 2 This is a schematic diagram of the roll profile of the BD2 rolling mill described in this invention.
[0025] In the diagram: 1. Rail head 2. Rail web 3. Rail base Detailed Implementation
[0026] The method for rolling rails of different standards using the same BD2 rolling mill roll pass, as described in this invention, is applicable to rails with symmetrical cross-sections; details are as follows:
[0027] Method 1: To produce other standard rails using the BD2 die pattern of Chinese standard rails, the following conditions must be met:
[0028] (1) The difference in single weight between other standard steel rails and Chinese standard steel rails is within 5 kg / m.
[0029] (2) Compared with the corresponding Chinese railway standard rail that meets the conditions (1), the difference in the proportion of the rail head cross-sectional area, rail web cross-sectional area, and rail bottom cross-sectional area to the total cross-sectional area of the rail is within 5% for other standard rails that are pre-rolled.
[0030] Method 2: Utilizing the BD2 shared die pattern to produce rails of the same specification, specifically including the following steps:
[0031] (1) Collect typical BD2 pass patterns used when rolling different standard rails on the BD2 mill;
[0032] (2) Parameterize the typical BD2 hole types collected in step (1) and classify the hole types according to the similarity of their cross-sectional areas;
[0033] (3) Based on step (2), the secondary development function of the finite element software is used to integrate and optimize the same type of BD2 hole type, and a series of BD2 common hole types are developed.
[0034] (4) For the series of BD2 common hole patterns obtained in step (3), calculate the cross-sectional area of the BD2 common hole pattern respectively using the curve integral method, and calculate the standard cross-sectional area of each part of the corresponding rail, including the standard cross-sectional area of the rail head, the standard cross-sectional area of the rail web and the standard cross-sectional area of the rail bottom, and set the maximum cross-sectional area difference of each part of the corresponding rail.
[0035] (5) When producing rails of different standards, first select the corresponding BD2 common die according to the cross-sectional area of the rail; then calculate the cross-sectional area of the rail head, the cross-sectional area of the rail web and the cross-sectional area of the rail bottom respectively. When the difference between the cross-sectional area of each part and the corresponding standard cross-sectional area is not greater than the difference of the corresponding maximum cross-sectional area, the selected BD2 common die is used for rolling.
[0036] Furthermore, the rails are rolled using a universal rolling mill method, and the rolling production line includes a BD1 rolling mill, a BD2 rolling mill, and a universal rolling mill.
[0037] Furthermore, the other standard rails mentioned include American standard rails, European standard rails, Japanese standard rails, and Russian standard rails.
[0038] This invention can achieve the goal of using the same BD2 rolling mill roll pass for different standard rails in two different ways. The first method is suitable for manufacturers that already have the production capacity and equipment for China Railway Standard series rails. They only need to align other standard rails with the existing rails according to the principle of proximity. Other standard rails that meet the conditions can be rolled using the existing BD2 rolling mill roll pass.
[0039] Another approach is applicable to the construction of new rail production lines and equipment, or to the production of various other standard rails. In this case, it is necessary to develop and design a series of BD2 common roll passes to enable rails, including those conforming to Chinese railway standards, as well as American, European, Japanese, and Russian standards, to be rolled using the same BD2 rolling mill roll passes.
[0040] To more intuitively illustrate the present invention, the embodiments of the present invention will be further described in conjunction with the examples. The following examples are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any technical solutions that can be obviously obtained by those skilled in the art within the scope of the technology disclosed in the present invention, including simple variations or equivalent substitutions, are all within the scope of protection of the present invention.
[0041]
Example
[0042] In this embodiment, the China Railway Standard TB / T 2344.1-2020.1 series rails are existing products of the manufacturer, with a complete universal rolling production line and supporting BD1, BD2 and universal rolling mill rolls.
[0043] The newly developed pre-rolled steel rails are American standard 115RE steel rails.
[0044] According to the Chinese railway standard TB / T 2344.1-2020.1, the weight per meter of a 60kg / m steel rail is 60.8kg / m, and the total cross-sectional area is 7748mm². 2 The rail head cross-sectional area accounts for 37.5% of the total rail cross-sectional area, the rail web cross-sectional area accounts for 25.3% of the total rail cross-sectional area, and the rail base cross-sectional area accounts for 37.2% of the total rail cross-sectional area.
[0045] Pre-rolled American standard 115RE steel rails, with a single meter weight of 56.7 kg / m and a total cross-sectional area of 7253 mm². 2 The rail head cross-sectional area accounts for 34.6% of the total rail cross-sectional area, the rail web cross-sectional area accounts for 27% of the total rail cross-sectional area, and the rail base cross-sectional area accounts for 38.2% of the total rail cross-sectional area.
[0046] The weight difference per meter between a 60kg / m rail and a US standard 115RE rail is 60.8-56.7=4.1kg / m, which meets the requirement that the weight difference per meter be within 5kg / m.
[0047] The differences between the proportions of various cross-sectional areas of a 60kg / m steel rail and the proportions of the total cross-sectional area of a standard 115RE steel rail are as follows:
[0048] The difference between the rail head cross-sectional area and the total rail cross-sectional area: 37.5% - 34.6% = 2.9%;
[0049] The difference between the ratio of the web cross-sectional area to the total cross-sectional area of the rail: 27% - 25.3% = 1.7%;
[0050] The difference between the ratio of the rail base cross-sectional area to the total rail cross-sectional area: 38.2% - 37.2% = 1%;
[0051] It meets the condition that the difference between the proportions of the rail head cross-sectional area, rail web cross-sectional area, and rail bottom cross-sectional area to the total cross-sectional area of the rail is all within 5%.
[0052] Therefore, in this embodiment, the BD2 rolling mill roll pass of the Chinese Railway Standard 60kg / m and the American Standard 115RE rail can be shared. Since the manufacturer already has the production conditions for the Chinese Railway Standard 60kg / m, the American Standard 115RE rail can use the existing Chinese Railway Standard 60kg / m BD2 rolling mill roll pass, and there is no need to design and manufacture it separately.
[0053] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A method for rolling rails of different standards using the same roll pass on a BD2 rolling mill, characterized in that, Applicable to rails with symmetrical cross-sections; details are as follows: Method 1: To produce other standard rails using the BD2 die pattern of Chinese standard rails, the following conditions must be met: (1) The difference in single weight between other standard steel rails and Chinese standard steel rails is within 5 kg / m. (2) Compared with the corresponding Chinese railway standard rail that meets the conditions (1), the difference in the proportion of the rail head cross-sectional area, rail web cross-sectional area, and rail bottom cross-sectional area to the total cross-sectional area of the rail is within 5% for other standard rails that are pre-rolled. Method 2: Utilizing the BD2 shared die pattern to produce rails of the same specification, specifically including the following steps: (1) Collect typical BD2 pass patterns used when rolling different standard rails on the BD2 mill; (2) Parameterize the typical BD2 hole types collected in step (1) and classify the hole types according to the similarity of their cross-sectional areas; (3) Based on step (2), the secondary development function of the finite element software is used to integrate and optimize the same type of BD2 hole type, and a series of BD2 common hole types are developed. (4) For the series of BD2 common hole patterns obtained in step (3), calculate the cross-sectional area of the BD2 common hole pattern respectively using the curve integral method, and calculate the standard cross-sectional area of each part of the corresponding rail, including the standard cross-sectional area of the rail head, the standard cross-sectional area of the rail web and the standard cross-sectional area of the rail bottom, and set the maximum cross-sectional area difference of each part of the corresponding rail. (5) When producing rails of different standards, first select the corresponding BD2 common die according to the cross-sectional area of the rail; then calculate the cross-sectional area of the rail head, the cross-sectional area of the rail web and the cross-sectional area of the rail bottom respectively. When the difference between the cross-sectional area of each part and the corresponding standard cross-sectional area is not greater than the difference of the corresponding maximum cross-sectional area, the selected BD2 common die is used for rolling.
2. The method for rolling different standard rails using the same BD2 rolling mill roll pass as described in claim 1, characterized in that, The rails are rolled using a universal rolling mill method, and the rolling production line includes a BD1 rolling mill, a BD2 rolling mill, and a universal rolling mill.
3. The method for rolling different standard rails using the same BD2 rolling mill roll pass as described in claim 1, characterized in that, The other standard rails mentioned include American standard rails, European standard rails, Japanese standard rails, and Russian standard rails.
Citation Information
Patent Citations
Steel rail rolling method
CN101712044A
Method for rolling square steel
CN102039307A