Method for rolling different standard steel rails by sharing BD2 rolling mill roller pass

Abstract

The invention relates to a method for rolling different standard steel rails by sharing a BD2 rolling mill roller pass. The method is realized in two modes. According to the first mode, other standard steel rails are produced through the BD2 hole pattern of the China railway standard steel rail; according to the second mode, the same kind of steel rails are produced through the newly-designed BD2 common hole pattern; for steel rails with similar specifications, the method of sharing the BD2 rolling mill roller hole pattern is adopted, the development period of the steel rails is greatly shortened, on-time delivery is guaranteed, meanwhile, the roller cost is saved, and the production cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of rail rolling, and in particular to a method for rolling rails of different standards using a common BD2 rolling mill roll pass profile. Background Art

[0002] Rails are special-shaped steels among steel sections. Their main function is to guide the travel of rail vehicles and bear the weight of vehicles and cargo and the pressure of wheels. Rails are divided into three types according to their weight per meter: crane rails, light rails and heavy rails. The cross section of a rail is an "I" shape, consisting of three parts: the rail head 1, the rail waist 2 and the rail bottom 3 (such as Figure 1 The rail head is the part of the track that contacts the wheel, and the contact surface is called the rail surface; the rail waist is the connecting part between the rail head and the rail bottom, and the rail bottom is the main load-bearing part of the track, with a larger width and bottom area.

[0003] At present, the mainstream rolling method of heavy rails is universal rolling mill; the main frame of the universal rolling mill consists of a pair of main rollers and a pair of horizontal rollers. The axes of the four rollers are in the same plane, the horizontal rollers are active rollers, and the vertical rollers are driven rollers, which can process the four sides of the rolling body at the same time. When rolling heavy rails by the universal rolling method, two slab mills are used for rough rolling. The basic production process is as follows: (1) After heating and descaling the rectangular continuous casting billet, it is rolled by the first slab mill (i.e., BD1 mill, usually a two-roller reversible slab mill); (2) The first slab mill rolls the cast billet into a hat-shaped rolled piece and then sends it to the second slab mill (i.e., BD2 mill, usually a two-roller reversible slab mill) for rolling. Since the metal content of the head, waist and bottom of the finished rail is quite different, there will inevitably be uneven deformation during the slab rolling process. During the slab stage, the BD hole system is used to gradually roll the rectangular billet into the prototype of the rail through trapezoidal holes, rail-shaped deep cutting holes, rail-shaped extension holes and pilot holes. In order to reduce uneven deformation during the slab process, 3-5 hat-shaped holes are generally used; (3) Figure 2 As shown in the figure, the rail-shaped hole of the second slab mill rolls the hat-shaped workpiece into the prototype of the rail, and after descaling, it is sent to the universal mill for rolling; (4) After rolling and descaling at the universal rough mill, it is sent to the universal medium mill for rolling. After rolling, the size and shape of the cross section of the workpiece are close to the finished rail; (5) After rolling at the universal medium mill, it is sent to the universal finishing mill for rolling, and the rolling process of the rail is completed. The waist of the workpiece that has taken the shape of the rail is subjected to the action of the horizontal upper and lower rollers in the universal pass of the universal mill, and the rail head and rail bottom sides are processed by vertical rollers in the vertical rolling pass of the edge rolling mill, so as to ensure that the width of the rail head and rail bottom and the geometric shape of the side meet the requirements, and ensure the uniformity and symmetry of the deformation of the rail during the rolling process.

[0004] With the economic globalization and the continuous development of my country's foreign trade exports, rail production involves different standards in different countries. For example, the production standards for symmetrical cross-section rails include American standards, European standards, Chinese railway standards, Japanese standards, Russian standards, etc. Rail models are usually renamed according to each meter, including 115RE (56.7 kg / m) and 136RE (68 kg / m) in American standards, 54E1 (54 kg / m) and 60E1 (60.8 kg / m) in European standards, 50 kg / m, 60 kg / m and 75 kg / m in Chinese railway standards, and P65 (65 kg / m) in Russian standards. Under normal circumstances, the corresponding roller pass profile needs to be developed separately for each different type of rail, and the development cycle, including design and procurement, is relatively long. Moreover, the hole profile design of the rails involves the BD1 rolling mill, BD2 rolling mill and universal rolling mill. Compared with the universal rolling mill, the roller hole profile design and production time of the BD2 rolling mill is nearly 2 months longer, which seriously affects the smooth production of the rails and even makes it impossible to guarantee delivery on time. Summary of the invention

[0005] The present invention provides a method for rolling different standard rails using a common BD2 rolling mill roll pass profile. For rails with similar specifications, the method of using a common BD2 rolling mill roll pass profile greatly shortens the development cycle of the rails, ensures on-time delivery, saves roll costs, and reduces production costs.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for rolling different standard rails using the same BD2 rolling mill roll pass profile is applicable to rails with symmetrical cross-sections; the details are as follows:

[0008] Method 1: Using the BD2 hole type of China Railway Standard Rail to produce other standard rails, the following conditions must be met:

[0009] (1) The difference in unit weight between pre-rolled other standard rails and China Railway standard rails is within 5kg / m;

[0010] (2) The difference between the cross-sectional area of ​​the head, the cross-sectional area of ​​the waist and the cross-sectional area of ​​the bottom of the pre-rolled other standard rails and the corresponding Chinese railway standard rails meeting condition (1) is within 5% of the total cross-sectional area of ​​the rails;

[0011] Method 2: Using BD2 common hole type to produce rails of the same specification, specifically including the following steps:

[0012] (1) Collect the typical BD2 pass profiles used when rolling different standard rails in the BD2 rolling mill;

[0013] (2) parameterizing the typical BD2 hole profiles collected in step (1) and classifying the hole profiles according to the similarity of the 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 profiles and develop a series of BD2 common hole profiles;

[0015] (4) for a series of BD2 common hole profiles obtained in step (3), the cross-sectional areas of the BD2 common hole profiles are calculated respectively by using the curve integration method, and the standard cross-sectional areas of the corresponding rail parts are calculated, including the standard cross-sectional areas of the rail head, the rail waist and the rail bottom, and the maximum cross-sectional area difference of the corresponding rail parts is set;

[0016] (5) When producing rails of different standards, first select the corresponding BD2 common hole profile according to the cross-sectional area of ​​the rail; then calculate the cross-sectional area of ​​the rail head, rail waist and rail bottom of the rail respectively. When the difference between the cross-sectional area of ​​each part and the corresponding standard cross-sectional area is not greater than the corresponding maximum cross-sectional area difference, the selected BD2 common hole profile is used for rolling.

[0017] Furthermore, the rolling of the rails adopts 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 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 sharing the BD2 rolling mill roll pass is adopted, which greatly shortens the rail development cycle and ensures that the products are delivered on time;

[0021] 2) Save roller costs, reduce production costs, and improve product market competitiveness;

[0022] 3) Practice has proven that the method of the present invention is feasible, the rail specifications meet the standard requirements, and the straightness is good, meeting the technical agreement requirements of the customer. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a cross-section diagram of a rail.

[0024] Figure 2 It is a schematic diagram of the roll profile of the BD2 rolling mill described in the present invention.

[0025] In the figure: 1. Rail head 2. Rail waist 3. Rail bottom DETAILED DESCRIPTION

[0026] The method for rolling different standard rails using the same BD2 rolling mill roll pass profile is applicable to rails with symmetrical cross-sections. The specific details are as follows:

[0027] Method 1: Using the BD2 hole type of China Railway Standard Rail to produce other standard rails, the following conditions must be met:

[0028] (1) The difference in unit weight between pre-rolled other standard rails and China Railway standard rails is within 5kg / m;

[0029] (2) The difference between the cross-sectional area of ​​the head, the cross-sectional area of ​​the waist and the cross-sectional area of ​​the bottom of the pre-rolled other standard rails and the corresponding Chinese railway standard rails meeting condition (1) is within 5% of the total cross-sectional area of ​​the rails;

[0030] Method 2: Using BD2 common hole type to produce rails of the same specification, specifically including the following steps:

[0031] (1) Collect the typical BD2 pass profiles used when rolling different standard rails in the BD2 rolling mill;

[0032] (2) parameterizing the typical BD2 hole profiles collected in step (1) and classifying the hole profiles according to the similarity of the 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 profiles and develop a series of BD2 common hole profiles;

[0034] (4) for a series of BD2 common hole profiles obtained in step (3), the cross-sectional areas of the BD2 common hole profiles are calculated respectively by using the curve integration method, and the standard cross-sectional areas of the corresponding rail parts are calculated, including the standard cross-sectional areas of the rail head, the rail waist and the rail bottom, and the maximum cross-sectional area difference of the corresponding rail parts is set;

[0035] (5) When producing rails of different standards, first select the corresponding BD2 common hole profile according to the cross-sectional area of ​​the rail; then calculate the cross-sectional area of ​​the rail head, rail waist and rail bottom of the rail respectively. When the difference between the cross-sectional area of ​​each part and the corresponding standard cross-sectional area is not greater than the corresponding maximum cross-sectional area difference, the selected BD2 common hole profile is used for rolling.

[0036] Furthermore, the rolling of the rails adopts 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 include American standard rails, European standard rails, Japanese standard rails and Russian standard rails.

[0038] The present invention can achieve the purpose of rolling different standard rails using the same BD2 rolling mill roll pass in two different ways. The first way is suitable for manufacturers that already have the production capacity and equipment for China Railway Standard series rails. They only need to move other standard rails closer to the current rails according to the principle of proximity, and other standard rails that meet the conditions can be rolled using the existing BD2 rolling mill roll pass.

[0039] Another method is suitable for newly built rail production lines and equipment, or for producing a variety of other standard rails. In this case, it is necessary to develop and design a series of BD2 common hole profiles so that rails including Chinese railway standard, American standard, European standard, Japanese standard and Russian standard rails can be rolled using the common BD2 rolling mill roller hole profile.

[0040] In order to more intuitively embody the present invention, the embodiments of the present invention are further described in conjunction with examples. The following examples are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any technical solution that can be obviously obtained by a person skilled in the art within the technical scope disclosed in the present invention, including simple changes or equivalent replacements, is within the protection scope 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 rollers.

[0043] The newly developed pre-rolled rail is the American standard 115RE rail.

[0044] The weight of a 60kg / m rail in China Railway Standard TB / T 2344.1-2020.1 is 60.8kg / m per meter and the total cross-sectional area is 7748mm. 2 , the cross-sectional area of ​​the rail head accounts for 37.5% of the total cross-sectional area of ​​the rail, the cross-sectional area of ​​the rail waist accounts for 25.3% of the total cross-sectional area of ​​the rail, and the cross-sectional area of ​​the rail bottom accounts for 37.2% of the total cross-sectional area of ​​the rail;

[0045] Pre-rolled American standard 115RE rail, unit weight is 56.7kg / m, total cross-sectional area is 7253mm 2 The cross-sectional area of ​​the rail head accounts for 34.6% of the total cross-sectional area of ​​the rail, the cross-sectional area of ​​the rail waist accounts for 27% of the total cross-sectional area of ​​the rail, and the cross-sectional area of ​​the rail bottom accounts for 38.2% of the total cross-sectional area of ​​the rail;

[0046] The difference in unit weight per meter between 60kg / m rail and 115RE rail of American standard is 60.8-56.7=4.1kg / m, which meets the requirement that the unit weight difference should be within 5kg / m.

[0047] The difference between the cross-sectional area of ​​each part of the 60kg / m rail and the American standard 115RE rail in the proportion of the corresponding rail total cross-sectional area is as follows:

[0048] The difference between the cross-sectional area of ​​the rail head and the total cross-sectional area of ​​the rail: 37.5%-34.6%=2.9%;

[0049] The difference between the cross-sectional area of ​​the rail waist and the total cross-sectional area of ​​the rail: 27%-25.3%=1.7%;

[0050] The difference between the cross-sectional area of ​​the rail bottom and the total cross-sectional area of ​​the rail: 38.2%-37.2%=1%;

[0051] The difference between the cross-sectional area of ​​the rail head, the cross-sectional area of ​​the rail waist and the cross-sectional area of ​​the rail bottom in the total cross-sectional area of ​​the rail is within 5%.

[0052] Therefore, in this embodiment, the BD2 rolling mill roller pass profiles of the Chinese Railway Standard 60kg / m and the American Standard 115RE rails 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 / mBD2 rolling mill roller pass profile, and there is no need to design and manufacture it separately.

[0053] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for rolling different standard rails using the same BD2 rolling mill roll pass, characterized in that: Applicable to rails with symmetrical cross-sections; details are as follows: Method 1: Using the BD2 hole type of China Railway Standard Rail to produce other standard rails, the following conditions must be met: (1) The difference in unit weight between pre-rolled other standard rails and China Railway standard rails is within 5kg / m; (2) The difference between the cross-sectional area of ​​the head, the cross-sectional area of ​​the waist and the cross-sectional area of ​​the bottom of the pre-rolled other standard rails and the corresponding Chinese railway standard rails meeting condition (1) is within 5% of the total cross-sectional area of ​​the rails; Method 2: Using BD2 common hole type to produce rails of the same specification, specifically including the following steps: (1) Collect the typical BD2 pass profiles used when rolling different standard rails in the BD2 rolling mill; (2) parameterizing the typical BD2 hole profiles collected in step (1) and classifying the hole profiles according to the similarity of the 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 profiles and develop a series of BD2 common hole profiles; (4) for a series of BD2 common hole profiles obtained in step (3), the cross-sectional areas of the BD2 common hole profiles are calculated respectively by using the curve integration method, and the standard cross-sectional areas of the corresponding rail parts are calculated, including the standard cross-sectional areas of the rail head, the rail waist and the rail bottom, and the maximum cross-sectional area difference of the corresponding rail parts is set; (5) When producing rails of different standards, first select the corresponding BD2 common hole profile according to the cross-sectional area of ​​the rail; then calculate the cross-sectional area of ​​the rail head, rail waist and rail bottom of the rail respectively. When the difference between the cross-sectional area of ​​each part and the corresponding standard cross-sectional area is not greater than the corresponding maximum cross-sectional area difference, the selected BD2 common hole profile is used for rolling.

2. The method for rolling different standard rails using the same BD2 rolling mill roll groove according to 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 groove according to claim 1, characterized in that: The other standard rails include American standard rails, European standard rails, Japanese standard rails and Russian standard rails.

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