CN109078988B

CN109078988B - Method for controlling extension coefficient of rail head bottom

Info

Publication number: CN109078988B
Application number: CN201810872250.2A
Authority: CN
Inventors: 陶功明; 朱华林; 吴郭贤
Original assignee: Pangang Group Panzhihua Steel and Vanadium Co Ltd
Current assignee: Pangang Group Panzhihua Steel and Vanadium Co Ltd
Priority date: 2018-08-02
Filing date: 2018-08-02
Publication date: 2020-04-07
Anticipated expiration: 2038-08-02
Also published as: CN109078988A

Abstract

The invention relates to the field of steel rail rolling methods, in particular to a method for effectively controlling the extension coefficient of a steel rail head bottom so as to reduce the extension coefficient of the steel rail head bottom at a high point, which comprises a rail head, a rail web and a rail bottom of a rolled piece, wherein when the rolled piece is about to leave a previous pass of a finished product, the relative lengths of the rail head, the rail web and the rail bottom at the rolling tail end of the rolled piece are processed, namely the lengths of the rail head and the rail bottom are ensured to be longer than that of the rail web, and the length difference ranges from 10 mm to 50 mm. The invention ensures that the length of the rail head and the rail bottom is longer than that of the rail waist, wherein the length difference range is 10-50 mm. After the treatment, the time difference that the horizontal roller is separated from the rolled piece later than the vertical roller is greatly eliminated, so that the generation of high points is effectively controlled, the quality of products is greatly improved, and meanwhile, the improvement method does not need to modify the existing equipment, so that the method also has a very wide market popularization prospect. The invention is especially suitable for the process control of reducing the high point of the steel rail in universal continuous rolling.

Description

Method for controlling extension coefficient of rail head bottom

Technical Field

The invention relates to the field of steel rail rolling methods, in particular to a method for controlling the extension coefficient of the head bottom of a steel rail.

Background

The universal rolling mill consists of an upper horizontal roller, a lower horizontal roller and vertical rollers at two sides, the edging mill consists of an upper horizontal roller and a lower horizontal roller, and the two rolling mills form a continuous rolling unit at a distance of 3 meters. Generally, the horizontal roll diameter of the universal mill is 1200mm (driving roll), the vertical roll diameter is 800mm (driven roll), and the horizontal roll diameter of the edger is 800 mm.

In actual use, the layout of the universal line rolling mill is two rough rolling stands, one or two continuous rolling stands (universal and edging mills) and one UF finishing mill group. The rolling reduction of the last pass of the continuous rolling mill cannot be too small during the distribution of the rolling reduction, so that the tension changes when the tail of the steel rail is separated from the universal rolling mill under the condition of large deformation, the drift change is large, and the specification has large fluctuation at the moment. It is stated that the maximum rail height fluctuation is up to 0.8mm, typically in the range of 0.4-0.8 mm. The requirement of high-speed rail straightness cannot be met. Through the 'high point' state of the steel rail observed on site at the temperature of 500 plus 700 ℃, the situation that the roll pass is filled at the rail head opening is obviously changed, and the boundary line of the 'high point' part and the roll pass at the rail head opening is obviously narrowed, which shows that the 'high point' part has more metal amount in front of the finished product hole, so that the filling degree of the 'high point' part of the finished product hole is higher than that of other parts, and the 'high point' in the rail height direction is formed. The high point condition of the steel rail in a cold state through real object measurement. The measured fluctuation of 0.25mm is generated on the length of 120mm, which is the lower fluctuation condition in the whole industry, but still exceeds the requirement that the rail body is less than or equal to 0.2mm/1m, the polishing method is usually adopted for polishing, and the labor cost is greatly increased.

The reason for the above-mentioned fluctuation is: as shown in fig. 3, in actual rolling, the tip of the rail is a waist length part, while the rail head and rail bottom part are shorter, and the length difference of the deformation zone is larger due to the difference of the diameters of the universal rolls, so that the vertical rolls are separated from the rolled piece during tail flicking, and the horizontal rolls are separated from the rolled piece later than the vertical rolls. The rolling force when the vertical roller is separated from the rolled piece instantly (the vertical roller is a driven roller) is greatly reduced, the corresponding rotating speed is increased due to the reduction of the resistance of the motor, a forward feeding force of the horizontal roller clamping the steel rail is generated, and the forward feeding force is calculated to be about 6-10 tons, so that the abnormal deformation of the steel rail at the edge rolling mill part is caused.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for effectively controlling the extension coefficient of the head bottom of a steel rail, thereby lightening the extension coefficient of the head bottom of the steel rail at a high point.

The technical scheme adopted by the invention for solving the technical problems is as follows: the method for controlling the extension coefficient of the rail head bottom comprises the rail head, the rail web and the rail bottom of a rolled piece, when the rolled piece is about to leave the previous pass of a finished product, the relative lengths of the rail head, the rail web and the rail bottom at the rolling tail end of the rolled piece are processed, namely the lengths of the rail head and the rail bottom are ensured to be longer than the length of the rail web, wherein the length difference range is 10-50 mm.

Further, the rail head and the rail bottom tip are longer than the rail waist by increasing the roll gap of the hat-shaped hole, wherein the increase range of the roll gap of the hat-shaped hole is 2-8 mm.

And further, the rolling piece comprises a splitting hole, and the rolled piece enters the splitting hole for continuous rolling after being turned over through the cap-shaped hole.

Furthermore, the central axes of the universal horizontal upper roller and the universal horizontal lower roller are arranged in parallel.

Furthermore, the central axes of the universal vertical roll left roll and the universal vertical roll right roll are mutually perpendicular to the central axes of the universal horizontal upper roll and the universal horizontal lower roll.

The invention has the beneficial effects that: because the actual shape of the rolled piece of the steel rail in the prior rolling is that the rail waist part is long and the rail head and the rail bottom part are short, namely the tip of the steel rail is the waist part, the rail head and the rail bottom part are short, and simultaneously, the vertical roller firstly leaves the rolled piece and the horizontal roller leaves the rolled piece later than the vertical roller due to the difference of the diameters of the universal rollers during tail flicking, the vertical roller serving as a driven roller can instantly leave the rolled piece due to the small time difference, and the rolling force is greatly reduced, thereby the defect of a tail high point is generated. Aiming at the current situation, the relative lengths of the rail head, the rail waist and the rail bottom at the rolling tail end of the rolled piece are processed when the rolled piece is about to leave the front pass of a finished product, so that the lengths of the rail head and the rail bottom are longer than the length of the rail waist, wherein the length difference ranges from 10 mm to 50 mm. After the treatment, the time difference that the horizontal roller is separated from the rolled piece later than the vertical roller is greatly eliminated, so that the generation of high points is effectively controlled, the quality of products is greatly improved, and meanwhile, the improvement method does not need to modify the existing equipment, so that the method also has a very wide market popularization prospect. The invention is especially suitable for the process control of reducing the high point of the steel rail in universal continuous rolling.

Drawings

Fig. 1 is a schematic view of the structure of the roll of the present invention.

Figure 2 is a schematic representation of a rolled rail of the present invention.

Fig. 3 is a schematic view showing the structure of the rail after the rail web is elongated and the rail head and the rail are shortened in the actual rolling.

Fig. 4 is a schematic diagram of the relative lengths of the rail head, web and rail foot at the rolled end of the product after processing.

Fig. 5 is a schematic structural view of a cap-shaped hole.

Fig. 6 is a schematic view of the structure of the dicing hole.

FIG. 7 is a schematic view showing the positional relationship of the respective members in actual rolling.

Labeled as: the universal vertical roller comprises a universal horizontal upper roller 1, a universal horizontal lower roller 2, a universal vertical roller left roller 3, a universal vertical roller right roller 4, a steel rail rolling roller gap 5, a rail head 6, a rail web 7, a rail lower 8, an upper roller 9 of an edging mill, a lower roller 10 of the edging mill, a steel rail 11, a hat-shaped hole 12, a splitting hole 13, a length difference D and a hat-shaped hole roller gap H.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

The method for controlling the elongation coefficient of the rail head base as shown in fig. 1 to 7 comprises the rail head 6, the rail web 7 and the rail base 8 of a rolled piece 11, and when the rolled piece 11 is about to leave the previous pass of a finished product, the relative lengths of the rail head 6, the rail web 7 and the rail base 8 of the rolling tail end of the rolled piece 11 are processed, namely the lengths of the rail head 6 and the rail base 8 are ensured to be longer than the length of the rail web 7, wherein the length difference D ranges from 10 mm to 50 mm.

First, fig. 3 shows a schematic side view of a rail in actual rolling, and it can be seen from fig. 3 that the web 7 is elongated and the head 6 and the foot 8 are shorter, which shape leads to the result: the vertical rollers in contact with the rail head 6 and the rail lower 8 leave the rolled piece firstly, and the universal horizontal upper roller 1 and the universal horizontal lower roller 2 leave the rolled piece later than the vertical rollers, so that the vertical rollers serving as driven rollers are separated from the rolled piece instantly to cause drift, and meanwhile, the rolling force is greatly reduced, so that high points are caused. Aiming at the core of the problem, the invention designs: and when the rolled piece 11 is about to leave the previous pass of the finished product, processing the relative lengths of the rail head 6, the rail web 7 and the rail bottom 8 at the rolling tail end of the rolled piece 11, namely ensuring that the lengths of the rail head 6 and the rail bottom 8 are longer than the length of the rail web 7, wherein the length difference D ranges from 10 mm to 50 mm. After the method is carried out, as shown in fig. 4, at the moment of departure of the universal rolling mill, the time for separating the universal horizontal upper roll 1 and the universal horizontal lower roll 2 from the rolled piece is basically consistent with the time for separating the universal vertical roll left roll 3 and the universal vertical roll right roll 4 from the rolled piece, so that the possibility of forward feeding of the horizontal roll caused by reduction of rolling force due to premature departure of the vertical rolls from the rolled piece is reduced, and high points are effectively controlled. Generally, it is preferable that the central axes of the universal horizontal upper roll 1 and the universal horizontal lower roll 2 are arranged in parallel, and the central axes of the universal vertical roll left roll 3 and the universal vertical roll right roll 4 are arranged perpendicular to the central axes of the universal horizontal upper roll 1 and the universal horizontal lower roll 2.

In order to ensure smooth production, the relative lengths of the rail head 6, the rail web 7 and the rail foot 8 of the rolled end of the rolled piece 11 can be selected to be treated in such a way that: the rail head 6 and the tip of the rail bottom 8 are longer than the rail web 7 by increasing the roller gap H of the hat-shaped hole 12, wherein the increase range of the roller gap H of the hat-shaped hole is 2-8 mm. Generally, in the rolling process of the universal continuous rolling, when the rail web 7 is longer than the rail head 6 and the rail 8 by less than 200mm in the last front tail state, the segmentation hole 13 has certain unfilled allowance, the method of on-site roll gap adjustment can be adopted, the range of the hat-shaped hole roll gap H of the hat-shaped hole 12 is increased to be 2-8mm (under the condition that the segmentation hole is not filled enough), the later-stage head bottom metal is increased, so that the extension of the head bottom is longer than the waist by about 10-50mm, and the corresponding length adjustment is realized. Generally, after the adjustment of the roll gap H of the hat-shaped hole is completed, the rolled piece 11 can be turned over through the hat-shaped hole 12 and then enters the splitting hole 13 for continuous rolling.

The invention ensures that the length of the rail head and the rail bottom is longer than that of the rail waist, wherein the length difference range is 10-50 mm. After the treatment, the time difference that the horizontal roller is separated from the rolled piece later than the vertical roller is greatly eliminated, so that the generation of high points is effectively controlled, the quality of products is greatly improved, and meanwhile, the improvement method does not need to modify the existing equipment, so that the method also has a very wide market popularization prospect. The invention is especially suitable for the process control of reducing the high point of the steel rail in universal continuous rolling.

Claims

1. Method for controlling the coefficient of elongation of the head base of a steel rail, comprising the head (6), the web (7) and the foot (8) of a rolled piece (11), characterized in that: when the rolled piece (11) is about to leave a front pass of a finished product, the relative lengths of a rail head (6), a rail waist (7) and a rail bottom (8) at the rolling tail end of the rolled piece (11) are processed, namely the lengths of the rail head (6) and the rail bottom (8) are ensured to be longer than the length of the rail waist (7), wherein the length difference (D) ranges from 10 mm to 50mm and comprises a cap-shaped hole (12), the lengths of the tips of the rail head (6) and the rail bottom (8) are longer than the length of the rail waist (7) by increasing the cap-shaped hole roll gap (H), and the increasing range of the cap-shaped hole roll gap (H) is 2mm to 8 mm.

2. A method of controlling the coefficient of elongation of the rail head base as claimed in claim 1, wherein: the device comprises a splitting hole (13), wherein a rolled piece (11) enters the splitting hole (13) for continuous rolling after being overturned through a cap-shaped hole (12).

3. A method of controlling the coefficient of elongation of the rail head base as claimed in claim 1, wherein: the central axes of the universal horizontal upper roller (1) and the universal horizontal lower roller (2) are arranged in parallel.

4. A method of controlling the coefficient of elongation of the rail head base as claimed in claim 1, wherein: the central axes of the universal vertical roll left roll (3) and the universal vertical roll right roll (4) are mutually and vertically arranged with the central axes of the universal horizontal upper roll (1) and the universal horizontal lower roll (2).