CN116550749A - Rolling method for controlling negative deviation of bar - Google Patents

Abstract

The invention discloses a rolling method for controlling negative deviation of a bar, which comprises the following steps: temperature regulation, wherein in the rough rolling, medium rolling and finish rolling processes, the temperature of the head part of the steel billet is 25-35 ℃ higher than the temperature of the middle part of the steel billet, and the temperature of the tail part of the steel billet is 30-50 ℃ higher than the temperature of the middle part of the steel billet; tension is adjusted, tension is adjusted to be free of tension in rough rolling or micro-stack rolling, micro-tension rolling is performed in middle rolling, and a finish rolling loop is automatically adjusted to be free of tension; and adjusting the line difference, namely adjusting the pre-cutting opening of the K4 rolling mill to be horizontal, enabling the center line to coincide with the center line of the steel billet, enabling the length of the steel billet passing through the two side grooves to be consistent after being subjected to cooling bed, and adjusting the K4 rolling mill and the front pass rolling mill thereof, so that the length of the steel billet passing through the middle groove is consistent with the length of the steel billet passing through the two side grooves after being subjected to cooling bed. According to the method, the negative deviation of the bar is regulated and controlled in three aspects of temperature, tension and line difference, and the negative deviation can be effectively reduced.

Description

Rolling method for controlling negative deviation of bar

Technical Field

The invention relates to the technical field of deformed steel bar splitting rolling, in particular to a rolling method for controlling negative deviation of bars.

Background

In the bar rolling process, the control range of negative deviation is limited by the big trend of the small head and the big trend of the tail of a finished product, the head cutting buckle is not subjected to leveling operation after being separated by a cutting gun in sampling, the negative difference is easy to calculate inaccurately by directly weighing, the negative difference control means has no influence on the cost in the period of bar gauge delivery, the building material market in Guangdong province starts to implement a gauge delivery mode in 2023, 1 month and 1 day, the production cost is greatly improved in the gauge delivery mode, and the material is wasted.

Therefore, how to reduce the negative bias is especially necessary for deformed steel rolling. In view of this, the present invention has been made.

Disclosure of Invention

The invention aims to provide a rolling method for controlling negative deviation of bars, which reduces the negative deviation.

The invention is realized in the following way:

in a first aspect, the present invention provides a rolling method for controlling negative deviations of bars, comprising:

temperature regulation, wherein in the rough rolling, medium rolling and finish rolling processes, the temperature of the head part of the steel billet is 25-35 ℃ higher than the temperature of the middle part of the steel billet, and the temperature of the tail part of the steel billet is 30-50 ℃ higher than the temperature of the middle part of the steel billet;

tension is adjusted, tension is adjusted to be free of tension in rough rolling or micro-stack rolling, micro-tension rolling is performed in middle rolling, and a finish rolling loop is automatically adjusted to be free of tension; for two adjacent rolling mills, the negative deviation of the current or moment of the next rolling mill compared with the current or moment of the previous rolling mill is 0-2%, and the positive deviation of the current or moment of the next rolling mill compared with the current or moment of the previous rolling mill is 0-2%;

and adjusting the line difference, namely adjusting the pre-cutting opening of the K4 rolling mill to be horizontal, enabling the center line to coincide with the center line of the steel billet, enabling the length of the steel billet passing through the two side grooves to be consistent after being subjected to cooling bed, and adjusting the K4 rolling mill and the front pass rolling mill thereof, so that the length of the steel billet passing through the middle groove is consistent with the length of the steel billet passing through the two side grooves after being subjected to cooling bed.

In an alternative embodiment, for the same rolling mill, if the billet temperature increases, the tension is reduced; if the temperature decreases, the tension increases.

In an alternative embodiment, in the step of adjusting the tension, a reverse adjustment mode is used for adjusting the speed proportional relationship of each rolling mill.

In an alternative embodiment, in the step of adjusting the tension, when the speed of the rolling mill is adjusted, the outlet linear speed of the last rolling mill is used as a reference of speed adjustment, and when the speed of any rolling mill is adjusted, the speed matching relationship between other adjacent rolling mills in the whole linear range is unchanged.

In an alternative embodiment, in the finish rolling step, a front pinch roller, a sleeve lifting wheel and a rear pinch roller are sequentially arranged between two adjacent rolling mills along the rolling direction, and a loop height detection device is arranged between the sleeve lifting wheel and the rear pinch roller.

In an alternative embodiment, when the loop height detection device detects that the loop height is greater than a preset range, the loop height detection device enables each rolling mill main transmission motor at the upstream of the loop to be in cascade speed reduction; when the loop height detection device detects that the loop height is smaller than the preset range, the motors of the upstream rolling mills are in cascade speed increase until the loop height detection device detects that the loop height is within the preset range.

In an alternative embodiment, the severely worn pass is replaced if the ear size exceeds a preset value as the billet passes through the mill pass.

In an alternative embodiment, the billet is sequentially subjected to rough rolling, middle rolling and finish rolling in the rolling process, and the billet sequentially passes through 6 rolling mills in the rough rolling step, and the numbers are sequentially 1#, 2#, 3#, 4#, 5# and 6#; the steel billets in the middle rolling step sequentially pass through 4 rolling mills, and the numbers are 7#, 8#, 9#, 10#; the finish rolled billets sequentially pass through 8 rolling mills, the numbers of which are 11#, 12#, 13#, 14#, 15#, 16#, 17# and 18#, and the K4 rolling mill is a 15# rolling mill.

In an alternative embodiment, when the line difference is unstable, at least one of the following is used to adjust the line difference:

(1) adjusting the clamping relation between a guide corresponding to the inlet of the pre-splitting pass rolling mill and the splitting pass rolling mill and a rolled piece;

(2) if the steel billet passing through the middle rolling mill is irregular, round materials are misplaced, hole type filling is not full, tension is overlarge or the head and tail full degree fluctuation of the hole type of the same steel billet is large, the roller of the rolling mill is replaced;

(3) the fullness of the pre-cutting hole of the rolling mill is smaller than a preset value, and the shape of a billet is adjusted or the worn pre-cutting hole of the rolling mill is replaced;

(4) the head difference of the materials is large, the rolling line tension is reduced or the temperature rising amplitude of the billet is reduced;

(5) the corresponding roll gap deviation of the 17# rolling mill and the 18# rolling mill is smaller than 0.1mm.

In an alternative embodiment, a grinder is used to cut the bar during sampling, with the cut perpendicular to the bar axis.

The invention has the following beneficial effects:

according to the method, the negative deviation of the bar is regulated and controlled in three aspects of temperature, tension and line difference, and the negative deviation can be effectively reduced.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram of a loop structure.

The diagram is: 1-a sleeve lifting wheel; 2-a front pinch roller; 3-a rear pinch roller.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.

The features and capabilities of the present invention are described in further detail below in connection with the examples.

Some embodiments of the invention provide a rolling method for controlling negative deviations of bars, comprising:

temperature regulation, wherein in the rough rolling, medium rolling and finish rolling processes, the temperature of the head part of the steel billet is 25-35 ℃ higher than the temperature of the middle part of the steel billet, and the temperature of the tail part of the steel billet is 30-50 ℃ higher than the temperature of the middle part of the steel billet;

tension is adjusted, tension is adjusted to be free of tension in rough rolling or micro-stack rolling, micro-tension rolling is performed in middle rolling, and a finish rolling loop is automatically adjusted to be free of tension; wherein for two adjacent rolling mills, the negative deviation of the current or moment of the next rolling mill compared with the current or moment of the previous rolling mill is 0-2%, such as 0, 0.5%, 1%, 1.5% or 2%, and the positive deviation of the current or moment of the next rolling mill compared with the current or moment of the previous rolling mill is 0-2%, such as 0, 0.5%, 1%, 1.5% or 2%;

and adjusting the line difference, namely adjusting the pre-cutting opening of the K4 rolling mill to be horizontal, enabling the center line to coincide with the center line of the steel billet, enabling the length of the steel billet passing through the two side grooves to be consistent after being subjected to cooling bed, and adjusting the K4 rolling mill and the front pass rolling mill thereof, so that the length of the steel billet passing through the middle groove is consistent with the length of the steel billet passing through the two side grooves after being subjected to cooling bed.

For the temperature of the rolling process, to overcome the "small head and large tail" caused by tension, the ideal steel temperature is: the temperature of the head part (30-50 cm) of the steel billet is 25-35 ℃ higher than the temperature of the middle part of the steel billet, the temperature of the tail part (30-50 cm) of the steel billet is 30-50 ℃ higher than the temperature of the middle part of the steel billet, the temperature of the middle part of the steel billet is relatively uniform, and the temperature of the joint of the middle part of the steel billet and the head part and the tail part of the steel billet slowly changes. Specifically, in the temperature control process, when the steel billet is kept to meet the above conditions, stable production of the whole binding wire is kept as much as possible, including reducing deviation of the temperature of each batch of steel billets, avoiding waiting of the steel billets outside the furnace, and the like. When the cold billet is rolled, the residence time of the billet in the furnace is longer than that of the hot billet, so that when the billet is expected to be rolled, the billet can be produced in a slow speed in advance, so that the temperature of the cold billet is the same as that of the hot billet. When the production rhythm is adjusted, the front operators are informed in advance, so that the operation and sampling of the front operators are facilitated, and especially when the production rhythm is quickened, the operation time is reserved for the front operators.

For the tension in the rolling process, the rough rolling tension adjustment adopts a current (moment) memory method: when a steel head bites into the nth rolling mill, the motor dynamic speed is reduced and recovered until the steel block bites into the n+1st rolling mill. The n-th rolling mill corresponds to free rolling without front tension, and the rolling current at this time is sampled after filtering, i.e., the free rolling current. When the steel block bites into the n+1th frame, and after dynamic speed reduction is recovered, current is sampled again after filtering, if tension deviation exists between two rolling mills, the current deviation is inevitable, tension difference can be obtained according to a related formula of electromechanics, speed is modified according to the tension deviation, and the speed of the n frame and the speed of the rolling mill before the n frame are adjusted to achieve a micro-tension or micro-stack state. And continuously adjusting the rolling mill controlled by all micro-tension closed loops of the whole line to reach a micro-tension state according to the advancing process of the blank in sequence and the rolling mill controlled by all micro-pile closed loops of the whole line to reach a micro-pile state, so that the tension is automatically adjusted.

For line difference adjustment, the length of the upper cooling bed of the two lines of the side groove is adjusted to be consistent in the horizontal pair of the K4 pre-cutting inlet, and the actual sleeve lifting height of the grooves on the two sides of a 6# loop (a loop close to the last rolling mill) can be used as a reference, so that the symmetry of the pre-cutting fullness is synchronously ensured; when the length of the two side lines is basically consistent, the size and the length difference of the middle groove and the side groove are adjusted by adjusting K4 and the previous defective material; the existence of the tension can shorten the grooves on two sides, and when the rolling line tension is high, the main operator can manually adjust the tension to lengthen the grooves on two sides.

In an alternative embodiment, for the same rolling mill, if the billet temperature increases, the tension is reduced; if the temperature decreases, the tension increases.

The main operator needs to adjust the tension in time according to the temperature change, if the steel billet is pricked from the cold billet to the red billet, the tension needs to be reduced, and if the steel billet is pricked from the hot billet to the cold billet, the tension needs to be increased, if the tension cannot keep up with the cold billet, a large quantity of products which do not meet the national standard can be caused suddenly.

In an alternative embodiment, in the step of adjusting the tension, a reverse adjustment mode is used for adjusting the speed proportional relationship of each rolling mill.

To ensure stable rolling of the rolling line, a certain continuous rolling speed relation is required to be maintained among all rolling mills in the whole line, and the speed proportion relation of all rolling mills in the rolling process can be ensured by adopting speed cascade adjustment control.

In an alternative embodiment, in the step of adjusting the tension, when the speed of the rolling mill is adjusted, the outlet linear speed of the last rolling mill is used as a reference of speed adjustment, and when the speed of any rolling mill is adjusted, the speed matching relationship between other adjacent rolling mills in the whole linear range is unchanged.

When the speed of the rolling mill is regulated, the finished rolling mill is always used as a reference rolling mill for regulating the speed, and the setting of the rolling line speed follows the basic principle: a. in the case that the manual speed adjustment mode is cascade, the speed matching relationship among any other rolling mill in the whole line range is not affected when the speed of any rolling mill is adjusted. b. The full line speed is determined by a unique full line outlet speed variable, which is the finishing outlet line speed.

In an alternative embodiment, in the finish rolling step, a front pinch roller 2, a sleeve lifting wheel 1 and a rear pinch roller 3 are sequentially arranged between two adjacent rolling mills along the rolling direction, and a loop height detection device is arranged between the sleeve lifting wheel 1 and the rear pinch roller 3, as shown in fig. 1.

In an alternative embodiment, when the loop height detection device detects that the loop height is greater than a preset range, the loop height detection device enables each rolling mill main transmission motor at the upstream of the loop to be in cascade speed reduction; when the loop height detection device detects that the loop height is smaller than the preset range, the motors of the upstream rolling mills are in cascade speed increase until the loop height detection device detects that the loop height is within the preset range.

The loopers are caused by storing redundant rolled pieces with the length of a rolling line between rolling mills, and the redundant rolled pieces play a role in effectively buffering the pile-up of the rolled pieces, so that pile-up of steel caused by various reasons can be avoided in a steel continuous rolling line, and the quality of finished products is guaranteed. In the process of controlling the tension of the finish rolling step, the purpose of controlling the loop can be achieved by taking the loop amount as a target and taking the speed adjustment as a means. The specific method comprises the following steps: and each loop is provided with a loop height detector which is used for detecting the actual loop height and comparing the actual loop height with a set loop height value, when the actual loop height is larger than a set value, the main transmission motors of the rolling mill at the upstream of the loop are in cascade connection for reducing speed, and when the actual loop height is smaller than the set value, the motors of the rolling mill at the upstream of the loop are in cascade connection for increasing speed until the loop height is controlled within the set value range, and then the normal rolling speed is recovered. In the loop control process, the speed of each upstream rolling mill can be regulated by a cascade control system, and the speed value of the regulated stable loop is stored as a set value of the next steel.

The control process of the loop comprises the steps of loop lifting, loop measurement and loop falling.

And (3) sleeve lifting: after triggering a loop scanner between two rolling mills forming loops, the head of a rolled piece can delay, and then give a loop lifting signal, the loop lifting wheel 1 acts, and meanwhile, the downstream rolled piece is taken care of to run at a speed slightly lower than a set speed so as to quickly form loops;

measuring a loop magnitude, if the set value is H2 (mm), and when the loop scanner detects that the height value is H1, the loop has larger tension at the moment, and the loop control system commands the cascade speed rise of the upstream rolling mill; when the height value is detected to be H3, the loop is in an excessive steel piling state, and the loop control system commands the upstream rolling mill to perform cascading speed reduction, so that the loop amount is finally stabilized at the design value.

And (3) sleeve falling: when a hot metal detector or a loop scanner in front of the loop upstream rolling mill sends out a steel-free signal, the loop upstream rolling mill runs at a lower speed than the rolling speed, when the tail part of a rolled piece leaves the rolling mill in front of the loop, the loop height is reduced to the lowest, the loop lifting wheel 1 falls down in a delayed manner, and the rolling mill is restored to the set speed again, so that the loop collecting process is completed.

In an alternative embodiment, the severely worn pass is replaced if the ear size exceeds a preset value as the billet passes through the mill pass.

The fine adjustment of the tension is carried out by matching a main operator with ground operation, the material type is required to prevent the hole type from being overfilled so as to lead out the ear, the main operator is difficult to control in the area which is far away from the adjacent frame or has no loop, and the main operator is required to command and adjust on site; in addition, the wear of the rolling mill hole type seriously causes a big tail lug, and the rolling mill hole type is particularly sensitive to timely replacement: 17# rolling mill pass, 13# rolling mill pre-cut pass, 14# rolling mill cut pass. The steel temperature is ensured to be uniform, each pass has no 'steel pouring', and each pass has no lug.

In an alternative embodiment, the billet is sequentially subjected to rough rolling, middle rolling and finish rolling in the rolling process, and the billet sequentially passes through 6 rolling mills in the rough rolling step, and the numbers are sequentially 1#, 2#, 3#, 4#, 5# and 6#; the steel billets in the middle rolling step sequentially pass through 4 rolling mills, and the numbers are 7#, 8#, 9#, 10#; the finish rolled billets sequentially pass through 8 rolling mills, the numbers of which are 11#, 12#, 13#, 14#, 15#, 16#, 17# and 18#, and the K4 rolling mill is a 15# rolling mill.

In an alternative embodiment, when the line difference is unstable, at least one of the following is used to adjust the line difference:

(1) adjusting the clamping relation between a guide corresponding to the inlet of the pre-splitting pass rolling mill and the splitting pass rolling mill and a rolled piece;

(2) if the steel billet passing through the middle rolling mill is irregular, round materials are misplaced, hole type filling is not full, tension is overlarge or the head and tail full degree fluctuation of the hole type of the same steel billet is large, the roller of the rolling mill is replaced;

(3) the fullness of the pre-cutting hole of the rolling mill is smaller than a preset value, and the shape of a billet is adjusted or the worn pre-cutting hole of the rolling mill is replaced;

(4) the head difference of the materials is large, the rolling line tension is reduced or the temperature rising amplitude of the billet is reduced;

(5) the corresponding roll gap deviation of the 17# rolling mill and the 18# rolling mill is smaller than 0.1mm.

In an alternative embodiment, a grinder is used to cut the bar during sampling, with the cut perpendicular to the bar axis.

Sampling is carried out after the bar is subjected to finish rolling, and standard sampling is required in the sampling process, wherein the sampling length is more than 500mm; the incision needs to be polished strictly and leveled during sampling, and the incision can not be obtained by using hydraulic shears and flame cutting, and the incision must be cut off by using a grinder and is vertical, so that the incision is level.

In addition, in order to accurately control the fixed-size length, the cold shrinkage of the sheared length of the bars with various specifications is required to be searched out, and the fixed-size length is controlled by a production class in the production process; meanwhile, in the production process, each shift measures and monitors the fixed length of the cold and hot steel every 2 hours, which is beneficial to improving the accuracy of the fixed length.

The rolling method before improvement comprises the following steps: in the temperature control, the temperature of a billet is increased, the current of a motor of a rolling mill is reduced, the tension adjustment is performed to ensure the production stability by drawing and rolling steel, but the end of the billet is small, the end of the billet is big, the line difference control is not accurate, and the effect of adjusting the line difference time for a long time is poor; when sampling is carried out, the cutting gun is used for separating, the head cutting buckle is not subjected to leveling operation, weighing calculation is directly carried out, the negative difference calculation is inaccurate, the negative difference control means has no influence on the cost in the period of rod meter delivery, but the production cost can be greatly increased in the period of meter delivery, and the material waste is caused.

According to the method, the negative deviation of the bar is regulated and controlled through three aspects of temperature, tension and line difference, compared with a rolling method before improvement, the negative deviation can be effectively reduced, the negative deviation is improved from-3.7% to-3.9% in the month, and the negative deviation control level is improved by more than 5%.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A rolling method for controlling negative deviations of bars, comprising:

temperature regulation, wherein in the rough rolling, medium rolling and finish rolling processes, the temperature of the head part of the steel billet is 25-35 ℃ higher than the temperature of the middle part of the steel billet, and the temperature of the tail part of the steel billet is 30-50 ℃ higher than the temperature of the middle part of the steel billet;

tension is adjusted, tension is adjusted to be free of tension in rough rolling or micro-stack rolling, micro-tension rolling is performed in middle rolling, and a finish rolling loop is automatically adjusted to be free of tension; for two adjacent rolling mills, the negative deviation of the current or moment of the next rolling mill compared with the current or moment of the previous rolling mill is 0-2%, and the positive deviation of the current or moment of the next rolling mill compared with the current or moment of the previous rolling mill is 0-2%;

and adjusting the line difference, namely adjusting the pre-cutting opening of the K4 rolling mill to be horizontal, enabling the center line to coincide with the center line of the steel billet, enabling the length of the steel billet passing through the two side grooves to be consistent after being subjected to cooling bed, and adjusting the K4 rolling mill and the front pass rolling mill thereof, so that the length of the steel billet passing through the middle groove is consistent with the length of the steel billet passing through the two side grooves after being subjected to cooling bed.

2. The rolling method for controlling negative deviations of bars according to claim 1, characterized in that, for the same rolling mill, if the temperature of the billet increases, the tension is reduced; if the temperature decreases, the tension increases.

3. The rolling method for controlling negative deviations of bar materials according to claim 1, wherein in the tension adjusting step, a reverse adjustment mode is adopted for adjusting the speed proportional relationship of each rolling mill.

4. A rolling method for controlling negative deviation of bar according to claim 3, wherein in the tension adjusting step, when the speed of the rolling mill is adjusted, the speed of any rolling mill is adjusted by taking the last rolling mill outlet line speed as a reference for speed adjustment, and the speed matching relationship between other adjacent rolling mills in the whole line range is unchanged.

5. The rolling method for controlling negative deviation of bar according to claim 1, wherein in the finish rolling step, a front pinch roller, a sleeve lifting wheel and a rear pinch roller are sequentially arranged between two adjacent rolling mills along the rolling direction, and a loop height detection device is arranged between the sleeve lifting wheel and the rear pinch roller.

6. The rolling method for controlling the negative deviation of the bar according to claim 5, wherein when the loop height detecting device detects that the loop height is greater than a preset range, the cascade speed of each rolling mill main drive motor at the upstream of the loop is reduced; when the loop height detection device detects that the loop height is smaller than the preset range, the motors of the upstream rolling mills are in cascade speed increase until the loop height detection device detects that the loop height is within the preset range.

7. The rolling method for controlling negative deviations of bars according to claim 1, characterized in that the worn hole pattern is replaced if the ear size exceeds a preset value when the billet passes through the rolling mill hole pattern.

8. The rolling method for controlling the negative deviation of bar materials according to claim 1, wherein the billet is subjected to rough rolling, medium rolling and finish rolling in sequence during rolling, and the billet is subjected to 6 rolling mills in sequence in the rough rolling step, and the numbers are 1#, 2#, 3#, 4#, 5# and 6#; the steel billets in the middle rolling step sequentially pass through 4 rolling mills, and the numbers are 7#, 8#, 9#, 10#; the finish rolled billets sequentially pass through 8 rolling mills, the numbers of which are 11#, 12#, 13#, 14#, 15#, 16#, 17# and 18#, and the K4 rolling mill is a 15# rolling mill.

9. The rolling method for controlling negative deviations of bars according to claim 8, wherein when the line difference is unstable, at least one of the following is adopted for adjustment:

(1) adjusting the clamping relation between a guide corresponding to the inlet of the pre-splitting pass rolling mill and the splitting pass rolling mill and a rolled piece;

(2) if the steel billet passing through the middle rolling mill is irregular, round materials are misplaced, hole type filling is not full, tension is overlarge or the head and tail full degree fluctuation of the hole type of the same steel billet is large, the roller of the rolling mill is replaced;

(3) the fullness of the pre-cutting hole of the rolling mill is smaller than a preset value, and the shape of a billet is adjusted or the worn pre-cutting hole of the rolling mill is replaced;

(4) the head difference of the materials is large, the rolling line tension is reduced or the temperature rising amplitude of the billet is reduced;

(5) the corresponding roll gap deviation of the 17# rolling mill and the 18# rolling mill is smaller than 0.1mm.

10. The rolling method for controlling negative deviations of bars according to claim 1, characterized in that the bars are cut off by a grinder during sampling and the cut is perpendicular to the bar axis.