阅读说明：本技术 一种高速线材风冷线调整冷速区间的方法 (Method for adjusting cooling speed interval of high-speed wire air-cooled line ) 是由 麻晗 周云 于 2020-04-26 设计创作，主要内容包括：本申请公开了一种高速线材风冷线调整冷速区间的方法,其特征在于：测量高线热轧盘条吐丝温度T<Sub>0</Sub>；在风冷线上盘条开始相变前的任一位置设置测温点a,测量测温点a处盘条在风冷线宽度方向上不同位置的温度,最高温度为Ta<Sub>1</Sub>,最低温度为Ta<Sub>2</Sub>；测量盘条从吐丝移动到测温点a的时间ta；计算得到盘条从吐丝到测温点a的平均冷速,最低平均冷速为Va<Sub>1</Sub>＝(T<Sub>0</Sub>-Ta<Sub>1</Sub>)/ta,最高平均冷速为Va<Sub>2</Sub>＝(T<Sub>0</Sub>-Ta<Sub>2</Sub>)/ta,则盘条整体的平均冷速区间为Va<Sub>1</Sub>～Va<Sub>2</Sub>；通过调整风冷线风机风量、风挡开度、保温罩开启、辊道运行速率、终轧速率,将冷速区间调整到工艺冷速窗口内。使用本发明方法调整冷速区间,可提高工艺命中率、提高盘条的组织性能均匀性。(The application discloses method for adjusting cooling speed interval of high-speed wire air-cooling line, which is characterized by comprising the following steps: measuring the hot-rolled wire rod spinning temperature T of high-speed wire 0 (ii) a Setting a temperature measuring point a at any position of the wire rod on the air cooling line before the wire rod starts to change phase, measuring the temperature of the wire rod at the temperature measuring point a at different positions in the width direction of the air cooling line, and setting the highest temperature to be Ta 1 The lowest temperature is Ta 2 (ii) a Measuring the time ta of the wire rod moving from the laying to the temperature measuring point a; calculating to obtain the average cooling speed of the wire rod from the spinning to the temperature measuring point a, wherein the lowest average cooling speed is Va 1 ＝(T 0 ‑Ta 1 ) The maximum average cooling rate is Va 2 ＝(T 0 ‑Ta 2 ) And/ta, the average cooling speed interval of the whole wire rod is Va 1 ～Va 2 (ii) a And adjusting the air quantity of an air cooling line fan, the opening degree of a windshield, the opening of a heat preservation cover, the running speed of a roller way and the finish rolling speed to adjust the cooling speed interval into a process cooling speed window. Use the present inventionThe cold speed interval is adjusted by the bright method, so that the hit rate of the process can be improved, and the structural property uniformity of the wire rod can be improved.)

1. A method for adjusting a cooling speed interval of a high-speed wire air-cooling line is characterized by comprising the following steps: measuring the hot-rolled wire rod spinning temperature T of high-speed wire₀(ii) a Setting a temperature measuring point a at any position of the wire rod on the air cooling line before the wire rod starts to change phase, measuring the temperature of the wire rod at the temperature measuring point a at different positions in the width direction of the air cooling line, and setting the highest temperature to be T_a1Minimum temperature of T_a2(ii) a Measuring the time t for moving the wire rod from the laying to the temperature measuring point a_a(ii) a Calculating the average cooling speed of the wire rod from the spinning to the temperature measuring point a, wherein the lowest average cooling speed is V_a1＝(T₀-T_a1)/t_aThe highest average cooling rate is V_a2＝(T₀-T_a2)/t_aThe average cooling rate of the whole wire rod is V_a1～V_a2(ii) a Adjusting the air quantity of an air cooling line fan, the opening degree of a windshield, the opening of a heat preservation cover, the running speed of a roller way and the finish rolling speed to ensure that the cooling speed interval V is_a1～V_a2Adjusting the temperature to be in a process cooling speed window; and after the cooling speed interval is adjusted to be in the process cooling speed window, stopping adjustment, and continuously producing by a production line.

2. The method for adjusting the cooling rate interval of the high-speed wire rod air-cooling line according to claim 1, wherein not less than 1 temperature measuring point is arranged on the air-cooling line, the temperature measuring point is positioned at any position on the air-cooling line, the state corresponding to the wire rod can be positioned before phase change, during phase change or after phase change, and when the temperature measuring points are more than 1, the average cooling rate interval V between the adjacent temperature measuring points is respectively calculated_n1～V_n2Adjusting the setting of the air cooling line to cool the zone V_n1～V_n2Is adjusted toAnd the temperature measuring point interval corresponds to the process cooling speed windows in the phase change pre-stage, the phase change middle stage and the phase change post stage.

3. The method for adjusting the cooling rate interval of the high-speed wire rod air-cooling line according to any one of claims 1 and 2, wherein the temperature of the wire rod at the upper part in the width direction of the air-cooling line is used as the highest temperature T_a1The temperature of the middle wire rod in the width direction of the air cooling line is taken as the lowest temperature T_a2And calculating the average cooling rate interval V_a1～V_a2。

4. The method for adjusting the cooling rate interval of the high-speed wire according to any one of claims 1 and 2, wherein a temperature measuring point is provided with a temperature measuring device, the temperature measuring device uses an infrared thermometer or an infrared thermal imager, and the temperature measuring mode can adopt handheld mobile temperature measurement or fixed point temperature measurement.

Technical Field

The invention relates to a method for adjusting a cooling speed interval of a high-speed wire air cooling line, belongs to the field of steel rolling, and is suitable for adjusting and optimizing cooling processes of various air cooling wire products.

Background

In the steel field, wire is a coiled hot-rolled round steel, also called wire rod. Most of wires are produced by adopting a high-speed hot continuous rolling and air cooling method, in order to adapt to the characteristics of thin and long wires, in the modern wire production process, a stelmor cooling control mode is mostly adopted, wires are spun into a continuous ring shape after hot rolling, the wire is spread on a series of rotating air cooling roller ways and gradually runs along the rolling direction, a high-power fan supplies air below the roller ways, the stacking density of wire rods is controlled by controlling the advancing speed of the roller ways, and the wire rod cooling process is controlled by adopting a mode of arranging heat preservation covers in sections and adjusting the air volume of the fan and the opening degree of a windshield, so that the wire rods are cooled. The method enables the wire rods to be uniformly spread along the length direction of the air cooling line, but the wire rods are not fully spread in the width direction, and the stacking density of the wire rods is very non-uniform in the width direction of the air cooling line, the lapping phenomenon of the air cooling wire rods is serious, the stacking density of the wire rods at the lapping position is obviously higher than that of the non-lapping position, the cooling of the wire rods at the lapping position is slow, the wire rods at the non-lapping position are loosely arranged, and the cooling is rapid.

In actual production, the temperature and cooling rate determination and adjustment processes of the edge or middle wire rod are mostly adopted, and the middle or edge wire rod is often deviated from a cooling process window, so that the problems of structure and performance are caused. At present, alloying of wire rod variety steel relates to multiple elements, wherein the addition of alloy elements such as C, Mn, Cr, Mo and B can greatly improve the average strength of a wire rod, meanwhile, the sensitivity of the structure and the strength of the wire rod to the cooling speed is greatly improved, the structure formed under different cooling speeds of the wire rod with the same composition has obvious difference due to different positions, so that the fluctuation of the strength of a main rod of the wire rod is larger, namely the strength of the wire rod and the uniformity of the strength of the main rod are closely related to the cooling mode after the wire rod is rolled. For alloy steel wires with yield strength of 400MPa or above, the strength fluctuation of the wire rods in the same batch can reach 50-150 MPa, and even higher. When the wire rod is subsequently processed, a plurality of wire rods need to undergo the processes of drawing, cold heading and the like, the wire rods with different tensile strengths are different in subsequent processing hardening degree, the processing hardening degree of the wire rod with high tensile strength is higher, and in the subsequent processing process, the strength difference of semi-finished products and finished products is continuously increased and can be broken seriously. Therefore, how to control the cooling process of the wire rod after spinning and reduce the cooling difference of the poker wire rod has great significance in ensuring the uniformity of the structure and the strength of the wire rod.

Patent CN 103406373B mentions a suspension moving high-speed wire cooling device, which is equipped with a series of supporting equipments such as a special laying pipe, a coiled steel conveying line, a coiled steel collecting device, etc. to collect the whole coiled wire rod after laying wire in the collecting device, and in the device, the heat preservation and slow cooling of the wire rod are realized, and the cooling is changed from laying on a roller way to hanging on a steel wire rope for cooling, so as to solve the problem of poor coiled steel wire rod property caused by uneven cooling of stelmor air cooling line. On one hand, the production line provided by the method is only suitable for steel grades needing delayed cooling and does not have the capability of producing other steel grades needing standard type cooling and rapid cooling modes, and on the other hand, the production line has high modification cost and complex equipment, and is not beneficial to simplifying operation and reducing cost.

The patent CN 104307885A provides a high-speed wire production method for controlling the same-circle mechanical property fluctuation of a high-carbon steel wire rod, the method ensures the uniform distribution of a coil on a stelmor air cooling line by reducing the vibration of a laying head, controls the density degree of the wire rod by controlling the speed of a starting roller way, controls the cooling air speed by controlling a fan and a baffle plate, and controls the uniform cooling of the wire rod by integrating the above modes so as to control the uniform strength of the wire rod. However, in the production of wire steel, the strength of the wire rod is reduced. Wire rods are densely stacked in the production of the wire steel, the effect of homogenizing the cold speed of the wire rods by reducing the vibration of the wire laying machine is limited, and the control of the starting roller speed and the bell baffle is not suitable for the use.

Patent CN 103216789 a proposes a method for manufacturing a wire steel with low tensile strength, which controls the heating temperature of a billet, the initial rolling temperature, the finish rolling temperature, the laying temperature and the roller speed for the wire steel with specific components, thereby completing the slow cooling of the wire steel. However, the method is only suitable for a certain special welding wire steel, and the strength fluctuation is as high as 40 MPa.

At present, the production method which is suitable for steel rolling of wire rods of different varieties and different strength grades, ensures uniform structure of a wire rod, has small fluctuation of tensile strength of a whole wire rod and is low in cost is rarely reported.

Disclosure of Invention

The invention aims to provide a method for adjusting a cooling speed interval of a high-speed wire rod air cooling line, which is characterized in that temperature measuring points are arranged at the spinning position of a wire rod and in the width direction of wire rod distribution to obtain the average cooling speed interval of the whole wire rod which is Va₁～Va₂(ii) a And adjusting the air quantity of an air cooling line fan, the opening degree of a windshield, the opening of a heat preservation cover, the running speed of a roller way and the finish rolling speed to adjust the cooling speed interval into a corresponding process cooling speed window. So as to improve the hit rate of the process and the uniformity of the structure performance of the wire rod.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for adjusting a cooling speed interval of a high-speed wire air-cooling line is characterized by comprising the following steps: measuring the hot-rolled wire rod spinning temperature T of high-speed wire₀(ii) a A temperature measuring point a is arranged at a certain position on the air cooling line before the wire rod starts to change phase, the temperature of the wire rod at the temperature measuring point a at different positions in the width direction of the air cooling line is measured, and the highest temperature is Ta₁The lowest temperature is Ta₂(ii) a Measuring the time ta of the wire rod moving from the laying to the temperature measuring point a; calculating to obtain the average cooling speed of the wire rod from the spinning to the temperature measuring point a, wherein the lowest average cooling speed is Va₁＝(T₀-Ta₁) The maximum average cooling rate is Va₂＝(T₀-Ta₂) And/ta, the average cooling speed interval of the whole wire rod is Va₁～Va₂。

In the wire rod steel rolling process, in order to control the structure and the strength uniformity of the wire rod, the phase change condition of different wire rods in the cooling process after spinning needs to be comprehensively considered, and the average cooling speed interval Va in the width direction of the wire rod is measured by measuring the spinning temperature, the temperature before phase change and the interval time₁～Va₂And the cooling conditions of the wire rod at the same position on the air cooling line on different widths can be checked. And adjusting the air quantity of an air cooling line fan, the opening degree of a windshield, the opening of a heat preservation cover, the running speed of a roller way and the finish rolling speed to adjust the cooling speed interval into a corresponding process cooling speed window. The larger the air quantity of the fan is, the smaller the opening degree of the windshield is, the more the heat-insulating cover is opened, and the running speed of the roller wayThe faster the temperature, the slower the roller table speed and the finishing rolling speed, both of which can accelerate the cooling speed. Va (Va)₁～Va₂When the cooling speed interval exceeds the process window range and is 0-0.3 ℃/s, the effect of the cooling speed interval needs to be adjusted by matching with the air quantity of the fan, the heat-insulating cover and the roller speed, Va₁～Va₂When the cooling speed interval exceeds the process window range and is 0.3-0.6 ℃/s, the cooling speed interval needs to be adjusted by matching with the air quantity of a fan, the opening degree of a windshield, the speed of a heat-insulating cover and the speed of a roller way, Va₁～Va₂When the cooling speed interval exceeds the process window range and is more than 0.6 ℃/s, the air quantity of a fan, the opening degree of a windshield, a heat-insulating cover, the speed of a roller way and the final rolling speed need to be comprehensively adjusted to adjust the cooling speed interval. The range of each adjustment includes: the air quantity of the fan is adjusted by 5-10%, the opening degree of a windshield is adjusted by 10-15 degrees, 1 heat-insulating cover is arranged, the speed of a roller way is 0.3m/s, and the final rolling speed is 5 m/s. And determining a process cooling speed window according to the thermal simulation continuous cooling curve, and referring to actual production measurement data and an inspection result.

The wire rod is uniformly spread along the length direction of the air cooling line, but is not spread in the width direction, and the stacking density of the wire rods is very non-uniform when viewed from the width direction of the air cooling line, so that the lapping phenomenon of the wire rods on the air cooling line is obvious. The lap joint is slowly cooled, and if the temperature is collected and is judged and adjusted according to the cooling condition, the wire rod at the lap joint loose part is possibly higher than the range of a process window; the non-lap joint wire rods are loosely arranged and are rapidly cooled, and if the wire rods are collected and adjusted according to the data, the cooling speed of the lap joint wire rods is possibly lower than the range of a process window, and the process hit rate is low. Further, at least one temperature measuring point is arranged on the air cooling line, the temperature measuring points can be located at any position on the air cooling line, the corresponding state of the wire rod can be located before phase change, during phase change or after phase change, and when the number of the temperature measuring points is more than 1, the average cooling speed interval V between the adjacent temperature measuring points is respectively calculated_an～V_amAdjusting the setting of the air cooling line to cool the zone V_an～V_amAnd adjusting the temperature to be in the process cooling rate windows of the phase change before, during and after the phase change corresponding to the temperature measuring point interval.

The proportion and the size of each matrix phase composition, the proportion and the size of a precipitated phase, the comprehensive mechanical property, the loop shape and the surface quality in the wire rod structure are all influenced by the process parameter conditions of the control process before, during and after the phase change, the cooling speed in different stages is further obtained, the sectional control and the accurate positioning are implemented, the control of various wire rod structures is facilitated, and the comprehensive performance control level of the wire rod is improved.

Further, to improve efficiency, the temperature of the upper edge wire rod in the width direction of the air cooling line is adopted to replace the highest temperature T_a1The temperature of the middle wire rod in the width direction of the air cooling line is adopted to replace the lowest temperature T_a2And calculating the cooling speed interval V_a1～V_a2。

Furthermore, the temperature measuring point is provided with temperature measuring equipment, the temperature measuring equipment can use an infrared thermometer or an infrared thermal imager, and the temperature measuring mode can adopt handheld mobile temperature measurement or fixed point temperature measurement.

Advantageous effects

Compared with the prior art, the beneficial effects of the invention are embodied in the following aspects:

according to the invention, the cooling speed interval is adjusted to the corresponding process cooling speed window by acquiring the integral average cooling speed of the wire rod and combining adjustment of the air quantity of an air cooling line fan, the opening degree of a windshield, the opening of a heat preservation cover, the running speed of a roller way and the finish rolling speed, so that the process hit rate and the structural property uniformity of the wire rod can be obviously improved, and the strength fluctuation of the wire rod at the strength level of 450-600 MPa is less than or equal to 20-45 MPa.

Detailed Description

The present invention will be further specifically described with reference to the following examples. The embodiment and the comparative example adopt a walking beam furnace-high pressure water dephosphorization-multi-pass high-speed rolling-spinning-stelmor cooling technical route, and the coil is collected after cooling.