Differential temperature rolling method for high-speed wire rod

Abstract

The invention belongs to the technical field of steel rolling wire rod austenite structure control, and particularly relates to a high-speed wire rod differential temperature rolling method which comprises the steps that A, a first dephosphorization device is installed at the discharging position of a heating furnace; b, a second dephosphorization device is installed at the position 3 m in front of the first rough rolling machine; c, a first annular cooling device is installed at the position 2 m in front of the first rough rolling machine; d, a second annular cooling device is installed at the position 1 m in front of the first rough rolling machine; in the rolling process, rapid cooling and rolling are conducted at the same time, the surface temperature is lower than the core, deformation resistance is large, deformation is not prone to occurring, the core is high in temperature and prone to deforming, deformation can be promoted to penetrate into the core of the casting blank, core defects can be eliminated, and the core quality is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of controlling austenite structure of rolled steel wires, and in particular relates to a high-speed wire differential temperature rolling method. Background Art

[0002] Wire rod is a hot-rolled threaded steel coil produced by high-speed wire rolling mill, mainly in ￠8mm and ￠10mm specifications. HRB400E wire rod has high yield strength and better holding force than HPB300 plain round steel bar. It is very popular among users and has a very large market demand.

[0003] At present, when producing high-strength rebar wire (coil), the raw steel billets of most domestic high-speed wire mills are micro-alloyed, and the manganese content is relatively high (1.3%-1.4%). During rolling, high-temperature conventional rolling process is adopted, which is conducive to the precipitation strengthening of micro-alloy compounds. This conventional process has a high alloy cost for steel rolling, which increases production costs and reduces corporate benefits. Summary of the invention

[0004] In order to reduce the alloy composition of steel and ensure the performance of steel, the present invention provides a method that can quickly reduce the surface temperature of the ingot to 900°C, and the temperature difference between the center and the surface reaches 100°C, thereby increasing the deformation of the center area of ​​the rolled piece, and can improve the organization and mechanical properties of the center area of ​​the steel according to conventional controlled rolling theory. The specific scheme of the present invention is: A high-speed wire rod differential temperature rolling method, comprising: A. Install the first dephosphorization device at the exit of the heating furnace; B. Install the second dephosphorization device 3 meters in front of the roughing mill 1#; C. Install the first annular cooling device 2 meters in front of the roughing mill 1#; D. Install the second annular cooling device 1 meter in front of the roughing mill 1#; The annular cooling device comprises a base 1, on which an auxiliary support column 2 and a main support column 7 are fixedly connected in sequence; a water pipe 3 is fixedly connected above the auxiliary support column 2 and the main support column 7; a nozzle 5 is connected to the side of the water pipe 3; the spray direction of the nozzle 5 is concentrated on the casting embryo (6).

[0005] Preferably, the first dephosphorization device is 2 meters away from the heating furnace.

[0006] Preferably, the first dephosphorization device and the second dephosphorization device are both phosphorus breaking machines.

[0007] Preferably, the temperature of the steel billet surface drops by 30°C after the treatment in step A, and the temperature of the steel billet surface drops by 30°C after the treatment in step B.

[0008] Preferably, the number of the auxiliary support columns 2 is 2, which are distributed on both sides of the main support column 7.

[0009] Preferably, the main support column 7 is located at the center of the base 1 .

[0010] Preferably, there are four water pipes 3, which are sequentially connected through arc-shaped connecting pipes 4 to form a rounded square ring.

[0011] Preferably, the number of nozzles 5 connected to each water pipe 3 is 3.

[0012] Preferably, the temperature of the steel billet surface drops by 20°C after the treatment in step C, and the temperature of the steel billet surface drops by 20°C after the treatment in step D.

[0013] Compared with the prior art, the technical effects of the present invention are embodied in: 1. Compared with the prior art, the present invention is to cool rapidly while rolling during the rolling process, and the cooling does not have time to penetrate into the interior of the ingot, so that low temperatures are formed on the surface around the ingot, while the center layer still maintains a high temperature distribution state. In this way, during rolling, the surface temperature is lower than the core, the deformation resistance is large, and it is not easy to deform, while the core temperature is high and it is easy to deform. This will promote deformation to penetrate into the core of the ingot, which is conducive to eliminating defects in the core and improving the quality of the core.

[0014] 2. This process technology can meet the requirements of flexible equipment layout, high cooling intensity, wide cooling rate control range, good cooling performance and precise temperature control.

[0015] 3. In this process technology, the surface cools quickly during differential temperature rolling, and the temperature does not have time to penetrate into the interior of the ingot. The low temperature on the surface belongs to low-temperature controlled rolling, while the center of the ingot still maintains the original higher temperature rolling, which will form steel with fine crystallization on the surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The diagram shows the process layout of differential temperature rolling; Figure 2 Shown is a diagram of a cooling device; Among them: 1-base, 2-auxiliary support column, 3-water pipe, 4-arc connecting pipe, 5-nozzle, 6-casting embryo, main support column. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is further defined below in conjunction with specific implementation methods, but the scope of protection required is not limited to the description.

[0018] Example 1 A high-speed wire rod differential temperature rolling method, characterized by comprising: A. Install the first dephosphorization device 2 meters away from the heating furnace, which can reduce the surface temperature of the steel billet by 30°C; the dephosphorization device is a phosphorus crusher; B. Install the second dephosphorization device 3 meters in front of the rough rolling mill 1#, which can reduce the surface temperature of the steel billet by 30℃; C. Install the first ring cooling device 2 meters in front of the rough rolling mill 1#, which can reduce the surface temperature of the steel billet by 20℃; D. Install a second ring cooling device 1 meter in front of the rough rolling mill 1#, which can reduce the surface temperature of the steel billet by 20℃; The annular cooling device comprises a base (1), on which an auxiliary support column (2) and a main support column (7) are fixedly connected in sequence; the number of the auxiliary support columns (2) is two, which are distributed on both sides of the main support column (7), and the main support column (7) is located at the center of the base (1); a water pipe (3) is fixedly connected above the auxiliary support column (2) and the main support column (7), and the number of the water pipes (3) is four, which are connected in sequence to form a rounded square ring through an arc-shaped connecting pipe (4); a nozzle (5) is connected to the side of the water pipe (3); the spray direction of the nozzle (5) is concentrated on the casting embryo (6); and the number of the nozzles (5) connected to the water pipe (3) is three.

[0019] In actual use, the following steps are mainly included: 1. Turn on the first and second dephosphorization devices and open them to the maximum in the fourth gear; 2. Open the valves of the first and second annular cooling devices; 3. Adjust the valve opening degree according to the measured cooling temperature of the ingot surface.

[0020] This embodiment produces temperature control: Metallographic structure inspection of this embodiment: It can be seen from the table that the present invention has a significant cooling effect, the metallographic structure has complete grains, and the product is excellent.

Claims

1. A high-speed wire rod differential temperature rolling method, characterized in that: include: A. Install the first dephosphorization device at the exit of the heating furnace; B. Install the second dephosphorization device 3 meters in front of the roughing mill 1#; C. Install the first annular cooling device 2 meters in front of the roughing mill 1#; D. Install the second annular cooling device 1 meter in front of the roughing mill 1#; The annular cooling device comprises a base (1), to which an auxiliary support column (2) and a main support column (7) are fixedly connected in sequence; a water pipe (3) is fixedly connected above the auxiliary support column (2) and the main support column (7); a nozzle (5) is connected to the side of the water pipe (3); and the spray direction of the nozzle (5) is concentrated on the casting embryo (6).

2. A high-speed wire rod differential temperature rolling method according to claim 1, characterized in that: The first dephosphorization device is 2 meters away from the heating furnace.

3. A high-speed wire rod differential temperature rolling method according to claim 1, characterized in that: The first dephosphorization device and the second dephosphorization device are both phosphorus breaking machines.

4. A high-speed wire rod differential temperature rolling method according to claim 1, characterized in that: After the treatment in step A, the temperature of the surface of the steel billet drops by 30°C, and after the treatment in step B, the temperature of the surface of the steel billet drops by 30°C.

5. A high-speed wire rod differential temperature rolling method according to claim 1, characterized in that: The auxiliary support columns (2) are two in number and are distributed on both sides of the main support column (7).

6. A high-speed wire rod differential temperature rolling method according to claim 1, characterized in that: The main support column (7) is located at the center of the base (1).

7. A high-speed wire rod differential temperature rolling method according to claim 1, characterized in that: There are four water delivery pipes (3), which are connected in sequence through arc-shaped connecting pipes (4) to form a rounded square ring.

8. A high-speed wire rod differential temperature rolling method according to claim 1, characterized in that: The number of nozzles (5) connected to each water delivery pipe (3) is three.

9. A high-speed wire rod differential temperature rolling method according to claim 1, characterized in that: After the treatment in step C, the temperature of the steel billet surface drops by 20°C, and after the treatment in step D, the temperature of the steel billet surface drops by 20°C.

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