A fast-changing process for continuous casting tundish of special-shaped billets below 600kg / m

Abstract

The present invention belongs to the technical field of steelmaking and continuous casting, and specifically relates to a process organization method for quick replacement of a tundish of a continuous casting machine for profiled blanks with a cross section of less than 600kg / m. This invention provides a process operation method and device for quick replacement of a tundish for continuous casting of profiled blanks with a cross section of less than 600kg / m. By taking measures to shorten the process time of quick replacement of the tundish and reduce friction to reduce vibration load, the problem of the failure of vibration during quick replacement of profiled blanks with small cross sections is solved. The success of quick replacement of tundishes with small cross sections fills the gap of quick replacement of tundishes with small cross sections for domestic profiled blank continuous casting machines.

Description

Technical Field

[0001] The invention belongs to the technical field of steelmaking and continuous casting, and specifically relates to a process operation method and device for quick replacement of a tundish of a continuous casting machine for profiled blanks with a cross section of less than 600 kg / m. Background Art

[0002] The quick-change tundish is to use the tail billet of the upper tundish to replace the ingot rod. There is no need to pull the tail billet to send the ingot and other processes, which can achieve non-stop production and efficiency improvement. The thin web of the profiled billet and the fast solidification make it difficult to quickly change the tundish. At present, the domestic Ma Steel, Jinxi Steel, and Rizhao Steel profiled billet continuous casting machines have successfully implemented the quick change of tundish through the transformation of the continuous casting machine program. Among them, the cross-sectional specifications of the profiled billets of Jinxi Steel are basically the same as those of our factory. However, the small cross-section of the profiled billet with a weight of less than 600kg per meter has a weaker heat supplement effect on the solidified billet shell due to the small liquid core (high-temperature molten steel) in the billet shell relative to the large cross-section. The cooling and solidification are faster, the billet shell strength is harder, and the friction with the copper plate of the crystallizer will be greater, resulting in a large load on the crystallizer vibration system. In just a few minutes, the vibration becomes less and less vibrating as time goes by, and the success rate of injection and pouring is low, which affects the quick change of the tundish. Therefore, the domestic profiled billet continuous casting machine has not successfully implemented the quick change of the tundish with a cross-section below 600kg / m. Summary of the invention

[0003] The purpose of the present invention is to provide a process operation method and device for quick replacement of the tundish for continuous casting of special-shaped billets with a cross-section of less than 600kg / m, and to solve the problem that the special-shaped billets with a cross-section of less than 600kg / m cannot vibrate during quick replacement by taking measures and devices to shorten the process time of quick replacement of the tundish and reduce friction to reduce vibration load.

[0004] The technical solution of the present invention is:

[0005] A quick-change process for continuous casting tundish of profiled billets below 600 kg / m, comprising the following steps:

[0006] ①. 10 minutes before changing the tundish, reduce the protective slag in the crystallizer;

[0007] ② After each flow is blocked, the operation box performs the following operations in sequence:

[0008] The pulling speed returns to 0 → stop straightening → click the quick change mode on the P3 panel and confirm that the quick change button light is always on; quickly block the flow and immediately stir the box with an L-type oxygen tube → put the plug connector into the liquid steel → start the online tundish and start straightening at the same time to pull the crystallizer liquid level to a position of 600mm from the upper mouth of the crystallizer, stop straightening and prepare for pouring;

[0009] ③. Install the long wooden plug centering device on the spare middle ladle car in advance, plug in the connectors and make the spare middle ladle car and the online middle ladle car move at the same time. After the spare middle ladle car is in place, pour the large ladle;

[0010] ④. After pouring, quickly make the liquid level of the tundish reach the 10-ton mark and measure the temperature. At the same time, start pouring each stream. When the liquid level of the tundish rises to the 15-ton mark, measure the temperature again and slowly adjust the liquid level of the tundish according to the temperature of the molten steel.

[0011] Before pouring, set the pulling speed in the operating box to BB0: 0.3m / min, BB1\BB2: 0.2m / min, BB3: 0.15m / min. When the steel liquid level in the crystallizer rises to 45-55mm from the lower mouth of the funnel, that is, when the operating box displays 20%-30%, add protective slag and start pulling and straightening, and then adjust the pulling speed according to the actual liquid level.

[0012] A centering device specially used in the quick-change process of continuous casting tundish for special-shaped billets below 600kg / m, comprising a columnar intermediate body, with conical extension bodies of the same length provided at both ends of the columnar intermediate body, the outer end diameter of the conical extension body being smaller than the inner end diameter, and an arc-shaped transition section being provided between the columnar intermediate body and the conical extension body.

[0013] The invention discloses a quick-change process for continuous casting tundish of 600 kg / m or less special-shaped billets, which has the following remarkable effects:

[0014] 1. Take measures and devices to shorten the time of quick-change tundish process and control the quick-change tundish process within 5 minutes.

[0015] In the process of quick change, the hardness of the casting billet is reduced and the vibration load is reduced.

[0016] 2. Reduce the friction area between the crystallizer and the ingot, reduce the friction force and reduce the vibration load by 30% compared with the original.

[0017] Each quick change of tundish reduces downtime by 1.5 hours and increases production by about 300 tons. Based on 15 sets of quick changes per month, production can be increased by 300 tons*15 sets / month*12 months=54,000 tons. When the beam blank continuous casting machine is open alone, the production consumables required for casting are about 2300-678=1622 yuan / set. Based on 15 sets of quick changes per month, the annual material cost savings is 290,000 yuan. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a time flow chart of the quick change process of the present invention; Figure 2 It is a schematic diagram of the structure of a long wooden plug centering device.

[0019] In the figure, 1-columnar intermediate body; 2-arc-shaped transition section; 3-conical extension body. DETAILED DESCRIPTION

[0020] In order to make the purpose, process operation method, device and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below.

[0021] See attached Figure 1 The invention provides a tundish quick-change process for continuous casting of profiled billets below 600kg / m, adds a tundish quick-change mode on the basis of the original profiled billet continuous casting machine, realizes the casting speed returning to zero, and realizes automatic adjustment of the water flow rate of the crystallizer and automatic gap water supply of the fan-shaped segments, and automatic lifting and pressing down of the straightening machine by tracking the connection point position in the quick-change mode.

[0022] The quick change process operation is divided into Figure 1 The 11 projects shown were designed and produced Figure 2 The long wooden plug centering device shown enables three projects to be carried out simultaneously, controlling the quick-change tundish process within 5 minutes.

[0023] Before the "standby car is in place", the long wooden plug centering device is installed and fixed to each water injection port of the standby tundish. After the "standby car is in place" project is completed, the two projects of "large ladle pouring and liquid level rising" and "tundish car centering" are carried out simultaneously. When the liquid level reaches the 10-20 ton mark position, each flow starts to drain, and when the liquid level rises to the 15-30 ton mark position, the pouring operation is realized.

[0024] In the above-mentioned "liquid level pulling into place" project, the steel liquid level in the crystallizer is quickly lowered to a position 450-600mm from the upper mouth of the crystallizer, further reducing the friction area between the crystallizer and the ingot and reducing the vibration load.

[0025] Example 1

[0026] The tundish capacity is 30 tons, the cross-sectional thickness of the crystallizer is 130 mm, and the length of the crystallizer is 1100 mm. The specific implementation process is as follows:

[0027] Step 1: About 10 minutes before changing the tundish, reduce the protective slag in the crystallizer.

[0028] Step 2: After each flow is blocked, operate the operation box: return the pulling speed to 0 → stop pulling and straightening → click the quick change mode on the P3 disk and confirm that the quick change button light is always on; immediately stir the box with an L-type oxygen tube after the flow is blocked → put the plug connector into the liquid molten steel → start the online ladle car and start the pulling and straightening at the same time to pull the crystallizer liquid level to a position of 600mm from the upper mouth of the crystallizer, stop pulling and straightening and prepare to start pouring.

[0029] During the above operation, the long wooden plug centering device is installed on the spare middle ladle car in advance. After the connecting parts are inserted, the spare middle ladle car and the online middle ladle car are operated at the same time. After the spare middle ladle car is in place, the large ladle is poured immediately.

[0030] Step 3: Issue the order to start pouring, quickly raise the liquid level in the tundish to the 10-ton mark and measure the temperature. Start pouring in all streams at the same time. When the liquid level in the tundish continues to rise rapidly to the 15-ton mark, measure the temperature again and slowly adjust the liquid level in the tundish according to the temperature of the molten steel.

[0031] Before pouring, set the pulling speed in the operation box to BB0: 0.3m / min, BB1\BB2: 0.2m / min, BB3: 0.15m / min. When the steel liquid level in the crystallizer rises to about 50mm from the bottom of the funnel (the operation box displays 20%-30%), add protective slag and start pulling and straightening (no need to press the start button for vibration, the tundish mode directly changes to the casting state, and the button with light turns off automatically), and then adjust the pulling speed according to the actual liquid level. The subsequent pouring is the same as the single opening operation.

[0032] Through the above embodiments, the quick-change tundish for continuous casting of beam blanks below 600kg / m was successfully realized, filling the gap of small-section quick-change tundish for domestic beam blank continuous casting machines. The annual material cost can be saved by 290,000 yuan, and the annual production can be increased by 300t*15 groups / month*12 months=54,000 tons.

[0033] Example 2

[0034] A centering device specially used in the quick-changing process of the tundish for continuous casting of special-shaped billets below 600kg / m as claimed in claim 1, wherein the structure comprises a columnar intermediate body 1, conical extension bodies 3 are arranged at both ends of the intermediate body, and an arc-shaped transition section 2 is arranged between the two, wherein the columnar intermediate body is 54mm long and 33mm in diameter, the arc-shaped transition section is 18mm long and has an arc radius of 30mm, and the outer end diameter of the conical extension body is 14.5mm, the inner end diameter is 16mm, and the length is 205mm.

Claims

1. A quick-change process for continuous casting tundish of 600kg / m2 or less special-shaped billets, characterized in that The steps include: ①. 10 minutes before changing the tundish, reduce the protective slag in the crystallizer; ② After each flow is blocked, the operation box performs the following operations in sequence: The pulling speed returns to 0 → stop straightening → click the quick change mode on the P3 panel and confirm that the quick change button light is always on; quickly block the flow and immediately stir the box with an L-type oxygen tube → put the plug connector into the liquid steel → start the online tundish and start straightening at the same time to pull the crystallizer liquid level to a position of 600mm from the upper mouth of the crystallizer, stop straightening and prepare for pouring; ③. Install the long wooden plug centering device on the spare middle ladle car in advance, plug in the connectors and make the spare middle ladle car and the online middle ladle car move at the same time. After the spare middle ladle car is in place, pour the large ladle; ④. After pouring, quickly make the liquid level of the tundish reach the 10-ton mark and measure the temperature. At the same time, start pouring each stream. When the liquid level of the tundish rises to the 15-ton mark, measure the temperature again and slowly adjust the liquid level of the tundish according to the temperature of the molten steel. Before pouring, set the pulling speed in the operating box to BB0: 0.3m / min, BB1\BB2: 0.2m / min, BB3: 0.15m / min. When the steel liquid level in the crystallizer rises to 45-55mm from the lower mouth of the funnel, that is, when the operating box displays 20%-30%, add protective slag and start pulling and straightening, and then adjust the pulling speed according to the actual liquid level.

2. A centering device for quick-change process of continuous casting tundish of 600kg / m or less special-shaped billets as claimed in claim 1, characterized in that It comprises a columnar intermediate body (1), with conical extension bodies (3) of the same length provided at both ends of the columnar intermediate body, the outer end diameter of the conical extension body being smaller than the inner end diameter, and an arc-shaped transition section (2) being provided between the columnar intermediate body and the conical extension body.

Images