CN110181004B - Detection method for judging continuous casting solidified blank shell according to point crack positions - Google Patents
Detection method for judging continuous casting solidified blank shell according to point crack positions Download PDFInfo
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- CN110181004B CN110181004B CN201810382726.4A CN201810382726A CN110181004B CN 110181004 B CN110181004 B CN 110181004B CN 201810382726 A CN201810382726 A CN 201810382726A CN 110181004 B CN110181004 B CN 110181004B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D2/00—Arrangement of indicating or measuring devices, e.g. for temperature or viscosity of the fused mass
- B22D2/005—Arrangement of indicating or measuring devices, e.g. for temperature or viscosity of the fused mass for the thickness of a frozen shell
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- Investigating And Analyzing Materials By Characteristic Methods (AREA)
Abstract
The invention relates to a detection method for judging a continuous casting solidified blank shell according to a point crack position, which is characterized by comprising the following steps of: after the continuous casting billet is lightly pressed, point-shaped cracks exist at the zero plasticity temperature position on a longitudinal sample of the continuous casting billet, the point-shaped cracks can reflect the thickness of a solidified billet shell of the press roll, the billet shell of each press roll is determined and measured by judging and measuring the point-shaped cracks on the longitudinal sample of the continuous casting billet, and a solidification heat transfer model is optimized according to the determination result. The solidified blank shell corresponding to the press roller is obtained by judging and measuring the point-like cracks of the longitudinal sample of the blank and is used for optimizing a solidified heat transfer mathematical model.
Description
Technical Field
The invention belongs to the technical field of continuous casting solidified shell detection in the metallurgical industry, and particularly relates to a detection method for judging a continuous casting square billet solidified shell according to a spot crack position.
Background
At present, the continuous casting solidification shell detection mainly adopts a nail shooting experiment.
The nail-shooting experiment is commonly used for measuring the thickness of a solidified shell of a casting blank in domestic large-scale steel works since the 90 s of the 20 th century. The nail-shooting method is to use nail-shooting gun to shoot the steel nail as tracer material into the solidified shell, then to sample the corresponding position of casting blank for analysis. The nail gun is composed of gun body, control box, nail shooting bullet and nail, the nail is made of ordinary carbon steel, two grooves containing sulfide are made on the nail, and after the nail is shot into the liquid cavity of casting blank, the sulfide with low melting point can be quickly diffused, so that the thickness of the solidified shell of the continuous casting blank can be measured by acid corrosion and sulfur imprint method according to the diffusion condition of sulfide, and the thickness of liquid core of the casting blank can be determined. The nail shooting method has the characteristics of accurate measurement, low cost, strong universality and the like, but the experiment period is long and the data accuracy is poor.
At present, the basic research of the continuous casting process is mainly to simulate and analyze the cooling and solidification process of a casting blank by establishing a two-dimensional solidification heat transfer mathematical model, but whether the mathematical model can be adapted to the conditions of a casting machine, production process parameters, steel grades and the like, and the solidification coefficient must be determined through surface temperature measurement and nail shooting tests to revise and optimize. The biggest process difficulty of the current continuous casting soft reduction tapping is how to determine a reasonable reduction position, the solidification thickness of a blank shell is determined by shooting nails on a casting blank in a solidification process, and a solidification coefficient, the length of a liquid cavity and the solid phase ratio of a two-phase region at the solidification tail end are calculated.
If the detection method for judging the continuous casting solidified blank shell according to the position of the point crack is successfully developed, the method belongs to a great breakthrough for judging the continuous casting square billet solidification condition.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a detection method for judging a solidified billet shell of a continuous casting billet according to the position of a point crack in the prior art, so that a long-time field experiment is avoided, the production efficiency is improved, the cost is greatly reduced, and the physical quality of the billet is improved.
The technical scheme adopted by the invention for solving the problems is as follows: a method for detecting the shell of continuously cast solidified billet features that after the continuously cast billet is slightly pressed down, the point-shaped crack at zero-plasticity temp on the longitudinal specimen of billet has the function of reflecting the thickness of shell of solidified billet of press roller, and the shell of each press roller is measured by judging and measuring the point-shaped crack on the longitudinal specimen of billet.
Preferably, the ladle is hoisted into a continuous casting ladle turret:
1) conducting dummy ingot sealing operation;
2) centering a tundish nozzle by using a large tundish;
3) adding a tundish covering agent, and using proper crystallizer covering slag;
4) starting a pressing roller to perform light pressing when the square billet reaches the zero plasticity temperature, and then tracking and recording the pressing condition of each roller;
5) taking a longitudinal sample with a certain length from the produced square billet;
6) subdividing, milling and pickling corrosion are carried out on the longitudinal sample;
7) judging and measuring the point-like cracks on the longitudinal sample;
8) recording the position of the corresponding point-shaped crack of each press roller;
9) optimizing a solidification heat transfer mathematical model according to the obtained data;
10) and designing a soft reduction process according to a calculation result of the mathematical model, guiding actual production and improving the quality of the material object.
Preferably, the drawing speed of the square billet is controlled to be 0.30-0.6 m/min and the superheat degree is controlled to be 20-60 ℃ in the continuous casting process; the total pressing amount is 5-10 mm under light pressing.
Preferably, the following processes are specifically included in the dummy ingot sealing operation:
1) starting to block the dummy ingot more than 30min before the continuous casting on the molten steel;
2) drying the crystallizer steel plate and the dummy bar head;
3) filling the asbestos rope into the gaps around the dummy bar head by using a copper drill rod;
4) sealing gaps around the dummy bar head by using a mud rope, and properly placing the flat mud rope in the middle part; uniformly scattering scrap iron on the dummy ingot head;
5) placing an iron frame and reinforcing steel bars, wherein the reinforcing steel bars are required to be placed in the iron frame, and the reinforcing steel bars at the position where the central water gap descends are 5 cm lower; a gap is properly reserved in the middle part so that molten steel flows into the dovetail groove during casting.
Preferably, when centering the tundish nozzle, the following process is specifically included:
1) measuring the temperature and sampling the ladle subjected to continuous casting, commanding a travelling crane to seat the ladle on a ladle revolving platform and unhook the travelling crane, installing a ladle sliding gate oil cylinder, inserting an oil cylinder safety pin, covering a ladle cover, and lifting a ladle arm;
2) after the tundish car is driven to a pouring position, centering a tundish nozzle and monitoring the tundish nozzle to descend;
3) the flow of argon gas is 600ppm after the long water gap is sleeved;
4) a pressing handle is arranged, and the stopper rod is tightly closed;
5) starting and timely increasing the pulling speed to the standard pulling speed within a specified range, if the abnormal pulling speed can be higher than the standard pulling speed, adjusting the pulling speed after the temperature is measured, and if the temperature of the bale is very high and the baking effect of the tundish is good, slowly increasing the pulling speed.
Preferably, the geometric center of the removed sample is found out and sawed, the thickness of the sample is controlled to be about 100mm, the sawed sample is subjected to surface milling treatment, then the sample is corroded by diluted 5% sulfuric acid, and the picture is taken.
Preferably, the point-like cracks with a length of less than or equal to 1mm on the longitudinal specimen are identified, the distance to the inner arc surface is measured and recorded.
Compared with the prior art, the invention has the advantages that:
the solidified blank shell corresponding to the press roller is obtained by judging and measuring the point-like cracks of the longitudinal sample of the blank and is used for optimizing a solidified heat transfer mathematical model.
Detailed Description
The present invention will be described in further detail with reference to examples.
In the embodiment, the detection method for judging the continuous casting solidified shell according to the position of the spot-shaped crack is mainly applied to the continuous casting billet, the spot-shaped crack is formed on the longitudinal sample of the continuous casting billet after the continuous casting billet is slightly pressed down, the spot-shaped crack appears at the zero plasticity temperature, namely the solid phase ratio is 1.0, and the thickness of the solidified shell of the press roll can be reflected. The internal quality of the continuous casting square billet is greatly improved after the solidification heat transfer model is optimized through the measurement of the billet shell of each press-down roller. The spot cracks of the longitudinal samples of the square billets were judged and measured, and are shown in table 1.
TABLE 1 Point crack positions for the hold-down rolls
| Point-like crack | Position/mm |
| Point 1 | 113.75 |
| Point 2 | 119.17 |
| Point 3 | 130.00 |
| Point 4 | 140.83 |
The method specifically comprises the following steps: hoisting the ladle into a continuous casting ladle revolving platform:
(1) and carrying out dummy ingot sealing operation.
Firstly, blocking dummy ingot more than 30min before continuous casting on molten steel.
And secondly, drying the crystallizer steel plate and the dummy bar head to ensure that the crystallizer copper plate, the dummy bar head and the dummy bar material are dried.
Filling the gaps around the dummy bar head with asbestos ropes by using a copper drill rod, and filling and leveling, especially dovetail groove oblique waves.
And fourthly, sealing gaps around the dummy bar head by using a mud rope, and properly placing the flat mud rope in the middle part to prevent molten steel from directly rushing on the dummy bar head to dissolve and damage the dummy bar head. The dummy ingot head is pressed flat by a mud rope in the places with uneven head, rough head and cracks so as to prevent the dummy ingot from falling off. And then uniformly scattering scrap iron on the dummy ingot head.
Fifthly, placing an iron frame and reinforcing steel bars, wherein the reinforcing steel bars are required to be placed in the iron frame, and the reinforcing steel bars at the position where the central water gap descends are 5 centimeters lower; a gap is properly reserved in the middle part so that molten steel flows into the dovetail groove during casting.
(2) And (4) centering a tundish nozzle by using a large tundish.
Firstly, the temperature of the ladle of the upper continuous casting is measured and sampled, and the temperature must be measured when the ladle is cast for the first furnace for the continuous casting. The command travelling crane seats the bale on a bale rotary table, unhooks the travelling crane, installs a bale sliding water gap oil cylinder, inserts an oil cylinder safety pin, covers a bale cover and lifts a bale arm;
secondly, after the tundish car is driven to a pouring position, a captain is assisted to center the tundish nozzle and simultaneously monitor the descent of the tundish nozzle, and the nozzle is prevented from being pushed to a cold strip when people monitor the descent of the tundish.
And thirdly, sleeving the long water gap, opening the argon flow to be 600ppm (the argon flow is less than 500ppm and an audible and visual alarm is given).
Fourthly, the pressing handle is installed and the stopper rod is closed tightly. After the ladle is cast, whether a tundish nozzle is opened automatically or not is checked, the tundish nozzle must be opened first when the tundish nozzle is opened automatically, and the steel flow is controlled properly to prevent steel from being dead or overflowing.
And fifthly, starting pouring on any section, controlling the flow of molten steel and starting time according to the section, starting in a specified range and timely increasing the pulling speed to the standard pulling speed. If abnormity occurs (the baking effect of the tundish and the nozzle is poor, the temperature of the molten steel is low, and the waiting time for heating the molten steel or casting the tundish is long), the pulling speed can be higher than the standard pulling speed, and the pulling speed is adjusted after the temperature is measured. If the temperature of the large ladle is very high and the baking effect of the medium ladle is good, the pulling speed needs to be slowly increased.
(3) A tundish covering agent is added, and proper crystallizer covering slag is used.
Firstly, in the process of pouring, slag is forbidden to be fished, and stirring in a crystallizer by using an oxygen lance is forbidden.
Secondly, in the pouring process, the covering slag is required to be added frequently, the covering slag is less frequently and evenly paved, the operation of black slag surface is carried out, and the exposure of molten steel is strictly forbidden. An oil cylinder of a plug rod dismounting mechanism and an accident flashboard oil cylinder. Preparing raw and auxiliary materials: crystallizer casting powder, covering agent, iron stool, etc. When steel is normally poured, four persons monitor the periphery of the crystallizer.
(4) The typical drawing speed is controlled to be 0.30 m/min-0.6 m/min, and the typical superheat degree is controlled to be 20-60 ℃; the total pressing amount is 5-10 mm under light pressing. And (3) clicking a soft pressing button for throwing after the billet head passes through a third withdrawal and straightening machine (the surface of the square billet reaches zero plastic temperature at the moment, namely the solid phase rate is 1.0), and tracking and recording the pressing condition of each roller.
(5) A500 mm long longitudinal specimen was taken from the produced square billet.
(6) And (4) splitting, milling the surface and carrying out acid pickling corrosion on the longitudinal sample. The geometric center of the taken sample is found out firstly, the sample is sawed, the thickness of the sample is controlled to be about 100mm, the sawed sample is subjected to surface milling treatment, then diluted 5% sulfuric acid is used for corroding the sample, and a picture is taken.
(7) And judging and measuring the point-like cracks on the longitudinal sample. And identifying the point-like cracks with the length less than or equal to 1mm on the longitudinal sample, measuring the distance between the point-like cracks and the inner arc surface, and recording.
(8) The position of the corresponding spot crack for each of the rolls was recorded. The data recorded were analyzed and the examples for the three steel grades are given in table 1.
TABLE 1 Point crack location of three Steel grades
(9) And optimizing the solidification heat transfer mathematical model according to the obtained data. And correcting a calculation value of the solidification heat transfer model according to the estimated thickness of the blank shell, and finely adjusting the calculation model.
(10) And designing a soft reduction process according to a calculation result of the mathematical model, guiding actual production and improving the quality of the material object.
The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and the non-fundamental modifications, substitutions, improvements, etc. within the scope of the present invention should be included.
Claims (4)
1. A detection method for judging a continuous casting solidified blank shell according to a point crack position is characterized in that point cracks exist at a zero plasticity temperature position on a longitudinal sample of a continuous casting square billet after the continuous casting square billet is slightly pressed down, the point cracks can reflect the thickness of the solidified blank shell of a press roll, the blank shell of each press roll is determined by judging and measuring the point cracks of the longitudinal sample of the continuous casting square billet, and a solidification heat transfer model is optimized according to the determination result, and the detection method is characterized in that: hoisting the ladle into a continuous casting ladle revolving platform:
1) conducting dummy ingot sealing operation;
2) centering a tundish nozzle by using a large tundish;
3) adding a tundish covering agent, and using proper crystallizer covering slag;
4) starting a pressing roller to perform light pressing when the square billet reaches the zero plasticity temperature, and then tracking and recording the pressing condition of each roller;
5) taking a longitudinal sample with a certain length from the produced square billet;
6) subdividing, milling the surface and carrying out acid pickling corrosion on the longitudinal sample, specifically, finding out a geometric center of the taken sample, sawing the sample, controlling the thickness of the sample to be about 100mm, carrying out surface milling treatment on the sawn sample, corroding the sample by using diluted 5% sulfuric acid, and taking a picture;
7) judging and measuring the point-like cracks on the longitudinal sample, specifically identifying the point-like cracks with the length less than or equal to 1mm on the longitudinal sample, measuring the distance between the point-like cracks and the inner arc surface, and recording the distance;
8) recording the position of the corresponding point-shaped crack of each press roller;
9) optimizing a solidification heat transfer mathematical model according to the obtained data;
10) and designing a soft reduction process according to a calculation result of the mathematical model, guiding actual production and improving the quality of the material object.
2. The detection method for judging the continuously cast solidified shell according to the position of the spot crack as claimed in claim 1, wherein: the drawing speed of the square billet is controlled to be 0.30-0.6 m/min in the continuous casting process, and the superheat degree is controlled to be 20-60 ℃; the total pressing amount is 5-10 mm under light pressing.
3. The detection method for judging the continuously cast solidified shell according to the position of the spot crack as claimed in claim 1, wherein: the method specifically comprises the following steps during dummy ingot sealing operation:
1) starting to block the dummy ingot more than 30min before the continuous casting on the molten steel;
2) drying the crystallizer steel plate and the dummy bar head;
3) filling the asbestos rope into the gaps around the dummy bar head by using a copper drill rod;
4) sealing gaps around the dummy bar head by using a mud rope, and properly placing the flat mud rope in the middle part; uniformly scattering scrap iron on the dummy ingot head;
5) placing an iron frame and reinforcing steel bars, wherein the reinforcing steel bars are required to be placed in the iron frame, and the reinforcing steel bars at the position where the central water gap descends are 5 cm lower; a gap is properly reserved in the middle part so that molten steel flows into the dovetail groove during casting.
4. The detection method for judging the continuously cast solidified shell according to the position of the spot crack as claimed in claim 1, wherein: the method specifically comprises the following steps when the tundish nozzle is centered:
1) measuring the temperature and sampling the ladle subjected to continuous casting, commanding a travelling crane to seat the ladle on a ladle revolving platform and unhook the travelling crane, installing a ladle sliding gate oil cylinder, inserting an oil cylinder safety pin, covering a ladle cover, and lifting a ladle arm;
2) after the tundish car is driven to a pouring position, centering a tundish nozzle and monitoring the tundish nozzle to descend;
3) the flow of argon gas is 600ppm after the long water gap is sleeved;
4) a pressing handle is arranged, and the stopper rod is tightly closed;
5) starting and timely increasing the pulling speed to the standard pulling speed within a specified range, if the abnormal pulling speed can be higher than the standard pulling speed, adjusting the pulling speed after the temperature is measured, and if the temperature of the bale is very high and the baking effect of the tundish is good, slowly increasing the pulling speed.
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| CN112475254B (en) * | 2020-10-28 | 2021-10-19 | 东北大学 | Method and device for controlling pulling speed and casting strip thickness of thin strip continuous casting machine |
| CN112784367A (en) * | 2020-12-10 | 2021-05-11 | 江阴兴澄特种钢铁有限公司 | Method for calculating thickness of blank shell at position of continuous casting roller row and solidification tail end of casting machine |
| CN112765535B (en) * | 2020-12-10 | 2024-04-19 | 江阴兴澄特种钢铁有限公司 | Continuous casting roller array position solid phase rate calculation method |
| CN113145812B (en) * | 2021-04-01 | 2022-10-25 | 东北大学 | Method for optimizing flow of continuous casting transient molten steel |
| CN114088503A (en) * | 2021-11-19 | 2022-02-25 | 中天钢铁集团有限公司 | Method for verifying accuracy of secondary cooling solidification model |
| CN114871400B (en) * | 2022-06-13 | 2024-02-27 | 中天钢铁集团有限公司 | Continuous casting solidification process judging method based on single-roll pressing operation and application thereof |
| CN117272761B (en) * | 2023-11-21 | 2024-04-26 | 北京科技大学 | Method and system for monitoring middle cracks of bloom |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20010040438A (en) * | 1999-08-19 | 2001-05-15 | 이구택 | A continuous casting method of austenitic stainless steel containing high si content |
| KR20040058814A (en) * | 2002-12-27 | 2004-07-05 | 주식회사 포스코 | Method for manufacturing slab of martensitic stainless steel |
| CN104493121A (en) * | 2014-11-28 | 2015-04-08 | 东北大学 | Online detection method for solidified bottom end position in bloom continuous casting production process |
| CN106513611A (en) * | 2016-10-17 | 2017-03-22 | 江阴兴澄特种钢铁有限公司 | Continuous casting process for producing 450mm extremely-thick plate blank on straight arc-shaped continuous casting machine |
-
2018
- 2018-04-26 CN CN201810382726.4A patent/CN110181004B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20010040438A (en) * | 1999-08-19 | 2001-05-15 | 이구택 | A continuous casting method of austenitic stainless steel containing high si content |
| KR20040058814A (en) * | 2002-12-27 | 2004-07-05 | 주식회사 포스코 | Method for manufacturing slab of martensitic stainless steel |
| CN104493121A (en) * | 2014-11-28 | 2015-04-08 | 东北大学 | Online detection method for solidified bottom end position in bloom continuous casting production process |
| CN106513611A (en) * | 2016-10-17 | 2017-03-22 | 江阴兴澄特种钢铁有限公司 | Continuous casting process for producing 450mm extremely-thick plate blank on straight arc-shaped continuous casting machine |
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