KR101175435B1 - molten steel temperature realtime measuring apparatus of mold for continuous casting - Google Patents

molten steel temperature realtime measuring apparatus of mold for continuous casting Download PDF

Info

Publication number
KR101175435B1
KR101175435B1 KR1020100017606A KR20100017606A KR101175435B1 KR 101175435 B1 KR101175435 B1 KR 101175435B1 KR 1020100017606 A KR1020100017606 A KR 1020100017606A KR 20100017606 A KR20100017606 A KR 20100017606A KR 101175435 B1 KR101175435 B1 KR 101175435B1
Authority
KR
South Korea
Prior art keywords
molten steel
protective tube
mold
thermocouple
continuous casting
Prior art date
Application number
KR1020100017606A
Other languages
Korean (ko)
Other versions
KR20110098142A (en
Inventor
서해영
문홍길
안재환
하태준
최주태
Original Assignee
현대제철 주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 현대제철 주식회사 filed Critical 현대제철 주식회사
Priority to KR1020100017606A priority Critical patent/KR101175435B1/en
Publication of KR20110098142A publication Critical patent/KR20110098142A/en
Application granted granted Critical
Publication of KR101175435B1 publication Critical patent/KR101175435B1/en

Links

Images

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Measuring Temperature Or Quantity Of Heat (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)

Abstract

The present invention relates to an apparatus for continuously measuring molten steel temperature of a continuous casting mold, comprising: a thermocouple, an inner protective tube for embedding and protecting the thermocouple, and an outer protective tube, the outer protective tube being made of ZrO 2 -C-based refractory material. Includes external sheath.
The present invention protects the thermocouple with a double structure of an inner protective tube made of Al 2 O 3 and an outer protective tube made of ZrO 2 -C-based material, so that it is useful to continuously measure the temperature of the molten steel in the mold for a long time (about 1 hour). There is an advantage.

Description

Molten steel temperature realtime measuring apparatus of mold for continuous casting

The present invention relates to an apparatus for continuously measuring molten steel temperature of a mold for combustion casting, and more particularly, to an apparatus for continuously measuring molten steel temperature of a molten steel mold for measuring molten steel temperature in a state of being deposited on molten steel in a mold.

In the continuous casting process of manufacturing molten steel into slabs, molten steel contained in the ladle is continuously supplied to the mold in a state of temporarily storing the molten steel in the tundish of the continuous casting machine, and the mold is cooled to produce the slabs.

Slabs manufactured by continuous casting generate internal and surface cracks and defects due to high temperature cracks, central segregation and thermal stress due to microscopic segregation.

It is important to detect the behavior of molten steel in the mold in order to suppress the occurrence of defects during continuous casting and to produce a high quality slab. In order to detect the behavior of the molten steel, it is required to continuously detect the temperature change of the molten steel in the mold for a long time (about 1 hour).

SUMMARY OF THE INVENTION An object of the present invention is to provide a molten steel continuous measurement apparatus for a continuous casting mold capable of continuously measuring the temperature of molten steel in a mold for a long time (about 1 hour) while being deposited on molten steel in the mold.

According to a feature of the present invention for achieving the object as described above, the present invention is configured to surround the outside of the thermocouple, the inner protective tube and the inner protective tube, the inner protective tube, Zr-C-based refractory It includes an outer sheath made up.

The inner protective tube is made of alumina (Al 2 O 3 ).

The Zr-C-based refractory has a composition of ZrO 2 : 70-85 wt%, C: 15-30 wt% and unavoidable impurities.

The unavoidable impurity comprises less than 1 wt% SiO 2 .

The outer protective tube has a thickness of 8 ~ 10mm.

The thermocouple uses platinum.

The present invention protects the thermocouple with a double structure of the inner protective tube of Al 2 O 3 material and the outer protective tube of ZrO 2 -C-based material. In this case, the ZrO 2 -C-based material is chemically stable because it does not react with the mold powder, and it is physically stable because it withstands high temperature, so that the temperature of molten steel in the mold can be continuously measured for a long time (about 1 hour).

In addition, since platinum is used as the thermocouple, the stability is excellent and the thermal conduction error is small.

In addition, since the inner protective tube made of Al 2 O 3 prevents CO gas generated by C included in ZrO 2 -C from reacting with the thermocouple, the life of the thermocouple is also extended.

Therefore, it is possible to detect the abnormal flow by measuring the temperature change of the molten steel in the mold, there is a useful effect that can improve the quality of the continuous casting slab by controlling the flow of molten steel in the mold.

1 is a configuration diagram showing a state of molten steel injected between molds.
Figure 2 is a schematic diagram showing a molten steel continuous measurement apparatus of a continuous casting mold according to the present invention.
3 and 4 is a side and front cross-sectional view showing a preferred embodiment of the molten steel temperature continuous measuring apparatus of the continuous casting mold according to the present invention.
Figure 5 is a perspective view of the outer protective tube according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail.

The molten steel continuous measurement apparatus 20 of the continuous casting mold of the present invention is configured to surround the outer side of the inner protective tube 25 and the inner protective tube 25 to protect the thermocouple 21, the thermocouple 21 built-in. And an outer protective tube 27 made of a Zr-C-based refractory material.

Wrapping the thermocouple 21 with the double structure of the inner protective tube 25 and the outer protective tube 27 protects the thermocouple 21 from high temperature molten steel and continuously molten steel in the mold 13 for a long time (about 1 hour or more). This is to allow the temperature of the to be measured.

During continuous casting, the behavior of molten steel in the mold greatly affects the slab quality.

As shown in FIG. 1, when the vortex occurs near the molten surface of the molten steel, foreign substances such as a mold powder are mixed into the molten steel to degrade the slab quality. In extreme cases, the cast may burst during continuous casting, causing break out phenomenon of molten steel.

This is because when an abnormal flow such as vortex occurs, the molten steel temperature near it changes to cause solidification unevenness. In addition, even within the cast steel receives a thermal stress according to the solidification non-uniformity, which may cause a non-uniform distribution of temperature in the mold may cause mold distortion due to thermal stress.

By knowing the temperature of the molten steel, the flow can be controlled to suppress the generation of vortices. In addition, in order to detect the abnormal flow generating the vortex, the molten steel temperature must be continuously measured for a long time (about 1 hour).

In order to continuously measure the molten steel temperature in the mold, a molten steel temperature continuous measuring device (hereinafter, referred to as a "measuring device") of a continuous casting mold is provided.

As shown in FIG. 2, the measuring device 20 is installed in the mold cover 11 and fixed to the frame 15 arranged above the mold 13, and the lower part is deposited on the molten steel in the mold 13. And the molten steel temperature is measured.

3 and 4, the thermocouple 21 is inserted into an insulating tube 23 having two holes of two metal strands consisting of + and-, and the tip is exposed to the outside of the insulating tube 23 and joined. The tip exposure type is adopted. The insulator tube 23 is for preventing the short-circuiting of the metal strands of + and-except the contact point.

The driving principle of the thermocouple is that when heat is applied to the joined ends, thermoelectric power is generated depending on the temperature at both ends, and the molten steel temperature is measured by the magnitude of the thermoelectric power.

The thermocouple 21 uses platinum (Pt) as two metal strands. Platinum has a stable temperature range of 1500 ℃ or higher, good resistance to oxidizing atmospheres and small thermal conductivity errors. The insulating tube 23 is made of alumina (Al 2 O 3 ) material excellent in chemical stability and thermal shock resistance.

The inner protective tube 25 is for protecting the thermocouple 21. The inner protective tube 25 is made of alumina (Al 2 O 3 ) material.

Platinum, which is a component of the thermocouple 21, has excellent high temperature stability but is vulnerable to a high temperature reducing component crisis, that is, carbon monoxide (CO) and hydrogen (H 2 ). In addition, since the Zr-C refractory used as the outer protective tube 27 includes carbon, CO gas may be generated at a high temperature.

When this gas reacts with the thermocouple 21 made of platinum, deterioration occurs, so that the molten steel temperature measurement error is increased and the life of the thermocouple 21 is shortened. Therefore, the inner protective tube 25 made of alumina is further placed between the thermocouple 21 and the outer protective tube 27 to protect the thermocouple 21 from a high temperature reducing component crisis. Alumina is not only excellent in chemical stability and thermal shock resistance, but also resistant to high temperature reducing components.

The inner protective tube 25 has a lower portion housed in the outer protective tube 27.

As shown in FIG. 5, the outer protective tube 27 is formed in a rod shape having a conical end portion, and has an insertion hole 29 opened upward to accommodate the inner protective tube 25 therein. The outer protective tube 27 is formed with a screw thread for fixing on the upper side.

Since the outer protective tube 27 is immersed in molten steel for a long time, the corrosion protection against physical and chemical erosion of molten steel and slag should be excellent, and the thermal shock resistance against rapid heat flow should also be high. In consideration of this, the outer protective tube is made of Zr-C-based refractory material.

Zr-C-based refractory has a composition of ZrO 2 : 70 ~ 85wt%, C: 15 ~ 30wt% and unavoidable impurities.

ZrO 2 is to ensure excellent corrosion resistance of the outer protective tube. ZrO 2 is chemically stable from acid to alkali region and does not react with mold powder. If ZrO 2 is less than 70wt%, it is difficult to secure corrosion resistance, and if it exceeds 85wt%, the thermal shock resistance is inferior.

C is added to the sintered compact of ZrO 2 . C enhances the bonding strength between particles by promoting the sintering effect. If the C content is less than 15wt%, the strength is not obtained, and thus the impact resistance of the Zr-C-based refractory is lowered, and if it exceeds 30wt%, the content of ZrO 2 is relatively lowered and the erosion resistance is lowered.

Unavoidable impurities include less than 1 wt% SiO 2 . SiO 2 is an impurity contained in ZrO 2 . Therefore, the higher the purity of ZrO 2, the better the corrosion resistance.

The outer protective tube may be composed of Al 2 O 3 -SiO 2 -C-based refractory, but since the mold powder and Al 2 O 3 , SiO 2 reacts, corrosion resistance of the outer protective tube is inferior. Therefore, it consists of a refractory Zr-C system.

ZrO 2 -C series refractory is resistant to high temperature of 2400 ℃ and is resistant to high temperature, corrosion and gas environment. The outer protective tube 27 made of ZrO 2 -C-based refractory has a thickness of 8 to 10 mm. This is because if the thickness of the outer protective tube 27 is too thick, the molten steel temperature measurement error may be large, and in the case of thin, the continuous life temperature of the ZrO 2 -C-based material may be difficult.

The length of the outer protective tube 27 is not limited but set in consideration of the depth to be inserted into the molten steel. The length of the outer protective tube 27 of the present embodiment has a range of 240 ~ 300mm.

Hereinafter, the present invention will be described in detail through experiments.

Experiment 1

Table 1 shows the reaction between the components of the mold powder and Al 2 O 3 , SiO 2 .

division Mold Powder A (wt%) Mold Powder B (wt%) Remarks SiO 2 32.8 32.3 CaO 40.9 24.4 Separation of bond by reaction with Al 2 O 3 , SiO 2 MgO 0.3 5.2 Al 2 O 3 4.0 6.7 Na 2 O 3.7 10.9 Separation of bond by reaction with Al 2 O 3 , SiO 2 CaF 2 7.6 9.0

According to Table 1, CaO and CaF 2 components in the mold powder components react with Al 2 O 3 and SiO 2 . Through this, when the outer protective tube immersed in the molten steel using Al 2 O 3 or SiO 2 it can be seen that it is difficult to measure the temperature of the molten steel in the mold continuously for a long time (about 1 hour) by erosion.

Experiment 2

Table 2 shows the external protective tube material test.

The corrosion resistance and thermal shock resistance of the mold powder were simulated for the two refractory materials of Al-C and Zr-C based on the actual operating conditions in the air induction melting furnace.

division material Evaluation characteristic Evaluation results One Al 2 O 3 -SiO 2 -C and ZrO 2 -C Thermal shock resistance
Corrosion resistance Thermal shock resistance: Al 2 O 3 -SiO 2 -C> ZrO 2 -C, Al 2 O 3 -SiO 2 -C is slightly superior.
Corrosion resistance: ZrO 2 -C> Al 2 O 3 -SiO 2 -C, Al 2 O 3 -SiO 2 -C are inferior. 2 ZrO 2 -C Corrosion resistance
(By time) Erosion depth for 1 hour immersion: 3.5mm 3 ZrO 2 -C + ingredients Corrosion resistance
(By time) 4 hours immersion depth: 4 mm

According to Table 2, it can be seen that when the outer protective tube is made of a Zr-C-based refractory, the corrosion resistance is high, and thus it is possible to continuously measure the temperature of the molten steel in the mold for a long time (about 1 hour).

Experiment 3

Table 3 tests the thermal shock resistance according to the protective tube material.

division thermocouple Inner sheath Outer protective officer 1500 ℃ 1550 ℃ 1600 ℃ Remarks Inventive Example platinum Al 2 O 3 ZrO 2 -C Good Good Cracking - Comparative Example 1 platinum - Al 2 O 3 -SiO 2 -C Good Good Cracking  CO generated by C reacts with platinum thermocouple Comparative Example 2 platinum - ZrO 2 -C Good Good Cracking  CO generated by C reacts with platinum thermocouple

According to Table 3, when the outer protective tube is made of Zr-C-based refractory, it exhibits similar thermal shock resistance to Al 2 O 3 -SiO 2 -C-based refractory at 1500 ~ 1600 ℃, and the inner protective tube and Zr- of Al 2 O 3 material. Incorporating the thermocouple into the double structure of the outer protective tube made of C-based material not only ensures corrosion resistance and thermal shock resistance, but also reduces the possibility that the platinum thermocouple reacts with the CO gas.

Through this, it can be seen that it is possible to continuously measure the temperature of the molten steel in the mold for a long time (about 1 hour) in the state of being deposited in the molten steel in the mold.

In addition, it can be seen that the abnormal flow can be detected by measuring the temperature change of the molten steel in the mold, and the quality of the continuous casting slab can be improved by controlling the molten steel flow in the mold.

Within the scope of the basic technical idea of the present invention, many other modifications are possible to those skilled in the art, and the scope of the present invention should be interpreted based on the appended claims. will be.

11: Mold cover 13: Mold
15: frame 20: measuring device
21: thermocouple 23: insulated tube
25: Inner Sheriff 27: Outer Sheriff
29: insertion hole

Claims (6)

Thermocouple,
An inner protective tube for protecting the thermocouple by embedding it;
It is configured to surround the outside of the inner protective tube, and comprises an outer protective tube made of Zr-C-based refractory,
The Zr-C-based refractory has a composition of ZrO 2 : 70 ~ 85wt%, C: 15 ~ 30wt% and inevitable impurities, the inevitable impurities include less than 1wt% SiO 2 , the outer protective tube of 8 ~ 10mm A molten steel temperature continuous measuring device of a continuous casting mold, characterized in that it has a thickness. The method according to claim 1,
The inner protective tube is a continuous molten steel temperature measuring apparatus of the continuous casting mold, characterized in that consisting of alumina (Al 2 O 3 ). delete delete delete The method according to claim 1,
The thermocouple is a molten steel continuous measurement device of a continuous casting mold, characterized in that using platinum.
KR1020100017606A 2010-02-26 2010-02-26 molten steel temperature realtime measuring apparatus of mold for continuous casting KR101175435B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020100017606A KR101175435B1 (en) 2010-02-26 2010-02-26 molten steel temperature realtime measuring apparatus of mold for continuous casting

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020100017606A KR101175435B1 (en) 2010-02-26 2010-02-26 molten steel temperature realtime measuring apparatus of mold for continuous casting

Publications (2)

Publication Number Publication Date
KR20110098142A KR20110098142A (en) 2011-09-01
KR101175435B1 true KR101175435B1 (en) 2012-08-20

Family

ID=44951730

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020100017606A KR101175435B1 (en) 2010-02-26 2010-02-26 molten steel temperature realtime measuring apparatus of mold for continuous casting

Country Status (1)

Country Link
KR (1) KR101175435B1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018021635A1 (en) * 2016-07-29 2018-02-01 주식회사 포스코 Continuous casting abnormality prediction device

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102847888A (en) * 2011-06-30 2013-01-02 苏州品翔电通有限公司 Mould temperature sensing structure
KR101320353B1 (en) * 2011-09-28 2013-10-23 현대제철 주식회사 Device for generating ultrasonic wave of submerged type
KR102190510B1 (en) * 2019-04-22 2020-12-11 현대제철 주식회사 Melting metal temperature sensing apparatus of mold part

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10197353A (en) 1997-01-09 1998-07-31 Nippon Thermotec Kk Sensor for measurement of temperature of molten metal

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10197353A (en) 1997-01-09 1998-07-31 Nippon Thermotec Kk Sensor for measurement of temperature of molten metal

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018021635A1 (en) * 2016-07-29 2018-02-01 주식회사 포스코 Continuous casting abnormality prediction device

Also Published As

Publication number Publication date
KR20110098142A (en) 2011-09-01

Similar Documents

Publication Publication Date Title
CA2807856C (en) Device for measuring the temperature in molten metal
KR101175435B1 (en) molten steel temperature realtime measuring apparatus of mold for continuous casting
KR101230331B1 (en) A continuous temperature detecting device
ES2288772T3 (en) REFRACTORY MATERIAL OF ALUMINA-MAGNESIA-GRAFITO.
EP2090554B1 (en) Refractory article incorporating a cold slag band
JPH0333212B2 (en)
JPS61246636A (en) Protective tube for continuously measuring temperature of molten steel
KR100591711B1 (en) Thermocouple sheath for molten metal temperature measurement
JP2010243171A (en) Method for continuous measurement of temperature of molten steel
JP2015096266A (en) Immersion nozzle
KR20130077277A (en) Temperature probe enabling multiple measuring
JP2011099840A (en) Continuous temperature measurement probe for ladle
JP2018075601A (en) Semi-immersion nozzle
KR100779121B1 (en) Filler for ladle receiving molten steel
JP6077636B1 (en) Oxygen sensor and method for manufacturing oxygen sensor
JP5877123B2 (en) Degassing equipment dip tube
JP4790575B2 (en) Temperature probe for molten metal
KR100858717B1 (en) Filler for ladle receiving molten steel
KR20100085561A (en) Refractories for ladle of molen steel
KR100774918B1 (en) Refractories for continuos casting
JPH07333068A (en) Protecting tube of thermocouple
CN113999008A (en) Low-carbon submersed nozzle lining and preparation method thereof
JPH04344857A (en) Nozzle for casting molten metal
JPH06206774A (en) Refractory frame made of amorphous refractory
JP2987228B2 (en) Protection tube type continuous thermometer

Legal Events

Date Code Title Description
A201 Request for examination
E902 Notification of reason for refusal
E701 Decision to grant or registration of patent right
GRNT Written decision to grant
FPAY Annual fee payment

Payment date: 20150730

Year of fee payment: 4

LAPS Lapse due to unpaid annual fee