Causes of perforation of ladle nozzle in use and solutions

 Sometimes when steel is poured, a local area of the down nozzle will be melted and formed, and the molten steel will pass through from here, which seriously affects the normal operation of continuous casting.

Possible reasons for perforation:

(1) The ladle slide plate is half-open for pouring steel for a long time. The molten steel flows seriously in the nozzle, and swirls are formed on the inner wall of the nozzle. Local erosion and erosion are serious, and it is easy to form pits. In severe cases, the molten steel will pass through this position; When forming, the local position is relatively loose, the strength is low, and it is easy to be eroded.

(2) After many times of use, the drain is subjected to severe temperature differences, resulting in thermal shock cracks in the nozzle, and air passages are easily formed at the intersection of the cracks. Due to the negative pressure inside the ladle nozzle, the cracks will absorb oxygen and be oxidized. The structure is loose and eroded by molten steel, forming holes and perforations.

 

Solution:

The drain material with good thermal shock resistance and corrosion resistance should be selected. When hot repairing, pay attention to observe whether the inner wall of the drain is evenly eroded and whether there are pits, so as to prevent the occurrence of perforations.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality ladle magnesia carbon bricks are good sold to many countries say South Africa, Bangladesh, Indonesia, Malaysia, etc. Shall any interests, welcome to contact us. Our team would make best to be your reliable partner!

Article Source:Causes of perforation of ladle nozzle in use and solutions
Company name: Henan Changxing Refractory Materials Co.,Ltd
More refractory products:https://www.cxrefractories.com/en-product-solution
Email:info@cxrefractories.com
Website:https://www.cxrefractories.com

 

Analysis of the causes of the fracture of the ladle nozzle

 The ladle nozzle is broken, and the specific reasons may have the following problems:

1. Reasons for sliding nozzle mechanism

1) The sliding mechanism is used for a long time at high temperature, or accidentally collided during operation, etc., which causes a large amount of deformation of the sliding gate mechanism, resulting in uneven force on the interface of the skateboard, and a small gap will be formed in the part with a small force surface, which may cause the skateboard. Infiltration steel.

2) The sliding trolley with the lower slide plate will slowly produce errors between the upper slide plate mechanism and the upper slide plate due to the long time loading and unloading of the slide plate, resulting in a small gap between the upper and lower slide plates.

3) Because the springs used in the mechanism have been used in high temperature environments for a long time, sometimes even though they are not in service, they may deform and fail. Under the static pressure of molten steel, there will be gaps between the skateboards, which may lead to steel seepage between the skateboards. It may be possible to wear steel into the entire body.

4) The deformation of the drain top sleeve makes the drain installation incorrect, or the pin buckle of the drain top sleeve sliding trolley is worn for a long time, so that the drain and the lower sliding plate cannot be tightly tightened. Steel infiltration.

2. Reasons for Skateboarding

1) The flatness of the skateboard surface does not meet the requirements, the flatness is low, and a microwave gap is formed between the skateboards.

2) There is a problem with the quality of the skateboard. When pouring, especially on the continuous sliding secondary skateboard, the surface scratches are serious, or a horseshoe-shaped melting loss is formed at the mouth of the skateboard. The molten steel will penetrate into the deeper scratches, where the temperature is relatively relative. If it is lower, the molten steel will condense to form steel clamping. If you continue to operate the slide plate, especially in continuous casting with large strokes, the gap between the slide plates may increase due to the steel clamping, which may cause a leakage accident.

3. Reasons for on-site operation

1) The refractory mortar is not working well, and the thickness is inappropriate. If the fire mortar in the installation nozzle is too thin, it will be squeezed out, and it will not provide good support. If it is too thick, it will not spread well. Moreover, when the residual mud in the nozzle eye is blown with high-pressure compressed air, the too thin refractory mud will be blown out of the gap, which lays a hidden danger for the sewer seepage.

2) The dry refractory mud in the upper nozzle mechanism is not cleaned up, or there is steel slag, there is a little refractory mud on the surface of the skateboard, and it is not cleaned up due to negligence during use. When the fire mud is applied to the drain, the fire mud is mixed with particles The dry refractory sludge of the steel, which brings many hidden dangers to the production.

3) Problems in the operation of the continuous casting machine. When the ladle is opened for pouring, a large ladle nozzle is hung on the nozzle for protective pouring. At this time, you should try to avoid pulling the slide plate with the ladle nozzle with a large stroke. This may cause the nozzle to become loose due to improper operation. It may cause steel seepage in the drain. The flow rate can be adjusted by inching mode instead.

Article Source:Slag regulating material for converter slag splash protection
Company name: Henan Changxing Refractory Materials Co.,Ltd
More refractory products:https://www.cxrefractories.com/en-product-solution
Email:info@cxrefractories.com
Website:https://www.cxrefractories.com

Measures to solve the problems of tundish refractory

 Some of the problems that occur during the use of tundish refractory materials are the quality of the material itself, and some are related to the on-site construction and need to be carefully observed and analyzed.

(1) Dry material has no strength

Before the tundish is put into use, the dry material of the working layer needs to have a certain low temperature strength, which is mainly obtained by vibration and baking. After the dry material is demolded by vibration and baking, there will often be local lack of strength or low strength, which is very easy to cause collapse and affect the production of continuous casting cases.

After long-term observation and analysis, the main reasons for the lack of strength or low strength of the dry material are:

①Baking problem: The tundish baking device used in the steel plant is a gas baking device, which will cause a large number of pipelines to focus after long-term use. The tar or the burner is damaged, causing the partial baking effect to be poor and leading to no strength or low strength.

②The dry material is damp: The dry material is composed of 70% particles and 30% fine powder. The fine powder contains magnesia and binder. Because of its high specific surface area, the fine powder is easy to absorb water and become damp. The magnesia and the binder absorb water after they absorb water. Chemical deterioration causes the bonding agent to fail and cannot produce bonding strength during baking;

③Uneven mixing of binder: When producing dry materials, various particles, fine powders and binders need to be put together and mixed uniformly. Sometimes, the mixing is uneven due to human factors or mixing equipment. Some dry materials do not have binder or the content of bonding agent is rarely resulting in partial loss of strength after baking and demoulding.

Solution: First of all, it is necessary to ensure the baking effect of the roaster, regularly purge the gas pipe, remove tar and dust, and replace the damaged burner in time. Secondly, it is necessary to ensure that the dry material is dry and mixed evenly.

(2) Nozzle cracking steel infiltrating the tundish nozzle with zirconium core in the pouring process is easy to crack and lead to steel infiltration, often forcing continuous casting to block production or abnormal shutdown. The analysis believes that the nozzle cracking is mainly due to the poor thermal shock resistance of the zirconium core.

Solution: The bulk density of the zirconium core should not be too high. The higher the bulk density, the worse the thermal shock resistance. Appropriately thickening the nozzle body can prevent molten steel from seeping out.

(3) Ladle casing fracture. The ladle casing is located between the ladle nozzle and the tundish. Its metallurgical function is to prevent the molten steel from splashing and being oxidized during the process of the molten steel flowing from the ladle into the tundish. The most common problem in the use of large-clad casing is fracture. There are two reasons for the fracture. One is the poor thermal shock resistance of the large-clad casing, and the other is that the large-clad casing and the steel ladle need to be replaced when replacing the ladle. The nozzle is separated. When the casing and the ladle upper nozzle are tightly adhered, the steelworker applies an external force to the ladle casing, causing the casing to break.

Solution: First, use materials with small thermal expansion coefficient and elastic mold to produce the casing to improve thermal shock resistance; Second, when the casing and the water outlet cannot be shared, no external force can be applied to the lower part of the casing, and the upper part of the casing can be steel external force is applied to the shell to separate it.

Article Source：Measures to solve the problems of tundish refractory
Company name: Henan Changxing Refractory Materials Co.,Ltd
More refractory products: https://www.cxrefractories.com/en-product-solution
Email:info@cxrefractories.com
Website:https://www.cxrefractories.com

The main refractory wear mechanism at the bottom of the ladle

 The damage to the bottom of the ladle, especially the impact area, may be the second reason why the ladle cannot be used and needs to be repaired or relined. The typical feature is: the higher the height of the ladle, the worse the wear of the refractory in the bottom area. Other relevant factors may include tapping temperature and furnace height.

There are three main stages:

1. Thermal spalling-temperature gradient and tapping cause the formation of cobweb-like vertical cracks on the bottom hot surface at the early stage of the furnace age;
2. The penetration of molten steel and slag—the penetration of molten steel and slag into the bottom hot surface , Especially through those vertical cracks formed on the surface;
3. Structural cracking-the subsequent thermal cycle causes the structural cracking of the alternating hot surface area, and then a new refractory surface is formed. Once the newly formed refractory surface is exposed to molten steel and slag, the second and third stages will be repeated.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality refractory products are good sold to many countries say South Africa, Bangladesh, Indonesia, Malaysia, etc. Shall any interests, welcome to contact us. Our team would make best to be your reliable partner!

Article Source：The main refractory wear mechanism at the bottom of the ladle
Company name: Henan Changxing Refractory Materials Co.,Ltd
More refractory products: https://www.cxrefractories.com/en-product-solution
Email:info@cxrefractories.com
Website:https://www.cxrefractories.com

Production process of cold head series molten steel in a steel making plant

 1. Converter → LF furnace → vacuum RH furnace → billet continuous caster.

2. Converter → vacuum RH furnace → LF furnace → billet continuous caster.
3. Converter → LF furnace → billet continuous caster.
After the LF furnace exits the station, the slagging is cooled during the pouring process, and the crust is still hung at the position of the ladle slag line after the molten steel is poured. This makes the ladle cleaning operation more difficult and workload, and the reuse of the steel slag left by the ladle will cause problems.

For example: the slagging on the wall of the ladle hangs in the air after the casting of the continuous caster, and falls to the bottom of the ladle under the action of gravity to form slagging at the bottom of the ladle. At the same time, some steel slag will be scattered in the ladle nozzle, blocking the nozzle, causing the molten steel to be unable to start pouring after reaching the continuous caster platform.

We Changxing Refractory Material Co.,LTD is professional manufacturer and supplier of refractory materials for more than 30 years. Our high quality magnesia carbon bricks are good sold to many countries say South Africa, Bangladesh, Indonesia, Malaysia, etc. Shall any interests, welcome to contact us. Our team would make best to be your reliable partner!

Article Source:Production process of cold head series molten steel in a steel making plant
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
Email: info@cxrefractories.com
Website:http://www.cxrefractories.com

Remarks for the installing of tundish exchangeable nozzle

1.All the bolts should be smeared with high temperature butter when mounting sliding mechanism, or it will be difficult to fasten. It is also helpful for dismounting.
2.When installing upper nozzle, the clamping ring surface should be smered with a layer of graphite to make it easier for dismounting. Use upper nozzles set rule to fix the position of argon blowing hole.
3.The lower bulgy surface of upper nozzle which will be in touch with submerged entry nozzle should be 2~3mm after the upper nozzles is fixed, which also should be adjusted to make sure the allowance around is even.
Changxing refractory provides refractory products, calcium silicate products, castable & mortar, china refractory brick, ceramic fiber felt, ladle & tundish nozzle, ceramic fiber with high quality for you. Such as high alumina refractory bricks, magnesia carbon brick, clay refractory bricks and other refractory products.
Article Source:Remarks for the installing of tundish exchangeable nozzle
Company name: Henan Xinmi Changxing Refractory Materials Co.,Ltd
Email: sales1@chinafirebrick.com
Website:http://www.chinafirebrick.com/

what are the details of Ladle Nozzle Well Block?

Ladle Nozzle Well Block

Introduction:

The ladle nozzle well block connects the wearing refractory lining of the ladle bottom to the mechanism or ladle gate for the flow control. To the well block is asked a huge wearing resistance and moreover it has to protect the nozzle placed inside it. Our ladle nozzle well block is made with magnesia carbon material or alumina carbon material, which can be made according to customized.

The ladle nozzle well block can be realized in any size and shape and strengthened with steel fibers to improve its mechanical resistance.

The series of well blocks for nozzles are made from high-purity, high-density, high-strength materials. Based on different materials, they have corundum, magnesia carbon and alumina spinel carbon. 

Advantages:

They show the features of stable structure, excellent thermal shock resistance, good corrosion/erosion resistance and long service life.

Application:

It is mainly used to fix upper nozzle in steelmaking.

Specific Application:Used to fix upper nozzle.


Service Life:Make plain carbon steel, 100 heats MIN; for refining ladle, 30 heats MIN.

Article source:  Ladle Nozzle Well Blocks