Sunday, February 28, 2021

Roll use system

 1. Roll change requirements during normal rolling: work rolls continuously roll 150-200t steel, normal roll change; intermediate rolls continuously roll 500800t steel, normal roll change; support roll continuous rolling 4000-5000t steel, normal roll change. Under normal circumstances, the lower limit is selected for thin specifications, the upper limit is selected for thick specifications, and the middle is estimated by the team.

The influence of plate shape control technology on the contact and wear between rolls

Six-high UCM cold rolling mills currently use work roll shifting, intermediate roll shifting and roll bending to improve the shape quality, but the above-mentioned processes also have a certain impact on the contact stress between the rolls and the wear of the rolls. It will affect the shape control ability of the rolling mill. 

Rebar production video! See it soon! Thread technology

Do you add scrap or hot metal to the converter first?

In the converter steelmaking, the normal feeding sequence is: scrap-molten iron, that is, first add a certain amount of scrap to the converter, and then start adding molten iron.

Monday, February 22, 2021

Roll failure caused by rolling process and raw material quality, roll technology

During rolling, the cold roll is subjected to strong internal and external forces such as rolling pressure, bending moment, and shear stress, resulting in cracks in the roll and peeling of the working surface, 

Friday, February 19, 2021

SUMMARY OF SCRAP PREHEATING METHODS

Today we are not talking about (iron ore and steel scrap) prices, only the method of (scrap preheating), to increase the converter scrap ratio, not only in one link, it should eat scrap in all links of the entire process, the following is what we are Let me share with you the experiences and methods learned and practiced by steel companies.

  • The roaster preheats the scrap steel.
The scrap steel is preheated by the roaster: Advantages, no investment is required. The original steel-clad roaster can be used. Because of its low flame temperature, poor rigidity, and low scrap preheating temperature, The temperature difference is large (1/5 of the surface layer, not fully baked), and the effect is not ideal.

Monday, February 1, 2021

Heating-free direct rolling technology for long sections



1. The background and purpose of the research

The energy consumption of the iron and steel industry accounts for about 23% of the country's total industrial energy consumption and 16.1% of the country's total energy consumption. The energy consumption of the rolling process accounts for about 10% of the total energy consumption of the steel industry. Therefore, the study of energy-saving and consumption-reducing technologies in the rolling process is of great significance for reducing energy consumption per ton of steel in my country. In recent years, although my country’s newly constructed long section steel rolling production lines generally use energy-saving technologies such as hot delivery and hot charging, on-line accelerated cooling, and endless rolling, my country’s low-level steel rolling production lines still account for a considerable proportion, making my country’s overall The energy consumption index of the steel rolling process is relatively high.

In hot rolling production, billet heating energy consumption is high in the rolling process. Taking a typical bar mill production energy consumption as an example, billet heating consumes about 80% of the energy, and the energy consumption for steel rolling only accounts for about 15%. With the application of energy-saving technologies, the proportion of energy consumption used for billet heating has gradually decreased, but it is still maintained at a high level. Therefore, the energy saving potential of ordinary steel rolling process mainly comes from the heating furnace. The long-section direct rolling technology enables the steel billet after continuous casting to be directly sent to the rolling mill for rolling without passing through the heating furnace or even supplementary heating. Without calculating the energy consumption of the heating furnace, the energy saving effect on the steel rolling process is significant.

 

2.Technical solutions

The core of the long-section direct rolling technology lies in the connection of continuous casting and rolling processes, and its foundation is the stable production of high-speed continuous casting and the stability control of the rolling process. The guarantee of continuous casting technology should realize defect-free billet production, higher casting speed, and stable production process; the guarantee of steel rolling technology should realize the temperature connection with the billet, partial induction heating, and high rigidity rolling with larger temperature window , Performance stability control and other technologies.

The long-section direct rolling technology solves the contradiction between low-energy production and high-quality products in the long-section non-heating rolling production process. It can realize the direct rolling process of continuous casting billets in short, medium and long distances. Realize low energy consumption production and significantly reduce production costs.

 


Figure 1: Schematic diagram of direct rolling technology for long sections

3.Main innovative achievements

(1)Control technology of continuous casting billet with high temperature, constant temperature and constant quantity

By studying the temperature field of the billet at different R angles, the breakout prediction model and control system, the co-design of the layout of the casting machine, the casting speed, and the cutting of the billet, the temperature difference between the head and the tail of the billet does not exceed 50℃, and the billet tapping temperature Stable production of high temperature continuous casting slabs above 1000℃.

Figure 2: High-speed production with constant temperature and constant volume of continuous casting slab

Figure 3: Hydraulic cutting at the end of metallurgical length after on-site multi-process optimization


(2) Long section casting-rolling interface billet queuing control technology

Based on the method of queuing theory, the continuous casting billet queuing system of the multi-strand continuous caster under different production processes was constructed, and the factors such as different molten steel volume, different flow numbers, and different fixed lengths were studied for the continuous casting billet conveying process at the casting-rolling interface. And rolling rhythm. This model can optimize the production rhythm of different production lines and improve the straight rolling rate and output.

(3)Long profile green and low energy consumption casting-rolling connection technology

According to the different distances, different plane positions, and different height differences between the continuous casting machine and the rolling mill of different steel enterprises, the methods of non-heating rolling, induction heating, and high-temperature billet soaking are selected to make the head, tail, and cross section of the continuous casting billet The temperature difference between the surface and the core of the product meets the production requirements and realizes the efficient connection of various on-site process arrangements. The straight rolling rate of a typical production line reaches 99%.



Figure 4: Performance stability control technology for billet direct rolling

(4)The performance stability control technology of long profile without heating rolling

Aiming at the influence of the chemical composition difference of different heats in the same pass and the temperature fluctuation caused by the connection of the casting-rolling interface on the mechanical properties of long sections in the non-heating rolling process, high-rigidity temperature-controlled rolling, variable-speed rolling, and post-rolling are studied. The cooling path and other processes balance the effects of microalloying elements and metallurgical structure on the mechanical properties of long profiles, and realize that the fluctuation of the yield strength of the same pouring second long profile does not exceed 10%.


Figure 5: a) Direct rolling production without uniform temperature control b) Direct rolling production with uniform temperature process control

4.Application situation

During the "Twelfth Five-Year Plan" period, the Institute of Metallurgical Technology of Central Iron and Steel Research Institute undertook the national science and technology support program "Steel Enterprise Long Section Direct Rolling Technology Project Demonstration". To tackle key technical issues such as quality control technology for long sections without phase change before production, finally, Guangdong Yuebei United Iron and Steel Co., Ltd. has successfully built a long section straight rolling demonstration line with an annual output of 500,000 tons. The demonstration line mainly produces HRB400 and HRB400E rebars, with specifications ranging from Φ20 to Φ35. The continuous casting machine of the demonstration line is well matched with the steel rolling process, the continuous casting billet is stable at high temperature, and the temperature fluctuation is less than 50 ℃. The heating furnace was eliminated on the production line of the demonstration line, and the rolling temperature was 9001100℃. The demonstration line has realized the continuous production of continuous casting billet direct rolling, with a direct rolling rate of 99% and a product qualification rate of 100%.

Classification, application, ratio of raw materials and damage mechanism of blast furnace mud


Clay is an amorphous functional refractory material, used in the process of plugging the taphole of the ironmaking blast furnace. The composition of gun mud can be divided into two parts: refractory aggregate and binder. Refractory aggregate refers to refractory raw materials such as corundum, mullite, coke gemstone and modified materials such as coke and mica, which are used to improve the refractoriness, high temperature performance and slag resistance of gun mud; the binder is water, tar pitch or phenolic Organic materials such as resin can also be mixed with SiC, Si₃N₄, expansion agents and additives to improve the physical properties and product quality of the gun mud.

According to the different binders, gun mud can be divided into two categories: water gun mud and waterless gun mud. Domestically, medium and small blast furnaces (<2000m³) with low top pressure and low level of intensified smelting use water blasting mud; while large and medium blast furnaces (>2000m³) with high top pressure and high level of intensive smelting are generally used Anhydrous cannon mud. Many foreign blast furnaces represented by Japanese blast furnaces generally use high-quality anhydrous gun mud, and are equipped with special opening methods and opening machines.

The water cannon mud is usually made of clay, coke powder, bauxite clinker and tar pitch as the main materials, and then mixed and stirred with water as a binder. Water cannon mud is a kind of cannon mud that was used in large quantities in the early days, but because of its relatively small bulk density, its ability to resist scouring of iron slag solution is weak, it is easy to cause insufficient hole depth when used on large and medium blast furnaces and runaway during tapping. Phenomena such as coke, iron tapping and venting and unclean iron slag will affect the normal production of the blast furnace. So far, due to the low cost of water gun mud, many medium and small blast furnaces (<2000m³) are still improving their composition and working hard to adapt to the smelting environment, and their unit consumption is above 1.2kg·t⁻¹.

Anhydrous gun mud generally uses corundum, high alumina bauxite, clay, sericite, pitch, silicon carbide, coke powder, etc. as raw materials, and tar, resin, etc. as binders. The bulk density of corundum and high alumina bauxite is relatively large, and they play the role of supporting the skeleton in the gun mud, which is the foundation of the gun mud strength, which greatly improves the ability of the gun mud to resist the scouring of the iron slag solution; the coke powder has good reduction It can protect other carbon components, maintain the reducing atmosphere of the blast furnace taphole, and has good thermal conductivity, which can be quickly sintered and has a certain sintering strength; silicon carbide has small thermal expansion coefficient, good thermal conductivity, and excellent thermal shock resistance, which can improve The refractoriness, volume stability, high temperature strength and erosion resistance of gun mud; clay and asphalt improve the plasticity of gun mud; sericite improves the sintering strength and plasticity of gun mud. Anhydrous gun mud has the advantages of no dampness, high strength, stable taphole depth, small taphole changes in the tapping process, etc., and will not cause a large flow.

The main factors affecting the performance and quality of blast furnace clay are raw materials, binders, additives and production processes.

Blast furnace taphole clay must have the following properties:

(1) Easy to open holes. When the tap hole needs to be tapped, the sintered gun mud in the tap hole can be easily drilled through the hole and tapped in time;

(2) It is easy to block the tap hole. When the tap hole is completed, the tap hole can be blocked in a short time, and sufficient mud volume is ensured to maintain a stable tap depth;

(3) Good adhesion. The new gun mud driven into the tap hole must have good adhesion with the old gun mud in the hole to make the new and old gun mud form a whole to prevent the existence of gaps. Iron seepage, slag seepage, impact on tapping and safety accidents in front of the furnace;

(4) Good sinterability. The shot mud can be sintered to different degrees in the three temperature stages of low temperature, medium temperature and high temperature. The iron hole is blocked in time and a large enough mud bag is formed in the hearth. Play the role of protecting the hearth lining bricks.

(5) It has good jet scouring and corrosion resistance, so that the tap hole diameter is not sharply enlarged, and the tapping time is guaranteed to be 150 to 180 minutes/time, which reduces the labor intensity in front of the furnace and reduces the consumption of materials in front of the furnace.

The main damage mechanism of blast furnace mud

Thermal stress damage. When the iron is tapped, the center of the iron hole is drilled by a drill bit, and hot molten iron and molten slag flow out of the iron hole, so that the iron hole can withstand high temperature above 1500 ℃. When the iron slag is discharged and the iron hole is re-blocked with gun mud, the old gun mud contacts the newly plugged gun mud, and the temperature drops rapidly from 1500°C to about 200°C. This repeated action generates huge heat inside the old gun mud. Stress can easily lead to arc-shaped cracks with the iron hole as the center.

Thermal chemical attack. Prolonged contact with molten iron and molten slag can cause chemical reactions to cause erosion of the mud. The reaction generates a low-melting mineral phase, which is lost with the scouring of the molten iron slag during the tapping period, which enlarges the hole diameter of the tap hole, causing the molten iron to rush out of the tap hole quickly, affecting the stability of the tap hole.

The biggest weakness of the current blast furnace mud is that the iron mouth expands quickly and the resistance to hot metal erosion is insufficient, which causes the molten iron in the hearth of the blast furnace to be unclean, affects the output, and is not conducive to the smooth movement of the blast furnace. In addition, it is difficult to open the iron hole, which causes the iron hole to be unable to open on time and affects the normal iron casting. Therefore, many large-scale blast furnaces at home and abroad use the plunger method or are equipped with opening machines with strong positive and reverse impact capabilities to solve the problem of difficult opening of blast furnace mud. Under normal circumstances, after the blast furnace is finished, the surface of the original gun mud seeps into the iron slag. After the new gun mud is plugged into the iron hole, a barrier is formed at the junction of the old and the new gun mud, which is not conducive to bonding. As a result, the molten iron in the blast furnace will enter along the gap between the new and old gun mud, resulting in a slag-iron penetration area in the middle of the gun mud. The formation of the slag-iron penetration area also increases the difficulty of the taphole opening to a certain extent. The iron gate is not easy to open, which can easily lead to major safety production accidents. At home and abroad, great attention is paid to the on-site operability of blast furnace taphole mud.

Explanation of some problems about integral casting materials and masonry of ladle

 

What are the refining methods of ladle?

Answer: The main methods of ladle refining are: slag washing, vacuum, stirring, heating, spraying (including wire feeding and shot peening). At present, the commonly used refining methods at home and abroad are nothing more than the single use or combined application of these methods. The specific methods are shown in the following table 1-1



Note: The symbol "+" indicates the means that can be added and the metallurgical function that can be obtained.

*LF is called LFV after adding vacuum means, which has the same refining means and metallurgical functions as SKF.


How is the mixed masonry of the ladle carried out?

Answer: The mixed masonry methods of ladle are divided into: 

(1) fiber felt for thermal insulation layer, high alumina brick for permanent layer, aluminum-magnesium castable for working layer; 

(2) fiber felt for thermal insulation layer, aluminum-magnesium for working layer High-quality castable; 

(3) fiber felt for thermal insulation layer, lightweight high-aluminum castable for permanent layer, bricks for working layer (such as magnesia carbon and brick aluminum-magnesia carbon); 

(4) fiber felt for thermal insulation layer, Permanent layer uses high-aluminum self-flowing castable, working layer (such as: magnesia carbon and brick aluminum-magnesia carbon) bricks; 

(5) but considering the working layer (such as: a slag line uses magnesia carbon brick, other parts are cast with aluminum-magnesium Material, b slag line uses magnesia-carbon bricks, and other parts of the aluminum-magnesium-carbon bricks should also be a kind of mixing method. The typical mixing method is slag-line magnesia-carbon bricks, and aluminum-magnesium castables are used for low corrosion areas. Masonry slag When lining magnesia carbon bricks, pay attention to the following two points: A. When pouring the ladle wall, measure the slag line part and stop pouring; B. Smooth the ladle wall castable, and use fire mud to put the bricks layer by layer after solidification The masonry is good.

The temperature of the steel shell after the molten steel is poured into the ladle. Explained separately from the three types of bricklaying, integral pouring and comprehensive masonry.

Answer: We know that in order to meet the needs of continuous casting, molten steel must have a certain temperature, especially for refining ladle. Maintaining a certain temperature is a prerequisite for completing the refining operation. However, in the actual operation process, the phenomenon of molten steel radiating heat to the outside through the steel shell is inevitable. We often make up for the temperature loss in two ways: one is to increase the tapping temperature, and the other is to take heating measures after the furnace.

Due to different types of smelted steel, different smelting methods, and different ladle structures and refractory materials, the temperature of the outer surface of the steel cladding is also different, but the premise must be that the surface temperature of the cladding is less than the creep temperature of the cladding material. Generally, it should be less than 300~350℃ to prevent the occurrence of bag wearing accidents. According to experience, the cladding temperature of the brick-built ladle is between 300 and 320℃; the temperature of the integrally cast ladle is below 280℃; the cladding temperature of the mixed steel is 330-340℃.

What is the basis for the selection of brick ladle and integral casting ladle?

Answer: Due to differences in metallurgical processes, operating conditions and application concepts, the lining materials of ladle in different regions and different steel plants are very different. The following four aspects are considered in terms of economy, practicality, smelting method and slag composition:

(1) From economic considerations. Under the same smelting conditions, the general brick ladle refractory material is expensive, the construction consumes a lot of manpower and material resources, and the cost per ton of steel is high. However, the price of the cast ladle refractory material is relatively cheap, the construction consumes less manpower and material resources, and the cost per ton of steel is low.

(2) Considering practicality. Under the same smelting conditions, integral casting is often used for small and medium-sized ladle. Because the overall pouring is simple and quick, and the use of sleeve pouring can shorten the ladle on-line time, increase the turnover rate, reduce the consumption of refractory materials, increase the package service, and reduce the cost of steel per ton.

(3) Consider from the method of smelting. Currently, ladle smelting methods are different. The tapping temperature of the molten steel connected to the ordinary ladle is low, and the residence time of the molten steel is short. After a simple furnace treatment, it reaches the continuous casting platform. The requirements for refractory materials are relatively low, and the integral cast aluminum-magnesium castable can meet the needs. However, the inner lining of refined ladle is often in an environment of heating, stirring, vacuum, slag washing, and spraying, which has strict requirements on refractory materials: high temperature resistance, erosion resistance, corrosion resistance, peeling resistance, thermal shock resistance, low porosity, high Density etc. Especially at the slag line, the requirements for refractory materials are more stringent. This requires some high-grade materials for the working layer: such as MgO-C bricks, MgO-Al2O3-C bricks, MgO-Cr2O3 bricks, magnesia-calcium bricks, etc.

(4) Consider from the slag composition. The slag composition of ordinary ladle and refined ladle is different. The slag of ordinary ladle comes from the final slag of converter or electric furnace and belongs to the CaO-MgO-FeOn-SiO2 system; the slag composition of refined ladle generally includes SiO2, CaO, It is composed of MgO, Al2O3, FeOn, MnO, Cr2O3, and its composition only depends on the slagging agent. These oxides will chemically react or dissolve in equilibrium with the chemical components in the refractory material of the working layer at a certain temperature, resulting in erosion of the working layer. When selecting the working lining, it is necessary to avoid the above two reactions of slag and refractory materials.

What are the factors that affect the life of the ladle? Please explain.

Answer: Mainly include: lining material, ladle lining structure design and refractory material selection, construction method and process control, smelting process, converter or electric furnace final slag control, slagging agent, molten steel composition, hot repair and other factors.

What is the corrosion mechanism of the slag line of the ladle? How to determine the upper and lower slag line?

Answer: The damage to the magnesia carbon brick of the refining ladle slag line is firstly the oxidation of carbon in the hot surface of the working lining to form a thin decarburization layer. The oxidation of carbon is due to the continuous iron oxide in the slag and O2 in the air. The result of oxidation of CO2, SiO2, etc., and the gasification of carbon by MgO dissolved in molten steel or bricks; followed by high-temperature liquid slag penetration into the pores of the decarburized layer or cracks caused by thermal stress , It reacts with the magnesium oxide in the brick to form a low-melting compound, causing the surface layer of the brick to change and weaken, and fall off layer by layer under the stress of strong steel slag agitation, mechanical erosion, etc., resulting in the damage of the magnesia carbon brick, and so on: Oxidation → decarburization → porosity → erosion → erosion → shedding → damage.

The method of determining the upper and lower slag lines: find the slag line area, the upper slag line is the part above the interface between slag and molten steel; the lower slag line is the part of the slag line below the interface between slag and molten steel. From the ladle after pouring steel, The upper slag line is more eroded than the lower slag line, and a ring zone will be formed in the upper slag line area.

What is the effect of the in-situ generation of aluminum-magnesium in the aluminum-magnesium castable and the direct addition of aluminum-magnesium spinel during the production process on the corrosion resistance and penetration resistance of the castable?

Answer: (1) Al-magnesium spinel is pre-introduced into the ingredients during production. It has no obvious hydration reaction with water. It has good volume stability during health maintenance or baking stage. The high-temperature flexural strength, thermal shock resistance and expansion resistance are better than the aluminum-magnesium castable that generates the aluminum-magnesium spinel in situ;

(2) The aluminum-magnesium castable that generates the aluminum-magnesium spinel in situ, because the needle-shaped MA is evenly staggered in the matrix, it can prevent the penetration of slag. For the pre-introduced aluminum-magnesium spinel castable, the slag can easily migrate around the particles, and the corrosion resistance and permeability resistance are not good.


How to judge the initial setting time and final setting time of aluminum-magnesium castables?

Answer: After the unshaped refractory is mixed with water or liquid binder, the property of the mixture gradually losing thixotropy or plasticity and being in a solidified state is called coagulation, and the time required for this process is called coagulation time. The time when the mixture starts to change from visco-plastic or visco-plastic-elastomeric to plastic-elastomeric is the initial setting time, and the time from plastic-elastomeric to elastomeric is the final setting time.

Judgment method of initial setting time: hold the material in hand to form a mass, twist it a few times in the hand, and disperse the material into lumps; there is no flow value when measuring the flow value.

Judgment method of final setting time: The material is completely solidified into a fixed shape, and the material block must be forced to break apart. The section is the aggregate surface.

In order to meet the requirements of construction operation time, it is generally required that the initial setting time should not be earlier than 40min, and the final setting time should not be later than 8h.

Please explain the respective baking systems and baking curves of brick ladle, pouring ladle, and comprehensive masonry ladle.

Answer: (1) Ladle baking system for integral pouring (summer): low-fire baking time: temperature <300℃, 24 hours; medium-fire baking time: temperature 300~600℃, 20 hours; high-fire baking time: Temperature 600~800℃, 12 hours; Temperature 800~1000℃, 8 hours.

Ladle baking system for integral pouring (winter):
Low-fire baking time: temperature <300℃, 36 hours; medium-fire baking time: temperature 300~600℃, 36 hours; high-fire baking time: temperature 600~800℃, 24 hours; temperature 800~1000℃, 8 hour.

 Where is the installation position of the breathable brick in the ladle?

Answer: When selecting the position of the blowing element at the bottom of the ladle, it should be determined according to the purpose of ladle processing. The water model test shows that the air-permeable bricks installed at the center of the ladle bottom and deviated from the center of the ladle (the blowing point is at a radius of 1/2 to 1/3 from the center of the ladle) have different mixing effects on molten steel. Blowing is conducive to the reaction between the slag and gold in the ladle and the desulfurization reaction of the top slag, while the eccentric bottom blowing is conducive to the mixing of molten steel in the ladle, the homogenization of the temperature and the floating of inclusions.

Therefore, for the purpose of uniform molten steel composition, temperature and promotion of inclusions floating up, breathable bricks should be installed at a distance of 1/2 to 1/3 radius from the bottom of the bag (subject to the lining of the bag), and avoid impact The area is located on both sides of the vertical center line of the bottom of the package with the nozzle block bricks.

What is the effect of moistening the peeled surface material with water before pouring the peeling sleeve?

Answer: The role of water spray: (1) When re-pouring, prevent the dry original layer from absorbing the moisture of the new pouring material, which will affect the construction performance;

(2) Wetting the original layer is conducive to forming a close combination with the new castable, and is conducive to sintering at high temperature to form a whole; (3) suppressing dust and improving the construction environment; (4) accelerating the cooling effect.


What is the cause of the erosion of the ladle castable by the slag?

Answer: The process of slag erosion is mainly the melting process of the castable into the slag and the process of the slag intruding into the castable. During the intrusion process, the slag agent composition reacts with the refractory material to form a metamorphic layer. As the molten slag penetrates into the castable and expands its reaction area and depth, the composition and structure of the material surface and nearby undergo qualitative changes, forming a metamorphic layer with high solubility and accelerating damage. In the end, the permeable layer after the structural change is peeled off due to the differential expansion.

How to position the tire mold at the center of the bottom of the new ladle for pouring the new ladle?

Answer: In the actual application of the ladle, the erosion of the ladle wall is irregular, and it is difficult to determine the center and radius at the bottom of the ladle. At this time, the center can be determined from the top of the ladle: (1) First take a line equal to the diameter of the ladle and take another A line with a heavy hammer at one end is used as the vertical center line of the first line. The point of the heavy hammer is the center of the circle, and the circle is made with the radius of the fetal membrane; then the fetal membrane is hoisted into the ladle to match the circle made. Sit together.

(2) First hoist the fetal membrane into the ladle, measure the thickness of the bag wall, and calibrate it with a hoist.

How to evaluate the performance of ladle castable after use?

Answer: Consider from two aspects: (1) Construction performance: water addition, flow value, initial setting time, final setting time, ease of demoulding, and whether there are cracks after baking;

(2) Use performance: the peeling resistance of the package wall, the erosion resistance of the side wall of the breathable brick, the erosion resistance and erosion resistance of the slag line, the erosion resistance and erosion resistance of the impact area of the bottom of the package;

Combining the above aspects, can we reasonably evaluate the comprehensive performance of ladle castables.

What data need to be recorded in the field test?

(1) Before the ladle goes online: water addition, initial setting time, final setting time, demolding time, natural curing time, baking time, wall thickness of ventilated brick side/to bread wall thickness, side slag line thickness of ventilating brick/opposite Thickness of slag line, thickness of impact zone at the bottom of bag/thickness of non-impact zone at the bottom of bag:

(2) Ladle online: Ladle serial number, number of furnaces used in ladle, steel connection time, argon blowing time after furnace, pouring time of continuous casting platform, turnover time, intermittent time:

(3) After the ladle is off the assembly line: bag wall residual: (residual thickness of the side wall of the ventilating brick/residual thickness of the bread wall), residual thickness of the slag line (residual thickness of the slag line on the side of the ventilating brick/residual thickness of the opposite slag line), and bottom of the bag Residual thickness (residual thickness in the impact area of the bottom of the bag / residual thickness in the non-impact area of the bottom of the bag).