CN109487178B

CN109487178B - High-purity ultrahigh manganese steel and preparation process thereof

Info

Publication number: CN109487178B
Application number: CN201811628836.0A
Authority: CN
Inventors: 赵四勇; 廖钊; 康建; 田辉; 周正
Original assignee: Guangxi Changcheng Mechanical Ltd By Share Ltd
Current assignee: Guangxi Changcheng Mechanical Ltd By Share Ltd
Priority date: 2018-12-29
Filing date: 2018-12-29
Publication date: 2020-06-16
Anticipated expiration: 2038-12-29
Also published as: CN109487178A

Abstract

The invention discloses high-purity ultrahigh manganese steel which comprises the following components in percentage by mass: 0.75-1.76% of C, 22.0-30.0% of Mn, 0.1-0.8% of Si, 0.021-0.043% of P, 0.016-0.035% of S, 0.07-2.5% of Cr, 0.52-2.3% of Mo, 0.01-1.34% of Ni, 0.03-1.5% of Cu, 0.01-0.2% of Nb, 0.032-0.083% of Al, 0.0006-0.0010% of O, 0.00014-0.00042% of H, the balance of trace elements less than or equal to 0.82%, and the balance of Fe. By adopting the preparation process of the high-purity ultrahigh manganese steel, the oxygen and hydrogen contents are effectively reduced, and the comprehensive mechanical properties of the high manganese steel are improved.

Description

High-purity ultrahigh manganese steel and preparation process thereof

Technical Field

The invention belongs to the technical field of high-performance new materials and metallurgy, and particularly relates to high-purity ultrahigh manganese steel and a preparation process thereof.

Background

High manganese steels are conventional wear resistant materials. Over a hundred years of development, three series of manganese 13, manganese 18 and manganese 25 have formed. Wherein, the manganese 13 forms the international and domestic standard and is mature. The manganese 18 has only international standard, the manganese 25 has high manufacturing difficulty, and only has the internal standard of an enterprise for the time being. The high manganese steel has good toughness and plasticity, low crack propagation rate and safe and reliable use because of single-phase austenite or austenite plus a small amount of carbide in the microstructure. The other characteristic is that under the action of larger impact load or contact stress, the surface is rapidly processed and hardened, the surface hardness is rapidly increased to play a good role in abrasion resistance, the inside still keeps good toughness, and the fracture does not occur when the large impact load is born. These properties of high manganese steel make it widely used in conditions of impact wear and high stress abrasive wear. Such as jaw plates of jaw crushers, cones of cone crushers, hammers of large hammer crushers, lining plates of partial drum mills, lining plates of gyratory crushers and the like, and is one of the most widely applied wear-resistant materials in the world at present. The research on high manganese steel at home and abroad has not been stopped so far, but in the actual production, the high manganese steel meeting the requirements can be produced according to the requirements, which is not easy. The main problems are that no good slag-making material is formed during the production of the induction furnace, manganese is a strong oxidizing element, is easy to oxidize to form oxidizing slag, and is easy to segregate to cause uneven components. This is the main reason why high manganese steels are widely used, but their use effect is always not ideal.

The purity degree of the high manganese molten steel directly influences the quality of castings, and the content of impurities such as oxides, inclusions, gas content and the like in the high manganese molten steel directly influences the material performance.

Oxygen is one of the most serious elements that tends to be segregated during the solidification of steel, and the solubility of oxygen is rapidly reduced during the solidification and subsequent cooling of molten steel, and most of the oxygen originally dissolved in steel is concentrated at γ or α grain boundaries in the form of fine inclusions such as iron oxides, sulfur oxides, and the like, which cause grain boundary embrittlement, easily become starting points of grain boundary cracking during the processing and use of steel, and finally cause brittle fracture of steel.

The increase of the oxygen content in the steel can reduce the ductility, impact toughness and fatigue failure resistance of the steel, improve the ductile-brittle transition temperature of the steel and reduce the corrosion resistance of the steel. Further, a steel material containing high oxygen is also prone to age-aging, and a low-melting-point film is formed by impurity segregation at grain boundaries during high-temperature processing, resulting in hot embrittlement of the steel.

The hydrogen can also be diffused and separated out in the cooling process of the steel, and because the diffusion speed in the solid steel is very slow, only a small amount of hydrogen diffuses to the surface of a continuous casting billet (or steel ingot), and most hydrogen diffuses into microscopic pores, or the vicinity of inclusions, or pores on grain boundaries to form hydrogen molecules. Since hydrogen molecules are continuously accumulated at the deposition site, the KH value is small at low temperature, but pH2 is large, causing internal stress of steel. This internal stress, together with the sum of the structural, thermal, deformation stresses, etc., exceeds the strength limit of the steel and will crack and form cracks.

For the above reasons, hydrogen causes the following defects of the steel:

(1) and (4) hair cracks. During hot working of steel, hydrogen-containing pores in the steel are elongated in the working direction to cause cracking, which in turn causes a decrease in the strength, plasticity, and impact toughness of the steel, which is called "hydrogen embrittlement". The hydrogen embrittlement has a particularly prominent effect on the transverse properties of the steel.

(2) A laminar fracture. Due to the characteristics of the crystal structure in some steels, hydrogen molecules are easy to gather on the dendritic crystal or deformed crystal boundary, so that internal stress is caused, the intercrystalline tension is weakened, and the transverse plasticity and impact toughness of the steel are reduced. The more developed the dendrites of steel, the more easily lamellar fracture defects are formed.

In the process of smelting the high manganese molten steel, a certain amount of oxides, non-metallic inclusions, harmful gases and the like exist in the high manganese molten steel due to the effects of air suction, oxidation and the like, and in order to ensure that the high manganese molten steel forms a casting in a pure state, the molten high manganese molten steel needs to be refined and purified to achieve the purification effect.

At present, three manufacturing processes of domestic and foreign pure steel are mainly adopted:

1) blast furnace-pretreatment of cast steel liquid-converter-external refining (LF, RH). The process method needs to be provided with external refining equipment, and has complex process and complex operation;

2) ultra high power, high power Electric Arc Furnace (EAF) -external refining (LF, RH). The process method also needs to be provided with external refining equipment and has higher requirements on raw materials;

3) vacuum Induction Furnace (VIF) and electroslag remelting (ESR). The vacuum melting equipment used by the process method is large in investment, and the remelting needs large electricity consumption.

At present, domestic smelting equipment and processes mostly adopt non-oxidation smelting processes, but the current system for refining high manganese steel has the following defects: firstly, the degree of flushing argon to a furnace lining in the purification treatment process of high manganese molten steel cannot be detected, and the cost is higher due to the selection of better argon pressure and flow; secondly, when molten high manganese molten steel seeps out of the furnace lining and is communicated with the furnace shell, the furnace penetration accident cannot be well avoided; thirdly, the effect of purifying and treating the high manganese steel by oxygen and hydrogen is poor, and the quality of the product is influenced; fourthly, the quality of the air brick used in the system for refining the high manganese steel is poor, the argon blowing effect is influenced, and the purification effect of oxygen and hydrogen in refined molten steel is influenced, so that the existing intermediate frequency induction furnace is urgently needed to be improved aiming at the defects.

At present, most ladle bottom argon-blowing air bricks used at home and abroad are treated at 1500 ℃, so that the combustion cost is high, the production period is long, and correspondingly, the production cost is high. In order to shorten the production period, achieve the purposes of energy conservation, emission reduction, cost reduction, consumption reduction and the like, research on unfired ladle bottom argon-blowing air bricks is started by some domestic and foreign research institutions and enterprises, but the development and the effect are not ideal. In foreign countries, few companies, mainly represented by vesuwei, adopt the unburned ladle bottom argon-blowing air brick technology, but most of the companies add steel fibers in the product formula so as to improve the quality stability of the product, and thus, the corrosion resistance of the product is reduced. In the prior art, the unburned ladle bottom argon-blowing air brick has the following difficult problems which need to be overcome urgently:

(1) when the traditional air brick is used, the problems of peeling, block falling and the like are easily caused due to the rapid change of the use temperature; some of the argon blowing furnace even breaks in use, so that argon blowing is not smooth, and molten steel leakage can be seriously caused. Both the unsmooth air blowing and the leakage of molten steel seriously affect the normal smelting of a steel mill and cause loss in different degrees, so that the problems of air brick peeling, block falling, breaking and the like are very necessary to be solved.

(2) At present, the corundum-spinel air brick commonly adopted in China is easy to generate volume expansion under a high-temperature environment due to the characteristics of the material, and once the air seam channel is not designed reasonably, the phenomenon of unsmooth air blowing caused by expansion can occur, so that the air brick partially or completely loses the air permeability function.

(3) The product has low strength at medium and low temperature, and an inflection point exists at medium temperature.

(4) The volume of each temperature section of the product is unstable, and cracks are easy to generate in the using process.

(5) The firing cost is high.

(6) The production cycle is long.

Therefore, how to improve the defects of poor slag corrosion resistance and thermal shock resistance, poor mechanical property and air permeability and the like of the traditional air brick to obtain the air brick with higher comprehensive performance is a problem to be urgently solved by popularizing and applying the air brick in a wider field and meeting the demand of industrial production.

The slag-forming material is used in the process of refining the high manganese steel, so that harmful gases such as oxygen, hydrogen and the like can be reduced to a certain degree, but the existing slag-forming material becomes sticky and hard after being used for a long time, slag is easily adhered to the ladle wall, particularly to the ladle edge, and the refractory material of the ladle wall can be damaged during slag removal, so that the service life of the slag-forming material is greatly shortened; meanwhile, the over-adhered and over-hard steel slag causes the inner diameter of the temperature measuring gun insertion pipe to be reduced, and the outer wall of the insertion pipe is solidified with a slag shell and is difficult to penetrate through a slag layer. The traditional method adopts slag skimming measures to reduce the thickness of a slag layer. However, excessive slag skimming can cause secondary oxidation on the surface of molten steel, and can also cause the temperature of the molten steel to be reduced quickly, so that the problems that excessive slag adhering impurities cannot float upwards, a steel ladle cannot adhere to slag and the like cannot be solved, and the speed of adhering slag to the steel wall is reduced.

Disclosure of Invention

The invention provides high-purity ultrahigh manganese steel and a preparation process thereof, and aims to solve the practical technical problem of reducing the oxygen and hydrogen content and improving the comprehensive mechanical property of the high manganese steel.

In order to solve the technical problems, the invention adopts the following technical scheme:

the high-purity ultrahigh manganese steel comprises the following components in percentage by mass: 0.75-1.76% of C, 22.0-30.0% of Mn, 0.1-0.8% of Si, 0.021-0.043% of P, 0.016-0.035% of S, 0.07-2.5% of Cr, 0.52-2.3% of Mo, 0.01-1.34% of Ni, 0.03-1.5% of Cu, 0.01-0.2% of Nb, 0.032-0.083% of Al, 0.0006-0.0010% of O, 0.00014-0.00042% of H, the balance of trace elements less than or equal to 0.82%, and the balance of Fe.

Preferably, the high-purity ultrahigh manganese steel comprises the following components in percentage by mass: 1.46% of C, 28.64% of Mn, 0.72% of Si, 0.036% of P, 0.028% of S, 2.19% of Cr, 1.57% of Mo, 0.91% of Ni, 1.02% of Cu, 0.12% of Nb, 0.058% of Al, 0.0006% of O, 0.00026% of H, the balance being 0.61% of trace elements and the balance being Fe.

The invention also provides a preparation process of the high-purity ultrahigh manganese steel, which comprises the following steps:

(1) and (3) knotting the crucible: installing the air brick at the bottom of the system according to requirements, knotting the crucible by using a furnace lining material and a mold, and drying and sintering;

(2) the gas diffuser is designed and manufactured according to the volume of the induction electric furnace, the gas diffuser is formed by hydraulic high-temperature baking of chromium, magnesium or corundum refractory materials, and the particle size of the gas diffuser is designed to optimize gas flow and resist metal penetration;

(3) the gas diffuser is arranged in the center of the bottom of the induction furnace and is connected with an argon blowing system, and the argon blowing system is formed by sequentially connecting an argon bottle, a pressure reducing valve, a flow regulator, a pressure-resistant rubber pipe and a movable joint;

(4) preparing materials: weighing various materials for smelting the cast molten steel according to the chemical composition requirements of the cast molten steel for later use;

(5) charging and smelting: the prepared materials are gradually put into a furnace for smelting, when furnace burden is melted to form a molten pool, namely, when casting molten steel covers 30.6cm of the furnace bottom, a flow regulator is started to blow and inject argon to participate in the casting molten steel smelting process, and the pressure and flow of the blown argon are increased along with the increase of the casting molten steel along with the continuation of smelting, and the specific control process is as follows: controlling the pressure of argon blowing to be 6.2-6.4kg and the flow of argon to be 16-17L/min in the first 8-13 min; controlling the argon blowing pressure to be 6.5-6.7kg and the argon flow to be 17.1-17.3L/min in 14-20 min; controlling the argon blowing pressure to be 6.8-7kg and the argon flow to be 17.4-17.6L/min in 21-30 min; covering the surface of the molten steel with a slagging material at the beginning of 31min, wherein the addition amount is 0.91-0.98 kg/t.s; controlling the argon blowing pressure to be 6.3-6.5kg and the argon flow to be 17.2-17.4L/min within 31-52 min; until furnace burden is melted down, sampling and analyzing components in the furnace;

(6) adjusting chemical components: calculating and adding the adjusting material according to the sampling analysis result until the adjusting material is completely melted;

(7) and (3) sedation in a furnace: stopping power supply after the cast steel liquid in the furnace reaches the required temperature, continuously blowing argon to ensure that the cast steel liquid is uniform in temperature and homogeneous, and impurities and gases are fully floated and combined with liquid level slagging materials;

(8) controlling temperature and tapping: controlling the temperature, tapping and pouring to prepare the high-purity ultrahigh manganese steel.

Preferably, the slagging material in the step (5) comprises the following raw materials in parts by weight: 25-53 parts of active white soil powder, 7-13 parts of talcum powder, 10-16 parts of palygorskite powder, 4-6 parts of montmorillonite powder, 32-64 parts of quicklime powder, 9-15 parts of fluorite powder, 5-8 parts of mineral wool and 1-2 parts of adhesive.

Preferably, the quality indexes of the active kaolin powder raw material are as follows: SiO 2₂：59.16-62.34％；Al₂O₃: 17.24-18.36%; MgO: 3.61-5.44%; CaO: 1.65-2.09%; the granularity is 800-1000 meshes.

Preferably, the quality indexes of the talcum powder raw material are as follows: SiO 2₂: 58.34 to 62.01 percent; MgO: 27.52 to 31.36 percent; the granularity is 1200 meshes and 1300 meshes.

Preferably, the quality indexes of the palygorskite powder raw material are as follows: SiO 2₂: 52.68-56.96%; MgO: 23.83-27.19%; the granularity is 1000-1100 meshes.

Preferably, the quality indexes of the montmorillonite powder raw material are as follows: SiO 2₂：55.17-65.28％；Al₂O₃: 12.31 to 25.43 percent; the granularity is 800-1000 meshes.

Preferably, the quality indexes of the quicklime powder raw material are as follows: CaO: not less than 96.32%; the granularity is 600-800 meshes.

Preferably, the quality indexes of the fluorite powder raw material are as follows: CaF₂: not less than 72.36%; the granularity is 600-800 meshes.

The technical principle and the effect of the invention are as follows:

(1) the slag forming material with the improved proportion has a lower melting point and high activity, the slag is rapidly melted under the condition of intermediate frequency furnace smelting, the slag fully participates in metallurgical reaction, and the capabilities of deoxidizing, hydrogenizing, removing impurities and the like are strong.

(2) Argon is blown to stir molten steel in the smelting process, the temperature of the molten steel of the induction furnace is uniform in the melting period, the furnace lining is uniformly heated, the phenomenon of large furnace lining is eliminated, and partial impurities and harmful gases can be brought away.

(3) And new slag is produced in the refining period, molten steel in the furnace can fully participate in the interface reaction of the steel slag, and the molten steel can fully remove oxygen and hydrogen and impurities under the double effects of argon purification and full reaction of the steel slag.

(4) The invention adopts the induction furnace to refine the molten steel, and argon is blown under the atmospheric condition, so that the investment of external refining equipment can be reduced, and the operation process of the refining process is simplified; argon is an inert gas, is insoluble in molten steel, does not react with elements in the steel to form inclusions, and does not pollute the molten steel; argon is blown into molten steel through the air brick, the air brick enables argon bubbles to be fine and fully and uniformly dispersed, when the argon passes through the molten steel, dissolved H, O and the like in the molten steel can be automatically diffused, enter into an argon bubble and are removed from the molten steel along with the rising of the bubbles, non-metallic inclusions are adhered to inert gas, and the combination of the non-metallic inclusions floats to the surface of the molten steel and then is adhered to slag-making materials, so that the molten steel is purified; argon blowing refining can homogenize the chemical components of the molten steel and the temperature of the molten steel; because argon has high specific gravity, the argon is separated out from molten steel after being melted down, and a layer of protective film is formed on the molten steel surface to cover the molten steel.

(5) The slag-making material contains active white earth powder, talcum powder, palygorskite powder, montmorillonite powder, quicklime powder and fluorite powder with low melting point and high activity, is favorable for removing impurities such as hydrogen, oxygen and the like in molten steel, reduces the content of harmful elements and impurities in the steel, achieves the slag-absorbing effect, greatly improves the quality of the molten steel, is favorable for preparing a high-purity wear-resistant material, and simultaneously reduces the consumption of the slag-making material and the cost.

(6) By additionally arranging the furnace lining protection device, the invention can achieve the following effects:

1) the method can detect the degree of the inert gas scouring the furnace lining in the purification treatment process of the high manganese molten steel, thereby selecting better inert gas pressure and flow and saving the cost;

2) the service life of the furnace lining can be accurately controlled, and when the furnace bottom is contacted with the inductive contact due to the corrosion points caused by high-temperature high-manganese molten steel, the early warning that the service life of the furnace lining is up is required, and the furnace lining needs to be replaced;

3) the furnace body and the whole set of electric furnace control system can be effectively protected, when molten high manganese molten steel seeps out of the furnace lining and is communicated with the furnace shell, the contact protector is opened, the melt main power supply is closed in time, and the furnace penetration accident is avoided.

(7) The preparation process of the high-purity ultrahigh manganese steel effectively reduces the oxygen and hydrogen contents and improves the comprehensive mechanical properties of the high manganese steel.

Drawings

FIG. 1 is a schematic structural diagram of a system for preparing high-purity ultrahigh manganese steel.

Detailed Description

In order to facilitate a better understanding of the invention, the following examples are given to illustrate, but not to limit the scope of the invention.

The preparation process of the high-purity ultrahigh manganese steel comprises the design of a system for preparing the high-purity ultrahigh manganese steel and the control of process parameters and components.

System for designing and preparing high-purity ultrahigh manganese steel

As shown in fig. 1, includes: the furnace comprises a furnace shell 1, a furnace lining 2, a furnace wall layer (crucible) 3, a base 4, a gas diffuser 5, air bricks 6, an air inlet pipe 7, a movable joint 8, a furnace body protection contact 9, a contact protector 10, a lead 11, a furnace cover 12, a flow regulator 13, a pressure reducing valve 14 and an argon bottle 15, wherein the furnace lining 2 is wrapped by the furnace shell 1, the furnace wall layer 3 is arranged on the outer surface of the furnace lining 2, the base 4 is arranged at the bottom of the furnace shell 1, the gas diffuser 5 and the air bricks 6 are arranged above the base 4, the gas diffuser 5 is wrapped by the air bricks 6, the air inlet pipe 7 is connected with the gas diffuser 5, the movable joint 8 is connected with the air inlet pipe 7 and fixed on the base 4, the furnace body protection contact 9, the contact protector 10 and the lead 11 form a furnace lining protection device, the furnace body protection contact 9 is embedded in the furnace lining 2, and the contact, the furnace cover 12 is arranged at the top of a system for refining high manganese steel, the air inlet pipe 7 is connected with a flow regulator 13, the flow regulator 13 is connected with a pressure reducing valve 14, and the pressure reducing valve 14 is connected with an argon bottle 15.

The furnace wall layer 3 is a high-temperature-resistant synthetic material layer.

The high-temperature-resistant synthetic material layer is made of silicon carbide, alumina emery and a silicon iron material according to the weight ratio of 5:3: 2.

The thickness of the high-temperature resistant synthetic material layer is 0.8 cm.

The air inlet pipe 7 is a pressure-resistant rubber pipe.

The inner diameter of the pressure-resistant rubber tube is 0.3 cm.

The furnace body protection contact 9 is made of non-magnetic steel material.

The furnace body protection contact 9 is provided with 6.

The air brick comprises the following raw materials in parts by weight: 30-42 parts of forsterite sand with the particle radius of 1.62-2.31mm, 12-18 parts of forsterite sand with the particle radius of 1.08-1.62mm, 18-26 parts of forsterite sand with the particle radius of 0.83-1.08mm, 10-16 parts of fused magnesia with the particle radius of 1.34-1.98mm, 5-9 parts of fused magnesia with the particle radius of 0.92-1.34mm, 7-12 parts of fused magnesia with the particle radius of 0.75-0.92mm and 12-18 parts of corundum with the particle radius of 1.56-2.08mm, 4-7 parts of corundum with the particle radius of 1.12-1.56mm, 5-8 parts of magnesium silicate cement, 3-5 parts of sodium silicate with the particle radius of 1.03-3.16nm, 4-8 parts of sodium permanganate, 0.2-0.5 part of explosion-proof additive, 0.4-0.9 part of polycarboxylic acid dispersing water reducer and 10-15 parts of water;

the three different particlesRadius forsterite sand MgO: not less than 43.46%; SiO 2₂：36.81-39.72％；

The three types of fused magnesia MgO with different particle radiuses: not less than 98.12%;

the two kinds of corundum Al with different particle radiuses₂O₃：≥97.43％；

The anti-explosion additive is anti-explosion fiber, polypropylene is used as a raw material, the titer is 10-18 deniers, and the length is 3.21-6.02 mm;

the preparation process of the air brick comprises the following steps:

s1, batching: preparing raw materials according to the components and the parts by weight;

s2, premixing: placing the raw materials prepared in the step S1 into a premixing device, and stirring at the rotation speed of 200 and 300r/min for 20-25min to prepare a premix;

s3, vibration molding: transferring the premix prepared in the step S2 into a mold, and molding under the pressure of 100-120MPa by using a hydraulic press to prepare a green air brick;

s4, curing with a mold: placing the air brick green body prepared in the step S3 at 35-45 ℃, and maintaining for 4-8h with a mold;

s5, demolding: after the curing of the mold in the step S4 is finished, demolding at normal temperature to obtain a gas permeable brick blank;

s6, maintenance: curing the air brick blank prepared in the step S5 at 30-32 ℃ for 20-30 h;

s7, baking: and (5) baking the air brick blank cured in the step S6 at the temperature of 400-500 ℃ for 3-5 days to obtain the finished air brick.

The air brick of the invention has the following technical principle and effects:

(1) the forsterite sand is an alkaline refractory material, has the advantages of high temperature resistance, erosion resistance, good chemical stability and the like, has high refractoriness (1710 ℃) and metal oxidation erosion resistance, slowly expands at high temperature, is smaller than deformation, has no characteristic of sudden expansion, has good thermal shock resistance, and has the defect that a cast is difficult to produce main sand inclusion.

(2) The fused magnesia is an alkaline refractory material and has the advantages of compact structure, strong slag resistance, good thermal shock stability and the like.

(3) The corundum is an alkaline refractory material and has the advantages of good volume stability, extremely small re-burning shrinkage, good thermal shock stability, bending strength and the like.

(4) Magnesium silicate cement is used as a binder.

(5) The sodium silicate is a nano-grade material, and after the nano-sodium silicate is introduced into the air brick, micro-pores uniformly distributed are formed in the air brick, so that cracks can be effectively prevented from continuously diffusing in the using process, the toughness of the air brick is improved, the stripping is reduced, the service life is prolonged, the capability of resisting molten steel erosion and scouring is obviously improved in the using process, the slag adhesion on the surface of the air brick is little or even not, the stripping resistance effect is good, the labor intensity of field workers is reduced, and good social benefits are brought.

(6) The sodium permanganate is added during the preparation of the air brick, and can be decomposed in the brick preparation process, so that gas is generated in the blank system, the blank is rich in pores, and the air permeability of the product is further improved.

(7) The explosion-proof additive is explosion-proof fibre, it is mixed with other refractory material uniformly, after forming, it is baked, and the fibre is softened, contracted and melted with the continuous rise of baking temp. and when it reaches a certain temp., it is finally formed into pores and carbonized, and they are distributed in the air brick to form micro network pores, and can open pore channel, reduce internal stress and prevent burst, so that it can raise safety coefficient in the course of refining.

(8) The polycarboxylic acid dispersing water reducing agent is added to play a role in dispersing, so that the magnesium silicate cement, the nano sodium silicate, the sodium permanganate and the explosion-proof additive are fully dispersed, the water adding amount in the manufacturing process of the air brick is reduced, the water resource is saved, the drying speed is accelerated, and the production period of the air brick is shortened.

(9) The air brick has few straight air holes, large wetting angle, no steel infiltration and melting loss resistance, and can greatly improve the service life of the air brick, thereby reducing the replacement times of the air brick, improving the turnover rate of a steel ladle and the service life of a tank liner, and reducing the labor intensity of field workers and the pollution to the environment.

(10) The air brick of the invention can form uniformly distributed fine pores, the air permeability is more than 1.5 times of that of slit type and dispersion type air bricks, argon gas is diffused in molten steel through countless pores, the purification rate of the molten steel is obviously improved, and the content of oxygen and hydrogen in the molten steel is reduced; solves the problems that a small amount of straight coarse holes are caused by oxygen burning of the slag-removing iron, argon gas is concentrated and runs off on the liquid surface quickly through the molten steel, and the like, and obviously improves the purification rate of the molten steel.

(11) The air brick can avoid the steel leakage accident caused by the gaps generated by melting the iron sheet of the air brick at high temperature and the molten steel permeated through the air straight seams of the brick body, and improve the safety factor in the refining process.

(12) The invention uses forsterite sand, fused magnesia, corundum and the like as basic refractory raw materials to prepare the air brick, has the advantage of difficult chemical reaction with molten steel, selects a magnesia carbon material as a main material of the air brick for the ladle, and utilizes the high pressure and pressure uniformity during the molding of a hydraulic press to prepare the air brick with high density and high compressive strength, thereby solving the problems that the air brick has short service life, workers need to change the air brick for many times and the like, reducing the labor intensity of the workers, ensuring the continuous turnover of the ladle and saving the cost of refractory materials for steelmaking.

(13) The invention adopts solid forsterite sand, fused magnesia and corundum balls with different particle radiuses as main aggregates to manufacture the air brick, does not add any pore-forming agent, utilizes the close packing principle of forsterite sand, fused magnesia and corundum balls with different particle radiuses to form communicated dispersed air holes, and the spherical shape of the forsterite sand, the fused magnesia and the corundum is different from the granules formed by crushing common forsterite sand, the fused magnesia and the corundum, is almost close to a ball body and has the characteristics of high purity, high temperature resistance, high pressure resistance, good thermal shock stability and the like, so the air brick produced by adopting the raw materials can meet the technical problems to be solved by the invention.

(14) The air brick solves the problems that the strength of the product is low at medium and low temperatures, and the strength inflection point exists at the medium temperature; the volume of each temperature section of the product is unstable, and cracks are easy to generate in the using process; the using effect of the unburned product is poorer than that of the fired product, and the like.

(15) The air brick of the invention has the advantages of equivalent service performance to the fired product, reduced firing cost more than or equal to 1300 yuan/ton, shortened production cycle more than or equal to 5 days and the like.

(16) The air brick prepared by the invention is detected as follows: the breaking strength retention rate is 76.3-85.1%, the water cooling at 1100 ℃ is more than 47 times of thermal shock, and the service life is more than 35 times.

(II) control of technological parameters and components for preparing high-purity ultrahigh manganese steel

The simple process of the using process of the system for preparing the high-purity ultrahigh manganese steel is as follows:

knotting crucible, designing and manufacturing gas diffuser, connecting argon blowing system, preparing material, charging and smelting, adjusting chemical components, calming in furnace and controlling temperature to discharge molten steel.

The specific implementation method comprises the following steps:

(5) charging and smelting: the prepared materials are gradually put into a furnace for smelting, when furnace burden is melted to form a molten pool, namely, casting molten steel covers 30.6cm of the furnace bottom, a flow regulator is started to blow and inject argon, the argon participates in the casting molten steel smelting process through a gas permeable brick, the pressure and the flow of the blown argon are increased along with the increase of the casting molten steel along with the continuation of smelting, and the specific control process is as follows: controlling the pressure of argon blowing to be 6.2-6.4kg and the flow of argon to be 16-17L/min in the first 8-13 min; controlling the argon blowing pressure to be 6.5-6.7kg and the argon flow to be 17.1-17.3L/min in 14-20 min; controlling the argon blowing pressure to be 6.8-7kg and the argon flow to be 17.4-17.6L/min in 21-30 min; covering the surface of the molten steel with slagging materials in an amount of 0.91-0.98kg/t.s at the beginning of 31min, namely adding 0.91-0.98kg of slagging materials in each ton of molten steel; controlling the argon blowing pressure to be 6.3-6.5kg and the argon flow to be 17.2-17.4L/min within 31-52 min; until furnace burden is melted down, sampling and analyzing components in the furnace;

(8) controlling temperature and tapping: controlling the temperature, tapping and pouring to prepare the high-purity ultrahigh manganese steel, and adopting spectral analysis, wherein the high-purity ultrahigh manganese steel comprises the following components in percentage by mass: 0.75-1.76% of C, 22.0-30.0% of Mn, 0.1-0.8% of Si, 0.021-0.043% of P, 0.016-0.035% of S, 0.07-2.5% of Cr, 0.52-2.3% of Mo, 0.01-1.34% of Ni, 0.03-1.5% of Cu, 0.01-0.2% of Nb, 0.032-0.083% of Al, 0.0006-0.0010% of O, 0.00014-0.00042% of H, the balance of trace elements less than or equal to 0.82%, and the balance of Fe.

The high-purity ultrahigh manganese steel has the following component effects or influences:

c is a main element influencing the hardness and toughness of the alloy steel, the amount of carbide is large when the carbon content is high, the hardness of the alloy steel is high, but the toughness is reduced, and the alloy steel is easy to break in use; while low carbon content results in higher toughness, but the amount of carbides decreases, which reduces hardness and is detrimental to wear, and thus the carbon content needs to be strictly controlled.

The main function of Mn is to refine the metal matrix, but too high Mn content will cause austenite in the cast steel structure, which is not good for resisting impact wear, so the Mn content needs to be strictly controlled.

Si is a main element for improving the structure and morphology of carbide, and a high Si content contributes to the formation of a high hardness MC type eutectic carbide and the improvement of the morphology of carbide, but an excessively high Si content lowers the toughness, and therefore the Si content also needs to be strictly controlled.

P is a harmful element, increases the cold brittleness of steel, deteriorates the welding performance, reduces the plasticity, and deteriorates the cold bending performance, so that the reduction of the P content is beneficial to the improvement of the product quality.

S is a harmful element, so that the hot brittleness of the steel is generated, the ductility and the toughness of the steel are reduced, and cracks are caused during forging and rolling, so that the reduction of the S content is beneficial to improving the quality of products.

The Cr content is high, M3C7 type carbide is easy to form, and the wear resistance is improved, but the toughness of the cast steel is reduced due to the excessively high Cr content, and the production cost is excessively high, so the Cr content also needs to be strictly controlled.

The main functions of Mo are to refine the structure, improve the strength and toughness of the matrix and increase the hardenability of the steel, so that the Mo content needs to be strictly controlled.

Ni can improve the strength of steel, and keeps good plasticity and toughness, has higher corrosion resistance to acid and alkali, and has antirust and heat resistance at high temperature.

The prominent effect of Cu in steel is to improve the atmospheric corrosion resistance of common low alloy steel, and particularly when the Cu is used together with phosphorus, the Cu can also improve the strength and yield ratio of the steel without adverse effect on welding performance.

The deformation-induced precipitation of Nb in austenite and the precipitation of Nb in ferrite can play a certain role in precipitation strengthening. Therefore, Nb bonds with C, N atoms in the steel to form a Nb (cn) precipitate phase, thereby suppressing recrystallization and precipitation strengthening, and improving the strength.

Al can refine the grain structure of the steel, inhibit the aging of low-carbon steel, improve the toughness of the steel at low temperature, improve the oxidation resistance of the steel, improve the wear resistance and fatigue strength of the steel and the like.

O is one of the most serious elements that tends to segregate during the solidification of steel, and the solubility of O is rapidly decreased during the solidification and subsequent cooling of molten steel, and most of the O originally dissolved in steel is concentrated at γ or α grain boundaries in the form of fine inclusions such as iron oxides, sulfur oxides, and the like, which cause grain boundary embrittlement, thus easily becoming the starting point of grain boundary cracking during the processing and use of steel, and finally causing brittle fracture of steel.

The increase of the content of O in the steel can reduce the ductility, impact toughness and fatigue failure resistance of the steel, improve the ductile-brittle transition temperature of the steel and reduce the corrosion resistance of the steel. Further, a steel material containing high content of O is also susceptible to aging, and a low melting point film is formed by impurity segregation at grain boundaries during high temperature processing, resulting in hot embrittlement of the steel. Therefore, the reduction of the O content is beneficial to improving the quality of the product.

The H can also be diffused and separated out in the cooling process of the steel, and because the diffusion speed in the solid steel is very slow, only a small amount of H diffuses to the surface of a continuous casting billet (or steel ingot), and most of H molecules are formed by diffusing into microscopic pores, or the vicinity of inclusions, or pores on grain boundaries. Since H molecules are continuously accumulated at the precipitated place, KH value is small at low temperature, but pH2 is large, causing internal stress of steel. This internal stress, together with the sum of the structural, thermal, deformation stresses, etc., exceeds the strength limit of the steel and will crack and form cracks. Therefore, the H content is reduced, which is beneficial to improving the quality of the product.

By adopting the method for smelting, the chemical components of the cast steel liquid and the temperature of the cast steel liquid can be uniform, and the metallurgical quality of the cast steel liquid is improved.

The slagging material in the step (5) comprises the following raw materials in parts by weight: 25-53 parts of active white soil powder, 7-13 parts of talcum powder, 10-16 parts of palygorskite powder, 4-6 parts of montmorillonite powder, 32-64 parts of quicklime powder, 9-15 parts of fluorite powder, 5-8 parts of mineral wool and 1-2 parts of adhesive;

the quality indexes of the active kaolin powder raw materials are as follows: SiO 2₂：59.16-62.34％；Al₂O₃: 17.24-18.36%; MgO: 3.61-5.44%; CaO: 1.65-2.09%; the granularity is 800-1000 meshes;

the talcum powder comprises the following raw materials in percentage by mass: SiO 2₂: 58.34 to 62.01 percent; MgO: 27.52 to 31.36 percent; the granularity is 1200-1300 meshes;

the palygorskite powder comprises the following raw materials in percentage by mass: SiO 2₂: 52.68-56.96%; MgO: 23.83-27.19%; the granularity is 1000-1100 meshes;

the montmorillonite powder raw material has the following quality indexes: SiO 2₂：55.17-65.28％；Al₂O₃: 12.31 to 25.43 percent; the granularity is 800-1000 meshes;

the quality indexes of the quicklime powder raw materials are as follows: CaO: not less than 96.32%; the granularity is 600-800 meshes;

the quality indexes of the fluorite powder raw material are as follows: CaF₂: not less than 72.36%; the granularity is 600-800 meshes;

the adhesive is cassava starch; the granularity is 400-600 meshes;

the preparation process of the slagging material comprises the following steps:

(1) adding active white soil powder, talcum powder, palygorskite powder, montmorillonite powder, quicklime powder, fluorite powder, mineral wool and an adhesive into a stirrer according to parts by weight, adding 22-30 parts of water at the same time, and stirring at the rotating speed of 300-500r/min for 1-1.5h to prepare uniform slurry;

(2) adding the uniform slurry prepared in the step (1) into a mould, and preparing into particles with the particle size of 0.8-1.2cm after vacuum suction filtration molding;

(3) and (3) feeding the granules prepared in the step (2) into an oven, and drying for 8-10h at 82-93 ℃ to prepare the slagging material.

The technical principle and the effect of the slagging material are as follows:

(1) the active clay is prepared with clay as main material and through inorganic acidifying treatment, water rinsing and drying, and has high adsorption performance and is favorable to adsorbing oxygen, hydrogen and other impurities in molten steel. In addition, the activated clay begins to lose crystal water when heated to above 300 ℃, so that the structure is changed, and the activated clay has a lower melting point. (2) The talcum powder has excellent physical properties of flow aid, fire resistance, strong adsorption capacity and the like, and is favorable for adsorbing oxygen in molten steelHydrogen, and the like. Mainly contains magnesium oxide, silicon oxide and other impurities such as alumina, and has a melting point of about 800 ℃ and a lower melting point. (3) The palygorskite has large specific surface area and adsorption capacity, good rheological property and catalytic performance, ideal colloidal performance and heat resistance, is a good adsorption material, and is beneficial to adsorbing impurities such as oxygen, hydrogen and the like in molten steel. Also thermal insulation and expansion materials, thermal effect during heating: losing adsorbed water and zeolite water at 90-150 deg.C; 240 ℃ and 300 ℃, and crystal water is lost; the temperature is 450-520 ℃, lattice water is lost, the heat release effect is between 900-1000 ℃, and the material is low in melting point. (4) Montmorillonite is a 2:1 type crystal water-containing silicate mineral which is formed by two layers of silicon-oxygen tetrahedron sheets linked together at the top and sandwiching a layer of aluminum (magnesium) oxygen (oxyhydrogen) octahedron sheets linked together at the edges, is a good thermal expansion material, can be increased in volume after heating, has strong adsorption force and cation exchange performance, and is beneficial to adsorbing impurities such as oxygen, hydrogen and the like in molten steel. (5) The CaO component of the quicklime powder in the slagging material can control the alkalinity of the steel ladle slag and is an important component for realizing molten steel desulfurization and reducing the reoxidation pollution of the molten steel. Too high or too low a CaO content does not control the basicity of the slag-forming material well. (6) SiO of montmorillonite or the like in slag-forming material₂The composition is another important factor for controlling the alkalinity of the slag-forming material, SiO in the slag₂The content needs to be strictly controlled, and the control of the alkalinity of the slagging material and the adsorption effect of the slagging material on impurities are influenced by too high or too low content. (7) Al of activated clay in slag-forming material₂O₃The content is controlled mainly in order to make the slag-forming material have ideal adsorption capacity for inclusions in molten steel and to exert an important influence on physical properties such as fluidity of the slag-forming material. Too high Al₂O₃In such an amount that Al is contained₂O₃Enter molten steel to form new inclusion, deteriorate physical properties of slag-forming materials, and excessively low Al content₂O₃The content of Al is strictly controlled because the adsorption of the inclusions is weakened₂O₃And (4) content. (8) CaF of fluorspar powder in slagging material₂The method aims to improve the physical properties of the ladle slag, reduce the melting point and viscosity of the ladle slag, improve the fluidity of the ladle slag and facilitate the metallurgical reactionToo high CaF₂The content of the slag former can make the slag former too thin, influence the service life of the refractory material and be unfavorable for controlling the alkalinity of the slag former and the adsorption capacity of inclusions. (9) The MgO of the talcum powder in the slagging material protects the refractory material of the lining of the steel ladle, reduces the erosion of the steel ladle slag on the refractory materials of the steel ladle and an RH processing device, ensures that the viscosity of the slagging material is too large due to too high MgO content, is not beneficial to the metallurgical reaction, and cannot achieve the purpose of protecting the refractory material due to too low MgO content. (10) The slag-making material is added with expansive materials such as palygorskite, montmorillonite and the like and mineral wool, and is made into a light heat-insulating particle form which can be directly put on the surface of a molten steel slag layer, so that the slag-making material is beneficial to suspending on a liquid surface for continuous heat insulation, and the loss of the temperature of the surface layer of the molten steel is effectively reduced, thereby avoiding a ladle covering agent and effectively reducing the production cost; (11) the slag-making material contains active white earth powder, talcum powder, palygorskite powder, montmorillonite powder, quicklime powder and fluorite powder with low melting point and high activity, is favorable for removing impurities such as hydrogen, oxygen and the like in molten steel, reduces the content of harmful elements and impurities in the steel, achieves the slag-absorbing effect, greatly improves the quality of the molten steel, is favorable for preparing a high-purity wear-resistant material, and simultaneously reduces the consumption of the slag-making material and the cost. (12) The slagging material prepared from the active white clay powder, the talcum powder, the palygorskite powder, the montmorillonite powder, the quicklime powder and the fluorspar powder has the advantages of low melting point and high activity, and the addition amount of each ton of molten steel is only 0.82-0.95kg, so that the production cost is greatly reduced.

The following is a more specific example.

Research and development of air brick

Example 1

The air brick comprises the following raw materials in parts by weight: 32 parts of forsterite sand with the particle radius of 1.62-2.31mm, 12 parts of forsterite sand with the particle radius of 1.08-1.62mm, 20 parts of forsterite sand with the particle radius of 0.87-1.08mm, 11 parts of fused magnesia with the particle radius of 1.34-1.79mm, 6 parts of fused magnesia with the particle radius of 0.92-1.34mm, 12 parts of fused magnesia with the particle radius of 0.81-0.92mm, 12 parts of corundum with the particle radius of 1.56-2.08mm, 4 parts of corundum with the particle radius of 1.07-1.56mm, 5 parts of magnesium silicate cement, 3 parts of sodium silicate with the particle radius of 1.52-2.94nm, 5 parts of sodium permanganate, 0.2 part of an explosion-proof additive, 0.4 part of a water reducer, 0.4 part of polycarboxylic acid dispersion and 12 parts of water;

the three types of forsterite sand MgO with different particle radiuses: not less than 43.46%; SiO 2₂：36.92-39.27％；

The three types of fused magnesia MgO with different particle radiuses: more than or equal to 98.35 percent;

the two kinds of corundum Al with different particle radiuses₂O₃：≥97.61％；

The anti-explosion additive is anti-explosion fiber, polypropylene is used as a raw material, the titer is 10-17 deniers, and the length is 3.58-5.67 mm;

the preparation process of the air brick comprises the following steps:

s2, premixing: putting the raw materials prepared in the step S1 into a premixing device, and stirring for 25min at the rotating speed of 200r/min to prepare a premix;

s3, vibration molding: transferring the premix prepared in the step S2 into a mold, and molding under 100MPa by using a hydraulic press to prepare a green air brick;

s4, curing with a mold: placing the air brick green body prepared in the step S3 at 35 ℃, and maintaining for 8 hours with a mold;

s6, maintenance: placing the air brick blank prepared in the step S5 at 30 ℃ and curing for 30 h;

s7, baking: and (5) baking the air brick blank cured in the step (S6) at 400 ℃ for 5 days to obtain the finished air brick.

Example 2

The air brick comprises the following raw materials in parts by weight: 36 parts of forsterite sand with the particle radius of 1.62-2.06mm, 16 parts of forsterite sand with the particle radius of 1.08-1.62mm, 22 parts of forsterite sand with the particle radius of 0.94-1.08mm, 14 parts of fused magnesia with the particle radius of 1.34-1.76mm, 8 parts of fused magnesia with the particle radius of 0.92-1.34mm, 10 parts of fused magnesia with the particle radius of 0.81-0.92mm, 15 parts of corundum with the particle radius of 1.56-1.96mm, 6 parts of corundum with the particle radius of 1.35-1.56mm, 6 parts of magnesium silicate cement, 4 parts of sodium silicate with the particle radius of 1.23-3.07nm, 6 parts of sodium permanganate, 0.4 part of explosion-proof admixture, 0.6 part of water reducer, 0.6 part of polycarboxylic acid dispersion and 13 parts of water;

the three types of forsterite sand MgO with different particle radiuses: not less than 46.02%; SiO 2₂：36.92-39.04％；

The three types of fused magnesia MgO with different particle radiuses: more than or equal to 98.25 percent;

the two kinds of corundum Al with different particle radiuses₂O₃：≥97.68％；

The anti-explosion additive is anti-explosion fiber, polypropylene is used as a raw material, the titer is 12-16 deniers, and the length is 3.35-5.86 mm;

the preparation process of the air brick comprises the following steps:

s2, premixing: putting the raw materials prepared in the step S1 into a premixing device, and stirring for 23min at the rotating speed of 300r/min to prepare a premix;

s3, vibration molding: transferring the premix prepared in the step S2 into a mold, and molding under 120MPa by using a hydraulic press to prepare a green air brick;

s4, curing with a mold: placing the air brick green body prepared in the step S3 at 42 ℃, and maintaining for 6 hours with a mold;

s6, maintenance: placing the air brick blank prepared in the step S5 at 31 ℃ and curing for 26 h;

s7, baking: and (5) baking the air brick blank cured in the step (S6) at 460 ℃ for 4 days to obtain the finished air brick.

Example 3

The air brick comprises the following raw materials in parts by weight: 40 parts of forsterite sand with the particle radius of 1.62-1.98mm, 17 parts of forsterite sand with the particle radius of 1.08-1.62mm, 24 parts of forsterite sand with the particle radius of 0.92-1.08mm, 15 parts of fused magnesia with the particle radius of 1.34-1.76mm, 8 parts of fused magnesia with the particle radius of 0.92-1.34mm, 12 parts of fused magnesia with the particle radius of 0.79-0.92mm, 16 parts of corundum with the particle radius of 1.56-1.83mm, 7 parts of corundum with the particle radius of 1.57-1.56mm, 8 parts of magnesium silicate cement, 5 parts of sodium silicate with the particle radius of 1.76-3.02nm, 8 parts of sodium permanganate, 0.4 part of an anti-explosion additive, 0.9 part of a water reducer, 0.9 part of polycarboxylic acid dispersion and 15 parts of water;

the three types of forsterite sand MgO with different particle radiuses: not less than 45.01%; SiO 2₂：37.38-39.04％；

the two kinds of corundum Al with different particle radiuses₂O₃：≥98.01％；

The anti-explosion additive is anti-explosion fiber, polypropylene is used as a raw material, the titer is 12-18 deniers, and the length is 3.71-5.63 mm;

the preparation process of the air brick comprises the following steps:

s2, premixing: putting the raw materials prepared in the step S1 into a premixing device, and stirring for 20min at the rotating speed of 300r/min to prepare a premix;

s3, vibration molding: transferring the premix prepared in the step S2 into a mold, and molding under 110MPa by using a hydraulic press to prepare a green air brick;

s4, curing with a mold: placing the air brick green body prepared in the step S3 at 42 ℃, and maintaining for 8 hours with a mold;

s6, maintenance: placing the air brick blank prepared in the step S5 at 32 ℃ and curing for 20 h;

s7, baking: and (5) baking the air brick blank cured in the step (S6) at 500 ℃ for 3 days to obtain the finished air brick.

Comparative example 1

The process is basically the same as that of the air brick preparation process in example 2, except that 36 parts of forsterite sand with the particle radius of 1.62-2.06mm, 16 parts of forsterite sand with the particle radius of 1.08-1.62mm, 22 parts of forsterite sand with the particle radius of 0.94-1.08mm, 14 parts of fused magnesia with the particle radius of 1.34-1.76mm, 8 parts of fused magnesia with the particle radius of 0.92-1.34mm, 10 parts of fused magnesia with the particle radius of 0.81-0.92mm, 15 parts of corundum with the particle radius of 1.56-1.96mm and 6 parts of corundum with the particle radius of 1.35-1.56mm are absent in the raw materials for preparing the air brick.

Comparative example 2

The process for manufacturing the air brick is substantially the same as that of example 2, except that 36 parts of forsterite sand with a particle radius of 1.62-2.06mm, 16 parts of forsterite sand with a particle radius of 1.08-1.62mm and 22 parts of forsterite sand with a particle radius of 0.94-1.08mm are absent in the raw materials for manufacturing the air brick.

Comparative example 3

The process for preparing the air brick is basically the same as that of the process for preparing the air brick in the example 2, except that 14 parts of fused magnesia with the particle radius of 1.34-1.76mm, 8 parts of fused magnesia with the particle radius of 0.92-1.34mm and 10 parts of fused magnesia with the particle radius of 0.81-0.92mm are absent in the raw materials for preparing the air brick.

Comparative example 4

The process for preparing the air brick is basically the same as that of the air brick prepared in the example 2, except that 15 parts of corundum with the particle radius of 1.56-1.96mm and 6 parts of corundum with the particle radius of 1.35-1.56mm are absent in the raw materials for preparing the air brick.

Comparative example 5

The process for preparing the air brick was substantially the same as that of example 2 except that 4 parts of sodium silicate having a particle radius of 1.23 to 3.07nm was absent from the raw material for preparing the air brick.

Comparative example 6

The process for making the air brick was substantially the same as that of example 2, except that the air brick was made with sodium permanganate in the absence of the starting material.

Comparative example 7

The air brick is prepared by adopting the method of the example 4 of Chinese application patent document 'air brick for magnesia carbon ladle and production method thereof (application number: 200710012906.5)', and concretely comprises the following steps: uniformly mixing 70% of fused magnesia, 14% of flake graphite, 8% of sintered tabular corundum, 4% of partially stabilized zirconia, 3% of antioxidant metal Al powder, 1% of antioxidant CaB6 powder and 0.5% of antioxidant B4C powder, adding 5% of liquid thermosetting phenolic resin as a bonding agent, and mulling for 40 minutes until all materials are uniform, namely pug; installing the plastic strip into the mold according to the air hole arrangement form; adding the kneaded pug into a mold, and molding under 200MPa by using isostatic pressing equipment; heat treatment at 200 deg.C for 24 hr; turning the blank according to the size of the drawing by using a lathe, and assembling according to the assembly process of the air brick after turning and drying to obtain the air brick product.

Wherein the fused magnesia is 96-98% of MgO, and the granularity is less than 5 mm;

wherein the sintered tabular corundum is Al₂O₃99.5-99.8% of particle size<2mm；

Wherein the partially stabilized zirconia is CaO stabilized ZrO₂93-95% of particle size<0.088mm；

Wherein the crystalline flake graphite is C96-98%, and the granularity is less than 0.15 mm;

wherein the bonding agent is thermosetting phenolic resin which is liquid at normal temperature, and the carbon residue rate is 45-48%.

The mechanical properties and thermal shock resistance of the air brick prepared in examples 1-3 and the air bricks prepared in comparative examples 1-7 were tested, and the specific test methods were as follows:

1. mechanical properties: detecting the normal-temperature compressive strength of the test piece after heat treatment at 110 ℃ for 24h and 1550 ℃ for 3h according to YB/T5201;

2. thermal shock resistance: keeping the temperature of the sample at 1100 ℃ for 20min, performing air cooling for 15min, repeating the steps for 3 times, measuring the residual breaking strength of the sample, and calculating the breaking strength retention rate after thermal shock; the thermal shock resistance of the material is evaluated by the retention rate of the breaking strength after thermal shock (strength retention rate ═ breaking strength after thermal shock/breaking strength before thermal shock x 100%);

the air bricks prepared in examples 1-3 and the air brick of comparative example 5 were tested for air permeability and slag corrosion resistance by the following specific test methods:

1. air permeability: detecting the apparent porosity of the test piece after heat treatment at 110 ℃ for 24h and 1550 ℃ for 3h according to YB/T5200;

2. slag erosion resistance: respectively putting the samples into 1# -10# crucibles, then putting the LF furnace final slag with the granularity of less than 0.5mm into the 1# -10# crucibles, wherein the slag loading of each crucible is 120g, heating the crucibles in an electric furnace to 1600 ℃, preserving the temperature for 4h, naturally cooling the crucibles to room temperature, then taking out the samples, symmetrically cutting the samples into two halves, and measuring the erosion depth; the smaller the value, the better the slag corrosion resistance.

The above test results are shown in the following table:

from the above table, it can be seen that: (1) as can be seen from the data of examples 1-3 and comparative example 7, the mechanical properties, thermal shock resistance, air permeability and slag corrosion resistance of the air bricks of examples 1-3 are all superior to those of the prior art; meanwhile, as can be seen from the data of examples 1 to 3, example 2 is the most preferred example.

(2) As can be seen from the data of the example 2 and the comparative examples 1 to 4, the spherical forsterite sand, the fused magnesia and the corundum with different particle radii play a synergistic effect in preparing the air brick, and the compressive strength and the breaking strength retention rate of the air brick are synergistically improved, namely: the forsterite sand is an alkaline refractory material, has the advantages of high temperature resistance, erosion resistance, good chemical stability, high compressive strength, breaking strength retention rate and the like, has high refractoriness (1710 ℃) and metal oxidation erosion resistance, slowly expands at high temperature, is smaller than deformation, has no characteristic of sudden expansion, has good thermal shock resistance, and is not easy to produce main sand inclusion defects of castings. The fused magnesia is an alkaline refractory material and has the advantages of compact structure, strong slag resistance, good thermal shock stability, high compressive strength and breaking strength retention rate and the like. The corundum is an alkaline refractory material and has the advantages of good volume stability, extremely small re-burning shrinkage, good thermal shock stability, compressive strength and breaking strength retention rate and the like. Solid forsterite sand, fused magnesia and corundum balls with different particle radiuses are used as main aggregates to manufacture the air brick, no pore-forming agent is added, the forsterite sand, the fused magnesia and the corundum balls with different particle radiuses are tightly stacked to form communicated dispersed air holes, the spherical shapes of the forsterite sand, the fused magnesia and the corundum are different from those of particles formed by crushing common forsterite sand, the fused magnesia and the corundum and almost approach to the balls, and the compressive strength and the breaking strength retention rate of the air brick are synergistically improved by utilizing the synergistic effect of the spherical forsterite sand, the fused magnesia and the corundum with different particle radiuses in preparing the air brick.

(3) As can be seen from the data of example 2 and comparative example 5, the lack of nano-sized sodium silicate as a raw material for preparing the air brick affects the improvement of compressive strength and flexural strength retention, which are: after the nano sodium silicate is introduced into the air brick, micro pores which are uniformly distributed are formed in the air brick, so that the continuous diffusion of cracks in the using process can be effectively prevented, the compressive strength and the breaking strength retention rate are improved, the toughness of the air brick is improved, the peeling is reduced, and the purpose of prolonging the service life is achieved.

(4) As can be seen from the data of example 2 and comparative example 6, the lack of sodium permanganate as a raw material for making the air brick affects the increase of apparent porosity, which is: the sodium permanganate is added during the preparation of the air brick, and can be decomposed during baking in the brick making process, gas is generated in a blank system, and the blank is rich in pores, so that the air permeability of the product is further improved, and the apparent porosity is improved.

Research and development of slagging material

Example 4

The slagging material comprises the following raw materials in parts by weight: 42 parts of active white soil powder, 10 parts of talcum powder, 12 parts of palygorskite powder, 5 parts of montmorillonite powder, 55 parts of quicklime powder, 13 parts of fluorite powder, 7 parts of mineral wool and 1.6 parts of adhesive;

the quality indexes of the active kaolin powder raw materials are as follows: SiO 2₂：60.52％；Al₂O₃: 17.94 percent; MgO: 4.85 percent; CaO: 1.79 percent; the granularity is 1000 meshes;

the talcum powder comprises the following raw materials in percentage by mass: SiO 2₂: 59.67 percent; MgO: 29.05 percent; the granularity is 1300 meshes;

the palygorskite powder comprises the following raw materials in percentage by mass: SiO 2₂: 55.78 percent; MgO: 25.61 percent; the granularity is 1100 meshes;

the montmorillonite powder raw material has the following quality indexes: SiO 2₂：63.74％；Al₂O₃: 24.61 percent; the granularity is 1000 meshes;

the quality indexes of the quicklime powder raw materials are as follows: CaO: 96.5 percent; the granularity is 800 meshes;

the quality indexes of the fluorite powder raw material are as follows: CaF₂: 72.91 percent; the granularity is 800 meshes;

the adhesive is cassava starch; the granularity is 600 meshes;

the preparation process of the slagging material comprises the following steps:

(1) adding active white soil powder, talcum powder, palygorskite powder, montmorillonite powder, quicklime powder, fluorite powder, mineral wool and an adhesive into a stirrer according to parts by weight, adding 28 parts of water simultaneously, and stirring at the rotating speed of 500r/min for 1h to prepare uniform slurry;

(2) adding the uniform slurry prepared in the step (1) into a mould, and preparing particles with the particle size of 1.1cm after vacuum suction filtration molding;

(3) and (3) feeding the granules prepared in the step (2) into an oven, and drying for 9 hours at the temperature of 92 ℃ to prepare the slagging material.

The product is detected physically: the melting point is 1362 ℃.

The slag forming material obtained in example 4 was actually used for steel making. The amount used was 0.82kg per ton of steel. According to the observation: the product has good auxiliary extensibility, can be directly reacted with the residues to reduce the melting point and viscosity of the residues, and the temperature measuring gun can easily and quickly measure the temperature of the molten steel through the residue layer; meanwhile, after the slagging material is used, the average temperature drop of steel in each furnace is reduced by 3.4 ℃ compared with the original steel ladle singly covered with a heat preservation agent; improves the slag fluidity, reduces the links of slag skimming and removes the slag adhered to the ladle wall. It can be seen that the slag-forming material prepared in example 4 has a low melting point and a high activity.

Example 5

The slagging material comprises the following raw materials in parts by weight: 27 parts of active white soil powder, 7 parts of talcum powder, 10 parts of palygorskite powder, 4 parts of montmorillonite powder, 34 parts of quicklime powder, 9 parts of fluorite powder, 7 parts of mineral wool and 1 part of adhesive;

the quality indexes of the active kaolin powder raw materials are as follows: SiO 2₂：59.16％；Al₂O₃: 18.36 percent; MgO: 5.44 percent; CaO: 2.09%; the granularity is 800 meshes;

the talcum powder comprises the following raw materials in percentage by mass: SiO 2₂: 62.01 percent; MgO: 27.52 percent; the granularity is 1200 meshes;

the palygorskite powder comprises the following raw materials in percentage by mass: SiO 2₂: 52.68 percent; MgO: 27.19 percent; the granularity is 1000 meshes;

the montmorillonite powder raw material has the following quality indexes: SiO 2₂：65.28％；Al₂O₃: 12.31 percent; the granularity is 1000 meshes;

the quality indexes of the quicklime powder raw materials are as follows: CaO: 96.32 percent; the granularity is 600 meshes;

the quality indexes of the fluorite powder raw material are as follows: CaF₂: 72.36 percent; the granularity is 600 meshes;

the adhesive is cassava starch; the granularity is 500 meshes;

the preparation process of the slagging material comprises the following steps:

(1) adding active white soil powder, talcum powder, palygorskite powder, montmorillonite powder, quicklime powder, fluorite powder, mineral wool and an adhesive into a stirrer according to parts by weight, adding 23 parts of water at the same time, and stirring at the rotating speed of 300r/min for 1.5 hours to prepare uniform slurry;

(2) adding the uniform slurry prepared in the step (1) into a mould, and preparing into particles with the particle size of 0.8cm after vacuum suction filtration molding;

(3) and (3) feeding the granules prepared in the step (2) into an oven, and drying for 10 hours at 82 ℃ to prepare the slagging material.

The product is detected physically: the melting point is 1397 ℃.

The slag forming material obtained in example 5 was actually used for steel making. The amount used was 0.95kg per ton of steel. According to the observation: the product has good auxiliary extensibility, can be directly reacted with the residues to reduce the melting point and viscosity of the residues, and the temperature measuring gun can easily and quickly measure the temperature of the molten steel through the residue layer; meanwhile, after the slagging material is used, the average temperature drop of steel in each furnace is reduced by 4.6 ℃ compared with the original steel ladle singly covered with a heat preservation agent; improves the slag fluidity, reduces the links of slag skimming and removes the slag adhered to the ladle wall. It can be seen that the slag-forming material prepared in example 5 has a low melting point and a high activity.

Example 6

The slagging material comprises the following raw materials in parts by weight: 50 parts of active white soil powder, 12 parts of talcum powder, 16 parts of palygorskite powder, 6 parts of montmorillonite powder, 64 parts of quicklime powder, 15 parts of fluorite powder, 8 parts of mineral wool and 2 parts of adhesive;

the quality indexes of the active kaolin powder raw materials are as follows: SiO 2₂：62.34％；Al₂O₃: 17.24 percent; MgO: 3.61 percent; CaO: 1.65 percent; the granularity is 1000 meshes;

the talcum powder comprises the following raw materials in percentage by mass: SiO 2₂: 58.34 percent; MgO: 31.36 percent; the granularity is 1200 meshes;

the palygorskite powder comprises the following raw materials in percentage by mass: SiO 2₂: 53.47 percent; MgO: 23.98 percent; the granularity is 1100 meshes;

the quality indexes of the quicklime powder raw materials are as follows: CaO: 97.26 percent; the granularity is 700 meshes;

the quality indexes of the fluorite powder raw material are as follows: CaF₂: 78.15 percent; the granularity is 800 meshes;

the adhesive is cassava starch; the granularity is 400 meshes;

the preparation process of the slagging material comprises the following steps:

(1) adding active white soil powder, talcum powder, palygorskite powder, montmorillonite powder, quicklime powder, fluorite powder, mineral wool and an adhesive into a stirrer according to parts by weight, adding 27 parts of water simultaneously, and stirring at the rotating speed of 500r/min for 1 to prepare uniform slurry;

(2) adding the uniform slurry prepared in the step (1) into a mould, and preparing particles with the particle size of 1.2cm after vacuum suction filtration molding;

(3) and (3) feeding the granules prepared in the step (2) into an oven, and drying for 8 hours at 93 ℃ to prepare the slagging material.

The product is detected physically: the melting point was 1381 ℃.

The slag forming material obtained in example 6 was actually used for steel making. The amount used was 0.86kg per ton of steel. According to the observation: the product has good auxiliary extensibility, can be directly reacted with the residues to reduce the melting point and viscosity of the residues, and the temperature measuring gun can easily and quickly measure the temperature of the molten steel through the residue layer; meanwhile, after the slagging material is used, the average temperature drop of steel in each furnace is reduced by 4.1 ℃ compared with the original steel ladle singly covered with a heat preservation agent; improves the slag fluidity, reduces the links of slag skimming and removes the slag adhered to the ladle wall. It can be seen that the slag-forming material prepared in example 6 has a low melting point and a high activity.

(III) design and preparation of high-purity ultrahigh manganese steel system and research on technological parameters and components for preparing high-purity ultrahigh manganese steel

Example 7

The air inlet pipe 7 is a pressure-resistant rubber pipe.

The inner diameter of the pressure-resistant rubber tube is 0.3 cm.

The furnace body protection contact 9 is made of non-magnetic steel material.

The furnace body protection contact 9 is provided with 6.

The air brick is prepared by adopting the process of the optimal embodiment 2, and specifically comprises the following steps: the air brick comprises the following raw materials in parts by weight: 36 parts of forsterite sand with the particle radius of 1.62-2.06mm, 16 parts of forsterite sand with the particle radius of 1.08-1.62mm, 22 parts of forsterite sand with the particle radius of 0.94-1.08mm, 14 parts of fused magnesia with the particle radius of 1.34-1.76mm, 8 parts of fused magnesia with the particle radius of 0.92-1.34mm, 10 parts of fused magnesia with the particle radius of 0.81-0.92mm, 15 parts of corundum with the particle radius of 1.56-1.96mm, 6 parts of corundum with the particle radius of 1.35-1.56mm, 6 parts of magnesium silicate cement, 4 parts of sodium silicate with the particle radius of 1.23-3.07nm, 6 parts of sodium permanganate, 0.4 part of explosion-proof admixture, 0.6 part of water reducer, 0.6 part of polycarboxylic acid dispersion and 13 parts of water;

the preparation process of the air brick comprises the following steps:

The specific implementation method comprises the following steps:

(4) preparing materials: weighing various materials for smelting the cast molten steel according to the chemical composition requirements of the cast molten steel, wherein the materials comprise: scrap steel, high-carbon ferromanganese, electrolytic manganese, micro-carbon ferrochromium, ferromolybdenum, ferronickel and copper for later use;

(5) charging and smelting: the prepared materials are gradually put into a furnace for smelting, when furnace burden is melted to form a molten pool, namely, casting molten steel covers 30.6cm of the furnace bottom, a flow regulator is started to blow and inject argon, the argon participates in the casting molten steel smelting process through a gas permeable brick, the pressure and the flow of the blown argon are increased along with the increase of the casting molten steel along with the continuation of smelting, and the specific control process is as follows: controlling the pressure of argon blowing to be 6.2-6.4kg and the flow of argon to be 16-17L/min in the first 8-13 min; controlling the argon blowing pressure to be 6.5-6.7kg and the argon flow to be 17.1-17.3L/min in 14-20 min; controlling the argon blowing pressure to be 6.8-7kg and the argon flow to be 17.4-17.6L/min in 21-30 min; covering the surface of the molten steel with 0.95kg/t.s of slagging material at the beginning of 31min, namely adding 0.95kg of slagging material into each ton of molten steel; controlling the argon blowing pressure to be 6.3-6.5kg and the argon flow to be 17.2-17.4L/min within 31-52 min; until furnace burden is melted down, sampling and analyzing components in the furnace;

(8) controlling temperature and tapping: controlling the temperature, tapping and pouring to prepare the high-purity ultrahigh manganese steel, and adopting spectral analysis, wherein the high-purity ultrahigh manganese steel comprises the following components in percentage by mass: 1.46% of C, 28.64% of Mn, 0.72% of Si, 0.036% of P, 0.028% of S, 2.19% of Cr, 1.57% of Mo, 0.91% of Ni, 1.02% of Cu, 0.12% of Nb, 0.058% of Al, 0.0006% of O, 0.00026% of H, the balance being 0.61% of trace elements and the balance being Fe.

The slagging material in the step (5) is prepared by adopting the process of the optimal embodiment 4, and the process comprises the following specific steps: the slagging material comprises the following raw materials in parts by weight: 42 parts of active white soil powder, 10 parts of talcum powder, 12 parts of palygorskite powder, 5 parts of montmorillonite powder, 55 parts of quicklime powder, 13 parts of fluorite powder, 7 parts of mineral wool and 1.6 parts of adhesive;

the adhesive is cassava starch; the granularity is 600 meshes;

the preparation process of the slagging material comprises the following steps:

Comparative example 8

The process is basically the same as that for preparing the high-purity ultrahigh manganese steel in example 7, except that the air brick is different from that used in the process of comparative example 7.

Comparative example 9

The process is basically the same as that of the process for preparing the high-purity ultrahigh manganese steel in the example 7, except that the adopted slagging material is different, and the slagging material is prepared by the method in the example 3 of 'a pre-melted slag for refining ultralow-aluminum steel, a preparation method and a using method (application number: 201310668245.7)' in Chinese patent document.

Comparative example 10

The process for preparing the high-purity ultrahigh manganese steel is basically the same as that of the process for preparing the high-purity ultrahigh manganese steel in the example 7, except that argon blowing for impurity removal is not carried out in the charging smelting in the step (5).

The comprehensive mechanical properties and the oxygen and hydrogen contents of the high manganese steels produced in example 7 and comparative examples 8 to 10 were measured, and the results were as follows:

note: the tensile strength, the yield strength, the elongation and the impact energy are detected by using relevant regulations of GB/T5680-2010; the oxygen and hydrogen contents are detected by spectral analysis.

From the above table, it can be seen that: (1) as can be seen from the data of example 7 and comparative example 8, the use of the air brick is different, which may affect the comprehensive mechanical properties and oxygen and hydrogen contents of the high manganese steel, and the air brick is prepared by the process of comparative example 7, and the obtained air brick has too low apparent porosity, which results in insufficient argon blowing, reduces the comprehensive mechanical properties of the high manganese steel and increases the oxygen and hydrogen contents.

(2) As can be seen from the data of example 7 and comparative example 9, the use of different slag-forming materials will affect the comprehensive mechanical properties and the oxygen and hydrogen contents of the high manganese steel, which may be caused by the fact that the slag-forming materials used contain components with good oxygen-removing effect and the hydrogen-removing components are too little.

(3) As can be seen from the data of example 7 and comparative example 10, the comprehensive mechanical properties and the oxygen and hydrogen contents of the high manganese steel are affected without blowing argon gas to remove impurities in the charging and smelting processes, which are as follows:

argon is an inert gas, is insoluble in molten steel, does not react with elements in the steel to form inclusions, and does not pollute the molten steel; argon is blown into molten steel through the air brick, argon bubbles are fine and fully and uniformly dispersed through the air brick, when the argon passes through the molten steel, dissolved H, O and the like in the molten steel can be automatically diffused, enter into the argon bubble and are removed from the molten steel along with the rising of the bubbles, non-metallic inclusions are adhered to inert gas, and the combination of the non-metallic inclusions floats to the surface of the molten steel and then is adhered to a slag-making material, so that the molten steel is purified, the oxygen and hydrogen content is reduced, and the comprehensive mechanical property of the high manganese steel is improved.

Claims

1. The high-purity ultrahigh manganese steel is characterized by comprising the following components in percentage by mass: 0.75-1.76% of C, 22.0-30.0% of Mn, 0.1-0.8% of Si, 0.021-0.043% of P, 0.016-0.035% of S, 0.07-2.5% of Cr, 0.52-2.3% of Mo, 0.01-1.34% of Ni, 0.03-1.5% of Cu, 0.01-0.2% of Nb, 0.032-0.083% of Al, 0.0006-0.0010% of O, 0.00014-0.00042% of H, the balance of trace elements less than or equal to 0.82%, and the balance of Fe;

the preparation process of the high-purity ultrahigh manganese steel comprises the following steps:

2. The high-purity ultrahigh manganese steel according to claim 1, characterized by comprising the following components in percentage by mass: 1.46% of C, 28.64% of Mn, 0.72% of Si, 0.036% of P, 0.028% of S, 2.19% of Cr, 1.57% of Mo, 0.91% of Ni, 1.02% of Cu, 0.12% of Nb, 0.058% of Al, 0.0006% of O, 0.00026% of H, the balance being 0.61% of trace elements and the balance being Fe.

3. A process for preparing a high purity ultra high manganese steel according to claim 1 or 2, comprising the steps of:

the talcum powder comprises the following raw materials in percentage by mass: SiO 2₂: 58.34 to 62.01 percent; MgO: 27.52 to 31.36 percent; granuleThe degree is 1200 and 1300 meshes;