A process for preventing sticking of steel

Abstract

The application provides a kind of anti-sticking steel process method, belongs to steel smelting technical field, comprising the following steps: pretreatment billet, oil dirt, impurity and oxide skin are removed;Calcium oxide, magnesium oxide and modifier are mixed according to preset weight percentage, to obtain composite dry powder, the modifier is selected from at least one of zirconium oxide powder, silicon nitride powder;According to the heating temperature of billet and in stove time, the risk level of billet sticking is determined, then the mixing ratio of composite dry powder and clean water is determined according to the risk level, to obtain anti-sticking steel suspension liquid;After pretreatment, billet is put into anti-sticking steel suspension liquid for soaking treatment, to form anti-sticking isolation layer on the surface of billet;The coverage thickness and uniformity of anti-sticking isolation layer on the surface of billet are detected, if it is unqualified, then billet is soaked again;Billet with qualified anti-sticking isolation layer is pushed into heating furnace.The anti-sticking steel process method provided by the application solves the problem that adjacent billets are prone to sticking in heating furnace.

Description

Technical Field

[0001] This invention belongs to the field of iron and steel smelting technology, and more specifically, relates to a process method for preventing steel from sticking. Background Technology

[0002] With the continuous growth in market demand for high-carbon steel wire rod, its application in machinery manufacturing, automotive industry, and construction machinery is becoming increasingly widespread. The carbon content of high-carbon steel is typically between 0.60% and 1.05%. Due to the segregation characteristics of carbon, steel billets are prone to defects such as dendritic crystals and central porosity during continuous casting. Therefore, they must undergo prolonged high-temperature heating (usually 1100℃-1300℃, holding time 3-8 hours) before rolling to improve compositional uniformity and enhance the material's mechanical properties through atomic diffusion. Currently, pusher-type heating furnaces are the mainstream heating equipment for steel wire rod production due to their simple structure, low investment cost, and high furnace bottom area utilization.

[0003] The working principle of a steel heating furnace is that a steel billet is pushed into the furnace chamber sequentially by a pusher. The billet moves along the bottom rail inside the furnace, passing through three stages: preheating, heating, and soaking, until it reaches the temperature required for rolling. However, in a high-temperature environment, a violent oxidation reaction occurs on the surface of the billet, generating a multi-layered iron oxide scale composed of FeO, Fe2O3, and Fe3O4. FeO has a melting point of only 1377℃, begins to soften above 1100℃, and approaches a molten state above 1250℃. When adjacent billets come into close contact under pushing pressure (typically 0.5MPa-1.2MPa), the softened iron oxide scale acts as a bonding medium, causing the metal atoms on the billet surface to diffuse and adhere, forming a strong metallurgical bond—the phenomenon known as "steel adhesion."

[0004] "Steel sticking" incidents prevent steel billets from being tapped normally, requiring machine shutdown for cleaning, severely impacting the continuity of subsequent rolling processes and causing steel billet losses. Furthermore, during the forced separation process, the sticky steel billets develop defects such as cracks and scratches on their surface. These defects cannot be completely eliminated in subsequent rolling, leading to a decrease in the pass rate of finished wire rods, and in severe cases, even causing the entire batch of products to be scrapped. Summary of the Invention

[0005] The purpose of this invention is to provide a process method for preventing steel from sticking together, which aims to solve the problem of adjacent steel billets easily sticking together in a heating furnace.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a method for preventing sticking to steel, comprising:

[0007] S1. Pre-treat the steel billet to remove oil, impurities, and oxide scale from the surface of the steel billet to be treated;

[0008] S2. Prepare a composite anti-sticking material by mixing calcium oxide, magnesium oxide and a modifier according to a preset weight percentage to obtain a composite dry powder. The modifier is selected from at least one of zirconium oxide micro powder and silicon nitride micro powder.

[0009] S3. Determine the sticking risk level of the billet based on the heating temperature and furnace time of the billet, and then determine the mixing ratio of composite dry powder and water according to the risk level. Stir evenly to obtain anti-sticking steel suspension.

[0010] S4. Immerse the pretreated steel billet in an anti-sticking steel suspension to form an anti-sticking isolation layer on the surface of the steel billet.

[0011] S5. Check the thickness and uniformity of the anti-sticking isolation layer on the surface of the steel billet. If it is not up to standard, return to step S4 and soak the steel billet again.

[0012] S6. Push the steel billet with a qualified anti-sticking isolation layer into the heating furnace.

[0013] In one possible implementation, step S1 specifically includes:

[0014] S11. Sandblasting for 1-2 minutes removes oxide scale from the surface of the steel billet;

[0015] S12. Use ultrasonic cleaning for 3-5 minutes to remove oil stains from the surface of the steel billet;

[0016] S13. Dry the steel billet with hot air at 60℃-85℃ for 5min-8min.

[0017] In one possible implementation, in step S2, the composite dry powder has the following weight percentage composition: calcium oxide 42%-52%, magnesium oxide 32%-42%, zirconium oxide micro powder 4%-9%, and silicon nitride micro powder 2%-7%.

[0018] In one possible implementation, step S3 specifically includes:

[0019] If the heating temperature of the steel billet is ≥1250℃ and the furnace time is ≥5h, the adhesion risk level of the steel billet is determined to be high risk, and the corresponding mixing ratio of composite dry powder and water is 1:1.5-1:1.7.

[0020] If the billet heating temperature is >1250℃ and the furnace time is 1h-3h, or the heating temperature is 1180℃-1250℃ and the furnace time is 3h-5h, the billet adhesion risk level is determined to be medium to high risk, and the corresponding mixing ratio of composite dry powder and water is 1:1.6-1:1.8.

[0021] If the heating temperature of the steel billet is 1130-1180℃ and the furnace time is 1h-3h, the adhesion risk level of the steel billet is determined to be low to medium risk, and the corresponding mixing ratio of composite dry powder and water is 1:1.9-1:2.1.

[0022] If the steel billet contains alloying elements, for every 1% increase in alloying elements, the mixing ratio of the composite dry powder and water should be adjusted to a higher concentration by 0.05-0.1 units.

[0023] In one possible implementation, in step S4, after soaking 5-8 groups of steel billets, the solid content of the anti-sticking steel suspension is detected, and composite dry powder is added and stirred evenly according to the detection results to maintain the solid content at 35%-45%.

[0024] In one possible implementation, in step S4, when there are multiple steel billets being soaked in groups, the soaking process includes:

[0025] S41. Immerse the billet group in the anti-sticking steel suspension for 2-3 seconds and then immediately lift it out.

[0026] S42. Immerse the billet group again in the anti-sticking steel suspension and let it stand for 12-20 seconds.

[0027] S43. Stir the anti-sticking steel suspension for 6-8 seconds, then lift the billet group.

[0028] In one possible implementation, in step S4, after the steel billet has been soaked, it is also necessary to allow it to stand and solidify.

[0029] In one possible implementation, the settling time for the billet static curing process is determined based on the ambient humidity, specifically including:

[0030] When the ambient humidity is ≤55%, the standing time is 10s-18s;

[0031] When the ambient humidity is 55%-75%, the settling time is 15s-25s;

[0032] When the ambient humidity is ≥75%, the standing time is 20s-30s, and compressed air is used to blow the surface of the steel billet at a wind speed of 0.5m / s-1m / s throughout the process.

[0033] In one possible implementation, before proceeding to step S6, compressed air is used to purge the anti-sticking isolation layer on the surface of the billet to remove excess suspended droplets accumulated on the surface of the anti-sticking isolation layer.

[0034] One possible implementation also includes:

[0035] S7. Collect the mixed sinter produced after heating the steel billet, separate the oxide scale and anti-sticking material residue in the mixed sinter, treat the anti-sticking material residue and replenish the components, and use it again as a raw material for composite dry powder.

[0036] The beneficial effects of the anti-sticking steel process provided by this invention are as follows: Compared with the prior art, the anti-sticking steel process of this invention improves the adhesion of the anti-sticking isolation layer through billet pretreatment, accurately proportions high-temperature resistant composite anti-sticking materials, dynamically adjusts the concentration of the suspension according to the adhesion risk level, optimizes the soaking and curing process according to the environmental humidity, and combines it with slag removal and closed-loop control of isolation layer detection. This can form a dense and stable anti-sticking isolation layer on the surface of the billet, effectively blocking the contact between adjacent billets and avoiding steel sticking from the root cause. At the same time, the recycling and regeneration design of the anti-sticking material residue realizes the resource utilization of solid waste, reduces material costs, and the overall process not only ensures production continuity and reduces billet loss, but also improves the stability of finished product quality, significantly improving the production efficiency and economic benefits of high-carbon steel rolling. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a flowchart of an anti-sticking steel process provided in an embodiment of the present invention. Detailed Implementation

[0039] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0040] Please see Figure 1 The present invention will now describe a method for preventing steel sticking. This method involves applying an anti-stick coating to the surface of a steel billet to form an anti-stick isolation layer, isolating adjacent steel billets and thus preventing them from sticking together during heating. The method specifically includes the following steps:

[0041] S1. Pre-treat the steel billet to remove oil, impurities, and oxide scale from the surface of the steel billet to be treated.

[0042] The core objective of billet pretreatment is to remove surface oil, impurities, and oxide scale, creating a micro-roughened surface structure to improve the adhesion between the anti-sticking layer and the billet substrate. The pretreatment effect directly determines the stability of the anti-sticking layer; if the treatment is incomplete, the layer is prone to detachment during transport or heating, leading to anti-sticking failure. This step specifically includes three sub-steps: sandblasting, ultrasonic cleaning, and hot air drying.

[0043] S11: Sandblasting

[0044] A pressure-driven sandblasting system is used, powered by compressed air at 0.3MPa-0.5MPa, to drive silica sand to impact and clean the surface of the steel billet. The silica sand particle size is selected as 0.8mm-1.2mm, which effectively removes oxide scale while avoiding excessive damage to the steel billet surface. The sandblasting time is controlled between 1min and 2min. For steel billets with thicker oxide scale (≥0.8mm), the upper limit of 2min is used; for steel billets with thinner oxide scale (<0.8mm), the lower limit of 1min is used.

[0045] After sandblasting, a micro-rough structure with Ra=1.8μm-3.2μm is formed on the surface of the steel billet. This structure enhances the adhesion of the anti-stick coating through a "mechanical interlocking" effect. Experiments have verified that within this roughness range, the adhesion of the isolation layer is increased by 40%-60% compared to a smooth surface, and the detachment rate during the steel pushing process is ≤0.5%. To ensure sandblasting uniformity, the sandblasting equipment adopts a symmetrical arrangement of dual nozzles, with the distance between the nozzles and the steel billet surface controlled at 150mm-200mm and the moving speed at 0.5m / s-0.8m / s. Simultaneously, the steel billet rotates at a speed of 30r / min to avoid sandblasting dead zones.

[0046] S12: Ultrasonic Cleaning

[0047] The surface of the steel billet after sandblasting retains quartz sand dust and oil stains (mainly rust-preventive oil and lubricating oil, containing mineral oil and additives), which need to be thoroughly removed by ultrasonic cleaning. A 40kHz, 500W ultrasonic cleaning device is used, and a neutral cleaning agent (pH 7.0-8.0, mainly composed of nonionic surfactants and complexing agents) is injected into the cleaning tank. The cleaning agent temperature is controlled at 40℃-50℃, which enhances the activity of the cleaning agent and strengthens the decontamination effect.

[0048] Ultrasonic cleaning time is 3-5 minutes, especially for surfaces with high oil content (oil adhesion ≥ 5g / m²). 2 For steel billets with low oil content (surface oil adhesion < 5g / m), the cleaning time should be 3-5 minutes; for billets with low oil content (surface oil adhesion < 5g / m), the cleaning time should be 3-5 minutes. 2For steel billets, the cleaning time is 3 minutes. The principle of ultrasonic cleaning is to generate cavitation through high-frequency vibration, forming microbubbles on the billet surface. The impact force generated when these bubbles burst can peel off oil and dust from the surface. Simultaneously, the complexing agent can combine with metal ions on the billet surface to prevent secondary oxidation. After cleaning, the residual oil on the billet surface is ≤0.5g / m³. 2 Dust residue ≤0.1g / m³ 2 This satisfies the adhesion requirements of subsequent anti-stick coatings.

[0049] S13: Hot air drying

[0050] The surface of the cleaned steel billet contains moisture. If it is not dried in time, the moisture will affect the film-forming quality of the anti-stick coating, leading to defects such as bubbles and cracks in the isolation layer. A continuous hot air drying tunnel is used, with the hot air temperature controlled at 60℃-85℃, the air velocity at 1m / s-1.5m / s, and the drying time at 5min-8min. The temperature-time matching relationship is as follows: when the temperature is 60℃-70℃, the drying time is 6min-8min; when the temperature is 70℃-85℃, the drying time is 5min-6min.

[0051] Hot air is generated by electric heating and filtered through a high-efficiency filter to prevent dust from adhering to the surface of the steel billet. During the drying process, the steel billet moves at a uniform speed (0.3 m / s) via a conveyor belt to ensure uniform heating of all areas of the surface. After drying, the moisture content of the steel billet surface is ≤0.1%, providing clean and dry surface conditions for the adhesion of the anti-stick coating.

[0052] S2. Prepare a composite anti-sticking material by mixing calcium oxide, magnesium oxide and a modifier according to a preset weight percentage to obtain a composite dry powder. The modifier is selected from at least one of zirconium oxide micro powder and silicon nitride micro powder.

[0053] The design and optimization of the composition and ratio of composite anti-stick materials are key to ensuring their anti-stick effect, requiring consideration of high temperature resistance, density, adhesion, and cost-effectiveness. This invention uses calcium oxide and magnesium oxide as base components, and zirconium oxide micro powder and silicon nitride micro powder as modifiers.

[0054] Calcium oxide provides a core insulating layer. At high temperatures, calcium oxide reacts with trace amounts of moisture on the surface of the steel billet to form calcium hydroxide, which is then further sintered to form a dense CaO-Ca(OH)2 composite sintered shell. This sintered shell effectively blocks the diffusion of metal atoms from adjacent steel billet surfaces and inhibits the penetration of oxygen into the billet, reducing decarburization. Furthermore, calcium oxide is chemically stable and does not react chemically with the steel billet matrix or iron oxide scale, thus preventing the formation of metallurgical bonds.

[0055] Magnesium oxide (MgO) exhibits excellent high-temperature stability and thermal shock resistance. The synergistic effect of MgO and calcium oxide can improve the pulverization problem of calcium oxide when used alone. Calcium oxide readily absorbs moisture from the air, forming Ca(OH)₂, which then decomposes into CaCO₃, leading to a loose and flaking isolation layer. The addition of MgO forms a CaO-MgO solid solution, reducing the hygroscopic activity of calcium oxide and improving the structural stability of the isolation layer. Simultaneously, MgO reduces the brittleness of the isolation layer and enhances its impact resistance, making it suitable for mechanical collisions during billet transport (such as contact impacts during pushing and vibrations during conveyor belt transport).

[0056] Zirconia micro powder possesses extremely high high-temperature strength and resistance to sintering. At extreme temperatures above 1250℃, zirconia micro powder can fill the tiny voids between calcium oxide and magnesium oxide particles, forming a dense "skeleton structure" that inhibits the shrinkage and deformation of the insulating layer at high temperatures, thus extending its service life. Furthermore, the coefficient of thermal expansion of zirconia is close to that of the steel billet matrix, which can reduce cracking of the insulating layer caused by differences in thermal expansion during heating.

[0057] Silicon nitride micropowder exhibits a fibrous microstructure, resulting in excellent mechanical properties and high-temperature stability. It can interweave between calcium oxide, magnesium oxide, and zirconium oxide particles, forming a network-like support structure that further enhances the density and adhesion of the insulating layer. Simultaneously, silicon nitride's high hardness (Mohs hardness 9.5) improves the wear resistance of the insulating layer, preventing damage caused by friction during steel pushing.

[0058] In applications, the composition ratio of composite anti-stick materials directly determines their high-temperature stability, isolation effect, and adhesion performance. If the calcium oxide ratio is too high, it is prone to absorbing moisture and turning into powder at high temperatures; if the magnesium oxide ratio is too high, the isolation layer becomes more brittle and is prone to falling off during transport; if the modifier (zirconia, silicon nitride) ratio is insufficient, the reinforcing effect cannot be achieved; if the ratio is too high, it leads to increased material costs and poorer flowability.

[0059] In this invention, the composite dry powder has the following weight percentage composition: calcium oxide 42%-52%, magnesium oxide 32%-42%, zirconium oxide micro powder 4%-9%, and silicon nitride micro powder 2%-7%.

[0060] When the calcium oxide content is less than 42%, the density of the isolation layer is insufficient, which cannot effectively block the diffusion of metal atoms and reduces the anti-sticking effect; when the content is higher than 52%, the brittleness of the isolation layer increases, the thermal shock stability deteriorates, and it is prone to cracking and falling off during heating.

[0061] When the magnesium oxide content is less than 32%, it cannot effectively inhibit the pulverization of calcium oxide, resulting in insufficient long-term stability of the isolation layer; when the content is higher than 42%, the adhesion of the isolation layer decreases, and the material cost increases significantly (the price of magnesium oxide is about 2.5 times that of calcium oxide).

[0062] When the proportion of zirconia micro powder is less than 4%, the high-temperature anti-sintering effect is not obvious, and the isolation layer is prone to shrinkage and deformation above 1250℃; when the proportion is higher than 9%, the material fluidity becomes poor, it is difficult to mix with water to form a uniform suspension, and the cost increases significantly (the price of zirconia micro powder is about 15 times that of calcium oxide).

[0063] When the proportion of silicon nitride micro powder is less than 2%, the network support structure of the isolation layer is incomplete, and the density and wear resistance are insufficient; when the proportion is higher than 7%, it is easy to cause the viscosity of the suspension to increase, making it difficult to form a uniform coating on the surface of the steel billet during the soaking process.

[0064] The composite dry powder was prepared using a mechanical mixing method, and the specific steps are as follows:

[0065] Raw material pretreatment: Calcium oxide and magnesium oxide are pulverized to a particle size ≤100μm, and zirconium oxide micro powder and silicon nitride micro powder are pulverized to a particle size ≤50μm. Then they are dried at 120℃ for 2h to remove free moisture and avoid clumping during the mixing process.

[0066] Graded mixing: First, put calcium oxide and magnesium oxide into a twin-helix mixer and mix at 300 r / min for 15 min to ensure uniform distribution of the basic components; then add zirconium oxide micro powder and silicon nitride micro powder and continue mixing at 400 r / min for 20 min to form composite dry powder.

[0067] Screening and testing: The mixed composite dry powder is screened through a 150-mesh sieve to ensure uniform particle size; the content of each component is detected by X-ray fluorescence spectrometry, and unqualified products are returned for remixing.

[0068] S3. Determine the sticking risk level of the billet based on its heating temperature and furnace time, and then determine the mixing ratio of composite dry powder and water according to the risk level. Stir evenly to obtain an anti-sticking steel suspension.

[0069] The concentration of the anti-sticking steel suspension directly affects the thickness and density of the anti-sticking isolation layer. It needs to be dynamically adjusted according to the adhesion risk level of the steel billet, while also considering the influence of alloying elements to ensure that the isolation layer is precisely matched with the working conditions.

[0070] In this step, the rule for determining the risk level of billet adhesion is as follows:

[0071] High risk: Heating temperature ≥1250℃, furnace time ≥5h. Under these conditions, the softening degree of FeO in the iron oxide scale reaches over 90%, approaching the molten state. The metal atoms on the steel billet surface have strong diffusion ability, and the probability of adhesion is extremely high (≥80%).

[0072] Medium to high risk: Heating temperature > 1250℃, furnace time 1h-3h; or heating temperature 1180℃-1250℃, furnace time 3h-5h. Under these conditions, FeO softening degree is 60%-90%, metal atom diffusion ability is strong, and adhesion probability is 40%-80%.

[0073] Low to medium risk: Heating temperature 1130℃-1180℃, furnace time 1h-3h. Under these conditions, FeO softening degree is 30%-60%, metal atom diffusion ability is weak, and adhesion probability is 10%-40%.

[0074] Based on the adhesion risk level, the mixing ratio (by mass) of the composite dry powder and water is determined as follows:

[0075] When the billet adhesion risk level is high, the mixing ratio of composite dry powder and water is 1:1.5-1:1.7. At this time, the solid content of the suspension is relatively high (44%-47%), which can form a dense isolation layer with a thickness of 0.22mm-0.3mm, effectively resisting the effects of high temperature and long-term heating.

[0076] When the risk level of billet adhesion is medium to high, the mixing ratio of composite dry powder and water is 1:1.6-1:1.8. At this time, the solid content of the suspension is 39%-44%, and the thickness of the isolation layer is 0.18mm-0.22mm, which takes into account both the anti-adhesion effect and the material economy.

[0077] When the billet adhesion risk level is low to medium, the mixing ratio of composite dry powder and water is 1:1.9-1:2.1. At this time, the solid content of the suspension is 35%-39%, and the thickness of the isolation layer is 0.12mm-0.18mm to avoid material waste and reduced heating uniformity caused by excessively thick isolation layers.

[0078] Furthermore, when steel billets contain alloying elements (such as Cr, Mn, Si, etc.), these elements react with oxygen to form alloy oxides, lowering the melting point of iron oxide scale (mainly FeO) and intensifying the softening and melting process. For example, for every 1% increase in Cr content in the steel billet, the melting point of FeO decreases by approximately 30°C; for every 1% increase in Mn content, the melting point of FeO decreases by approximately 20°C. Therefore, the suspension concentration needs to be adjusted according to the alloying element content: for every 1% increase in alloying element (single or multiple alloying elements combined), the mixing ratio of composite dry powder to water should be adjusted towards a higher concentration by 0.05-0.1 units. For example, under medium-to-high risk conditions, the original mixing ratio is 1:1.8; if the alloying element content in the steel billet increases by 2%, it should be adjusted to 1:1.6-1:1.7.

[0079] S4. Immerse the pretreated steel billet in an anti-sticking steel suspension to form an anti-sticking isolation layer on the surface of the steel billet.

[0080] In applications, to improve operational efficiency, multiple steel billets are often soaked in groups (usually 3-5 billets per group, adjusted according to billet specifications). When steel billets are soaked in groups, the soaking process includes the following steps:

[0081] S41: Preliminary wetting. The billet assembly is quickly immersed in the anti-sticking steel suspension using a hoisting device, and immediately lifted after 2-3 seconds of immersion. The purpose of this step is to break the air film on the billet surface, allowing the suspension to quickly cover the billet surface, laying the foundation for subsequent full adhesion.

[0082] S42: Static Adsorption. Immerse the billet group again in the suspension and let it stand for 12-20 seconds. During this process, the suspension fully adheres to the surface of the billet under the action of gravity and molecular adsorption, and gradually penetrates into the gaps between adjacent billets (the gap width is usually 5mm-10mm), ensuring that an effective isolation layer is formed within the gaps as well. The standing time is adjusted according to the surface roughness of the billet: when the roughness Ra = 2.8μm-3.2μm, take 12-15 seconds; when Ra = 1.8μm-2.8μm, take 15-20 seconds.

[0083] S43: Agitation Assistance. Start the agitator and gently agitate the suspension for 6-8 seconds, then lift the billet assembly. Agitation promotes the flow of the suspension within the gaps between the billets, preventing uneven concentration caused by static suspension and ensuring a uniform isolation layer thickness. The agitation direction alternates between clockwise and counterclockwise, switching every 2 seconds to prevent localized eddies that could lead to suspension sedimentation.

[0084] During step S4, after soaking 5-8 groups of steel billets, the solid content of the anti-sticking steel suspension is tested. Based on the test results, composite dry powder is added and re-stirred evenly to maintain the solid content at 35%-45%. The specific procedure is as follows:

[0085] After soaking 5-8 groups of steel billets, the solid content was determined by gravimetric method. 100 mL of the suspension was placed in a pre-weighed weighing bottle and dried in a 105℃ drying oven for 2 hours until constant weight was reached. The solid content was then calculated (solid content = mass of solids after drying / total mass of suspension × 100%).

[0086] When the solid content is below 35%, it should be calculated according to "per 1m 3 Suspension replenished with 0.08 ml 3 -0.12m 3 The calculation of the supplementary amount for the "compound dry powder" ratio (0.01 mg / ml for every 1% decrease in solid content). 3 -0.012m 3 / m 3 (Compound dry powder), ensuring that the solid content is restored to the target range of 35%-45% after replenishment;

[0087] After adding the composite dry powder, start the stirring device and stir for 5-8 minutes to ensure that the composite dry powder and suspension are evenly mixed without precipitation or excessively high local concentration.

[0088] The above measures have enabled closed-loop control of the concentration of the anti-sticking steel suspension, reduced the sticking rate differences between different batches of steel billets, and completely solved the problem of unstable anti-sticking effect caused by concentration fluctuations.

[0089] After the steel billet has been soaked, it is transported to a static area for static curing to ensure the stability of the anti-sticking layer.

[0090] In practice, ambient humidity significantly affects the curing process of the anti-sticking steel suspension: In low humidity environments (≤55%), the suspension evaporates quickly, easily curing to form a uniform isolation layer, but prolonged curing can lead to cracking; in medium humidity environments (55%-75%), the evaporation rate is moderate, requiring a longer settling time to ensure sufficient curing; in high humidity environments (≥75%), evaporation is slow, causing the suspension to flow easily, resulting in uneven isolation layer thickness, and even localized areas without any anti-sticking suspension. Therefore, in this step, the settling time for the billet curing process is determined based on the ambient humidity, as follows:

[0091] When the ambient humidity is ≤55%, the water evaporates quickly. The standing time should be controlled between 10s and 18s to allow the anti-stick steel suspension to solidify quickly and form a uniform anti-stick isolation layer, thus avoiding cracks caused by excessive time.

[0092] When the ambient humidity is 55%-75%, the water evaporation rate is moderate, and the standing time is extended to 15s-25s to ensure that the anti-stick steel suspension is fully cured, improve the adhesion of the anti-stick isolation layer, and prevent it from falling off during subsequent transportation.

[0093] When the ambient humidity is ≥75%, the water evaporates slowly, so the standing time is extended to 20s-30s. Compressed air is used throughout the process to blow the surface of the billet at a wind speed of 0.5m / s-1m / s. The blowing direction is parallel to the axis of the billet to accelerate the evaporation of surface moisture, prevent the anti-sticking steel suspension from flowing, and ensure that the thickness of the anti-sticking isolation layer is uniform.

[0094] S5. Check the thickness and uniformity of the anti-sticking isolation layer on the surface of the steel billet. If it is not up to standard, return to step S4 and soak the steel billet again.

[0095] In this step, an infrared detection device is used to perform a full-coverage scan of the anti-sticking isolation layer on the surface of the steel billet. The thickness threshold of the anti-sticking isolation layer is set at 0.12mm-0.3mm (which can be dynamically adjusted according to the risk level; 0.22mm-0.3mm for high risk and 0.12mm-0.18mm for low-to-medium risk), and the uniformity error threshold is ≤±0.04mm. The infrared detection device automatically identifies the thickness distribution and uniformity of the anti-sticking isolation layer on the surface of the steel billet through image analysis technology and generates a detection report. If there are areas where the thickness is below the threshold or the uniformity exceeds the standard, the infrared detection device automatically issues an alarm signal and feeds back to the control system, returning the steel billet to step S4 for re-soaking. If the detection is qualified, the process proceeds to the next step.

[0096] S6. Push the steel billet with a qualified anti-sticking isolation layer into the heating furnace.

[0097] After the steel billet is soaked, excess suspended droplets may remain on its surface. These droplets, upon solidification, will form locally raised slag deposits. When the steel billet is heated in the furnace, these slag deposits will harden into lumps due to high-temperature sintering, affecting the uniformity of heating. Therefore, before proceeding to step S6, compressed air is needed to purge the anti-sticking isolation layer on the surface of the steel billet to remove excess suspended droplets accumulated on the surface of the anti-sticking isolation layer. The specific operation process is as follows:

[0098] A ring-shaped purging device (arranged around the circumference of the billet with nozzles spaced 50mm apart) is used to ensure that there are no dead corners on the billet surface. The compressed air is clean and oil-free, with a purging pressure of 0.2MPa-0.3MPa (this pressure can effectively remove excess suspended droplets on the surface without damaging the solidified isolation layer), and a purging time of 3s-5s. The purging effect is then detected by a visual sensor to ensure that the removal rate of excess droplets on the surface is ≥99% and there is no obvious residue.

[0099] After the steel billet is heated, a layer of mixed sintered material adheres to its surface. This mixed sintered material is a mixture of oxide scale (containing iron oxides) and anti-sticking material residue. The oxide scale can be recycled as a steelmaking raw material, achieving full resource utilization of solid waste and reducing solid waste emissions. The anti-sticking material residue can also be recycled and regenerated. Based on this, the method provided by the present invention further includes the following steps:

[0100] S7. A three-stage filtration device is used to collect the mixed sintered material removed by high-pressure water descaling of steel billets, and the moisture is removed to obtain solid filter residue. The solid filter residue is sent to a magnetic separator, and the magnetic field strength is set to 1.2T-1.5T. The oxide scale (magnetic phase) is adsorbed and separated, and the anti-sticking material residue (non-magnetic phase) is used as the recycling base material. The anti-sticking material residue is sent to a box dryer and dried at 100℃-120℃ for 15min-20min to remove free moisture. The dried residue is pulverized to a particle size ≤50μm using an air jet mill to ensure that the particle size of the recycled base powder is consistent with that of the newly prepared composite dry powder. The content of calcium oxide, magnesium oxide, zirconium oxide and silicon nitride in the recycled base powder is detected by X-ray fluorescence spectrometry. According to the composition ratio of the composite dry powder, the missing components (such as zirconium oxide micro powder and silicon nitride micro powder) are added to obtain the regenerated composite dry powder.

[0101] This invention provides an anti-sticking steel process that, compared with existing technologies, enhances the adhesion of the anti-sticking isolation layer through billet pretreatment, precisely proportions high-temperature resistant composite anti-sticking materials, dynamically adjusts the suspension concentration according to the adhesion risk level, optimizes the soaking and curing processes to suit environmental humidity, and combines slag removal and closed-loop control of isolation layer detection. This process forms a dense and stable anti-sticking isolation layer on the billet surface, effectively preventing contact between adjacent billets and avoiding steel sticking at its source. Simultaneously, the recycling and regeneration design of the anti-sticking material residue enables the utilization of solid waste resources, reducing material costs. The overall process ensures production continuity, reduces billet loss, and improves the stability of finished product quality, significantly improving the production efficiency and economic benefits of high-carbon steel rolling.

[0102] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for preventing sticking of steel, characterized by, Includes the following steps: S1. Pre-treat the steel billet to remove oil, impurities, and oxide scale from the surface of the steel billet to be treated; S2. Prepare a composite anti-sticking material by mixing calcium oxide, magnesium oxide and a modifier according to a preset weight percentage to obtain a composite dry powder. The modifier is selected from at least one of zirconium oxide micro powder and silicon nitride micro powder. The weight percentage composition of the composite dry powder is: calcium oxide 42%-52%, magnesium oxide 32%-42%, zirconium oxide micro powder 4%-9%, and silicon nitride micro powder 2%-7%. The calcium oxide reacts with the moisture on the surface of the steel billet to generate calcium hydroxide, which is sintered to form a dense CaO-Ca(OH)2 composite sintered shell. S3. Determine the sticking risk level of the billet based on the heating temperature and furnace time of the billet, and then determine the mixing ratio of composite dry powder and water according to the risk level. Stir evenly to obtain anti-sticking steel suspension. S4. Immerse the pretreated steel billet in an anti-sticking steel suspension to form an anti-sticking isolation layer on the surface of the steel billet. After the steel billet is immersed, it needs to be allowed to stand and solidify. S5. Check the thickness and uniformity of the anti-sticking isolation layer on the surface of the steel billet. If it is not up to standard, return to step S4 and soak the steel billet again. S6. Use compressed air to blow away the anti-sticking isolation layer on the surface of the billet to remove excess suspended droplets accumulated on the surface of the anti-sticking isolation layer, and push the billet with a qualified anti-sticking isolation layer into the heating furnace.

2. A process for preventing sticking of steel as claimed in claim 1 wherein, Step S1 specifically includes: S11. Sandblasting for 1-2 minutes removes oxide scale from the surface of the steel billet; S12. Use ultrasonic cleaning for 3-5 minutes to remove oil stains from the surface of the steel billet; S13. Dry the steel billet with hot air at 60℃-85℃ for 5min-8min.

3. A process for preventing sticking of steel as claimed in claim 1 wherein, Step S3 specifically includes: If the heating temperature of the steel billet is ≥1250℃ and the furnace time is ≥5h, the adhesion risk level of the steel billet is determined to be high risk, and the corresponding mixing ratio of composite dry powder and water is 1:1.5-1:1.

7. If the billet heating temperature is >1250℃ and the furnace time is 1h-3h, or the heating temperature is 1180℃-1250℃ and the furnace time is 3h-5h, the billet adhesion risk level is determined to be medium to high risk, and the corresponding mixing ratio of composite dry powder and water is 1:1.6-1:1.

8. If the heating temperature of the steel billet is 1130-1180℃ and the furnace time is 1h-3h, the adhesion risk level of the steel billet is determined to be low to medium risk, and the corresponding mixing ratio of composite dry powder and water is 1:1.9-1:2.

1. If the steel billet contains alloying elements, for every 1% increase in alloying elements, the mixing ratio of the composite dry powder and water should be adjusted to a higher concentration by 0.05-0.1 units.

4. The anti-sticking steel process method as described in claim 1, characterized in that, In step S4, after soaking 5-8 groups of steel billets, the solid content of the anti-sticking steel suspension is tested. Based on the test results, composite dry powder is added and stirred again to maintain the solid content at 35%-45%.

5. The anti-sticking steel process method as described in claim 1, characterized in that, In step S4, when there are multiple steel billets being soaked in groups, the soaking process includes: S41. Immerse the billet group in the anti-sticking steel suspension for 2-3 seconds and then immediately lift it out. S42. Immerse the billet group again in the anti-sticking steel suspension and let it stand for 12-20 seconds. S43. Stir the anti-sticking steel suspension for 6-8 seconds, then lift the billet group.

6. The anti-sticking steel process method as described in claim 1, characterized in that, The settling time for the steel billet static curing treatment is determined based on the ambient humidity, and specifically includes: When the ambient humidity is ≤55%, the standing time is 10s-18s; When the ambient humidity is 55%-75%, the settling time is 15s-25s; When the ambient humidity is ≥75%, the standing time is 20s-30s, and compressed air is used to blow the surface of the steel billet at a wind speed of 0.5m / s-1m / s throughout the process.

7. The anti-sticking steel process method as described in claim 1, characterized in that, Also includes: S7. Collect the mixed sinter produced after heating the steel billet, separate the oxide scale and anti-sticking material residue in the mixed sinter, treat the anti-sticking material residue and replenish the components, and use it again as a raw material for composite dry powder.

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