Oriented steel fiber reinforced refractory material as well as preparation method and application thereof

Abstract

The invention discloses an oriented steel fiber reinforced refractory material as well as a preparation method and application thereof, and belongs to the technical field of refractory materials. The preparation method of the oriented steel fiber reinforced refractory material comprises the following steps: enabling refractory material mixed slurry containing a first component and a second component to flow downwards along a charging barrel of an extrusion type 3D printing device and to be extruded out of a nozzle, and performing extrusion 3D printing molding to obtain the oriented steel fiber reinforced refractory material, wherein the first component comprises refractory material aggregate, silica powder, steel fibers and a curing agent, the second component comprises a binder, a plasticizer and a water reducing agent, the viscosity of the refractory material mixed slurry is 15000-30000 mPa.s under the shear rate of 0.4 S <-1 >, the viscosity of the refractory material mixed slurry is 3500-5500 mPa.s under the shear rate of 30.59 S <-1 >, and the thixotropic ring area is not less than 120 Pa / s. The method not only can be used for forming complex structures, especially special-shaped steel fiber reinforced refractory materials, but also can effectively improve the orientation distribution of steel fibers in the refractory materials, so that the toughening effect of the refractory materials is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of refractory materials, and in particular relates to an oriented steel fiber reinforced refractory material and a preparation method and application thereof. Background Art

[0002] Due to the introduction of steel fibers, steel fiber reinforced refractory materials have excellent fracture toughness, mechanical properties and thermal shock stability, and are widely used in key parts of high-temperature industries (such as steel, cement, etc.) where furnaces are severely worn and in harsh service environments. Generally, the load and working conditions of steel fiber reinforced refractory materials are relatively fixed during use, and the main force directions of refractory materials are basically the same. However, the steel fibers are randomly distributed in the material (the theoretical analysis value of the steel fiber orientation factor is 0.405), and only a few are oriented in the load or stress direction, resulting in the steel fibers in the material The reinforcement and toughening effect cannot be fully exerted, affecting the performance of steel fiber reinforced refractory materials.

[0003] In response to the above problems, the applicant has conducted relevant research and achieved certain research results (Minghui Li, Peilin Li, Gang Qi, Saisai Li*, Ruoyu Chen*, Siwei Lv, Yi Ding, and Canhua Li. Enhancing mechanical properties and thermal shock resistance of steel fiber reinforced mullite castable through magnetic field treatment [J]. Construction and Building Materials, 2024, (432): 136668.). The document discloses a method for orienting steel fibers in refractory castables using an external magnetic field, and achieves excellent performance, wherein the steel fiber orientation factor can reach 0.96. Compared with traditional steel fiber reinforced refractory materials, the room temperature flexural strength, ultimate bending toughness, fracture energy and high temperature flexural strength of the oriented steel fiber reinforced refractory materials are increased by 6.57%, 56.73%, 26.24% and 18.62% respectively. In addition, its thermal shock resistance has also been significantly improved, greatly improving the comprehensive performance of the material.

[0004] At the same time, although no other relevant literature on steel fiber orientation has been retrieved in the field of refractory materials, there are patents disclosed on steel fiber orientation in the field of concrete. For example, Chinese patent CN114368055A discloses a device for preparing planar oriented steel fiber concrete. This application realizes magnetically controlled planar oriented steel fibers through the combination of rotating magnetic field and repulsive magnetic field, and prepares planar oriented steel fiber concrete, so that the direction of steel fibers is parallel to the planar two-dimensional stress direction and is distributed, and the steel fiber reinforcement effect is greatly improved, thereby improving the mechanical properties of concrete.

[0005] Although the above-mentioned literature has obtained oriented steel fiber reinforced refractory materials or concrete with excellent performance through an external magnetic field, the implementation process of the above-mentioned steel fiber magnetic induction orientation method is complicated, and it is necessary to arrange coils outside the mold or rely on the assistance of external strong magnets, and the preparation conditions are demanding. In order to avoid interference with the magnetic field strength, metal molds cannot be used. These technical and operational limitations work together to result in the fact that the magnetic induction orientation of steel fibers has not yet been applied in actual industry, especially for special-shaped parts with complex structures and different orientation requirements for steel fibers in actual industrial production, which is even more inconvenient to implement. Summary of the invention

[0006] The purpose of the present invention is to provide an oriented steel fiber reinforced refractory material and a preparation method and application thereof, so as to solve the problem that it is difficult to prepare an oriented steel fiber reinforced refractory material with excellent performance in the prior art, or the preparation process is complicated, the implementation conditions are harsh, and it is difficult to promote and apply it industrially. The steel fiber reinforced refractory material prepared by the present invention not only has the advantages of high mechanical strength and high fracture toughness, but also has a simple and easy to implement preparation process, which is particularly convenient for preparing special-shaped components.

[0007] In order to achieve the above object, the technical solution provided by the present invention is:

[0008] The first aspect of the present invention provides a method for preparing an oriented steel fiber reinforced refractory material, comprising:

[0009] The refractory material mixed slurry including the first component and the second component is made to flow downward along the barrel of the extrusion 3D printing device and be extruded from the nozzle, and the oriented steel fiber reinforced refractory material is obtained by extrusion 3D printing;

[0010] The first component comprises refractory aggregate, silicon powder, steel fiber and curing agent, the second component comprises binder, plasticizer and water reducer, and the refractory mixed slurry is subjected to a shear rate of 0.4S -1 The viscosity is 15000~30000mPa·s at a shear rate of 30.59S -1The viscosity is 3500-5500 mPa·s, and the thixotropic ring area is not less than 120 Pa / s.

[0011] In view of the technical problem that it is difficult to prepare oriented steel fiber reinforced refractory materials with excellent performance in the prior art, the present invention adopts extrusion 3D printing molding technology and optimizes the components of the refractory mixed slurry, wherein the first component is mainly used as the refractory base material, and the second component is used as an external additive, which is mainly used to regulate the rheological properties of the base material slurry. Therefore, it can not only be used to mold complex structures, especially special-shaped steel fiber reinforced refractory materials, but also can effectively improve the orientation distribution of steel fibers in the refractory materials, thereby ensuring its toughening effect.

[0012] It should be noted that the inventor's research group has been engaged in the research of oriented steel fiber reinforced refractory materials, and has improved the orientation distribution of steel fibers in refractory castables through the action of an external magnetic field. However, on the one hand, the above-mentioned technical operation is relatively complicated and not convenient for industrial promotion and application; on the other hand, under the action of magnetic induction, the steel fibers undergo a large orientation deflection, resulting in gaps in the refractory material, which has an adverse effect on the material properties.

[0013] Based on the above situation, specifically, the present invention utilizes extrusion 3D printing technology to load a refractory material slurry mixed with steel fibers into a barrel. On the one hand, the flow rate difference of each component in the slurry (friction of the barrel side wall) causes the steel fiber to rotate, thereby causing the axial direction of the steel fiber to be parallel to the extrusion direction or to be at a certain small inclination angle; on the other hand, the closer the barrel is to the nozzle, the smaller the diameter is. Therefore, during the extrusion molding process, the barrel side wall provides additional resistance to the steel fiber, ensuring the effectiveness of the steel fiber orientation, so that the directional distribution of the steel fiber is basically consistent during extrusion, overcoming the influence of the gaps generated after the steel fiber is significantly deflected during the magnetic induction orientation process on the material properties.

[0014] In addition, the present application further optimizes the rheological properties of the refractory mixed slurry, thereby improving the rheological properties of the slurry on the basis of meeting the performance requirements of the refractory material itself and the 3D printing molding requirements, so that the refractory material in other positions can effectively fill the gaps generated after the steel fibers are deflected, thereby ensuring the performance of the final product.

[0015] According to any technical solution described in the first aspect of the present invention, the binder comprises at least one of dextrin, corn starch, and sodium carboxymethyl cellulose (CMC), and / or the plasticizer comprises bentonite, and / or the water reducer comprises sodium hexametaphosphate or polycarboxylate; and / or the curing agent comprises calcium aluminate cement.

[0016] As a further preferred embodiment, the binder is sodium carboxymethyl cellulose, the plasticizer is bentonite, and / or the water reducer is polycarboxylate FS20. Through the additional addition and joint action of the three additives, especially the compounding of sodium carboxymethyl cellulose and bentonite, the rheological properties of the refractory mixed slurry can be effectively improved, which not only ensures that the material has extrudability and continuous construction ability during the 3D printing process, but also maintains excellent interlayer bonding strength; in addition, it can also effectively prevent the generation of voids inside the material after the steel fiber is deflected.

[0017] Specifically, the addition of CMC adjusts the rheological properties of the matrix slurry, enhances the shear thinning behavior and thixotropy, and increases the yield stress. The excellent thixotropy can quickly restore the material to its original state after extrusion molding, which is conducive to maintaining structural stability. Bentonite, as a plasticizer, improves the thixotropic properties of the slurry and its plasticity through the gel-like substance formed by its water absorption and expansion, further enhances the structural stability of the 3D printing material, and optimizes the printability. Under the joint action of CMC and bentonite, the prepared refractory material has extrudability and good structural stability during the 3D printing process, and can effectively fill the voids generated inside the material after the steel fiber is deflected.

[0018] At the same time, the present invention adds part of silicon micropowder to the base material. On the one hand, since the particle size of silicon micropowder particles is small, the specific surface area and surface energy are relatively high, the spacing between the powder particles in the matrix slurry decreases with the increase of the amount of silicon micropowder added, thereby improving the interaction between the particles, further adjusting the rheological properties of the slurry, and increasing the thixotropy of the slurry. On the other hand, the shear thinning behavior of the matrix slurry can also be enhanced by adding silicon micropowder, and the shear thinning property is conducive to further adjusting the orientation of the steel fiber in the matrix when the steel fiber is extruded. In addition, increasing the amount of silicon micropowder added also makes the slurry have a higher yield stress, which helps to improve the stability of the refractory material.

[0019] According to any technical solution of the first aspect of the present invention, the amount of the binder added is 0.05%-0.3% by mass of the total amount of the first component, and / or

[0020] The amount of the plasticizer added is 0.5%-3% by weight of the total amount of the first component, and / or

[0021] The amount of the water reducing agent added is 0.05%-0.2% by mass of the total amount of the first component; and / or

[0022] The added amount of the curing agent accounts for 4% to 7% by mass of the total amount of the first component; and / or

[0023] The added amount of the steel fiber accounts for 1% to 5% of the total amount of the first component by mass, and / or

[0024] The amount of silicon powder added is 5%-8% by mass of the total amount of the first component; and / or

[0025] The refractory material mixed slurry also contains water in a mass percentage of 14% to 18% of the total mass of the first component.

[0026] It should be noted that the content of the above-mentioned additives can be any range value within the above-mentioned content range, or any point value within the above-mentioned range. For example, the added amount of the binder can be in a numerical range of 0.05%-0.1%, 0.15%-0.25%, 0.1%-0.2%, 0.2%-0.3%, etc., or it can be a specific numerical value such as 0.05%, 0.1%, 0.15%, 0.25%, 0.3%.

[0027] According to any technical solution described in the first aspect of the present invention, the refractory aggregate comprises the following components in parts by mass: 45-60 parts of mullite, 15-25 parts of andalusite, 2-5 parts of silicon carbide, 5-10 parts of corundum fine powder, and 5-7 parts of activated alumina fine powder.

[0028] According to any technical solution described in the first aspect of the present invention, the sum of the masses of the silicon micropowder and the activated alumina micropowder accounts for 10%-15% of the total mass of the first component.

[0029] According to any technical solution described in the first aspect of the present invention, the mullite is composited by fine powder with a particle size of 0-1 mm and a particle size of less than 325 mesh in a mass ratio of 20:3 to 25:3; and / or

[0030] The particle size of the andalusite is less than 1 mm; and / or

[0031] The particle size of the silicon carbide is less than 1 mm; and / or

[0032] The particle size of the corundum fine powder is less than 325 mesh; and / or

[0033] The particle size of the activated alumina powder is less than 325 mesh; and / or

[0034] The particle size of the silicon powder is less than 325 mesh; and / or

[0035] The length of the steel fiber is 10 mm and the equivalent diameter is 0.7 mm.

[0036] By optimizing the particle size distribution of each component, not only can the rheological properties of the slurry be improved, its extrusion and stacking properties be enhanced, but also the density of the sample can be increased, the pores inside the sample can be reduced, the strength of the sample can be effectively improved, and the mechanical properties of the sample can be improved.

[0037] According to any technical solution described in the first aspect of the present invention, the nozzle of the extrusion-type 3D printing device is made of non-metallic material, and a coil is wound around the outside thereof. When the coil is connected to an external power source, a magnetic field is generated, so that when the refractory material mixed slurry is extruded from the nozzle, the steel fibers are further guaranteed to be distributed parallel to the extrusion direction. By applying a certain external magnetic field to the slurry during extrusion, it is beneficial to further improve the orientation distribution of the steel fibers, so that the directional effect coefficient of the steel fibers is further improved.

[0038] According to any of the technical solutions described in the first aspect of the present invention, the process parameters of the extrusion 3D printing molding include: a printing speed of 130 to 150 mm / s, a layer height of 20 to 30 mm, and a magnetic field of 2.5 to 5 mT passed into the coil. The effectiveness of 3D printing depends to a large extent on the printing parameters. When the printing parameters match the model degree, it helps to reduce structural defects. Otherwise, the blank will be deformed, resulting in slurry accumulation, which will adversely affect the performance of the material.

[0039] According to any technical solution described in the first aspect of the present invention, it also includes: fully mixing the raw materials comprising the first component and the second component to obtain a refractory mixture; and adding water to the refractory mixture for wet grinding to obtain a refractory mixed slurry.

[0040] The second aspect of the present invention provides an oriented steel fiber reinforced refractory material, which is prepared by the method described in the first aspect of the present invention.

[0041] According to any technical solution described in the second aspect of the present invention, the steel fiber directional effect coefficient of the oriented steel fiber reinforced refractory material is not less than 0.90, and the ultimate bending toughness at 1100°C×3h is (200~260)×10 -3 J; the ultimate bending toughness at 1350℃×3h is (145~160)×10 -3 J.

[0042] The third aspect of the present invention also provides an oriented steel fiber reinforced refractory material, wherein the steel fiber direction effect coefficient of the oriented steel fiber reinforced refractory material is not less than 0.90, and the ultimate bending toughness at 1100°C×3h is (200~260)×10 -3 J; the ultimate bending toughness at 1350℃×3h is (145~160)×10 -3 J.

[0043] The fourth aspect of the present invention further provides an application of the oriented steel fiber reinforced refractory material described in the second aspect or the third aspect of the present invention, or prepared by the method described in the first aspect of the present invention, in refractory castables.

[0044] In summary, the technical solution provided by the present invention can achieve the following beneficial effects compared with the prior art:

[0045] (1) The present invention adopts extrusion 3D printing molding technology to prepare steel fiber reinforced refractory materials, and optimizes the rheological properties of the refractory material mixed slurry, so that it can not only be used to mold complex structures, especially special-shaped steel fiber reinforced refractory materials, but also effectively improve the orientation distribution of steel fibers in the refractory materials, thereby ensuring its toughening effect and preventing the generation of voids in the material after the steel fiber orientation is deflected.

[0046] (2) By adopting the extrusion 3D printing technology, the steel fibers can be arranged in a targeted manner during the printing process, and the distribution of the steel fibers can be optimized. Compared with the traditional steel fiber reinforced refractory materials, the prepared oriented steel fiber reinforced refractory materials have significantly improved the mechanical strength and bending toughness of the materials. This is because the orientation of the steel fibers enhances their effectiveness in bridging cracks and dispersing stresses inside the material matrix, and enhances the nonlinear elastic-plastic behavior of the material; at the same time, the orientation of the steel fibers complicates the crack propagation path of the material during the fracture process, resulting in crack deflection and crack bifurcation, which enhances the material's ability to resist crack propagation, and the formation and development of cracks inside the matrix are more effectively alleviated, and the tensile and bridging effects of the steel fibers are also fully exerted.

[0047] (3) The present invention effectively ensures the rheological properties of the obtained refractory mixed slurry by adding specific types of external binders, plasticizers and water reducers, especially by compounding bentonite and sodium carboxymethyl cellulose, and optimizing the content thereof.

[0048] (4) The present invention further wraps a coil around the outside of the nozzle of the extrusion 3D printing device. Therefore, when the refractory material mixed with steel fibers flows through the nozzle, the energized coil around the nozzle generates a magnetic field under the current, so that the steel fibers with a certain inclination angle are parallel to the extrusion direction under the action of the magnetic field, thereby further improving the steel fiber orientation factor. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 The schematic diagram of the preparation process of oriented steel fiber reinforced refractory material;

[0050] Figure 2 Schematic diagram of achieving steel fiber orientation for 3D printing process;

[0051] Figure 3 This is a schematic diagram of the steel fiber direction effect coefficient test;

[0052] Figure 4 It is the strain image of steel fiber reinforced refractory material in the X-axis direction;

[0053] Figure 5 This is a scanned image of steel fiber reinforced refractory material. DETAILED DESCRIPTION

[0054] In order to further understand the content of the present invention, the present invention is now described in detail in conjunction with specific embodiments. To avoid repetition, the technical parameters involved in the specific implementation methods are first described as follows, and will not be repeated in the embodiments, but it should be noted that the particle size of each component is not limited by the numerical value of the embodiments herein.

[0055] The mullite is a fine powder with a particle size of 0-1 mm and a particle size less than 325 mesh;

[0056] The andalusite is a particle with a particle size of 0-1 mm;

[0057] The silicon carbide is a particle with a particle size of 0-1 mm;

[0058] The activated alumina micropowder and silicon micropowder are a fine powder mixture with a particle size less than 325 mesh;

[0059] The dense corundum fine powder is a fine powder with a particle size less than 325 mesh;

[0060] The calcium aluminate cement is Secar 71;

[0061] The steel fiber is 446# melt-drawn steel fiber, with a length of 10 mm and an equivalent diameter of 0.7 mm.

[0062] Example 1

[0063] The method for preparing the oriented steel fiber reinforced refractory material of this embodiment comprises:

[0064] Step 1: Mix 46 parts of mullite, 20 parts of andalusite, 3 parts of silicon carbide, 10 parts of dense corundum fine powder, 6 parts of activated alumina powder, 7 parts of silicon powder, 5 parts of calcium aluminate cement, 3 parts of steel fiber, 0.2 parts of sodium carboxymethyl cellulose, 1.5 parts of bentonite and 0.1 parts of FS20 by planetary ball mill for 10 minutes according to the mass proportion; after mixing evenly, add 14 parts of water and wet mix for 10 minutes to obtain the pre-printed refractory material, wherein the rotation speed is set to 350r / min.

[0065] Step 2: After mixing evenly, the oriented steel fiber reinforced refractory material is prepared by an extrusion 3D printing device at a speed of 130 mm / s, a layer height of 20 mm, and a magnetic field of 2.5 mT passing through the coil. Figure 2 As shown, the nozzle of the extrusion 3D printing device is made of non-metallic material, and a coil is wound around the outside. The coil is connected to an external power supply to generate a magnetic field, so that the steel fibers are distributed parallel to the extrusion direction under the action of the magnetic field.

[0066] Example 2

[0067] The method for preparing the oriented steel fiber reinforced refractory material of this embodiment comprises:

[0068] Step 1: According to the formula, 49 parts of mullite, 21 parts of andalusite, 2.5 parts of silicon carbide, 9 parts of dense corundum fine powder, 5 parts of activated alumina powder, 6 parts of silicon powder, 5 parts of calcium aluminate cement, 2.5 parts of steel fiber, 0.2 parts of sodium carboxymethyl cellulose, 2 parts of bentonite and 0.075 parts of FS20 were mixed by a planetary ball mill for 12 minutes; after mixing evenly, 16 parts of water were added and wet mixed for 12 minutes to obtain a pre-printed refractory material, wherein the rotation speed was set to 350r / min.

[0069] Step 2: After mixing evenly, the oriented steel fiber reinforced refractory material is prepared by an extrusion 3D printing device at a speed of 140 mm / s, a layer height of 25 mm, and a magnetic field of 5 mT passed into the coil. At the same time, the nozzle of the extrusion 3D printing device is made of non-metallic material, and a coil is wound around the outside. The coil is connected to an external power supply to generate a magnetic field, so that the steel fibers are distributed parallel to the extrusion direction under the action of the magnetic field.

[0070] Example 3

[0071] The method for preparing the oriented steel fiber reinforced refractory material of this embodiment comprises:

[0072] Step 1: According to the formula, 50 parts of mullite, 18 parts of andalusite, 2 parts of silicon carbide, 10 parts of dense corundum fine powder, 6 parts of activated alumina powder, 7 parts of silicon powder, 4 parts of calcium aluminate cement, 3 parts of steel fiber, 0.15 parts of sodium carboxymethyl cellulose, 2 parts of bentonite and 0.1 parts of FS20 were mixed by a planetary ball mill for 14 minutes; after mixing evenly, 18 parts of water were added and wet mixed for 14 minutes to obtain a pre-printed refractory material, wherein the rotation speed was set to 350r / min.

[0073] Step 2: After mixing evenly, the oriented steel fiber reinforced refractory material is prepared by an extrusion 3D printing device at a speed of 150 mm / s, a layer height of 30 mm, and a magnetic field of 3.5 mT passed into the coil. At the same time, the nozzle of the extrusion 3D printing device is made of non-metallic material, and a coil is wound around the outside. The coil is connected to an external power supply to generate a magnetic field, so that the steel fibers are distributed parallel to the extrusion direction under the action of the magnetic field.

[0074] Comparative Example 1

[0075] The preparation method of the steel fiber reinforced refractory material in this comparative example has the same raw material composition as Example 3, with the main difference being that after the refractory material mixed slurry is prepared in this comparative example, the steel fiber reinforced refractory material is prepared by vibration molding.

[0076] Comparative Example 2

[0077] The preparation method of the steel fiber reinforced refractory material of this comparative example is basically the same as that of Example 3, with the main difference being that the raw material composition of the refractory material of this comparative example is different and bentonite is not added in this comparative example.

[0078] Comparative Example 3

[0079] The preparation method of the steel fiber reinforced refractory material of this comparative example is basically the same as that of Example 3, with the main difference being that the raw material ratio of the refractory material of this comparative example is different, and sodium carboxymethyl cellulose is not added in this comparative example.

[0080] Comparative Example 4

[0081] The preparation method of the steel fiber reinforced refractory material in this comparative example is basically the same as that in Example 3, the main difference is that the raw material ratio of the refractory material in this comparative example is different, and 0.8 parts of sodium carboxymethyl cellulose is added in this comparative example.

[0082] Comparative Example 5

[0083] The preparation method of the steel fiber reinforced refractory material in this comparative example is basically the same as that in Example 3, the main difference is that the raw material ratio of the refractory material in this comparative example is different, and 6 parts of bentonite are added in this comparative example.

[0084] Example 4

[0085] The preparation method of the oriented steel fiber reinforced refractory material in this embodiment has a process basically the same as that in Example 3, with the main difference being that the coil is not energized during extrusion printing in this embodiment, and the steel fiber directional effect coefficient in the refractory material obtained in this embodiment is 0.9.

[0086] Example 5

[0087] The preparation method of the oriented steel fiber reinforced refractory material in this embodiment has a process basically the same as that in Example 3, the main difference being that corn starch is used as an additional binder and sodium hexametaphosphate is used as a water reducer in this embodiment. The rheological properties of the refractory material mixed slurry in this embodiment are slightly worse than those in Example 3, and the flexural strength and ultimate bending toughness of the obtained refractory material are also lower than those in Example 3.

[0088] Example 6

[0089] The method for preparing the oriented steel fiber reinforced refractory material of this embodiment comprises:

[0090] Step 1: According to the formula, 55 parts of mullite, 15 parts of andalusite, 5 parts of silicon carbide, 5 parts of dense corundum fine powder, 7 parts of activated alumina powder, 5 parts of silicon powder, 7 parts of calcium aluminate cement, 1 part of steel fiber, 0.3 parts of sodium carboxymethyl cellulose, 0.5 parts of bentonite and 0.2 parts of polycarboxylate were mixed by a planetary ball mill for 15 minutes; after mixing evenly, 15 parts of water were added and wet mixed for 12 minutes to obtain a pre-printed refractory material, wherein the rotation speed was set to 380r / min.

[0091] Step 2: After mixing evenly, prepare oriented steel fiber reinforced refractory material by extrusion 3D printing device at a speed of 140 mm / s and a layer height of 22 mm. At the same time, the nozzle of the extrusion 3D printing device is made of non-metallic material, and a coil is wound around its outside. The coil is connected to an external power supply to generate a magnetic field, so that the steel fibers are distributed parallel to the extrusion direction under the action of the magnetic field.

[0092] Example 7

[0093] The method for preparing the oriented steel fiber reinforced refractory material of this embodiment comprises:

[0094] Step 1: According to the formula, 60 parts of mullite, 15 parts of andalusite, 2 parts of silicon carbide, 5 parts of dense corundum fine powder, 5 parts of activated alumina powder, 5 parts of silicon powder, 4 parts of calcium aluminate cement, 4 parts of steel fiber, 0.25 parts of sodium carboxymethyl cellulose, 3 parts of bentonite and 0.15 parts of sodium hexametaphosphate were mixed by a planetary ball mill for 15 minutes; after mixing evenly, 18 parts of water were added and wet mixed for 14 minutes to obtain a pre-printed refractory material, wherein the rotation speed was set to 340r / min.

[0095] Step 2: After mixing evenly, prepare oriented steel fiber reinforced refractory material by extrusion 3D printing device at a speed of 145 mm / s and a layer height of 26 mm. At the same time, the nozzle of the extrusion 3D printing device is made of non-metallic material, and a coil is wound around its outside. The coil is connected to an external power supply to generate a magnetic field, so that the steel fibers are distributed parallel to the extrusion direction under the action of the magnetic field.

[0096] Table 1 below shows the rheological properties of the slurries obtained in Examples 1-7 and Comparative Examples 1-5, and Table 2 shows the physical properties of the refractory materials obtained in Examples 1-7 and Comparative Examples 1-5. Figure 3-Figure 5 As shown in the figure, by adopting the extrusion 3D printing molding technology, the orientation distribution of steel fibers in the refractory material can be effectively improved, and the directional effect coefficient of the steel fibers is effectively improved; and the strain images ( Figure 4) It can be seen that crack deflection occurred in all samples. Compared with the samples made by the casting method, the crack deflection of the samples made by the 3D printing molding technology was more serious and had crack branching. The deflection and branching of the crack made the crack propagation path complicated and the stress resistance of the samples was enhanced.

[0097] At the same time, since the rheological properties of the slurry obtained in Examples 1-3 are relatively better than those in Example 5, it can not only meet the needs of 3D printing, but also effectively prevent the steel fiber from leaving gaps inside the material after deflection, thereby ensuring the structural strength and bending toughness of the obtained refractory material. As shown in Example 4, the sample obtained by the extrusion 3D printing molding technology without an external magnetic field has a relatively low orientation distribution of steel fibers in the refractory material, and the directional effect coefficient of the steel fibers is low, but it is still higher than the ordinary casting method. This is mainly because the refractory material and the steel fiber are squeezed in the barrel, resulting in different moving speeds. The difference in flow rate causes the steel fiber to rotate, so that its axial direction tends to the flow direction of the refractory material; on the other hand, the steel fiber contacts the side wall of the barrel, inducing the orientation of the steel fiber.

[0098] When only a binder or a plasticizer is added in Comparative Examples 2 and 3, the rheological properties thereof are reduced. This is because CMC, as a polymer, can increase the interaction between bentonite particles, thereby increasing the overall viscosity of the slurry.

[0099] Table 1 Rheological properties of the slurries obtained in Examples 1-7 and Comparative Examples 1-5

[0100]

[0101] Table 2 Physical properties of the refractory materials obtained in Examples 1-7 and Comparative Examples 1-5

[0102]

[0103]

Claims

1. A method for preparing an oriented steel fiber reinforced refractory material, characterized in that: include: The refractory material mixed slurry including the first component and the second component is made to flow downward along the barrel of the extrusion 3D printing device and be extruded from the nozzle, and the oriented steel fiber reinforced refractory material is obtained by extrusion 3D printing; The first component comprises refractory aggregate, silicon powder, steel fiber and curing agent, the second component comprises binder, plasticizer and water reducer, and the refractory mixed slurry is subjected to a shear rate of 0.4S -1 The viscosity is 15000~30000mPa·s at a shear rate of 30.59S -1 The viscosity is 3500-5500 mPa·s, and the thixotropic ring area is not less than 120 Pa / s.

2. The method for preparing an oriented steel fiber reinforced refractory material according to claim 1, characterized in that: The binder comprises at least one of dextrin, corn starch, and sodium carboxymethyl cellulose, and / or the plasticizer comprises bentonite, and / or the water reducer comprises sodium hexametaphosphate or polycarboxylate; and / or the curing agent comprises calcium aluminate cement.

3. The method for preparing an oriented steel fiber reinforced refractory material according to claim 1 or 2, characterized in that: The amount of the binder added is 0.05%-0.3% by weight of the total amount of the first component, and / or The amount of the plasticizer added is 0.5%-3% by weight of the total amount of the first component, and / or The amount of the water reducing agent added is 0.05%-0.2% by mass of the total amount of the first component; and / or The added amount of the curing agent accounts for 4% to 7% by mass of the total amount of the first component; and / or The added amount of the steel fiber accounts for 1% to 5% of the total amount of the first component by mass, and / or The amount of silicon powder added is 5%-8% by mass of the total amount of the first component; and / or The refractory material mixed slurry also contains water in a mass percentage of 14% to 18% of the total mass of the first component.

4. The method for preparing an oriented steel fiber reinforced refractory material according to claim 3, characterized in that: The refractory aggregate comprises the following components in parts by mass: 45-60 parts of mullite, 15-25 parts of andalusite, 2-5 parts of silicon carbide, 5-10 parts of corundum fine powder, and 5-7 parts of active alumina fine powder.

5. The method for preparing an oriented steel fiber reinforced refractory material according to claim 4, characterized in that: The sum of the mass of the silicon micropowder and the activated alumina micropowder accounts for 10%-15% of the total mass of the first component; and / or The mullite is composited by fine powder with a particle size of 0-1 mm and a particle size of less than 325 mesh in a mass ratio of 20:3 to 25:3; and / or The particle size of the andalusite is less than 1 mm; and / or The particle size of the silicon carbide is less than 1 mm; and / or The particle size of the corundum fine powder is less than 325 mesh; and / or The particle size of the activated alumina powder is less than 325 mesh; and / or The particle size of the silicon powder is less than 325 mesh; and / or The length of the steel fiber is 10 mm and the equivalent diameter is 0.7 mm.

6. The method for preparing an oriented steel fiber reinforced refractory material according to claim 3, characterized in that: The nozzle of the extrusion 3D printing device is made of non-metallic material, and a coil is wound around the outside of the nozzle. When the coil is connected to an external power source, a magnetic field is generated, so that when the refractory material mixed slurry is extruded from the nozzle, the steel fibers are further distributed parallel to the extrusion direction.

7. The method for preparing an oriented steel fiber reinforced refractory material according to claim 6, characterized in that: The process parameters of the extrusion 3D printing molding include: a printing speed of 130 to 150 mm / s, a layer height of 20 to 30 mm, and a magnetic field size of 2.5 to 5 mT passing through the coil; And / or also includes: fully mixing the raw materials including the first component and the second component to obtain a refractory mixture; and adding water to the refractory mixture for wet grinding to obtain a refractory mixture slurry.

8. An oriented steel fiber reinforced refractory material, characterized in that: The oriented steel fiber reinforced refractory material is prepared by the method described in any one of claims 1 to 7.

9. The oriented steel fiber reinforced refractory material according to claim 8, characterized in that: The steel fiber directional effect coefficient of the oriented steel fiber reinforced refractory material is not less than 0.90, and the ultimate bending toughness at 1100°C×3h is (200~260)×10 -3 J; the ultimate bending toughness at 1350℃×3h is (145~160)×10 -3 J.

10. Use of the oriented steel fiber reinforced refractory material as claimed in claim 8 or 9, or prepared by the method as claimed in any one of claims 1 to 7, in refractory castables.

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