A high-wear-resistance steel material for a pipe mold and a manufacturing process thereof

Abstract

The application relates to the technical field of steel materials, in particular to a high-wear-resistance steel material for a pipe mold and a preparation process thereof, which comprises the following preparation steps: step S1: smelting, step S2: casting and heat treatment, and step S3: preparation of the high-wear-resistance steel material for the pipe mold. In the smelting process, an inoculation modifier composed of an Al-Ti-Nb intermediate alloy and a vanadium iron nitride alloy is used, the Al-Ti-Nb intermediate alloy and the vanadium iron nitride alloy can play a mutual synergistic effect, and the strength and toughness of the steel material body can be improved; through high-temperature solid solution treatment at 1030-1040 DEG C and twice tempering treatment at 540-560 DEG C, the toughness of the steel material body is optimized on the basis of maintaining high hardness, the balance between hardness and toughness is realized; in the preparation process of the high-wear-resistance steel material for the pipe mold, laser cladding material mixed by AlCoCrNiTiB alloy powder and nano ytterbium oxide powder is used to perform surface modification on the steel material body, so that the high-wear-resistance steel material for the pipe mold simultaneously has the characteristics of low friction and wear resistance.

Description

Technical Field

[0001] This invention relates to the field of steel materials technology, and more specifically, to a high wear-resistant steel material for pipe molds and its preparation process. Background Technology

[0002] In the production process of sewer pipes (cast iron pipes, concrete pipes, etc.), the pipe mold is the core forming tool, and its material properties directly determine the dimensional accuracy, surface quality, production efficiency, and manufacturing cost of the pipe.

[0003] During long-term use, the inner wall of the pipe mold repeatedly comes into contact with and rubs against materials such as molten iron and concrete, and is subjected to the compressive stress during the solidification process of the materials. It is also subject to scraping and wear during demolding after the sewer pipe is formed. The pipe mold frequently undergoes cyclical operations of loading, forming, demolding, and cleaning. Under long-term cyclical loads, severe wear and scratches will occur on the inner wall of the pipe mold. This not only affects the number of times the pipe mold can be reused, but also leads to roughness and dimensional deviations in the inner wall of the sewer pipe. Therefore, the steel material used for pipe molds must possess high hardness, high wear resistance, and a good balance of strength and toughness to ensure the dimensional accuracy and service life of the pipe molds and reduce maintenance costs for pipe manufacturers.

[0004] Currently, the steel materials used in sewer pipe molds are mainly ordinary carbon structural steel, low alloy structural steel, or traditional mold steel (such as H13). Ordinary carbon structural steel and low alloy structural steel are widely used in the production of low- and mid-range sewer pipe molds due to their low cost and ease of processing and forming. However, these steel materials have low alloy element content and lack effective strengthening mechanisms, resulting in low hardness and strength, and poor wear resistance. Although the hardness of traditional mold steel is improved after quenching and tempering, it still has obvious performance shortcomings under the harsh working conditions of pipe molds, making it difficult to meet the wear resistance life requirements of high-frequency and long-cycle production. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high wear-resistant steel material for pipe molds and its preparation process.

[0006] A process for preparing a high wear-resistant steel material for pipe molds, wherein the high wear-resistant steel material for pipe molds comprises a steel material body and an alloy composite layer on the surface of the steel material body; The steel material body comprises, by weight percentage: C: 0.28–0.36%, Si: 0.35–0.75%, Mn: 0.6–1.0%, Cr: 1.3–2.1%, Mo: 0.41–0.55%, V: 0.036–0.054%, N: 0.008–0.015%, Al: 0.08–0.15%, Ti: 0.02–0.04%, Nb: 0.01–0.03%, with the balance being Fe and unavoidable impurities; The preparation steps include the following: Step S1: Smelting. Calculate the proportions of C, Si, Mn, Cr and Mo in the composition of the steel material as described above, weigh the required furnace charge, and smelt and refine the furnace charge to obtain a refined melt. Pour the refined melt into a ladle containing an inoculating modifier, keep it at a constant temperature, remove slag, and obtain molten steel. The inoculant is composed of Al-Ti-Nb master alloy and vanadium ferronitride alloy mixed in a mass ratio of (1-1.4):1; Step S2: Casting and heat treatment. The molten steel is poured into a casting mold to obtain a casting. The casting is heated to 790-810℃ and held for 60-90 minutes. Then, the temperature is raised to 960-980℃ and held for 60-90 minutes. Subsequently, the temperature is raised to 1030-1040℃ and held for 60-90 minutes. After that, it is oil quenched and cooled. The temperature is then raised to 540-560℃ and held for 1-3 hours. It is then air-cooled to room temperature. The temperature is then raised again to 540-560℃ and held for 1-3 hours. Finally, it is air-cooled to room temperature to obtain the steel material body. Step S3: Preparation of high wear-resistant steel material for pipe molds. Using Al, Co, Cr, Ni, Ti and B powders as raw materials, AlCoCrNiTiB alloy powder is prepared. Nano-ytterbium oxide powder and AlCoCrNiTiB alloy powder are ball-milled and dried to obtain laser cladding powder. The surface of the steel material is modified by laser cladding using the laser cladding powder to form an alloy composite layer on the steel material, thus obtaining high wear-resistant steel material for pipe molds.

[0007] Furthermore, the furnace charge includes ordinary scrap steel, carbon raisers, ferrochrome, ferrosilicon, ferromanganese, and ferromolybdenum.

[0008] Furthermore, the AlCoCrNiTiB alloy powder has the following elemental composition by atomic percentage: Al: 5.10%, Co: 27.15%, Cr: 24.63%, Ni: 25.32%, Ti: 16.45%, B: 1.35%.

[0009] Further, step S1: smelting, specifically includes the following steps: S1.1: Calculate the proportion of C, Si, Mn, Cr and Mo in the composition of the steel material, weigh the required furnace charge, add the furnace charge to the vacuum induction furnace, evacuate the vacuum induction furnace and introduce argon gas, and melt at 1520~1570℃ for 30~50min to obtain the melt. S1.2: Add a slag remover to the melt and refine for 5-10 minutes to obtain a refined melt; S1.3: Add the inoculating modifier to the ladle. The inoculating modifier is preheated to 1120-1160°C along with the ladle. The refined melt is then rapidly poured into the ladle at a rate of 3-5 L / min. The ladle is held at 1290-1360°C for 30-40 minutes. The slag is removed to obtain molten steel.

[0010] Furthermore, the slag remover is obtained by mixing calcium fluoride and calcium oxide at a mass ratio of 2:1, and the amount of slag remover used is 0.8 to 1.5% of the melt weight.

[0011] Furthermore, the amount of inoculant used is 0.4 to 0.8% of the weight of the refined melt.

[0012] Further, step S2: casting and heat treatment, specifically includes the following steps: S2.1: Pour molten steel into the casting mold container on the casting machine, and let it cool and solidify in the air until the temperature inside the casting mold container is 200-260℃. Then, remove the solidified casting from the casting mold container to obtain the casting. S2.2: Place the casting in a high-temperature resistance furnace and heat it to 790-810℃ at a heating rate of 6-10℃ / min. Hold it at this temperature for 60-90min. Then, heat it to 960-980℃ at a heating rate of 4-8℃ / min and hold it for 60-90min. After that, heat it to 1030-1040℃ at a heating rate of 3-5℃ / min and hold it for 60-90min. Finally, oil quench the casting to room temperature to obtain the quenched casting. S2.3: Heat the quenched casting to 540-560℃ at a heating rate of 6-8℃ / min, hold for 1-3 hours, air cool to room temperature, and then heat again to 540-560℃ at a heating rate of 6-8℃ / min, hold for 1-3 hours, and air cool to room temperature to obtain the steel material body.

[0013] Further, step S3: the preparation of high wear-resistant steel material for the tube mold, specifically includes the following steps: S3.1: Using Al, Co, Cr, Ni, Ti and B powders as raw materials, weigh the raw materials according to the elemental composition ratio of AlCoCrNiTiB alloy powder, and ball mill the weighed raw materials together at a ball mill speed of 180-200 r / min for 3-5 h. After ball milling, AlCoCrNiTiB alloy powder is obtained. Then, nano-ytterbium oxide powder is added to the AlCoCrNiTiB alloy powder at a mass of 0.8-1.2% of the AlCoCrNiTiB alloy powder. Ball milling is continued at a ball mill speed of 100-140 r / min for 1-3 h to obtain mixed powder. The mixed powder is then vacuum dried to obtain laser cladding powder. S3.2: Sand the surface of the steel material body with sandpaper and wipe it with alcohol to remove the oxide layer and oil stains on the surface of the steel material body. Then, use laser cladding powder to perform laser cladding modification on the cleaned steel material body surface to form an alloy composite layer on the steel material body. S3.3: After the steel material body is clad, it is placed in an insulated box at 340-400℃ for 1-3 hours and then air-cooled to room temperature to obtain high wear-resistant steel material for pipe mold.

[0014] Furthermore, the parameters for laser cladding are as follows: laser power of 1300-1500W, laser scanning speed of 5-10mm / s, powder feeding rate of 7.2-8.8g / min, spot diameter of 3-5mm, overlap rate of 40-60%, and the entire laser cladding process is carried out under the protection of high-purity argon gas with an argon gas flow rate of 3-6L / min.

[0015] A high wear-resistant steel material for pipe molds is prepared by the above-mentioned preparation process of a high wear-resistant steel material for pipe molds.

[0016] The present invention has the following advantages: 1. In the smelting process, this invention uses an inoculating modifier composed of an Al-Ti-Nb master alloy and a vanadium ferronitride alloy, which can play a combined role in modifying and refining the melt. In particular, under the synergistic effect of the Al-Ti-Nb master alloy and the vanadium ferronitride alloy in the inoculating modifier, high-melting-point nano-sized compounds such as TiN, AlN, NbC, VC and TiC can be precipitated in the early stage of steel solidification. These compounds can not only act as heterogeneous nucleation nuclei in the solidification process of the steel material at high temperature, promoting the refinement of grains and carbides, and hindering the growth of carbides, thus achieving a significant grain refinement effect and forming a fine microstructure, avoiding the decrease in toughness caused by coarse grains and carbides, but also effectively hinder dislocation movement and produce precipitation hardening effect, thereby simultaneously improving the strength and toughness of the steel material.

[0017] 2. In this invention, a high-temperature solution treatment at 1030–1040℃ and two tempering treatments at 540–560℃ are performed in synergy. During the high-temperature solution treatment stage at 1030–1040℃, the diffusion of alloying elements such as Cr, Mo, and V is enhanced, promoting the full dissolution of austenite. This facilitates the combination of alloying elements and carbon to form fine and dispersed secondary carbides, eliminating component segregation and coarse carbides in the as-cast structure, and controlling the austenite grain size. Consequently, a fine-grained lath martensite structure with high dislocation density is obtained after quenching, providing a high-strength and high-hardness matrix for the steel material. Subsequently, two tempering treatments at 540–560℃ can fully release the quenching internal stress, ensure the full transformation and decomposition of residual austenite, eliminate the instability of the structure, and avoid the continuous precipitation of coarse carbides along the grain boundaries. Thus, while maintaining high hardness, the toughness of the steel material is optimized, achieving a balance between hardness and toughness.

[0018] 3. In the preparation process of high wear-resistant steel material for pipe molds, the present invention uses a laser cladding material made by mixing AlCoCrNiTiB alloy powder and nano ytterbium oxide powder to modify the surface of the steel material body. During laser cladding, the elements in the AlCoCrNiTiB alloy powder of the laser cladding material melt and alloy, forming a high-strength, high-hardness solid solution matrix based on the high-entropy effect. Furthermore, through the introduction of element B, B and Ti elements can react in situ to generate a dispersed boride hard second phase such as TiB / TiB2, which can significantly improve the ability of high wear-resistant steel for pipe molds to resist abrasive wear and adhesive wear, and build a robust anti-wear skeleton on the surface of high wear-resistant steel for pipe molds, thereby improving wear resistance. In addition, nano-ytterbium oxide powder in the laser cladding material, as a rare earth modified phase, can play a heterogeneous nucleation core role during the cladding process, refining grains, purifying grain boundaries and improving the fluidity of the molten pool, effectively inhibiting the agglomeration and coarsening of hard phases. Moreover, nano-ytterbium oxide can form a stable rare earth oxide lubricating film at the friction interface on the surface of high wear-resistant steel for pipe molds, reducing the coefficient of friction and the tendency of interface adhesion, so that high wear-resistant steel for pipe molds simultaneously possesses the characteristics of high wear resistance, low friction and self-lubrication. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the preparation process of high wear-resistant steel material for tube molds in this embodiment of the invention.

[0020] Figure 2 The figures show the test results of wear rate and friction coefficient of the high wear-resistant steel material used for pipe molds in the embodiments and comparative examples 8-9 of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0022] A process for preparing high wear-resistant steel material for pipe molds, such as Figure 1 As shown, the specific steps include: The high wear-resistant steel material for the tube mold includes a steel material body and an alloy composite layer on the surface of the steel material body; The steel material body comprises, by weight percentage: C: 0.32%, Si: 0.55%, Mn: 0.8%, Cr: 1.7%, Mo: 0.48%, V: 0.045%, N: 0.0115%, Al: 0.115%, Ti: 0.03%, Nb: 0.03%, with the balance being Fe and unavoidable impurities; Step S1: Smelting, S1.1: Calculate the proportions of C, Si, Mn, Cr and Mo in the composition of the steel material body as described above, weigh the required furnace charge, which includes ordinary scrap steel, recarburizer, ferrochrome, ferrosilicon, ferromanganese and ferromolybdenum. First, add ordinary scrap steel to the bottom of the vacuum induction furnace, then add ferrochrome, ferrosilicon, ferromanganese and ferromolybdenum in sequence, and finally cover the surface with recarburizer. After the vacuum induction furnace is evacuated, argon gas is introduced and smelted at 1545℃ for 40 minutes to obtain the melt. S1.2: Add a slag remover to the melt and refine for 7.5 min to obtain a refined melt. The slag remover is obtained by mixing calcium fluoride and calcium oxide in a mass ratio of 2:1, and the amount of slag remover is 1.15% of the melt weight. S1.3: An inoculating modifier composed of Al-Ti-Nb master alloy and vanadium ferronitride alloy in a mass ratio of 1.2:1 is added to the ladle. The amount of the inoculating modifier is 0.6% of the weight of the refined melt. The inoculating modifier is preheated to 1140°C along with the ladle. The refined melt is then rapidly poured into the ladle at a rate of 4L / min. The ladle is held at 1325°C for 35 minutes, and the slag is removed to obtain molten steel. Step S2: Casting and heat treatment, S2.1: Pour molten steel into the casting mold container on the casting machine. After all the molten steel has entered the casting mold container, cool it in the air until the temperature inside the casting mold container reaches 230℃. Then, remove the solidified casting from the casting mold container to obtain the casting. S2.2: Place the casting in a high-temperature resistance furnace, heat it to 800℃ at a heating rate of 8℃ / min, hold it for 75min, then heat it to 970℃ at a heating rate of 6℃ / min, hold it for 75min, then heat it to 1035℃ at a heating rate of 4℃ / min, hold it for 75min, and then oil quench it to room temperature to obtain the quenched casting. S2.3: The quenched casting is heated to 550℃ at a heating rate of 7℃ / min, held for 2 hours, and then air-cooled to room temperature. The casting is then heated again to 550℃ at a heating rate of 7℃ / min, held for 2 hours, and then air-cooled to room temperature to obtain the steel material body. Step S3: Preparation of high wear-resistant steel material for the tube mold. S3.1: Using Al, Co, Cr, Ni, Ti, and B powders with a particle size in the range of 75–100 μm as raw materials, weigh the raw materials according to the AlCoCrNiTiB alloy powder ratio. The elemental composition of the AlCoCrNiTiB alloy powder, calculated by atomic percentage, includes: Al: 5.10%, Co: 27.15%, Cr: 24.63%, Ni: 25.32%, Ti: 16.45%, and B: 1.35%. Place the weighed raw materials in a ball mill and ball-mill them. The powders were ball-milled at 190 r / min for 4 hours to ensure uniform mixing of the various elements. After ball milling, AlCoCrNiTiB alloy powder was obtained. Subsequently, nano-ytterbium oxide powder was added to the ball mill at 1% of the mass of AlCoCrNiTiB alloy powder in the ball mill. The ball milling continued at 120 r / min for 2 hours to obtain mixed powder. The mixed powder was then placed in a vacuum drying oven at 110°C and dried for 2 hours to remove moisture, resulting in laser cladding powder. S3.2: Grind the surface of the steel material body with diamond sandpaper and wipe it with alcohol to remove the oxide layer and oil stains on the surface of the steel material body. Then, use laser cladding powder to modify the surface of the cleaned steel material body. The laser cladding parameters are: laser power of 1400W, laser scanning speed of 7.5mm / s, powder feeding rate of 8g / min, spot diameter of 4mm, and overlap rate of 50%. The entire cladding process is carried out under the protection of high-purity argon gas with an argon gas flow rate of 4.5L / min, forming an alloy composite layer on the steel material body. S3.3: After the steel material body is clad, it is placed in an insulated box and kept at 370℃ for 2 hours to carry out stress relief annealing treatment, eliminate the residual stress generated during the cladding process, and air-cooled to room temperature to obtain high wear-resistant steel material for pipe mold. Example

[0023] A process for preparing high wear-resistant steel material for pipe molds, such as Figure 1 As shown, the specific steps include: The high wear-resistant steel material for the tube mold includes a steel material body and an alloy composite layer on the surface of the steel material body; The steel material body comprises, by weight percentage: C: 0.36%, Si: 0.75%, Mn: 1.0%, Cr: 2.1%, Mo: 0.55%, V: 0.054%, N: 0.015%, Al: 0.15%, Ti: 0.04%, Nb: 0.03%, with the balance being Fe and unavoidable impurities; Step S1: Smelting, S1.1: Calculate the proportions of C, Si, Mn, Cr and Mo in the composition of the steel material body as described above, weigh the required furnace charge, which includes ordinary scrap steel, recarburizer, ferrochrome, ferrosilicon, ferromanganese and ferromolybdenum. First, add ordinary scrap steel to the bottom of the vacuum induction furnace, then add ferrochrome, ferrosilicon, ferromanganese and ferromolybdenum in sequence, and finally cover the surface with recarburizer. After the vacuum induction furnace is evacuated, argon gas is introduced and smelted at 1570℃ for 50 minutes to obtain the melt. S1.2: Add a slag remover to the melt and refine for 10 minutes to obtain a refined melt. The slag remover is obtained by mixing calcium fluoride and calcium oxide in a mass ratio of 2:1, and the amount of slag remover is 1.5% of the melt weight. S1.3: An inoculating modifier composed of Al-Ti-Nb master alloy and vanadium ferronitride alloy in a mass ratio of 1.4:1 is added to the ladle. The amount of the inoculating modifier is 0.8% of the weight of the refined melt. The inoculating modifier is preheated to 1160°C along with the ladle. The refined melt is then rapidly poured into the ladle at a rate of 5L / min. The ladle is held at 1360°C for 40 minutes, and the slag is removed to obtain molten steel. Step S2: Casting and heat treatment, S2.1: Pour molten steel into the casting mold container on the casting machine. After all the molten steel has entered the casting mold container, cool it in the air until the temperature inside the casting mold container reaches 260℃. Then, remove the solidified casting from the casting mold container to obtain the casting. S2.2: Place the casting in a high-temperature resistance furnace, heat it to 810℃ at a heating rate of 10℃ / min, hold it for 90min, then heat it to 980℃ at a heating rate of 8℃ / min, hold it for 90min, then heat it to 1040℃ at a heating rate of 5℃ / min, hold it for 90min, and then oil quench it to room temperature to obtain the quenched casting. S2.3: The quenched casting is heated to 560℃ at a heating rate of 8℃ / min, held for 3 hours, and then air-cooled to room temperature. The casting is then heated again to 560℃ at a heating rate of 8℃ / min, held for 3 hours, and then air-cooled to room temperature to obtain the steel material body. Step S3: Preparation of high wear-resistant steel material for the tube mold. S3.1: Using Al, Co, Cr, Ni, Ti, and B powders with a particle size in the range of 75–100 μm as raw materials, weigh the raw materials according to the AlCoCrNiTiB alloy powder ratio. The elemental composition of the AlCoCrNiTiB alloy powder, calculated by atomic percentage, includes: Al: 5.10%, Co: 27.15%, Cr: 24.63%, Ni: 25.32%, Ti: 16.45%, and B: 1.35%. Place the weighed raw materials in a ball mill and ball-mill them together. The ball milling speed was 200 r / min, and the milling time was 5 h to ensure uniform mixing of the powders of each element. After the ball milling was completed, AlCoCrNiTiB alloy powder was obtained. Subsequently, nano-ytterbium oxide powder was added to the ball mill. The amount of nano-ytterbium oxide powder added was 1.2% of the mass of AlCoCrNiTiB alloy powder in the ball mill. The ball milling was continued at a speed of 140 r / min for 3 h to obtain mixed powder. The mixed powder was placed in a vacuum drying oven at 120℃ and dried for 3 h to remove moisture, thus obtaining laser cladding powder. S3.2: Grind the surface of the steel material body with diamond sandpaper and wipe it with alcohol to remove the oxide layer and oil stains on the surface of the steel material body. Then, use laser cladding powder to modify the surface of the cleaned steel material body. The parameters of laser cladding are: laser power of 1500W, laser scanning speed of 10mm / s, powder feeding rate of 8.8g / min, spot diameter of 5mm, and overlap rate of 60%. The entire cladding process is carried out under the protection of high-purity argon gas with an argon gas flow rate of 6L / min, forming an alloy composite layer on the steel material body. S3.3: After the steel material body is clad, it is placed in an insulated box and kept at 400℃ for 3 hours to carry out stress relief annealing treatment to eliminate the residual stress generated during the cladding process. Then, it is air-cooled to room temperature to obtain high wear-resistant steel material for pipe molds. Example

[0024] A process for preparing high wear-resistant steel material for pipe molds, such as Figure 1 As shown, the specific steps include: The high wear-resistant steel material for the tube mold includes a steel material body and an alloy composite layer on the surface of the steel material body; The steel material body comprises, by weight percentage: C: 0.28%, Si: 0.35%, Mn: 0.6%, Cr: 1.3%, Mo: 0.41%, V: 0.036%, N: 0.008%, Al: 0.08%, Ti: 0.02%, Nb: 0.01%, with the balance being Fe and unavoidable impurities; Step S1: Smelting, S1.1: Calculate the proportions of C, Si, Mn, Cr and Mo in the composition of the steel material body as described above, weigh the required furnace charge, which includes ordinary scrap steel, recarburizer, ferrochrome, ferrosilicon, ferromanganese and ferromolybdenum. First, add ordinary scrap steel to the bottom of the vacuum induction furnace, then add ferrochrome, ferrosilicon, ferromanganese and ferromolybdenum in sequence, and finally cover the surface with recarburizer. After the vacuum induction furnace is evacuated, argon gas is introduced and smelted at 1520℃ for 30 minutes to obtain the melt. S1.2: Add a slag remover to the melt and refine for 5 minutes to obtain a refined melt. The slag remover is obtained by mixing calcium fluoride and calcium oxide in a mass ratio of 2:1, and the amount of slag remover is 0.8% of the melt weight. S1.3: An inoculating modifier composed of Al-Ti-Nb master alloy and vanadium ferronitride alloy in a mass ratio of 1:1 is added to the ladle. The amount of the inoculating modifier is 0.4% of the weight of the refined melt. The inoculating modifier is preheated to 1120°C along with the ladle. The refined melt is then rapidly poured into the ladle at a rate of 3L / min. The ladle is held at 1290°C for 30 minutes, and the slag is removed to obtain molten steel. Step S2: Casting and heat treatment, S2.1: Pour molten steel into the casting mold container on the casting machine. After all the molten steel has entered the casting mold container, cool it in the air until the temperature inside the casting mold container reaches 200℃. Then, remove the solidified casting from the casting mold container to obtain the casting. S2.2: Place the casting in a high-temperature resistance furnace, heat it to 790℃ at a heating rate of 6℃ / min, hold it for 60min, then heat it to 960℃ at a heating rate of 4℃ / min, hold it for 60min, then heat it to 1030℃ at a heating rate of 3℃ / min, hold it for 60min, and then oil quench it to room temperature to obtain the quenched casting. S2.3: The quenched casting is heated to 540℃ at a heating rate of 6℃ / min, held for 1 hour, and then air-cooled to room temperature. The casting is then heated again to 540℃ at a heating rate of 6℃ / min, held for 1 hour, and then air-cooled to room temperature to obtain the steel material body. Step S3: Preparation of high wear-resistant steel material for the tube mold. S3.1: Using Al, Co, Cr, Ni, Ti, and B powders with a particle size in the range of 75–100 μm as raw materials, weigh the raw materials according to the AlCoCrNiTiB alloy powder ratio. The elemental composition of the AlCoCrNiTiB alloy powder, calculated by atomic percentage, includes: Al: 5.10%, Co: 27.15%, Cr: 24.63%, Ni: 25.32%, Ti: 16.45%, and B: 1.35%. Place the weighed raw materials in a ball mill and ball-mill them together. The ball milling speed was 180 r / min, and the milling time was 3 h to ensure uniform mixing of the powders of each element. After the ball milling was completed, AlCoCrNiTiB alloy powder was obtained. Then, nano-ytterbium oxide powder was added to the ball mill. The amount of nano-ytterbium oxide powder added was 0.8% of the mass of AlCoCrNiTiB alloy powder in the ball mill. The ball milling was continued at a speed of 100 r / min for 1 h to obtain mixed powder. The mixed powder was placed in a vacuum drying oven at 100℃ and dried for 1 h to remove moisture to obtain laser cladding powder. S3.2: Grind the surface of the steel material body with diamond sandpaper and wipe it with alcohol to remove the oxide layer and oil stains on the surface of the steel material body. Then, use laser cladding powder to modify the surface of the cleaned steel material body. The laser cladding parameters are: laser power of 1300W, laser scanning speed of 5mm / s, powder feeding rate of 7.2g / min, spot diameter of 3mm, and overlap rate of 40%. The entire cladding process is carried out under the protection of high-purity argon gas with an argon gas flow rate of 3L / min, forming an alloy composite layer on the steel material body. S3.3: After the steel material body is clad, it is placed in an insulated box and kept at 340℃ for 1 hour to carry out stress relief annealing treatment to eliminate the residual stress generated during the cladding process. Then, it is air-cooled to room temperature to obtain high wear-resistant steel material for pipe molds.

[0025] Comparative Example 1 Compared with Example 1, the difference of Comparative Example 1 is that the vanadium iron nitride alloy in the inoculant is replaced with Al-Ti-Nb master alloy, that is, the inoculant is composed only of Al-Ti-Nb master alloy, the amount of inoculant is 0.6% of the weight of the refined melt, the other steps are unchanged, and the high wear-resistant steel material for the tube mold is prepared, which is referred to as Comparative Example 1.

[0026] Comparative Example 2 Compared with Example 1, Comparative Example 2 differs in that the Al-Ti-Nb master alloy in the inoculant is replaced with vanadium iron nitride alloy, that is, the inoculant is composed only of vanadium iron nitride alloy, the amount of inoculant is 0.6% of the weight of the refined melt, the other steps remain unchanged, and high wear-resistant steel material for tube mold is prepared, which is referred to as Comparative Example 2.

[0027] Comparative Example 3 Compared with Example 1, the difference of Comparative Example 3 is that the high-temperature solution temperature of 1035°C in step S2.2 is changed to 1020°C, while the other steps remain unchanged. The high wear-resistant steel material for the tube mold is prepared and is referred to as Comparative Example 3.

[0028] Comparative Example 4 Compared with Example 1, the difference of Comparative Example 4 is that the high-temperature solution temperature of 1035°C in step S2.2 is changed to 1025°C, while the other steps remain unchanged. The high wear-resistant steel material for the tube mold is prepared and is referred to as Comparative Example 4.

[0029] Comparative Example 5 Compared with Example 1, Comparative Example 5 differs in that the high-temperature solution temperature of 1035°C in step S2.2 is changed to 1045°C, while the other steps remain unchanged. This method is used to prepare high wear-resistant steel material for tube molds and is referred to as Comparative Example 5.

[0030] Comparative Example 6 Compared with Example 1, Comparative Example 6 differs in that the high-temperature solution temperature of 1035°C in step S2.2 is changed to 1050°C, while the other steps remain unchanged. This method is used to prepare high wear-resistant steel material for tube molds and is referred to as Comparative Example 6.

[0031] Comparative Example 7 Compared with Example 1, the difference of Comparative Example 7 is that only one tempering treatment is performed in step S2.3. Specifically, the quenched casting is heated to 550°C at a heating rate of 7°C / min, held for 2 hours, and air-cooled to room temperature to obtain the steel material body. The remaining steps remain unchanged to prepare high wear-resistant steel material for pipe molds, which is referred to as Comparative Example 7.

[0032] The hardness of the high wear-resistant steel materials used for pipe molds in Examples 1-3 and Comparative Documents 1-7 was tested in accordance with GB / T 230.1-2018, and the results are shown in Table 1. Referring to GB / T 228.1-2021, the tensile properties of the high wear-resistant steel materials for tube molds in Examples 1-3 and Comparative Documents 1-7 were tested using an electronic universal testing machine at a tensile rate of 2 mm / min. The results are shown in Table 1. The impact toughness of the high wear-resistant steel materials used for pipe molds in Examples 1-3 and Comparative Documents 1-7 was tested in accordance with GB / T 1817-2017, and the results are shown in Table 1. Table 1:

[0033] As shown in Table 1, the high wear-resistant steel materials for pipe molds prepared in Examples 1-3 exhibit better test results in hardness, tensile strength, and impact toughness than those in Comparative Examples 1-7. Specifically, compared to Comparative Example 1, which used only Al-Ti-Nb master alloy as an inoculant, and Comparative Example 2, which used only vanadium iron nitride alloy as an inoculant, the high wear-resistant steel materials for pipe molds in Examples 1-3 show significantly better hardness, strength, and toughness than those in Comparative Examples 1-2. This indicates that when Al-Ti-Nb master alloy and vanadium iron nitride alloy are used together as inoculants, they have a synergistic reinforcing effect, precipitating high-melting-point nanoscale compounds to achieve grain refinement and precipitation hardening, simultaneously improving strength and toughness. However, when only Al-Ti-Nb master alloy or vanadium iron nitride alloy is used as a single inoculant, the grain refinement and hardening effects cannot be fully utilized, resulting in a significant decrease in various performance indicators. The difference between Comparative Examples 3-6 and Comparative Example 1 lies in the use of different solution temperatures for high-temperature solution treatment. The solution temperatures for Comparative Examples 3-6 were 1020℃, 1025℃, 1045℃, and 1050℃, respectively. Although the hardness, tensile strength, and impact toughness test results of the high-wear-resistant steel material used in the tube molds of Comparative Examples 3-6 were slightly better than those of Comparative Examples 1-2, they were still far inferior to those of Examples 1-3. This indicates that controlling the solution temperature of the high-temperature solution treatment at 1030-1040℃ can promote the full dissolution of alloying elements, eliminate compositional segregation, and provide the prerequisite for obtaining a fine-grained martensitic matrix with high dislocation density, avoiding performance degradation caused by insufficient strengthening effect or grain coarsening due to improper temperature. Comparative Example 7 only used a single tempering operation, and its hardness, tensile strength, and impact toughness test results were also lower than those of Examples 1-3. This indicates that a single tempering cannot fully release the quenching internal stress, resulting in insufficient structural stability, leading to lower hardness and limited toughness compared to Examples 1-3.

[0034] Comparative Example 8 Compared with Example 1, Comparative Example 8 differs in that the AlCoCrNiTiB alloy powder in S3.1 is replaced with AlCoCrNiTi alloy powder. The elemental composition of the AlCoCrNiTi alloy powder, calculated by atomic percentage, includes: Al: 5.37%, Co: 27.42%, Cr: 24.9%, Ni: 25.59%, Ti: 16.72%. The AlCoCrNiTi alloy powder is ball-milled and mixed with nano-ytterbium oxide powder, with the amount of nano-ytterbium oxide powder added being 1% of the mass of the AlCoCrNiTi alloy powder, to obtain laser cladding powder. This laser cladding powder is used for laser cladding modification of the surface of the steel material body, while the remaining steps remain unchanged, to prepare high wear-resistant steel material for tube molds, and is referred to as Comparative Example 8.

[0035] Comparative Example 9 Compared with Example 1, the difference of Comparative Example 9 is that the nano-ytterbium oxide powder in the laser cladding powder is replaced with AlCoCrNiTiB alloy powder. The laser cladding powder is composed only of AlCoCrNiTiB alloy powder. The other steps remain unchanged. The high wear-resistant steel material for tube mold is prepared and is referred to as Comparative Example 9.

[0036] Referring to the ASTM G133-22 test standard, the coefficient of friction of the high wear-resistant steel surface of the pipe molds in Examples 1-3 and Comparative Examples 8-9 was measured using a friction sensor. The results are as follows: Figure 2 As shown; The wear resistance of the high wear-resistant steel materials used for the tube molds in Examples 1-3 and Comparative Examples 8-9 was tested using a reciprocating friction and wear testing machine. The test samples were all 50mm*50mm*2mm in size. After washing with ethanol and deionized water and drying with non-woven cloth, the test samples were weighed and recorded as m0. Subsequently, the weighed test samples were fixed so that the alloy composite layer of the test sample was rubbed against a grinding material. The grinding material was a 5mm diameter GCr15 high carbon chromium bearing steel ball, the load was 500g, the friction stroke was 10mm, the friction frequency was 5Hz, and the friction time was 30min. After the friction was completed, the test samples were washed with ethanol and deionized water, dried with non-woven cloth, and the mass of the worn test sample was recorded as m1. The wear rate of the sample was calculated using the formula: Wear rate (%) = (m0-m1) / m0*100%. The above test was repeated 3 times, and the average value was taken. The result is as follows: Figure 2 As shown.

[0037] like Figure 2 As can be seen, the wear rate of the high wear-resistant steel materials for pipe molds prepared in Examples 1-3 is all <0.4%, and the friction coefficient is all less than 0.1. The wear rate and friction coefficient are better than those of Comparative Examples 8-9. The AlCoCrNiTi alloy powder used in Comparative Example 8, due to the lack of B element in AlCoCrNiTiB alloy powder, has a significantly higher wear rate than that of Examples 1-3. This indicates that the introduction of B element in AlCoCrNiTiB alloy powder can significantly reduce the wear rate of high wear-resistant steel materials for pipe molds and improve their wear resistance. The laser cladding powder used in Comparative Example 9 is only AlCoCrNiTiB alloy powder, lacking the use of nano-ytterbium oxide powder. Although the wear rate is reduced compared to Comparative Example 8, the friction coefficient is increased. This indicates that nano-ytterbium oxide, as a rare earth modified phase, can help improve the wear resistance of high wear-resistant steel materials for pipe molds, while significantly reducing the friction coefficient, so that high wear-resistant steel materials for pipe molds have both high wear resistance and low friction characteristics.

[0038] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Parts not described in detail in this specification are prior art known to those skilled in the art.

Claims

1. A manufacturing process for a high wear-resistant steel material for pipe molds, characterized in that, The high wear-resistant steel material for the tube mold includes a steel material body and an alloy composite layer on the surface of the steel material body; The steel material body comprises, by weight percentage: C: 0.28–0.36%, Si: 0.35–0.75%, Mn: 0.6–1.0%, Cr: 1.3–2.1%, Mo: 0.41–0.55%, V: 0.036–0.054%, N: 0.008–0.015%, Al: 0.08–0.15%, Ti: 0.02–0.04%, Nb: 0.01–0.03%, with the balance being Fe and unavoidable impurities; The preparation steps include the following: Step S1: Smelting. Calculate the proportions of C, Si, Mn, Cr and Mo in the composition of the steel material as described above, weigh the required furnace charge, and smelt and refine the furnace charge to obtain a refined melt. Pour the refined melt into a ladle containing an inoculating modifier, keep it at a constant temperature, remove slag, and obtain molten steel. The inoculant is composed of Al-Ti-Nb master alloy and vanadium ferronitride alloy mixed in a mass ratio of (1-1.4):1; Step S2: Casting and heat treatment. The molten steel is poured into a casting mold to obtain a casting. The casting is heated to 790-810℃ and held for 60-90 minutes. Then, the temperature is raised to 960-980℃ and held for 60-90 minutes. Subsequently, the temperature is raised to 1030-1040℃ and held for 60-90 minutes. After that, it is oil quenched and cooled. The temperature is then raised to 540-560℃ and held for 1-3 hours. It is then air-cooled to room temperature. The temperature is then raised again to 540-560℃ and held for 1-3 hours. Finally, it is air-cooled to room temperature to obtain the steel material body. Step S3: Preparation of high wear-resistant steel material for pipe molds. Using Al, Co, Cr, Ni, Ti and B powders as raw materials, AlCoCrNiTiB alloy powder is prepared. Nano-ytterbium oxide powder and AlCoCrNiTiB alloy powder are ball-milled and dried to obtain laser cladding powder. The surface of the steel material is modified by laser cladding using the laser cladding powder to form an alloy composite layer on the steel material, thus obtaining high wear-resistant steel material for pipe molds.

2. The preparation process of a high wear-resistant steel material for pipe molds according to claim 1, characterized in that, The furnace charge includes ordinary scrap steel, carbon raiser, ferrochrome, ferrosilicon, ferromanganese, and ferromolybdenum.

3. The preparation process of a high wear-resistant steel material for pipe molds according to claim 2, characterized in that, The AlCoCrNiTiB alloy powder has the following elemental composition by atomic percentage: Al: 5.10%, Co: 27.15%, Cr: 24.63%, Ni: 25.32%, Ti: 16.45%, B: 1.35%.

4. The preparation process of a high wear-resistant steel material for pipe molds according to claim 1, characterized in that, Step S1: Melting, specifically including the following steps: S1.1: Calculate the proportion of C, Si, Mn, Cr and Mo in the composition of the steel material, weigh the required furnace charge, add the furnace charge to the vacuum induction furnace, evacuate the vacuum induction furnace and introduce argon gas, and melt at 1520~1570℃ for 30~50min to obtain the melt. S1.2: Add a slag remover to the melt and refine for 5-10 minutes to obtain a refined melt; S1.3: Add the inoculating modifier to the ladle. The inoculating modifier is preheated to 1120-1160°C along with the ladle. The refined melt is then rapidly poured into the ladle at a rate of 3-5 L / min. The ladle is held at 1290-1360°C for 30-40 minutes. The slag is removed to obtain molten steel.

5. The preparation process of a high wear-resistant steel material for pipe molds according to claim 4, characterized in that, The slag remover is obtained by mixing calcium fluoride and calcium oxide at a mass ratio of 2:1, and the amount of slag remover used is 0.8 to 1.5% of the melt weight.

6. The preparation process of a high wear-resistant steel material for pipe molds according to claim 5, characterized in that, The amount of inoculant used is 0.4% to 0.8% of the weight of the refined melt.

7. The preparation process of a high wear-resistant steel material for pipe molds according to claim 1, characterized in that, Step S2: Casting and heat treatment, specifically including the following steps: S2.1: Pour molten steel into the casting mold container on the casting machine, and let it cool and solidify in the air until the temperature inside the casting mold container is 200-260℃. Then, remove the solidified casting from the casting mold container to obtain the casting. S2.2: Place the casting in a high-temperature resistance furnace and heat it to 790-810℃ at a heating rate of 6-10℃ / min. Hold it at this temperature for 60-90min. Then, heat it to 960-980℃ at a heating rate of 4-8℃ / min and hold it for 60-90min. After that, heat it to 1030-1040℃ at a heating rate of 3-5℃ / min and hold it for 60-90min. Finally, oil quench the casting to room temperature to obtain the quenched casting. S2.3: Heat the quenched casting to 540-560℃ at a heating rate of 6-8℃ / min, hold for 1-3 hours, air cool to room temperature, and then heat again to 540-560℃ at a heating rate of 6-8℃ / min, hold for 1-3 hours, and air cool to room temperature to obtain the steel material body.

8. The preparation process of a high wear-resistant steel material for pipe molds according to claim 1, characterized in that, Step S3: Preparation of high wear-resistant steel material for the tube mold, specifically including the following steps: S3.1: Using Al, Co, Cr, Ni, Ti and B powders as raw materials, weigh the raw materials according to the elemental composition ratio of AlCoCrNiTiB alloy powder, and ball mill the weighed raw materials together at a ball mill speed of 180-200 r / min for 3-5 h. After ball milling, AlCoCrNiTiB alloy powder is obtained. Then, nano-ytterbium oxide powder is added to the AlCoCrNiTiB alloy powder at a mass of 0.8-1.2% of the AlCoCrNiTiB alloy powder. Ball milling is continued at a ball mill speed of 100-140 r / min for 1-3 h to obtain mixed powder. The mixed powder is then vacuum dried to obtain laser cladding powder. S3.2: Sand the surface of the steel material body with sandpaper and wipe it with alcohol to remove the oxide layer and oil stains on the surface of the steel material body. Then, use laser cladding powder to perform laser cladding modification on the cleaned steel material body surface to form an alloy composite layer on the steel material body. S3.3: After the steel material body is clad, it is placed in an insulated box at 340-400℃ for 1-3 hours and then air-cooled to room temperature to obtain high wear-resistant steel material for pipe mold.

9. The preparation process of a high wear-resistant steel material for pipe molds according to claim 8, characterized in that, The parameters for laser cladding are as follows: laser power of 1300-1500W, laser scanning speed of 5-10mm / s, powder feeding rate of 7.2-8.8g / min, spot diameter of 3-5mm, and overlap rate of 40-60%. The entire laser cladding process is carried out under the protection of high-purity argon gas with an argon gas flow rate of 3-6L / min.

10. A high wear-resistant steel material for pipe molds, characterized in that, It is prepared by the preparation process of a high wear-resistant steel material for pipe molds according to any one of claims 1-9.

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