A new material of cermet roll and its preparation method

Abstract

The application discloses a new cermet roller material and a preparation method thereof, and relates to the technical field of hard alloy. The new cermet roller material comprises the following components in proportion by weight: 10-50% of TiC, 14-52% of Co, 5-20% of Ni, 10-26% of Mo, 8-16% of WC, 0.5-2% of Cr3C2, 1-5% of TaC and 0.04-0.6% of Ce; wherein the proportion of the weight of Ni in the total weight of Ni and Co is less than 30%. The preparation method comprises four steps of ball milling mixing, drying granulation, pressing forming and sintering. The application takes TiC as a matrix, greatly reduces the WC dosage, controls the proportion of Ni in the binder phase, and realizes the synergistic optimization of the strength and toughness of the material, the high-temperature oxidation resistance and the great reduction of the cost of the material. The prepared roller has a hardness of 78-87 HRA and a bending strength of 2200-3000 MPa, the cost is significantly reduced compared with a traditional WC system roller, the roller can be adapted to high-temperature and high-load rolling conditions, and is suitable for industrialized batch production.

Description

Technical Field

[0001] This invention relates to the field of cemented carbide technology, specifically to a new metal-ceramic roll material and its preparation method. Background Technology

[0002] Rolls are core wear parts in metal plastic forming, and their material properties directly determine rolling efficiency, product surface quality, and production costs. Currently, the most widely used roll materials in industry are WC-based (WC-Co or WC-Co-Ni) cemented carbides. Although these materials have high hardness and wear resistance, they still have the following problems in practical use: WC-based cemented carbides have a high WC content (usually above 75%), and WC is expensive (currently 25 to 30 times that of TiC) and scarce, resulting in high roll material costs.

[0003] To improve roll performance and reduce manufacturing costs, the industry has experimented with various material systems. For example, some studies have proposed using a TiC system. However, in TiC alloys, the Co / Ni ratio plays a crucial role in the material's resistance to high-temperature oxidation. An inappropriate ratio can lead to a significant decrease in the material's resistance to high-temperature oxidation, making it difficult to meet the actual working requirements of the rolls. Some technical solutions have also attempted to add TiCN, a material with better performance, to the TiC system to improve product performance, but the actual application results have not been ideal. On the one hand, TiCN is also expensive. To improve product performance, the TiCN content must be increased, which will keep the product manufacturing cost high. If the amount of TiCN added is reduced, the performance advantages of TiCN cannot be fully utilized. On the other hand, through practice, the performance of rolls prepared by mixing TiC and TiCN is even worse than that of rolls prepared by using either material alone.

[0004] Meanwhile, most existing TiC-based cermet materials are used in the field of metal cutting tools, and the total Ni+Co content of these materials is usually controlled within the range of 10-18%. Directly transferring these materials for cutting tools to the rolling mill field cannot meet the complex working conditions of rolling mills, such as high loads, strong friction, and harsh high temperatures (700-1000℃) during the rolling process.

[0005] In summary, existing roll materials and related improvement schemes have failed to simultaneously solve the three core problems of high cost, short service life, and insufficient resistance to high-temperature oxidation. There is an urgent need to develop a new roll material that combines low cost, long service life, and excellent performance. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a new metal-ceramic roll material and its preparation method. Using TiC as the matrix, the method significantly reduces the amount of WC and achieves synergistic optimization of material strength, toughness, high-temperature oxidation resistance and low production cost by controlling the proportion of Ni in the binder phase and adding the rare earth element cerium (Ce).

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A novel metal-ceramic roll material comprises the following components in the indicated weight ratios: TiC 10%~50%, Co 14%~52%, Ni 5%~20%, Mo 10%~26%, WC 8%~16%, Cr3C2 0.5%~2%, TaC 1%~5%, and Ce 0.04%~0.6%; wherein the weight of Ni accounts for less than 30% of the total weight of Ni and Co.

[0009] This invention also provides a method for preparing the above-mentioned new metal-ceramic roll material, as follows:

[0010] S1: Ball milling: Add the raw materials to a ball mill according to the specified ratio and ball mill them to obtain a mixture;

[0011] S2: Drying and granulation: The mixture obtained in step S1 is placed in a dryer for drying and granulation to obtain powder;

[0012] S3: Pressing and molding: Make a mold according to the specifications of the finished roller, and put the powder obtained in step S2 into the mold and press it to obtain the roller blank;

[0013] S4: Sintering: The roll blank is placed in a low-pressure furnace for degreasing and sintering, and the sintered blank is the finished product.

[0014] Furthermore, in step S1, the ball mill is a drum ball mill with a ball-to-material ratio of 3:1. The ball milling media is a mixture of hexane and paraffin wax. The amount of paraffin wax added accounts for 1.5 to 2.5% of the raw material, and the amount of hexane added accounts for 35% of the ball mill cylinder. The ball milling time is 48 to 96 hours.

[0015] Furthermore, in step S3, a hydraulic press is used to press and shape the powder inside the mold, and the pressure of the hydraulic press is controlled at 500~800 kg / cm². 3 .

[0016] Furthermore, during the degreasing and sintering process in step S4, the temperature of the low-pressure furnace is raised at a constant rate to 1380~1460℃ and held for 1.5 hours.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) This invention uses a TiC-based metal-ceramic system to replace the high proportion of WC system in traditional rolls. By introducing high-entropy metallic binder phases and hard phases such as Co, Ni, Mo, and TaC, as well as trace reinforcing phases such as Cr3C2 and Ce, a material structure with good toughness, wear resistance, and high-temperature oxidation resistance is constructed. This system significantly improves the overall performance of rolls under high-temperature and high-load conditions.

[0019] (2) The Ni / (Ni+Co) ratio control proposed in this invention, which is less than 30%, was established after extensive experiments and theoretical analysis to simultaneously meet the multiple stringent requirements of high strength, good toughness, and excellent high-temperature oxidation resistance of the rolls. Traditional Ni / Co ratios are mainly for WC-based cemented carbides, and the addition of Ni is primarily for cost reduction, with a high degree of arbitrariness in the amount added. However, this approach cannot effectively reflect the direct impact of the mass percentage of Ni in the binder phase (Ni+Co) on the performance of TiC-based alloys. This invention achieves synergistic optimization of multiple performance factors by controlling the proportion of Ni in the binder phase:

[0020] Excessive Ni content severely impairs the material's oxidation resistance under high-temperature rolling conditions, leading to surface oxidation, cracking in the working parts of the product, and significantly shortening its lifespan. Controlling the Ni / (Ni+Co) ratio to below 30% effectively suppresses this adverse effect.

[0021] Ni improves the toughness of materials, but too low a content makes the material brittle; Co provides good strength and wettability. By controlling the proportion of Ni in the binder phase, rather than a simple Ni / Co ratio, the required strong and tough bonding properties of the material under high impact and high load rolling conditions can be more precisely controlled, avoiding the sacrifice of overall strength or oxidation resistance due to simply pursuing a high Ni / Co ratio.

[0022] (3) In this invention, the WC content is controlled between 8% and 16%, which is significantly lower than the WC content in traditional WC system rolls, which is usually higher than 75%. Due to the high price and limited resources of WC, the component design of this invention significantly reduces the cost of raw materials and improves the economic efficiency and market competitiveness of the product while ensuring that the performance of the roll meets the existing requirements.

[0023] (4) The metal-ceramic roll material provided by the present invention also includes rare earth element Ce, which can increase the toughness of the material by more than 15%, increase the high temperature bending strength by more than 15%, and significantly reduce the friction coefficient, thereby improving the service life and stability of the roll under high temperature and heavy load conditions.

[0024] (5) The preparation method provided by the present invention has mature process, clear parameters, and strong repeatability, and is suitable for industrial mass production. Detailed Implementation

[0025] The present invention will be further described below with reference to the embodiments. The embodiments of the present invention include, but are not limited to, the following embodiments.

[0026] Example 1

[0027] The new metal-ceramic roll material provided in this embodiment includes the following components in the following weight ratio: TiC 50%, Co21%, Ni 8.46%, Mo 11%, WC 8%, Cr3C2 0.5%, TaC 1%, Ce 0.04%, wherein Ni / (Ni+Co) = 28.72% (<30%).

[0028] The method for preparing cermet rolls using the above components is as follows:

[0029] S1: Ball milling: Add the raw materials to a drum ball mill according to the ratio and ball-to-material ratio of 3:1. The ball milling media is a mixture of hexane and paraffin. The amount of paraffin added accounts for 2% of the raw materials, and the amount of hexane added accounts for 35% of the volume of the ball mill cylinder. After ball milling for 48 hours, a mixture is obtained.

[0030] S2: Drying and granulation: The mixture obtained in step S1 is placed in a dryer for drying and granulation to obtain powder;

[0031] S3: Compression Molding: A mold is made according to the specifications of the finished roller. The powder obtained in step S2 is loaded into the mold and compressed using a hydraulic press. The pressure of the hydraulic press is controlled at 700 kg / cm² during compression. 3 After pressing, a roll blank is obtained;

[0032] S4: Sintering: The roll blank is placed in a low-pressure furnace for degreasing and sintering. During the sintering process, the temperature of the low-pressure furnace is raised to 1400℃ at a uniform rate and held for 1.5 hours to obtain the finished product.

[0033] The new metal-ceramic roll material prepared in this embodiment was subjected to performance testing, and its hardness was 87 HRA and its bending strength was 2600 MPa.

[0034] Example 2

[0035] The new metal-ceramic roll material provided in this embodiment includes the following components in the following weight ratio: TiC 10%, Co 32.4%, Ni 13%, Mo 23%, WC 14%, Cr3C2 2%, TaC 5%, Ce 0.6%, wherein Ni / (Ni+Co) = 28.63% (<30%).

[0036] The metal-ceramic rolls in this example were prepared using the same preparation method as in Example 1.

[0037] The metal-ceramic roll prepared in this embodiment was subjected to performance testing, and its hardness was 82 HRA and its bending strength was 2800 MPa.

[0038] Example 3

[0039] The new metal-ceramic roll material provided in this embodiment includes the following components in the following weight ratio: TiC 25%, Co 34.5%, Ni 14%, Mo 10%, WC 11.2%, Cr3C2 1%, TaC 4%, Ce 0.3%, wherein Ni / (Ni+Co) = 28.87% (<30%).

[0040] The metal-ceramic rolls in this example were prepared using the same preparation method as in Example 1.

[0041] The metal-ceramic roll prepared in this embodiment was subjected to performance testing, and its hardness was 80 HRA and its bending strength was 2700 MPa.

[0042] Example 4

[0043] The new metal-ceramic roll material provided in this embodiment includes the following components in the following weight ratio: TiC 15%, Co 47%, Ni 5%, Mo 13.4%, WC 16%, Cr3C2 1.5%, TaC 2%, Ce 0.1%, wherein Ni / (Ni+Co) = 9.6% (<30%).

[0044] The metal-ceramic rolls in this example were prepared using the same preparation method as in Example 1.

[0045] The metal-ceramic roll prepared in this embodiment was subjected to performance testing, and its hardness was 78 HRA and its bending strength was 3000 MPa.

[0046] Example 5

[0047] The new metal-ceramic roll material provided in this embodiment includes the following components in the following weight ratio: TiC 35%, Co 25%, Ni 10%, Mo 13.93%, WC 12%, Cr3C2 1%, TaC 3%, Ce 0.07%, wherein Ni / (Ni+Co) = 28.57% (<30%).

[0048] The metal-ceramic rolls in this example were prepared using the same preparation method as in Example 1.

[0049] The metal-ceramic roll prepared in this embodiment was subjected to performance testing, and its hardness was 85 HRA and its bending strength was 2200 MPa.

[0050] Comparative Example 1

[0051] The traditional roll material, WC-Co cemented carbide, has the following weight ratio: WC 78%, Co 22%, and no TiC, Ni, Mo, or Cr3C2.

[0052] The roll material provided in this comparative example has the following properties: hardness 86 HRA, bending strength 2100 MPa, but WC content is high, and the raw material cost is 3 to 4 times that of Example 1.

[0053] Comparative Example 2

[0054] The weight ratio of each component of the roll material provided in this comparative example is: TiC 50%, Co 15%, Ni 14%, Mo 11%, WC 8%, Cr3C2 2%; wherein Ni / (Ni+Co)=48.28% (>30%).

[0055] The roll material provided in this comparative example has the following properties: hardness 78HRA, bending strength 1500 MPa. It has poor resistance to high-temperature oxidation, and surface cracking occurs during high-temperature rolling. Cracks appear on the surface of the finished product, and the rolls made cannot be used.

[0056] Comparative Example 3

[0057] The weight ratio of each component is as follows: TiC 40%, TiCN 10%, Co 21%, Ni 8%, Mo 11%, WC 8%, Cr3C2 2%; among which, Ni / (Ni+Co)=27.59% (<30%).

[0058] The roll material provided in this comparative example has the following properties: hardness 84 HRA, bending strength 1800 MPa. Its performance is inferior to that of Example 1, and TiCN is expensive, with raw material costs 1.5 to 1.6 times that of Example 1.

[0059] A comprehensive comparison of Examples 1-5 and Comparative Examples 1-3 reveals that the new metal-ceramic roll material prepared by this invention possesses significant advantages in both overall performance and economy. From a mechanical property perspective, the product of this invention exhibits a hardness range of 78-87 HRA and a bending strength of 2200-3000 MPa, which is not only superior to Comparative Example 3 (containing TiCN) but also comparable to or even surpasses Comparative Example 1 (containing traditional WC-Co cemented carbide). From a cost perspective, this invention significantly reduces raw material costs by drastically reducing WC usage and eliminating the addition of expensive TiCN. Regarding operational adaptability, this invention strictly controls Ni / (Ni+Co) < 30%, effectively ensuring the material's resistance to high-temperature oxidation and avoiding the surface cracking problem observed in Comparative Example 2 due to excessive nickel content. In summary, the material provided by this invention achieves synergistic optimization of mechanical properties, high-temperature oxidation resistance, and production costs, fully meeting the requirements for rolls under high-temperature and high-load conditions.

[0060] The above embodiments are merely one of the preferred embodiments of the present invention and should not be used to limit the scope of protection of the present invention. Any modifications or refinements made to the main design concept and spirit of the present invention that are not of substantial significance, but solve the same technical problem as the present invention, should be included within the scope of protection of the present invention.

Claims

1. A novel metal-ceramic roll material, characterized in that, The components include the following weight ratios: TiC 10%~50%, Co 14%~52%, Ni 5%~20%, Mo 10%~26%, WC 8%~16%, Cr3C2 0.5%~2%, TaC 1%~5%, and Ce 0.04%~0.6%; wherein the weight of Ni accounts for less than 30% of the total weight of Ni and Co.

2. The method for preparing the new metal-ceramic roll material as described in claim 1, characterized in that, Includes the following steps: S1: Ball milling: Add the raw materials to a ball mill according to the specified ratio and ball mill them to obtain a mixture; S2: Drying and granulation: The mixture obtained in step S1 is placed in a dryer for drying and granulation to obtain powder; S3: Pressing and molding: Make a mold according to the specifications of the finished roller, and put the powder obtained in step S2 into the mold and press it to obtain the roller blank; S4: Sintering: The roll blank is placed in a low-pressure furnace for degreasing and sintering, and the sintered blank is the finished product.

3. The method for preparing a new metal-ceramic roll material according to claim 2, characterized in that, In step S1, a drum ball mill is used, the ball-to-material ratio is 3:1, the ball milling media is a mixture of hexane and paraffin, the amount of paraffin added accounts for 1.5~2.5% of the raw material, the amount of hexane added accounts for 35% of the ball mill cylinder, and the ball milling time is 48~96h.

4. The method for preparing a new metal-ceramic roll material according to claim 3, characterized in that, In step S3, a hydraulic press is used to press and shape the powder inside the mold. The pressure of the hydraulic press is controlled at 500~800 kg / cm². 3 .

5. The method for preparing a new metal-ceramic roll material according to claim 4, characterized in that, During the degreasing and sintering process in step S4, the temperature of the low-pressure furnace is raised at a constant rate to 1380~1460℃ and held for 1.5 hours.