High-carbon cobalt-based wear-resistant stellite 6b alloy plate precision rolling process

Abstract

The application provides a high-carbon cobalt-based wear-resistant Stellite 6B alloy plate precision rolling process, and mainly relates to the field of plate rolling. The rolling process comprises the following steps: Stellite 6B alloy plate blank heating, aluminum silicate fiber cotton sheath, hot rolling, machining, precision rolling, grinding, and inspection. The Stellite 6B alloy plate prepared by the application has excellent wear resistance, can meet the use requirements of high wear resistance, long service life and high strength of the plate, and has a good market application prospect.

Description

Technical Field

[0001] This invention mainly relates to the field of preparation technology of wear-resistant alloy plates for industries such as aerospace, petrochemical, and major equipment, specifically a precision rolling process for high-carbon cobalt-based wear-resistant Stellite 6B alloy plates. Background Technology

[0002] In aerospace, petrochemical, and heavy equipment industries, critical components frequently operate under complex loads and harsh environments, often failing prematurely due to high temperatures, wear, and corrosion. Currently, wear accounts for over 60% of all metal material failures worldwide. Wear not only wastes materials but also requires repairs and downtime when replacing parts, consuming significant human, material, and financial resources. According to incomplete statistics, in my country's metallurgical, building materials, coal, mining, tunnel, and power industries, metal parts operating in environments such as mud, ore, dust, and high temperatures suffer wear losses exceeding one million tons annually. Currently, wear-resistant and high-temperature-resistant materials developed domestically and internationally are mainly classified into three categories: iron-based, nickel-based, and cobalt-based wear-resistant and high-temperature-resistant materials. Stellite 6B alloy is a high-performance cobalt-chromium-tungsten-carbon alloy with a cobalt matrix and carbide reinforcement. It contains nickel, chromium, tungsten, carbon, and small amounts of alloying elements such as molybdenum, niobium, tantalum, titanium, and iron. It possesses excellent mechanical properties, corrosion and wear resistance, as well as resistance to oxidation and gas erosion, exhibiting superior overall performance. For parts subjected to prolonged exposure to high temperatures, dust, and muddy environments, using Stellite 6B alloy sheets significantly improves component lifespan, reduces production costs, and yields substantial economic benefits.

[0003] Stellite 6B is a high-temperature alloy, but unlike typical high-temperature alloys, it contains over 1% wt of carbon, with carbides such as M23C6 and M6C accounting for up to 10%. While this ensures excellent wear resistance, the carbides, acting as reinforcing phases, also serve as crack initiation points during hot working, making hot working and forming difficult. This results in significant challenges in rolling Stellite 6B alloy sheets. Although some researchers have studied Stellite 6B alloy sheets, their work has primarily focused on the alloy composition and the impact of heat treatment processes on the material's microstructure and properties. Research on precision rolling of these sheets, particularly for engineering applications, is scarce, lacking a solid technical foundation. This leads to difficulties in controlling the temperature of mass-produced Stellite 6B alloy sheets, resulting in easy cracking, low yield, and high costs. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a precision rolling process for high-carbon cobalt-based wear-resistant Stellite 6B alloy plates, which solves the problems of difficult temperature control, rapid heat dissipation, easy cracking, and low yield during the rolling process of alloy plates.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A precision rolling process for high-carbon cobalt-based wear-resistant Stellite 6B alloy plates includes the following steps:

[0007] S1: Slab heating; Place the Stellite 6B alloy slab into a high-temperature heating furnace for heating. The heating rate is controlled at 3℃~5℃ / minute, and the maximum heating temperature is 1180℃±20℃. After reaching the temperature, hold the temperature for 30 minutes to 60 minutes.

[0008] S2: Refractory aluminum silicate fiber cotton covering insulation; After the Stellite 6B alloy slab is heated, it is wrapped with aluminum silicate fiber cotton.

[0009] S3: Reheating in the furnace; The Stellite 6B alloy slab, which has been wrapped and insulated with refractory aluminum silicate fiber cotton, is reheated in the furnace at a temperature of 1180℃±20℃ for more than 20 minutes.

[0010] S4: Hot rolling; Stellite 6B alloy slabs are hot rolled after exiting the furnace. The rolling speed is controlled within the range of 50mm to 200mm / second. The final rolling temperature of the slab is greater than 1000℃. When the temperature is lower than 1000℃, the slab is reheated in the furnace. The holding time is not less than 15 minutes. The thickness of the slab rolled in the final heat is 3mm to 5mm thicker on one side than the final product. When the slab length is greater than 2000mm, it is cut in the middle.

[0011] S5: Plate grinding; After the plate is cooled to below 200℃, the surface is machined and ground, and the surface roughness of the plate is required to be below 3.2μm;

[0012] S6: Precision rolling; the ground plate is heated in a furnace at 1190℃±10℃ for more than 10 minutes. After the holding time, it is rolled out of the furnace. A 4-roll hot rolling mill is used, with the surface roughness of the rolls being less than 1.6μm. The final rolling temperature of the plate is greater than 1000℃. When the temperature is lower than 1000℃, it is reheated in the furnace. The single-sided machining allowance of the rolled plate is 0.2mm~0.5mm.

[0013] S7: Machining; The surface of Stellite 6B alloy sheet is finished by precision grinding and rolling using a grinding machine;

[0014] S8: Ultrasonic testing; using AAA-grade ultrasonic testing precision, longitudinal wave contact method to test the internal quality of Stellite 6B alloy plates.

[0015] Furthermore, in S2, the thickness of the refractory aluminum silicate fiber cotton ranges from 5mm to 10mm, and the size of the cut fiber cotton is based on completely covering the Stellite alloy blank. A layer of glass powder with a particle size of less than 250 is scattered on the side in contact with the Stellite 6B alloy.

[0016] Furthermore, in S4, the deformation amount of the specific rolling passes in hot rolling is controlled as 15% → 20% → 25% → … → 25%.

[0017] Furthermore, in S6, the deformation amount of the precision rolling pass is controlled at 20% → 25% → … → 25%, and the rolling speed is controlled within the range of 100mm to 400mm / second.

[0018] Furthermore, in step S8, when ultrasonic testing detects large particle inclusions in the board material, the defective portion is cut off.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] This invention addresses the challenges of temperature control, rapid heat dissipation, susceptibility to cracking, and low yield in the rolling of high-carbon Stellite 6B alloy sheets. It employs innovative process measures to solve these problems during the alloy sheet rolling process. Verification has shown that products prepared using this innovative process exhibit excellent performance. This rolling process helps improve the quality of Stellite 6B alloy, meeting the requirements for high wear resistance and long service life in the manufacture of components.

[0021] This patent provides a precision rolling process design. Addressing the problem of cracking during rolling of Stellite 6B high-temperature alloy sheets with a carbon content exceeding 1% wt, this invention, considering the characteristics of the alloy material, designs a precision rolling process for high-carbon, difficult-to-deform high-temperature alloy sheets. By controlling the rolling speed and final rolling temperature, this process improves the sheet yield and ensures smooth rolling operations. First, the rolling speed significantly affects the tensile properties of the high-temperature alloy sheet. As the rolling speed increases, the tensile properties first increase and then decrease. When the rolling speed exceeds 400 mm / s, the tensile strength of the Stellite 6B alloy sheet decreases. Furthermore, strictly controlling the final rolling temperature to not be lower than 1000℃ is crucial. Below this temperature, the sheet's resistance to rolling deformation increases sharply, making it prone to cracking. Compared to traditional rolling processes, this invention solves the current problem of cracking during rolling of high-carbon high-temperature alloy sheets in China, improves material yield, and significantly reduces production costs.

[0022] The present invention employs an aluminum silicate fiber cotton sheathing process, which not only avoids excessive cooling during the rolling process and ensures a uniform temperature field of the plate, but also optimizes the internal structure of the plate and the morphology of the precipitated reinforcing phase, thereby further improving the wear resistance of the plate. Detailed Implementation

[0023] The present invention will be further described in conjunction with specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined in this application.

[0024] Example 1:

[0025] The Stellite 6B alloy slab is placed in a high-temperature heating furnace and heated at a rate of 3°C / min, with a maximum temperature of 1170°C. After reaching this temperature, it is held for 30 minutes. A 5mm thick layer of refractory aluminosilicate fiber cotton is used for insulation. A layer of 300-mesh glass powder is sprinkled on the side in contact with the Stellite 6B alloy to bind the slab. The heated Stellite 6B alloy slab is removed from the furnace and covered with aluminosilicate fiber cotton; it is then reheated. The covered Stellite 6B alloy slab is then placed back into the heating furnace and heated to 1180°C for 25 minutes. The Stellite 6B alloy slab is then hot-rolled. The deformation per rolling pass is controlled at 15% → 20% → 25% → … → 25%. The rolling speed is controlled within a range of 50mm / second. The final rolling temperature is 1030°C. If the temperature drops below 1000°C, the slab is reheated and held for at least 15 minutes. The thickness of the sheet rolled in the final heat treatment is 3mm thicker than the final product's single-sided thickness. When the sheet length exceeds 2000mm, it is slit in the middle. The sheet is cooled to 150℃, then machined and ground to a surface roughness of 2.6μm. After grinding, the sheet is heated in a furnace to 1090℃ for 15 minutes. After the holding time, it is rolled using a 4-roll hot rolling mill with a roll surface roughness of 1.2μm. The deformation per rolling pass is controlled at 20%→25%→…→25%, and the rolling speed is controlled within a range of 100mm / second. The final rolling temperature is 1020℃. If the temperature drops below 1000℃, the sheet is reheated in the furnace. The single-sided machining allowance of the rolled sheet is 0.2mm. The surface of the Stellite 6B alloy sheet is precision ground using a grinding machine. The internal quality of the Stellite 6B alloy sheet is inspected using AAA-grade ultrasonic testing with longitudinal wave contact method. Large internal inclusions discovered during inspection are removed.

[0026] Example 2:

[0027] Heating of Stellite 6B alloy slabs: The Stellite 6B alloy slabs are placed in a high-temperature furnace and heated at a rate of 5°C / min, with a maximum heating temperature of 1200°C ± 20°C. After reaching this temperature, the slab is held for 60 minutes. A 10mm thick layer of aluminosilicate fiber cotton is prepared, and a layer of glass powder with a particle size of less than 250 mesh is sprinkled on the side in contact with the Stellite 6B alloy to bind the slab. The heated Stellite 6B alloy slab is removed from the furnace and covered with aluminosilicate fiber cotton. The covered Stellite 6B alloy slab is then returned to the furnace for heating at 1200°C for 30 minutes. The Stellite 6B alloy slab is then hot-rolled. The deformation per rolling pass is controlled as follows: 15% → 20% → 25% → … → 25%. The rolling speed is controlled within a range of 200mm / second. The final rolling temperature is greater than 1000°C. When the temperature is below 1000℃, the plate is reheated in the furnace for at least 15 minutes. The thickness of the plate rolled in the final heat is 5mm thicker on each side than the final product. For plates longer than 2000mm, they are slit in the middle. After cooling to below 200℃, the plate is machined and ground to a surface roughness of less than 3.2μm. The ground plate is then loaded into the furnace for heating at 1200℃ for at least 10 minutes. After the holding time, the plate is rolled using a 4-roll hot rolling mill with a roll surface roughness of 1.2μm. The deformation per rolling pass is controlled at 20% → 25% → … → 25%, and the rolling speed is controlled within a range of 400mm / second. The final rolling temperature is above 1000℃. When the temperature is below 1000℃, the plate is reheated in the furnace. The single-sided machining allowance of the rolled sheet is 0.5mm; the surface of the rolled Stellite 6B alloy sheet is precision ground; the internal quality of the Stellite 6B alloy sheet is tested using the longitudinal wave contact method with AAA-grade ultrasonic testing precision. Large internal inclusions discovered during the inspection are removed.

[0028] Taking Example 2 as an example, the high-temperature tensile strength of Stellite 6B alloy sheet produced using the processing technology of Example 2 was tested. The test results at different temperatures are as follows:

[0029]

[0030] In summary, the Stellite 6B alloy sheet prepared under the conditions of this process has better mechanical strength than the sheet prepared under the current conventional process conditions, and therefore has the advantages of wear resistance and long service life.

Claims

1. A precision rolling process for high-carbon cobalt-based wear-resistant Stellite 6B alloy plates, characterized in that, Includes the following steps: S1: Slab heating; Place the Stellite 6B alloy slab into a high-temperature heating furnace for heating. The heating rate is controlled at 3℃~5℃ / minute, and the maximum heating temperature is 1180℃±20℃. After reaching the temperature, hold the temperature for 30 to 60 minutes. S2: Refractory aluminum silicate fiber cotton covering insulation; After the Stellite 6B alloy slab is heated, it is wrapped with aluminum silicate fiber cotton. S3: Reheating in the furnace; The Stellite 6B alloy slab, which has been wrapped and insulated with refractory aluminum silicate fiber cotton, is reheated in the furnace at a temperature of 1180℃±20℃ for more than 20 minutes. S4: Hot rolling; Stellite 6B alloy slabs are hot rolled after exiting the furnace. The rolling speed is controlled within the range of 50mm to 200mm / second. The final rolling temperature of the slab is greater than 1000℃. When the temperature is lower than 1000℃, the slab is reheated in the furnace. The holding time is not less than 15 minutes. The thickness of the slab rolled in the final heat is 3mm to 5mm thicker on one side than the final product. When the slab length is greater than 2000mm, it is cut in the middle. S5: Plate grinding; after the plate has cooled to below 200℃, the surface is machined and ground, and the surface roughness is required to be below 3.2μm; S6: Precision rolling; the ground plate is heated in a furnace at 1190℃±10℃ for more than 10 minutes. After the holding time, it is rolled out. A 4-roll hot rolling mill is used, with a roll surface roughness of less than 1.6μm. The final rolling temperature of the plate is greater than 1000℃. When the temperature is lower than 1000℃, it is reheated in the furnace. The single-sided machining allowance of the rolled plate is 0.2mm~0.5mm. The deformation of the precision rolling passes is controlled as follows: 20% for the first pass and 25% for the remaining passes. The rolling speed is controlled within the range of 100mm~400mm / second. S7: Machining; The surface of Stellite 6B alloy sheet is finished by precision grinding and rolling using a grinding machine; S8: Ultrasonic testing; using AAA-grade ultrasonic testing precision, longitudinal wave contact method to test the internal quality of Stellite 6B alloy plates.

2. The precision rolling process for high-carbon cobalt-based wear-resistant Stellite 6B alloy plates according to claim 1, characterized in that: In S2, the thickness of the refractory aluminum silicate fiber cotton ranges from 5mm to 10mm. The size of the cut refractory aluminum silicate fiber cotton is based on completely covering the Stellite 6B alloy slab. A layer of glass powder with a particle size of less than 250 mesh is sprinkled on the side in contact with the Stellite 6B alloy slab.

3. The precision rolling process for high-carbon cobalt-based wear-resistant Stellite 6B alloy plates according to claim 1, characterized in that: In S4, the deformation amount of the first rolling pass is 15%, the deformation amount of the second rolling pass is 20%, and the deformation amount of the remaining rolling passes is 25%.

4. The precision rolling process for high-carbon cobalt-based wear-resistant Stellite 6B alloy plates according to claim 1, characterized in that: In step S8, when ultrasonic testing detects large particle inclusions in the board material, the defective portion is cut off.

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