Precise rolling process for high-carbon cobalt-based wear-resistant stellite 6B alloy plate

Abstract

The invention provides a precise rolling process for a high-carbon cobalt-based wear-resistant stellite 6B alloy plate, and mainly relates to the field of plate rolling. The rolling process comprises the working procedures of stellite 6B alloy plate blank heating, aluminum silicate fiber cotton wrapping, hot rolling, machining, precise rolling, coping, inspection and the like. The stellite 6B alloy plate prepared by the method is excellent in wear resistance, meets the use requirements of high-performance plates on wear resistance, long service life and high strength, and has a good market application prospect.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of preparation of wear-resistant alloy plates for aerospace, petrochemical, major equipment and other industries, and specifically is a precision rolling process for high-carbon cobalt-based wear-resistant Stellite 6B alloy plates. Background Art

[0002] Some important parts in the fields of aerospace, petrochemical, and major equipment are often in service under complex loads and harsh environments, and a large number of parts often fail prematurely due to high temperature, wear, and corrosion. At present, more than 60% of metal materials fail worldwide due to wear. Wear not only wastes materials, but also requires repairs and downtime when replacing parts, consuming a lot of manpower, material, and financial resources. According to incomplete statistics, in my country's metallurgical, building materials, coal, mining, tunnels, electric power and other industry equipment, metal parts with working media or environments such as mud, ore, dust, and high temperature consume more than one million tons each year due to wear. At present, the wear-resistant and high-temperature resistant materials developed at home and abroad are mainly divided into three categories: iron-based wear-resistant and high-temperature resistant materials, nickel-based wear-resistant and high-temperature resistant materials, and cobalt-based wear-resistant and high-temperature resistant materials. Stellite 6B alloy is a kind of cobalt-chromium-tungsten-carbon high-performance metal material with cobalt as the matrix and carbide reinforcement. It contains nickel, chromium, tungsten, carbon and a small amount of molybdenum, niobium, tantalum, titanium, iron and other alloy elements. It has excellent mechanical properties, corrosion resistance, wear resistance, oxidation resistance and gas erosion resistance, and has excellent comprehensive performance. For parts that are in high temperature, dust, mud and sand environment for a long time, the use of Stellite 6B alloy plate can increase the service life of parts, reduce production costs, and have significant economic benefits.

[0003] Stellite 6B is a high-temperature alloy, but unlike common high-temperature alloy materials, its carbon content exceeds 1%wt, and the carbide content of M23C6 and M6C generated in the alloy reaches 10%. Although this ensures the excellent wear resistance of the alloy, carbides, as strengthening phases, are also the source of cracks during hot working, making the hot working technology of the alloy material difficult and difficult to form, resulting in very high technical difficulty in rolling Stellite 6B alloy plates. Although some researchers have studied Stellite 6B alloy plates, they mainly focus on the influence of alloy composition and heat treatment process on the microstructure and properties of materials. There are few studies on the precision rolling of plates, especially the rolling of Stellite 6B alloy plates for engineering applications, and lack of technical foundation, resulting in the temperature of Stellite 6B alloy plates produced by mass rolling being difficult to control, easy to crack, low yield rate, and high cost. Summary of the invention

[0004] In order to solve the deficiencies of the prior art, the present invention provides a high-carbon cobalt-based wear-resistant Stellite 6B alloy plate precision rolling process, which solves the problems of difficult temperature control, fast heat dissipation, easy cracking and low yield rate during the rolling process of the alloy plate.

[0005] In order to achieve the above object, the present invention is implemented through the following technical solutions:

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

[0007] S1: slab heating: placing the Stellite 6B alloy slab into a high-temperature heating furnace for heating, with the heating rate controlled at 3°C ​​to 5°C / min, the maximum heating temperature at 1180°C ± 20°C, and keeping the temperature for 30 to 60 minutes after reaching the temperature;

[0008] S2: Refractory aluminum silicate fiber wool coating and heat preservation: The heated Stellite 6B alloy slab is taken out of the furnace and coated with aluminum silicate fiber wool;

[0009] S3: Return to the furnace for heating; the Stellite 6B alloy slab, which has been wrapped and insulated with refractory aluminum silicate fiber wool, is put back into the heating furnace for heating at a temperature of 1180°C ± 20°C for a holding time of more than 20 minutes;

[0010] S4: hot rolling; the stellite 6B alloy slab is taken out of the furnace for hot rolling, the rolling speed is controlled in the range of 50mm to 200mm / s, the plate final rolling temperature is greater than 1000℃, when the temperature is lower than 1000℃, it is returned to the furnace for heating, and the holding time is not less than 15 minutes, the thickness of the plate after the last heat rolling is 3mm to 5mm thicker than the single side thickness of the final product, and when the plate length is greater than 2000mm, it is cut in the middle;

[0011] S5: Plate grinding; the plate is cooled to a temperature below 200°C, and the surface is machined and ground. The surface roughness of the plate is required to be less than 3.2μm;

[0012] S6: Precision rolling; the plate after grinding is charged into the furnace for heating, the heating temperature is 1190℃±10℃, the holding time is greater than 10 minutes, after the holding time is up, it is taken out of the furnace for rolling; a 4-roll hot rolling mill is used, the surface roughness of the roll is less than 1.6μm, the plate final rolling temperature is greater than 1000℃, when the temperature is lower than 1000℃, it is returned to the furnace for heating, and the single-side machining allowance of the plate after rolling is 0.2mm~0.5mm;

[0013] S7: machining: grinding the surface of the Stellite 6B alloy plate after rolling;

[0014] S8: Ultrasonic testing: Use AAA-level ultrasonic testing accuracy and longitudinal wave contact method to detect the internal quality of Stellite 6B alloy plates.

[0015] Furthermore, in S2, the thickness of the refractory aluminum silicate fiber wool ranges from 5 mm to 10 mm, and the size of the cut fiber wool is based on the size of the completely coated Stellite alloy slab, and a layer of glass powder with a particle size 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 of the hot rolling is controlled to be 15%→20%→25%→…→25%.

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

[0018] Furthermore, in S8, when the ultrasonic detection finds that the plate has large particle inclusion defects, the defective portion is removed.

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

[0020] The invention adopts innovative process measures to solve the problems of high carbon content Stellite 6B alloy sheet, such as difficulty in rolling temperature control, fast heat dissipation, easy cracking, and low yield rate. It has been verified that the products prepared by the above innovative process have good use effect. Through this rolling process, it is helpful to improve the quality level of Stellite 6B alloy and meet the requirements of high wear resistance and long life of the prepared parts.

[0021] This patent provides a precision rolling process design. Aiming at the problem that the Stellite 6B high-temperature alloy sheet with a carbon content exceeding 1%wt is prone to cracking during rolling, the present invention combines the characteristics of alloy materials to design a process method for precision rolling high-carbon and difficult-to-deform high-temperature alloy sheet. By controlling the rolling speed and the final rolling temperature, the process improves the yield rate of the sheet and ensures the smooth progress of the rolling process. First, the rolling speed has a significant effect on the tensile properties of the high-temperature alloy sheet. As the rolling speed increases, the tensile properties of the sheet first increase and then decrease. When the rolling speed exceeds 400 mm / s, the tensile strength of the Stellite 6B alloy sheet decreases. In addition, the final rolling temperature of the sheet is strictly controlled to be not less than 1000℃. When it is lower than this temperature, the sheet rolling deformation resistance increases sharply and it is easy to crack. Compared with the traditional rolling process, the present invention solves the current problem of high-carbon high-temperature alloy sheet rolling cracking in China, improves the material yield rate, and significantly reduces the production cost.

[0022] The present invention adopts an aluminum silicate fiber cotton sheathing process, so that the rolling process of the present invention not only avoids excessive cooling of the plate when it is out of the furnace and during rolling, ensuring a uniform temperature field of the plate, but also optimizes the internal structure of the plate and the morphology of the precipitated strengthening phase, further improving the wear resistance of the plate. DETAILED DESCRIPTION

[0023] In conjunction with specific embodiments, the present invention will be further described. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope limited by the application.

[0024] Embodiment 1:

[0025] Put the Stellite 6B alloy slab into a high-temperature heating furnace for heating, and control the heating rate to 3℃ / min, the highest heating temperature to 1170℃, and keep it warm for 30 minutes after reaching the temperature; use a 5mm thick refractory aluminum silicate fiber cotton sheath for insulation. Spread a layer of glass powder with a particle size of 300 mesh for bonding the Stellite alloy slab on the side in contact with the Stellite 6B alloy; the heated Stellite 6B alloy slab is taken out of the furnace, and is coated with aluminum silicate fiber cotton; and returned to the furnace for heating. The coated Stellite 6B alloy slab is put back into the heating furnace for heating at a temperature of 1180℃ and a holding time of 25min; the Stellite 6B alloy slab is taken out of the furnace for hot rolling. The deformation of the rolling pass is controlled to be 15%→20%→25%→……→25%. The rolling speed control range is 50mm / second. The final rolling temperature of the plate is 1030℃. When the temperature is lower than 1000℃, return to the furnace for heating, and the holding time is not less than 15min. The thickness of the plate after the last heat rolling is 3mm thicker than the single-side thickness of the final product. When the length of the plate is greater than 2000mm, it is cut in the middle; the plate is cooled to a temperature of 150℃, and the surface is machined and ground, and the surface roughness of the plate reaches 2.6μm; the plate after grinding is heated in the furnace, the heating temperature is 1090℃, and the insulation time is 15 minutes. After the insulation time is up, it is rolled out of the furnace. A 4-roll hot rolling mill is used, and the surface roughness of the roller is 1.2μm. The deformation of the rolling pass is controlled to be 20%→25%→……→25%, and the rolling speed control range is 100mm / second. The final rolling temperature of the plate is 1020℃. When the temperature is lower than 1000℃, it is returned to the furnace for heating. The single-side machining allowance of the plate after rolling is 0.2mm; the surface of the Stellite 6B alloy plate after rolling is finely ground by a grinder; the internal quality of the Stellite 6B alloy plate is detected by the longitudinal wave contact method with AAA-level ultrasonic inspection accuracy. The internal large particle inclusion defects found in the inspection are removed.

[0026] Embodiment 2:

[0027] Heating of the Stellite 6B alloy slab. The Stellite 6B alloy slab is placed in a high-temperature heating furnace for heating, the heating rate is controlled at 5℃ / min, the maximum heating temperature is 1200℃±20℃, and the temperature is kept for 60 minutes after reaching the temperature; a 10mm thick aluminum silicate fiber cotton is prepared, and a layer of glass powder with a particle size of less than 250 mesh is scattered on the side in contact with the Stellite 6B alloy for bonding the Stellite alloy slab; the heated Stellite 6B alloy slab is taken out of the furnace and coated with aluminum silicate fiber cotton; the coated Stellite 6B alloy slab is put back into the heating furnace for heating at a temperature of 1200℃ and a holding time of 30min; the Stellite 6B alloy slab is taken out of the furnace for hot rolling. The specific rolling pass deformation is controlled to be 15%→20%→25%→……→25%. The rolling speed control range is 200mm / second. The final rolling temperature of the plate is greater than 1000℃. When the temperature is lower than 1000℃, return to the furnace for heating, and the holding time is not less than 15min. The thickness of the plate after the last heat rolling is 5mm thicker than the single-side thickness of the final product. When the length of the plate is greater than 2000mm, it is cut in the middle; the plate is cooled to a temperature below 200℃, and the surface is machined and ground. The surface roughness of the plate is required to be less than 3.2μm; the plate after grinding is loaded into the furnace for heating, the heating temperature is 1200℃, and the holding time is greater than 10 minutes. After the holding time is up, it is rolled out of the furnace. A 4-roll hot rolling mill is used, and the surface roughness of the roller is 1.2μm. The deformation of the rolling pass is controlled to be 20%→25%→……→25%, and the rolling speed control range is 400mm / second. The final rolling temperature of the plate is greater than 1000℃. When the temperature is lower than 1000℃, return to the furnace for heating. The single-side machining allowance of the plate after rolling is 0.5mm; the surface of the rolled Stellite 6B alloy plate is finely ground by a grinder; the internal quality of the Stellite 6B alloy plate is tested by the longitudinal wave contact method with AAA-level ultrasonic inspection accuracy. The internal large particle inclusion defects found during the inspection are removed.

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

[0029]

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

Claims

1. A high carbon cobalt-based wear-resistant Stellite 6B alloy plate precision rolling process, characterized in that: The following steps are involved: S1: slab heating: placing the Stellite 6B alloy slab into a high-temperature heating furnace for heating, with the heating rate controlled at 3°C ​​to 5°C / min, the maximum heating temperature at 1180°C ± 20°C, and keeping the temperature for 30 to 60 minutes after reaching the temperature; S2: Refractory aluminum silicate fiber wool coating and heat preservation: The heated Stellite 6B alloy slab is taken out of the furnace and coated with aluminum silicate fiber wool; S3: Return to the furnace for heating; the Stellite 6B alloy slab, which has been wrapped and insulated with refractory aluminum silicate fiber wool, is put back into the heating furnace for heating at a temperature of 1180°C ± 20°C for a holding time of more than 20 minutes; S4: hot rolling; the stellite 6B alloy slab is taken out of the furnace for hot rolling, the rolling speed is controlled in the range of 50mm to 200mm / s, the plate final rolling temperature is greater than 1000℃, when the temperature is lower than 1000℃, it is returned to the furnace for heating, and the holding time is not less than 15 minutes, the thickness of the plate after the last heat rolling is 3mm to 5mm thicker than the single side thickness of the final product, and when the plate length is greater than 2000mm, it is cut in the middle; S5: Plate grinding; the plate is cooled to a temperature below 200°C, and the surface is machined and ground. The surface roughness of the plate is required to be less than 3.2μm; S6: Precision rolling; the plate after grinding is charged into the furnace for heating, the heating temperature is 1190℃±10℃, the holding time is greater than 10 minutes, after the holding time is up, it is taken out of the furnace for rolling; a 4-roll hot rolling mill is used, the surface roughness of the roll is less than 1.6μm, the plate final rolling temperature is greater than 1000℃, when the temperature is lower than 1000℃, it is returned to the furnace for heating, and the single-side machining allowance of the plate after rolling is 0.2mm~0.5mm; S7: machining: grinding the surface of the Stellite 6B alloy plate after rolling; S8: Ultrasonic testing: Use AAA-level ultrasonic testing accuracy and longitudinal wave contact method to detect the internal quality of Stellite 6B alloy plates.

2. The high carbon cobalt-based wear-resistant Stellite 6B alloy plate precision rolling process according to claim 1, characterized in that: In the 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 the size of the completely coated Stellite alloy slab. A layer of glass powder with a particle size less than 250 is scattered on the side in contact with the Stellite 6B alloy.

3. The high carbon cobalt-based wear-resistant Stellite 6B alloy plate precision rolling process according to claim 1, characterized in that: In S4, the specific rolling pass deformation of the hot rolling is controlled to be 15%→20%→25%→…→25%.

4. The high carbon cobalt-based wear-resistant Stellite 6B alloy plate precision rolling process according to claim 1, characterized in that: In the above S6, the deformation amount of each rolling pass of the precision rolling is controlled to be 20%→25%→…→25%, and the rolling speed is controlled in the range of 100 mm to 400 mm / sec.

5. The high carbon cobalt-based wear-resistant Stellite 6B alloy plate precision rolling process according to claim 1, characterized in that: In S8, when the ultrasonic detection finds that the plate has large particle inclusion defects, the defective portion is cut off.

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