Novel molybdenum alloy light rail finished roller manufacturing method

Abstract

The invention relates to a manufacturing method of a novel molybdenum alloy light rail finished product roller. The manufacturing method comprises the following steps that S1, chemical components are reasonably optimized and prepared, wherein the chemical components comprise 0.40%-0.60% of C, 0.50%-1.50% of Ni, 0.30%-0.60% of Si, 1.50%-2.50% of Mo, 0.60%-1.10% of Mn, 0.80%-1.20% of V, smaller than or equal to 0.030% of P, 0.50%-1.00% of Nb and smaller than or equal to 0.020% of S; re is not less than 0.015%, and Cr is 0.80-1.20%; s2, smelting pure molten steel; s3, special heat treatment of the roller; and S4, detecting technical indexes of the roller. The roller manufactured through the method is high in hardness and good in abrasion resistance, the hole-shaped groove bottom of the roller face of the working layer basically has no hardness difference, the impact toughness, the tensile strength and the heat crack resistance are improved, the service life of the roller is prolonged, the production efficiency of steel rolling enterprises is improved, and the purposes of reducing cost and improving efficiency are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of rollers, in particular to a novel method for manufacturing a finished product roller of a molybdenum alloy light rail. Background Art

[0002] As a type of steel with special-shaped sections, light rail is an important steel material that cannot be missing in mines, bridges, ports, urban buildings, and track construction. The market has high requirements for the size accuracy, surface quality, and negative tolerance rolling of light rail and other profiles. In order to meet the above requirements, steel rolling companies have put forward higher requirements for the finishing rollers used in the finished light rail racks: the finished finishing rollers must further have excellent wear resistance, high yield strength, toughness, and strong resistance to thermal cracking.

[0003] At present, the finishing rollers used in the 550-unit finished product stand rolling 15-24# light rail in my country are mainly made of nickel-chromium-molybdenum pearlite III# ductile iron and nickel-molybdenum bainite ductile iron rollers. When using finishing rollers of this material, the hole type of the rollers is set deeper due to the special cross-section of the light rail; in addition, there is a certain hardness drop in the working layer of this type of rollers. When the rollers are re-rolled, the rolling amount of the single groove of the hole type is often inconsistent, with large fluctuations, and the average rolling amount is relatively low. In order to ensure the surface quality of the rolled piece, it is necessary to change the groove frequently. At the same time, the finished finishing rollers of this material. Because the roller hole type is in contact with the high-temperature rolled piece for a long time, affected by the high temperature and water cooling, the side wall of the hole type and the bottom of the hole type groove often have irregular wear marks, and will also oxidize, extend, and expand, directly affecting the surface quality of the rolled piece, thereby increasing the grinding amount of the rollers. With the increase in grinding amount, the roller consumption is increased, the operating efficiency of the rolling mill is reduced, and the production cost of the enterprise is increased. In order to improve the above situation, some steel mills use high carbon semi-steel rolls and graphite steel rolls. The finished finishing rolls of this material have a carbon content of more than 1.7% and a roll hardness of 55-65HSD. With the increase of the content of nickel-chromium-molybdenum alloy elements, tempered troostite and cast bainite appear in the roll body structure. The rolls show good wear resistance when they are in operation. Then, due to the increase of carbon content, the carbide content of this material rolls is more than 5%, and some carbides will exist in the roll matrix in the form of strips or nets, and will form a small amount of shrinkage and loose areas in some areas of the roll, especially the R connection between the roll body and the upper and lower roll necks and the core of the roll body. The existence of these shrinkage and loose areas will directly affect the tensile strength of the roll. Especially during the roll rolling operation, when the compressive stress and tensile stress are intertwined, the roll workpiece overload may even cause the roll to break during operation. Summary of the invention

[0004] The technical problem to be solved by the present invention is: in order to solve the problems existing in the above-mentioned background technology, a new molybdenum alloy light rail finished product roller manufacturing method is provided, which can better solve the problems of the above-mentioned traditional rollers in the process of use, and has excellent comprehensive performance adapting to the rolling operation environment: the roller specification is 550*900mm in diameter, the hardness drop of the roller working layer is ≤1.4HSD, the roller working layer is 63-68HSD, the tensile strength is ≥690MPa, and the metallographic basic structure is discontinuous metal carbide + tempered troostite + bainite + a small amount of martensite. The new roller has a single-hole rolling capacity of more than 880 tons / time, which is 31% higher than the rolling capacity of the traditional roller, and has achieved good corporate and social benefits, and is deeply welcomed by steel rolling enterprises.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a novel molybdenum alloy light rail finished product roller manufacturing method, comprising the following steps: S1, rationally optimizing and configuring chemical components: C: 0.40-0.60%, Ni: 0.50-1.50%, Si: 0.30-0.60%, Mo: 1.50-2.50%, Mn: 0.60-1.10%, V: 0.80-1.20%, P≤0.030%, Nb: 0.50-1.00%, S≤0.020%; Re≥0.015%, Cr: 0.80-1.20%; S2, smelting pure molten steel; S3, special heat treatment of the roller; S4, detecting the technical indicators of the roller.

[0006] Further, in the above technical solution, the S2 smelting of pure molten steel includes the following steps: S11, using a medium frequency induction furnace to melt the early molten steel; S22, process slag making: after the charge is melted, the first slag making is carried out when the steel temperature rises to 1380-1420°C, the slag making agent is made by mixing 5% fluorite, 65% broken glass, and 30% quartz sand for molding, and the amount added per ton of steel is 20-30kg. The slag is diluted and then quickly cleared. When the steel temperature rises to 1480-1520°C, the slag making agent is used to make the slag. Slag making: slag making agent is 10% fluorite powder, 65% new sand for molding, 25% crushed lime mixed and pressed into blocks, the dosage is 35kg / ton steel, stirred to form slag liquid, and then cleared for 2-3 minutes; then heat up and add alloy steel, and when the steel temperature reaches 1550-1580℃, molten steel is discharged from converter; S33, refining finished roll steel: transfer the molten steel melted to 1550-1580℃ in medium frequency induction furnace into LF ladle type refining finished roll steel, then take samples to fine-tune other alloys, and then continue to heat up, and the third Slag making, adding silicon carbide in batches, the amount added is 5-6kg / ton steel, foam slag is made, after foam slag is formed, when the steel temperature is ≥1580℃, add lime 30kg / ton steel, fluorite 3kg / ton, make white slag, keep the white slag for 20-25 minutes and then heat it up, when the steel temperature reaches 1600℃, add vanadium, niobium alloy oxidizable elements, and add yttrium-based heavy rare earth steel modifier at the same time, use the active elements in the heavy rare earth to remove P, S, H, O elements; S44: after sampling and testing to determine that the chemical composition is qualified, the steel When the temperature reaches 1600-1620℃, insert 0.03% / ton steel aluminum cake into the furnace for deoxidation, and tap steel after 3-5 minutes. During the tapping process, blow argon to lightly boil the steel, and then calm down for 5-8 minutes before transferring to the subsequent step 5; S55, pouring the blank roll: when the steel temperature reaches the liquidus temperature: +60-80℃ pouring, the pouring adopts the top pouring process, after the roll molten steel is poured, put an insulation cover on the outer periphery of the mold to slow down the cooling speed of the molten steel, so that the blank roll solidifies in sequence from bottom to top, and removes the shrinkage or loose area of ​​the roll.

[0007] Further, in the above technical solution, the special heat treatment of the S3 roll includes the following steps: S111, diffusion annealing: heating up by 10°C / h per hour, keeping the roll temperature at 650-680°C for 6-8h; heating up by 12°C / h, keeping the roll temperature at 1050-1080°C for 10-12h; air cooling the roll temperature; S222, spheroidizing treatment: putting the roll temperature into the furnace when it is cooled to 460-480°C by air cooling, heating up by 14°C / h to the spheroidizing treatment temperature; Use 3 waves of oscillation process, each wave is 720-730℃; after the oscillation is completed, keep warm for 10-12 / h, then hang out and air cool; S333, normalizing: hang out and air cool after spheroidizing treatment, and put into the furnace for normalizing when the roller temperature reaches 450-550℃; heating rate is 16℃ / h, after the roller temperature rises to 960-980℃, keep warm at 25mm / h; S444, after the insulation is completed, hang the roller on the rotating support wheel for water mist spray quenching; water pressure 0.4MPa, flow rate 240m 3 / h, when the roller temperature reaches 450-480℃, it is put into the furnace for tempering, with a heating rate of 15℃ / h, and when the roller temperature reaches 530-550℃, it is kept warm for 4-6 / h, and then cooled in the furnace to 50℃ before being taken out of the furnace for processing.

[0008] It is further defined that in the above technical scheme, the S4, the technical indicators of the roller detection include roller specifications, roller surface hardness, hardness difference from the working surface to the bottom of the hole groove, roller neck hardness, roller tensile strength, and roller metallographic matrix structure.

[0009] A new type of molybdenum alloy light rail finished roller using the manufacturing method as claimed in claim 1, comprising a first roller and a second roller arranged in parallel up and down; both ends of the first roller and the second roller are provided with water stop ring shoulders, one side of the water stop ring shoulder is provided with a roller neck, one side of the roller neck is provided with a connecting end, and one side of the connecting end is provided with a shaft shoulder sleeve.

[0010] It is further defined that in the above technical solution, a rail head groove and a rail leg groove are respectively arranged at relative positions on the first roller and the second roller, and the rail head groove and the rail leg groove are combined to form a new type of molybdenum alloy light rail cross section.

[0011] The beneficial effects of the present invention are as follows: the present invention proposes a novel method for manufacturing a finished light rail molybdenum alloy roller, wherein the roller manufactured by the method has high hardness and good wear resistance, and the bottom of the hole groove of the working layer roller surface has basically no hardness drop, and the impact toughness, tensile strength and thermal cracking resistance are greatly improved, which can meet the requirements of the light rail rolling working environment of the light rail rolling enterprise, prolong the service life of the roller, improve the production efficiency of the rolling enterprise, and achieve the goal of reducing costs and increasing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] Figure 1 It is a special heat treatment process curve diagram of the present invention;

[0014] Figure 2 It is a structural schematic diagram of a new type of molybdenum alloy light rail finished product roller in the present invention;

[0015] Figure 3 It is a cross-sectional schematic diagram of the light rail in the present invention.

[0016] The numbers in the attached drawings are: 1. first roller, 2. second roller, 3. water stop shoulder, 4. roller neck, 5. connecting end, 6. shaft shoulder sleeve, 7. rail head groove, 8. rail leg groove, 9. new molybdenum alloy light rail section, 10. flat square transmission end. DETAILED DESCRIPTION

[0017] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] In the present application, a flat square transmission end 10 is also provided on the connection end 5. The purpose of temperature oscillation during the spheroidizing process is to further eliminate the internal stress of the roller through the oscillation process, so that the carbides in the matrix structure of the roller are further expanded and evenly distributed, so as to further improve the toughness of the roller; after the roller spheroidizing oscillation is completed, it is kept warm for 6-8 hours and then hung out for air cooling.

[0019] See Figure 1 , Figure 2 and Figure 3 The invention shows a novel method for manufacturing a finished product roller of a molybdenum alloy light rail, comprising the following steps: S1, rationally optimizing and configuring the chemical composition: C: 0.40-0.60%, Ni: 0.50-1.50%, Si: 0.30-0.60%, Mo: 1.50-2.50%, Mn: 0.60-1.10%, V: 0.80-1.20%, P≤0.030%, Nb: 0.50-1.00%, S≤0.020%; Re≥0.015%, Cr: 0.80-1.20%; S2, smelting pure molten steel; S3, special heat treatment of the roller; S4, testing the technical indicators of the roller.

[0020] Among them, S2 smelting pure molten steel includes the following steps: S11, using medium frequency induction furnace to melt the early molten steel; S22, process slag making: after the charge is melted, the first slag is made when the steel temperature rises to 1380-1420℃, the slag making agent is made by mixing 5% fluorite, 65% broken glass, and 30% quartz sand for molding, and the amount added per ton of steel is 20-30kg. The slag is diluted and then quickly scraped off. When the steel temperature rises to 1480-1520℃, the second slag is made; the slag making agent is 10% Fluorite powder, 65% new sand for molding, 25% crushed lime are mixed and pressed into blocks, with a dosage of 35kg / ton steel. After stirring to form slag liquid, wait for 2-3 minutes to clear it; then heat up and add alloy steel, and when the steel temperature reaches 1550-1580℃, the molten steel is discharged from the converter; S33, refining finished roll steel: the molten steel melted to 1550-1580℃ in the medium frequency induction furnace is transferred to the LF ladle type refined finished roll steel, and then samples are taken to fine-tune other alloys, and then the temperature is continued to rise, and slag is made for the third time, and added in batches Add silicon carbide, the amount is 5-6kg / ton steel, to make foam slag. After the foam slag is formed, when the steel temperature is ≥1580℃, add lime 30kg / ton steel and fluorite 3kg / ton to make white slag. Keep the white slag for 20-25 minutes and then heat it up. When the steel temperature reaches 1600℃, add vanadium and niobium alloy oxidizable elements, and add yttrium-based heavy rare earth steel modifier at the same time, and use the active elements in the heavy rare earth to remove P, S, H, and O elements; S44: After sampling and testing to determine that the chemical composition is qualified, the steel temperature is 16 When the temperature is 00-1620℃, 0.03% / ton aluminum cake is inserted into the furnace for deoxidation. After 3-5 minutes, the steel is tapped. During the tapping process, argon is blown to lightly boil the steel. After 5-8 minutes of sedation, the steel is transferred to the subsequent step 5; S55, casting the blank roll: when the steel temperature reaches the liquidus temperature: +60-80℃ casting, the casting adopts the top pouring process. After the molten steel of the roll is poured, the outer periphery of the mold is covered with an insulation cover to slow down the cooling speed of the molten steel, so that the blank roll is solidified in sequence from bottom to top, and the shrinkage or loose area of ​​the roll is removed. S3 roller special heat treatment includes the following steps: S111, diffusion annealing: heating up 10℃ / h per hour, keeping the roller temperature at 650-680℃ for 6-8h; heating up 12℃ / h, keeping the roller temperature at 1050-1080℃ for 10-12h; roller temperature out of the furnace and air cooling; S222, spheroidizing treatment: roller temperature is air-cooled to 460-480℃ and then put into the furnace, heating up at 14℃ / h to the spheroidizing treatment temperature, using 3 waves of oscillation process, Each wave is 720-730℃; after the oscillation is completed, keep warm for 10-12 / h, then hang out and air cool; S333, normalizing: hang out and air cool after spheroidizing treatment, and put into the furnace for normalizing when the roller temperature reaches 450-550℃; heating rate is 16℃ / h, after the roller temperature rises to 960-980℃, keep warm at 25mm / h; S444, after the insulation is completed, hang the roller on the rotating support wheel for water mist spray quenching; water pressure 0.4MPa, flow rate 240m 3 / h, when the roller temperature reaches 450-480℃, it is put into the furnace for tempering, the heating rate is 15℃ / h, when the roller temperature reaches 530-550℃, it is kept warm for 4-6 / h, then cooled in the furnace, and removed from the furnace for processing after reaching 50℃. S4. The technical indicators of the roller to be tested include roller specifications, roller surface hardness, hardness difference between the working surface and the bottom of the groove, roller neck hardness, roller tensile strength, and roller metallographic matrix structure.

[0021] A novel molybdenum alloy light rail finished product roller comprises a first roller 1 and a second roller 2 which are arranged in parallel up and down; both ends of the first roller 1 and the second roller 2 are provided with water stop ring shoulders 3, one side of the water stop ring shoulder 3 is provided with a roller neck 4, one side of the roller neck 4 is provided with a connecting end 5, and one side of the connecting end 5 is provided with a shaft shoulder sleeve 6.

[0022] A rail head groove 7 and a rail leg groove 8 are respectively arranged at relative positions on the first roller 1 and the second roller 2 , and the rail head groove 7 and the rail leg groove 8 are assembled to form a new type of molybdenum alloy light rail section 9 .

[0023] The new molybdenum alloy light rail finished roller manufactured by the manufacturing method of the present application can have a diameter of 550*900mm; the roller surface hardness is 63-68HSD; the hardness drop from the working surface to the bottom of the hole groove is ≤1.4HSD, and the roller neck hardness is 40-45HSD; the roller tensile strength is ≥690MPa; the metallographic matrix structure of the roller is a discontinuous special type of metal carbide + tempered troostite + bainite + a small amount of martensite.

[0024] The new molybdenum alloy light rail finished product roller manufactured by the manufacturing method has a single-hole rolling capacity of more than 880 tons / time in use, which is 31% higher than the rolling capacity of traditional rollers and has achieved better use benefits.

[0025] What has been described above are only preferred specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A novel method for manufacturing a finished product roller of a molybdenum alloy light rail, characterized in that: The method comprises the following steps: S1, rationally optimizing and configuring the chemical composition: C: 0.40-0.60%, Ni: 0.50-1.50%, Si: 0.30-0.60%, Mo: 1.50-2.50%, Mn: 0.60-1.10%, V: 0.80-1.20%, P≤0.030%, Nb: 0.50-1.00%, S≤0.020%; Re≥0.015%, Cr: 0.80-1.20%; S2, smelting pure molten steel; S3, special heat treatment of rolling mill rolls; S4, testing the technical indicators of rolling mill rolls.

2. A novel molybdenum alloy light rail finished product roller manufacturing method according to claim 1, characterized in that: The S2 smelting of pure molten steel comprises the following steps: S11, using a medium frequency induction furnace to smelt the early molten steel; S22, process slag making: after the charge is melted, the first slag making is carried out when the steel temperature rises to 1380-1420°C, the slag making agent is made by mixing 5% fluorite, 65% broken glass, and 30% quartz sand for molding, and the amount added per ton of steel is 20-30kg. The slag is diluted and then quickly scraped. When the steel temperature rises to 1480-1520°C, the second slag making is carried out; the slag making agent is made by mixing and briquetting 10% fluorite powder, 65% new sand for molding, and 25% crushed lime, and the amount is 35kg / ton of steel. After stirring to form slag liquid, wait for 2-3 minutes to scrape it; Then heat up and add alloy steel, and when the steel temperature reaches 1550-1580℃, tap the molten steel from the converter; S33, refining finished roll steel: transfer the molten steel melted in the medium frequency induction furnace to a steel temperature of 1550-1580℃ into the LF ladle type refining finished roll steel, and then take samples to fine-tune other alloys, continue to heat up, and make slag for the third time, add silicon carbide in batches, the addition amount is 5-6kg / ton of steel, make foamy slag, after the foamy slag is formed, when the steel temperature is ≥1580℃, add 30kg / ton of lime and 3kg / ton of fluorite to make white slag, keep the white slag for 20-25 minutes and then heat up, when the steel temperature reaches 1600℃, add vanadium and niobium alloy easily oxidized elements, and add yttrium-based Heavy rare earth steel modifier, using active elements in heavy rare earth to remove P, S, H, O elements; S44: after sampling and testing to determine that the chemical composition is qualified, when the steel temperature is 1600-1620℃, insert 0.03% / ton steel aluminum cake into the furnace for deoxidation, and tap the steel after 3-5 minutes. During the tapping process, blow argon to lightly boil, and then calm for 5-8 minutes to proceed to the subsequent step 5; S55, casting blank rolls: when the steel temperature reaches the liquidus temperature: +60-80℃ casting, the casting adopts the top pouring process. After the molten steel of the rolls is poured, put an insulation cover on the outer periphery of the mold to slow down the cooling speed of the molten steel, so that the blank rolls solidify in sequence from bottom to top, and remove the shrinkage or loose areas of the rolls.

3. The method for manufacturing a new type of molybdenum alloy light rail finished product roller according to claim 1, characterized in that: The special heat treatment of S3 rolls includes the following steps: S111, diffusion annealing: heating up by 10℃ / h per hour, keeping the temperature for 6-8h when the roll temperature reaches 650-680℃; heating up by 12℃ / h, keeping the temperature for 10-12h when the roll temperature reaches 1050-1080℃; air cooling the roll temperature out of the furnace; S222, spheroidizing treatment: when the roll temperature is air-cooled to 460-480℃, the roll temperature is put into the furnace, and the heating rate is 14℃ / h to the spheroidizing treatment temperature, the oscillation process is used for 3 waves , each wave is 720-730℃; after the oscillation is completed, keep warm for 10-12 / h, then hang out and air cool; S333, normalizing: hang out and air cool after spheroidizing treatment, and put into the furnace for normalizing when the roller temperature reaches 450-550℃; heating rate is 16℃ / h, after the roller temperature rises to 960-980℃, keep warm at 25mm / h; S444, after the insulation is completed, hang the roller on the rotating support wheel for water mist spray quenching; water pressure 0.4MPa, flow rate 240m 3 / h, when the roller temperature reaches 450-480℃, it is put into the furnace for tempering, with a heating rate of 15℃ / h, and when the roller temperature reaches 530-550℃, it is kept warm for 4-6 / h, and then cooled in the furnace to 50℃ before being taken out of the furnace for processing.

4. The method for manufacturing a new type of molybdenum alloy light rail finished product roller according to claim 1, characterized in that: The S4, detection of roller technical indicators includes roller specifications, roller surface hardness, hardness difference from working surface to hole groove bottom, roller neck hardness, roller tensile strength, and roller metallographic matrix structure.

5. A new type of molybdenum alloy light rail finished roller using the manufacturing method as claimed in claim 1, characterized in that: It comprises a first roller and a second roller which are arranged in parallel up and down; both ends of the first roller and the second roller are provided with water-blocking shoulders, one side of the water-blocking shoulders is provided with a roller neck, one side of the roller neck is provided with a connecting end, and one side of the connecting end is provided with a shaft shoulder sleeve.

6. A new type of molybdenum alloy light rail finished product roller according to claim 5, characterized in that: A rail head groove and a rail leg groove are respectively arranged at relative positions on the first roller and the second roller, and the rail head groove and the rail leg groove are combined to form a new type of molybdenum alloy light rail cross section.

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