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CN-121674680-B - Cr5 alloy cast steel supporting roller and preparation method thereof

CN121674680BCN 121674680 BCN121674680 BCN 121674680BCN-121674680-B

Abstract

The application relates to the technical field of preparation of supporting rolls, and discloses a Cr5 alloy cast steel supporting roll and a preparation method thereof, comprising the following steps of melting down forged and stamped scrap steel, cr4 waste roll collars, steel scraps and waste rolls, melting down, using glass slag for slagging and deoxidizing, using silicon-calcium alloy for precipitation and deoxidizing, and obtaining molten steel by inserting aluminum into a furnace for final deoxidization; pouring molten steel into a supporting roller die, supplementing molten steel twice after pouring to obtain a casting blank, placing the casting blank obtained in the step S2 into a heat treatment furnace for heat treatment, sealing and shielding a roll neck conical surface by using an iron sheet protective cover after austenitizing, coating a small roll neck by using fiber cotton, discharging the casting blank obtained in the step S3 for spray quenching, starting a blowing and water spraying device, and removing the protective cover and the fiber cotton after spray quenching, and cooling to obtain the Cr5 alloy cast steel supporting roller.

Inventors

  • FU JIASHUANG
  • Ba Xun
  • CHENG DONG
  • WANG YONGZHONG
  • LI WENJUN

Assignees

  • 成都三强轧辊股份有限公司

Dates

Publication Date
20260508
Application Date
20260210

Claims (8)

  1. 1. The preparation method of the Cr5 alloy cast steel supporting roller is characterized by comprising the following steps of: S1, melting down forging stamping scrap steel, cr4 waste roll collar, steel scraps and waste rolls, melting down, using glass slag for slagging and deoxidizing, using silicon-calcium alloy for precipitation deoxidizing, and finally deoxidizing by inserting aluminum into a furnace to obtain molten steel; s2, pouring molten steel into a supporting roller die, supplementing the molten steel for the first time 4-8min after pouring, and supplementing the molten steel for the second time 55-65min after pouring to obtain a casting blank; s3, placing the casting blank obtained in the step S2 into a heat treatment furnace for heat treatment, sealing and shielding the conical surface of a roll neck by using an iron sheet protection cover after austenitizing, and coating a small roll neck by using fiber cotton; And S4, discharging the casting blank obtained in the step S3 for 1-3min, placing the casting blank in a spray quenching machine for spray quenching treatment, starting a blowing and water spraying device, stopping spraying water after 4-6min, keeping blowing for 0.4-0.6h, taking off a protective cover, stopping blowing, taking off fiber cotton after 3-4h, and cooling to obtain the Cr5 alloy cast steel supporting roller.
  2. 2. The method for producing a Cr5 alloy cast steel support roller as claimed in claim 1, wherein the mass ratio of the forged and stamped scrap steel, cr4 scrap collars, steel scraps and scrap rollers is 45:35:10:10.
  3. 3. The method for producing a Cr5 alloy cast steel support roller as claimed in claim 1, wherein the amount of the calcium-silicon alloy used in the step S1 is 0.48-0.52kg/t molten steel, and the amount of the aluminum used is 0.58-0.62kg/t molten steel.
  4. 4. The method for producing a Cr5 alloy cast steel backing roll according to claim 1, wherein the glass slag is used in an amount of 0.9-1kg/t molten steel, and the silica content in the glass slag is 70-80 wt%.
  5. 5. The method for producing a Cr5 alloy cast steel support roller as claimed in claim 1, wherein the spray quenching wind pressure is 0.5-0.7MPa and the water pressure is 0.25-0.4MPa.
  6. 6. The method for producing a Cr5 alloy cast steel support roller as claimed in claim 1, wherein the gas medium for the spray quenching treatment is nitrogen.
  7. 7. The method for producing a Cr5 alloy cast steel backing roll according to claim 1, wherein the liquid medium for the spray quenching treatment is a polyalkylene glycol solution comprising polyalkylene glycol having an average molecular weight of 12 ten thousand and polyalkylene glycol having an average molecular weight of 8000, and the polyalkylene glycol solution has a polyalkylene glycol mass concentration of 8 to 12wt%.
  8. 8. A Cr5 alloy cast steel support roller obtained by the preparation method as claimed in any one of claims 1 to 7, which is characterized by comprising the following components in percentage by mass: C: 0.42%-0.46%, Si: 0.5%-0.7%, Mn: 0.4%-0.6%, Cr: 4.8%-5.5%, Ni: 0.5%-0.55%, Mo: 0.4%-0.45%, The balance being iron and unavoidable impurities.

Description

Cr5 alloy cast steel supporting roller and preparation method thereof Technical Field The application relates to the technical field of preparation of support rolls, in particular to a Cr5 alloy cast steel support roll and a preparation method thereof. Background In the field of manufacturing large support rolls, the current mainstream technology still relies on forging processes to produce support roll forgings. Although the process can obtain uniform and compact organization and good comprehensive performance, the production process depends on an ultra-large press, so that the equipment investment is huge, the manufacturing period is long, and the production cost is high. To reduce manufacturing costs and increase production flexibility, the industry has long sought a "cast-in-place" technological route, i.e. to produce large support rolls by casting. When large support rolls are produced by casting, it is difficult to achieve the desired hardness gradient on a single workpiece in a conventional heat treatment furnace. Particularly, when Cr5 alloy steel materials with high permeability are adopted, the Cr5 alloy steel materials have extremely high permeability, so that the roll neck is easy to become brittle due to overhigh hardness during integral quenching, brittle fracture occurs during use, and the roll body wear resistance and the roll neck toughness cannot be simultaneously achieved. Disclosure of Invention In order to solve the problem that the Cr5 alloy cast steel support roller is difficult to have both roller body wear resistance and roller neck toughness when being prepared by casting, the Cr5 alloy cast steel support roller and the preparation method thereof are provided. The first object of the present invention is achieved by the following technical solutions: A preparation method of a Cr5 alloy cast steel supporting roller comprises the following steps: S1, melting down forging stamping scrap steel, cr4 waste roll collar, steel scraps and waste rolls, melting down, using glass slag for slagging and deoxidizing, using silicon-calcium alloy for precipitation deoxidizing, and finally deoxidizing by inserting aluminum into a furnace to obtain molten steel; s2, pouring molten steel into a supporting roller die, supplementing the molten steel for the first time 4-8min after pouring, and supplementing the molten steel for the second time 55-65min after pouring to obtain a casting blank; s3, placing the casting blank obtained in the step S2 into a heat treatment furnace for heat treatment, sealing and shielding the conical surface of a roll neck by using an iron sheet protection cover after austenitizing, and coating a small roll neck by using fiber cotton; And S4, discharging the casting blank obtained in the step S3 for 1-3min, placing the casting blank in a spray quenching machine for spray quenching treatment, starting a blowing and water spraying device, stopping spraying water after 4-6min, keeping blowing for 0.4-0.6h, taking off a protective cover, stopping blowing, taking off fiber cotton after 3-4h, and cooling to obtain the Cr5 alloy cast steel supporting roller. By adopting the technical scheme, the molten glass slag is used for slag making and deoxidizing, the molten glass slag is used for covering the surface of molten steel, air is isolated for preventing secondary oxidation, nonmetallic inclusions such as floating deoxidization products are adsorbed, and the calcium-silicon alloy calcium precipitation element has stronger affinity to oxygen and sulfur in the molten steel, generates low-melting-point composite inclusions and floats to slag, so that the molten steel is further purified; The liquid steel is fed twice, the first feeding after 4-8min after pouring is performed when the surface layer of the casting has formed a solidified shell and the inside is still in a liquid state, the liquid shrinkage is compensated, shrinkage holes are prevented from being formed in the surface layer area near the roll body or the roll neck, the second feeding after 55-65min is performed, the solid shrinkage is compensated for the central area of the casting, the central shrinkage defect can be effectively reduced, the second feeding is beneficial to compensating the shrinkage of the casting in the solidification process, the overall compactness of the casting blank is improved, the internal shrinkage porosity is reduced, and the overall bearing capacity, the fatigue strength and the toughness of the supporting roll are improved; The austenitizing process of heat treatment makes carbon and alloy elements fully dissolved in austenite, prepares for subsequent phase transformation, seals and shields the conical surface of the roll neck by using an iron sheet protecting cover, coats the small roll neck by using fiber cotton, reduces the cooling speed of the protected areas in the subsequent spray quenching cooling process by using the heat insulation performance of the protecting cover and the fiber co