CN-121428389-B - Manufacturing method of ultrahigh-strength steel ingot and ultrahigh-strength steel bar

Abstract

The application relates to the technical field of metallurgy, and particularly discloses a manufacturing method of an ultrahigh-strength steel ingot, which comprises the following steps of vacuum induction smelting, casting, annealing and vacuum consumable remelting, wherein the vacuum induction smelting comprises the following steps of batching, melting and refining, wherein materials except metal Al are added into a crucible according to the sequence of pure iron in the prior processing industry and metal materials added later, the vacuum is reduced to 20-90Pa, the melting temperature is 1500-1550 ℃ and molten steel is obtained after melting, the refining is carried out, the temperature is adjusted to 1520-1570 ℃ and the vacuum degree is less than or equal to 3Pa, the molten steel is refined for 30-120min under the electromagnetic stirring effect, and when the O content in the molten steel is less than or equal to 10ppm and the N content is less than or equal to 10ppm, the metal Al is added into the molten steel, and refined molten steel is obtained. The manufacturing method provided by the application can obtain the ultra-high strength steel with low impurity content and no defects such as radial segregation, annular pattern and the like.

Inventors

• Han shun
• LI JIANXIN
• LI TAO
• LI JIBAO
• WANG CHUNXU
• PANG XUEDONG
• CAO YUXIAN
• ZHAI YUJIA
• LIANG XIAODONG
• YANG CHAO
• Geng Ruming
• LI YONG

Assignees

• 钢铁研究总院有限公司
• 抚顺特殊钢股份有限公司

Dates

Publication Date

20260508

Application Date

20251114

Claims (5)

1. 1. The manufacturing method of the ultra-high strength steel ingot is characterized by comprising the following steps of vacuum induction melting, casting, annealing and vacuum consumable remelting, wherein the vacuum induction melting comprises the following steps of: preparing materials according to the following proportion, namely 0.14-0.25% of C, 1.5-3.0% of Cr, 13.00-15.00% of Ni, 1.00-2.00% of Mo, 9.00-11.00% of Co, 0.85-0.95% of Al and the balance of industrial pure iron; The chemical components of the industrial pure iron are, by mass, less than or equal to 0.24% of C, less than or equal to 0.0007% of S, less than or equal to 0.004% of P, less than or equal to 0.03% of Si, less than or equal to 0.03% of Mn, less than or equal to 0.010% of Al, less than or equal to 0.01% of Ti, less than or equal to 0.05% of Cu, less than or equal to 30ppm of O and less than or equal to 45ppm of N; The industrial pure iron is smelted by adopting an electric furnace, LF and VD to smelt argon protection casting steel ingot, and is cut into blocks with the diameter of 120 multiplied by 120mm multiplied by 300mm after hot rolling and barreling for standby; Melting, namely adding materials except metal Al into a crucible according to the sequence of adding pure iron in the first processing industry and adding metal materials later, vacuumizing to 20-90Pa, and melting at 1500-1550 ℃ to obtain molten steel after melting; refining, namely adjusting the temperature to 1520-1570 ℃ and the vacuum degree to be less than or equal to 3Pa, refining the molten steel for 30-120min under the electromagnetic stirring effect, and adding metal Al into the molten steel after the O content and the N content in the molten steel are less than or equal to 10ppm to obtain refined molten steel; the method comprises the specific steps of adding an electrode steel ingot obtained in an annealing step into a vacuum consumable furnace for remelting, wherein the average melting speed in a smelting stabilization stage is 4.5-6.5kg/min, cooling by adopting helium gas, the cooling time after melting is more than or equal to 75min, slowly cooling the steel ingot is more than or equal to 56h, then heating to 640-670 ℃ at the rate of less than or equal to 100 ℃/h, preserving heat at the temperature for more than or equal to 25h, cooling to below 300 ℃ along with the furnace, and air cooling to obtain an ultrahigh-strength steel ingot; The ultra-high strength steel ingot comprises the following chemical components, by weight, mn less than or equal to 0.02%, si less than or equal to 0.02%, cu less than or equal to 0.05%, S less than or equal to 0.0007%, P less than or equal to 0.006%, O less than or equal to 10ppm, and N less than or equal to 10ppm.
2. 2. The method for manufacturing the ultra-high strength steel ingot according to claim 1, wherein the concrete steps of casting are that refined molten steel obtained by vacuum induction melting is subjected to vacuum casting by an upper pouring method, the casting temperature is controlled to be 1540-1570 ℃, and after casting is completed, the casting is cooled for 120-180min by mold cooling, so that a prefabricated steel ingot is obtained.
3. 3. A method of manufacturing an ultra-high strength steel ingot according to claim 1, wherein the helium gas flow is 200-300L/min.
4. 4. The method for manufacturing the ultra-high strength steel ingot according to claim 1, wherein the specific step of annealing is to heat up the prefabricated steel ingot to 640-670 ℃ at a rate of less than or equal to 100 ℃ per hour, keep the temperature at the temperature for more than or equal to 15 hours, cool the prefabricated steel ingot to below 300 ℃ along with a furnace, and obtain the electrode steel ingot with the diameter of 550-560mm through polishing.
5. 5. A method of manufacturing an ultra-high strength steel ingot according to claim 1, wherein the diameter of the ultra-high strength steel ingot is 660mm.

Description

Manufacturing method of ultrahigh-strength steel ingot and ultrahigh-strength steel bar Technical Field The application relates to the technical field of metallurgy, in particular to a manufacturing method of an ultrahigh-strength steel ingot and an ultrahigh-strength steel rod. Background With the continuous development of the aviation field, the performance requirements on metallurgical materials are becoming increasingly stringent, especially in terms of strength, toughness and fatigue life. To meet these requirements, it is necessary to strictly control the impurity element, nonmetallic inclusion content of the material, and reduce the degree of segregation of the material. The NiCo series ultra-high strength steel with high alloy ratio, such as AF1410 steel, A-100 steel and the like, is widely applied in the field of aviation engine shaft materials because the NiCo series ultra-high strength steel basically meets the conditions. At present, for NiCo series ultra-high strength steel with high alloy ratio, the impurity content is controlled as follows in the industry, wherein the AF1410 steel and the A-100 steel are respectively required to be less than or equal to 0.015 percent of Al, less than or equal to 0.015 percent of Ti, less than or equal to 0.005 percent of S, less than or equal to 0.008 percent of P, less than or equal to 20ppm of O and less than or equal to 15ppm of N. However, the steel is still not fine enough in the aspects of controlling the chemical components and the impurity content, the impurity content such as Ti, S, P, N, O is still higher, the defects such as radial segregation and annular patterns are easy to occur in steel ingots, the ultra-high strength steel bar with more excellent mechanical properties is difficult to obtain, and further, the higher requirements of the new generation of high-performance aviation engine shaft materials on the mechanical properties cannot be met better. Disclosure of Invention In order to further optimize and control the chemical components and impurity content of the ultra-high strength steel and solve the problems that steel ingots are easy to have radial segregation, annular patterns and the like, so as to obtain ultra-high strength steel bars with more excellent mechanical properties, the application provides a manufacturing method of the ultra-high strength steel ingots and the ultra-high strength steel bars. In a first aspect, the present application provides a method for manufacturing an ultra-high strength steel ingot, which adopts the following technical scheme: The manufacturing method of the ultra-high strength steel ingot comprises the following steps of vacuum induction melting, casting, annealing and vacuum consumable remelting, wherein the vacuum induction melting comprises the following steps of: preparing materials according to the following proportion, namely 0.14-0.25% of C, 1.5-3.0% of Cr, 13.00-15.00% of Ni, 1.00-2.00% of Mo, 9.00-11.00% of Co, 0.85-0.95% of Al and the balance of industrial pure iron; Melting, namely adding materials except metal Al into a crucible according to the sequence of adding pure iron in the first processing industry and adding metal materials later, vacuumizing to 20-90Pa, and melting at 1500-1550 ℃ to obtain molten steel after melting; refining, namely, regulating the temperature to 1520-1570 ℃ and the vacuum degree to be less than or equal to 3Pa, refining the molten steel for 30-120min under the electromagnetic stirring effect, and adding metal Al into the molten steel after the O content and the N content in the molten steel are less than or equal to 10ppm to obtain refined molten steel. The application provides a manufacturing method of an ultrahigh-strength steel ingot, which uses industrial pure iron as a main raw material in the batching step of the manufacturing method, can reduce the content of impurity elements from a source, solves the problem that S, P, ti elements and other impurity elements in steel cannot be removed by vacuum induction furnace smelting, and effectively solves the problems that the steel ingot is easy to have radial segregation, annular patterns and the like by melting at a low vacuum of 20-90Pa and a temperature of 1500-1550 ℃ in the melting step. In the refining step, impurities and gas in molten steel can be effectively removed by refining under the action of specific temperature, vacuum degree and electromagnetic stirring, so that the O content and the N content in the molten steel reach specific levels, and then metal Al is added, the risk of increasing inclusions in high Al steel can be avoided, grains can be refined, and the strength and toughness of the steel are further improved. In conclusion, the vacuum induction melting step in the manufacturing method of the ultra-high strength steel ingot provided by the application can provide high-quality refined molten steel for subsequent casting, annealing and vacuum consumable remelting, and lays a solid foundation