CN112126743A - Production method of low-aluminum-content Cr5 steel ingot for supporting roll - Google Patents
Production method of low-aluminum-content Cr5 steel ingot for supporting roll Download PDFInfo
- Publication number
- CN112126743A CN112126743A CN202010839049.1A CN202010839049A CN112126743A CN 112126743 A CN112126743 A CN 112126743A CN 202010839049 A CN202010839049 A CN 202010839049A CN 112126743 A CN112126743 A CN 112126743A
- Authority
- CN
- China
- Prior art keywords
- steel
- equal
- less
- converter
- slag
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/06—Deoxidising, e.g. killing
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/072—Treatment with gases
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/076—Use of slags or fluxes as treating agents
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention discloses a production method of a low-aluminum-content Cr5 steel ingot for a supporting roll, which comprises the working procedures of a BOF converter, LF refining, VD vacuum treatment and pouring; the BOF converter process comprises the following steps: the molten iron entering the furnace is required to have P less than or equal to 0.110wt%, S less than or equal to 0.030wt%, Si 0.20-0.60 wt% and the temperature of 1300-1450 ℃; adding 45-60 kg/t of lime steel, 20-30 kg/t of light-burned dolomite steel and 40-50 kg/t of limestone steel in the whole smelting process of the converter; tapping C of the converter is more than or equal to 0.08wt%, tapping P is less than or equal to 0.008wt%, and the temperature is 1590-1620 ℃; steel sand aluminum, low-carbon ferrochromium, silicon-manganese alloy and ferromolybdenum are added in sequence in the tapping process; deoxidation alloying after converter tappingThe P is controlled to be less than or equal to 0.012wt%, the S is controlled to be less than or equal to 0.005wt%, the Al is controlled to be less than or equal to 0.010wt%, and the Ti is controlled to be less than or equal to 0.005 wt%. The method can effectively reduce Al content in steel ingot2O3Mainly containing impurities and reducing the gas content; the obtained steel ingot has uniform tissue, effectively improves the macroscopic defects of center porosity, segregation and the like, and reduces non-metallic inclusions; the obtained product has the characteristics of good mechanical property, stable performance, high qualification rate and the like.
Description
Technical Field
The invention belongs to the field of ferrous metallurgy, and particularly relates to a production method of a low-aluminum-content Cr5 steel ingot for a supporting roller.
Background
The supporting roll is an important stressed part of a rolling mill, and has the characteristics of large size, heavy weight, high manufacturing difficulty and the like in a roll product. The supporting roll product has the quality requirements of high surface hardness of the roll body, good hardness uniformity, deep hardening layer of the roll body, small residual stress, good toughness of the roll neck and the roll body core and the like. The steel is required to have mechanical properties such as high impact toughness, high wear resistance, high yield strength, good spalling resistance, high temperature resistance and the like.
The development of the supporting roll material in China goes through three stages. The first stage is from 60 to 80 of the 20 th century, and the supporting roller is mainly produced by 9Cr2Mo steel. When a large supporting roll is produced, the core part of the roll is easy to generate carbon element segregation and coarse net-shaped carbide, the quenching crack tendency is serious, the stripping resistance is poor, and the requirements of a modern rolling mill are difficult to meet. In the second stage, from the 80 s to the beginning of the 21 st century in the 20 st century, Cr3 series steels represented by 70Cr3Mo were developed for the characteristics of use of backup rolls of cold and hot continuous rolling mills. Although the Cr3 backup roll can satisfy the hardness requirement, the hardenability is slightly insufficient, and low-temperature tempering is required, which affects the release of residual stress to a certain extent. The current stage is the third stage, Cr5 series steel for the supporting roller is developed, the wear resistance and the anti-stripping capability of the supporting roller are obviously improved, and the high-performance supporting roller is generally produced by Cr5 steel ingots at present.
Al in Cr5 steel ingot2O3The primary inclusions cause the discontinuity of the steel matrix to be broken, resulting in unevenness of the steel structure and point defects on the surface of the backup roll, and also cause an internal fatigue source and a crack source. Cracks are easily formed in the use process of the supporting roll, the structure and mechanical properties of hardness, plasticity, impact toughness, fatigue and the like of the supporting roll are seriously deteriorated, and the surface of the roll fails or fractures. Therefore, in order to ensure the performance of the backup roll, the non-metallic inclusions and the low aluminum content of the Cr5 ingot must be strictly controlled.
Disclosure of Invention
The invention aims to provide a production method of a steel ingot with low aluminum content Cr5 for a supporting roller so as to achieve a high-performance product.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: the method comprises the working procedures of BOF converter, LF refining, VD vacuum treatment and pouring;
the BOF converter process comprises the following steps: the molten iron entering the furnace is required to have P less than or equal to 0.110wt%, S less than or equal to 0.030wt%, Si 0.20-0.60 wt% and the temperature of 1300-1450 ℃; after the smelting of the previous furnace is finished, leaving 2-5 t of steel slag in the converter, and blowing nitrogen at the bottom to perform slag splashing and furnace protection; pouring out early-stage slag after blowing for 3-5 minutes by the converter, and slagging again to carry out double-slag smelting operation; in the whole smelting process of the converter, 45-60 kg/t of steel lime, 20-30 kg/t of light-burned dolomite and 40-50 kg/t of steel limestone are added, and the oxygen consumption is 50-60 m3T, oxygen supply time is 15-22 min; the smelting period of the converter is 40-50 min, and the nitrogen consumption is 25-35 m3T; tapping C of the converter is more than or equal to 0.08wt%, tapping P is less than or equal to 0.008wt%, and the temperature is 1590-1620 ℃; steel sand aluminum, low-carbon ferrochromium, silicon-manganese alloy and ferromolybdenum are added in sequence in the tapping process; the converter tapping adopts lime and fluorite for slagging,the addition amount of lime is 5-6 kg/t steel, and the addition amount of fluorite is 0.8-1.2 kg/t steel; deoxidizing and alloying after converter tapping, and controlling P to be less than or equal to 0.012wt%, S to be less than or equal to 0.005wt%, Al to be less than or equal to 0.010wt% and Ti to be less than or equal to 0.005 wt%;
the LF refining process comprises the following steps: after LF is in place, feeding a calcium wire according to 0.05-0.07 kg/t steel, and adding lime, fluorite and quartz sand for slagging according to the melting condition and the fluidity of the refined slag; in the refining process, the consumption of lime is 6-8 kg/t steel, the consumption of fluorite is 0.5-1.0 kg/t steel and the consumption of quartz sand is 0.8-1.2 kg/t steel, the refining time is more than or equal to 90min, and the white slag holding time is more than or equal to 50 min; in the LF refining process, the consumption of silicon carbide is 3-5 kg/t of steel for diffusion deoxidation; the flow rate of argon in the LF process is controlled to be 300-800 NL/min, and the argon consumption is 0.3-0.5 m3T; adjusting the alloy content according to the target components in the LF refining process;
controlling range of LF slag system: 52-56% of CaO and Al2O3 15～20％、SiO2 13～18％、MgO 5～10％、(TFe+MnO)≤0.5％、R 3.2-3.6；
The VD vacuum treatment process comprises the following steps: VD high vacuum degassing treatment is carried out for 25-30 min; the flow rate of argon in the VD process is controlled to be 150-500 NL/min, and the argon consumption is 0.06-0.10 m3T, steam consumption is 35-42 kg/t steel; after the VD is broken, adding a pre-melted steel cladding covering agent, controlling the soft blowing time for 35-50 min, and controlling the argon flow to be less than or equal to 17L/min during soft blowing; the superheat degree of the ladle is 43-50 ℃, and the superheat degree of 43-47 ℃ during steel ingot casting is guaranteed;
the casting process comprises the following steps: controlling the mold temperature to be 50-80 ℃ when the steel ingot is poured; the pouring speed of the ingot body of the steel ingot is 1.2-1.5 t/min, and the pouring speed of the cap opening of the steel ingot is 0.3-0.7 t/min; the covering slag is hung in a mode of combining hanging and process supplementing according to 1.5-1.8 kg/t, the hanging height is 250-300 mm, the rest is supplemented in bulk, and the total amount of hanging and process supplementing is 1.5-2.5 kg/t; adding a heating agent at a ratio of 1.5-1.8 kg/t when the molten steel reaches 60% -70% of an upper riser line, and adding carbonized rice hulls at a ratio of 1.5-2.0 kg/t after open fire does not exist; the residual molten steel amount in the ladle after casting is more than or equal to 6 tons; and cooling the steel ingot strip mold for 9-12 hours after pouring, and demolding the steel ingot and carrying out hot-conveying forging when the surface temperature of the steel ingot is 650-750 ℃.
The BOF converter process of the invention comprises the following steps: bottom blowing nitrogen for sputteringWhen the slag is protected, the slag splashing time is 3-5 min, and the nitrogen flow is 23000-26000 m during slag splashing3H; the converter molten iron scrap steel proportion is: the iron water amount is 80-85 wt%, and the scrap steel amount is 15-20 wt%; 1.5-2.0 kg/t of steel, 1.5-20 kg/t of steel, 16-20 kg/t of low-carbon ferrochromium, 6-8 kg/t of silicon-manganese alloy and 5.5-7.0 kg/t of ferromolybdenum are added in sequence in the tapping process.
The LF refining process comprises the following steps: in the LF refining process, 3.0-4.0 kg/t of low-aluminum silicon iron and other required alloys are adopted to adjust the alloy content according to target components.
The VD vacuum treatment process of the invention comprises the following steps: and after the VD is broken, adding a pre-melted steel cladding covering agent according to the proportion of 1.0-1.5 kg/t.
The main component indexes of the mold casting covering slag in the pouring process are as follows: c17 +/-5.0 wt%, CaO 14 +/-5.0 wt%, and SiO2 36±5.0wt％，Al2O3≤13wt％，MgO≤8.0wt％，Fe2O3≤7.0wt％。
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: the method can effectively reduce Al content in steel ingot2O3Mainly containing impurities and reducing the gas content; the obtained steel ingot has uniform tissue, effectively improves the macroscopic defects of center porosity, segregation and the like, and reduces non-metallic inclusions; the obtained product has the characteristics of good mechanical property, stable performance, high qualification rate and the like.
Detailed Description
The present invention will be described in further detail with reference to specific embodiments.
Examples 1 to 8: the production method of the steel ingot with the low-aluminum Cr5 content for the supporting roll adopts the technological process of BOF (100t) -LF (120t) -VD (120t) -lower pouring steel ingot to produce the lower pouring low-aluminum Cr5 steel ingot with the ingot shape of 18-52 t, and the steel ingot is used for forging and producing the supporting roll after being subjected to hot-feeding annealing. The component design requirements of the Cr5 steel ingot are (wt): 0.50 to 0.60 percent of C, 0.40 to 0.70 percent of Si, 0.40 to 0.70 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.010 percent of S, less than or equal to 0.010 percent of Al, 4.80 to 5.60 percent of Cr, 0.50 to 0.60 percent of Mo, more than or equal to 0.05 percent of V, less than or equal to 0.25 percent of Ni, less than or equal to 0.010 percent of Ti, less than or equal to 0.15 percent of Cu, less than or equal to 1.5ppm of H, less than or equal to 20ppm of O, less than; the preferred composition design requirements are (wt): 0.53 to 0.57 percent of C, 0.50 to 0.65 percent of Si, 0.50 to 0.65 percent of Mn, less than or equal to 0.012 percent of P, less than or equal to 0.005 percent of S, 0.005 to 0.008 percent of Al, 4.90 to 5.20 percent of Cr, 0.52 to 0.55 percent of Mo, 0.05 to 0.07 percent of V, less than or equal to 0.20 percent of Ni, less than or equal to 0.005 percent of Ti, less than or equal to 0.10 percent of Cu, less than or equal to 1.2ppm of H, less than or equal to 15ppm of O, less than or equal to 70ppm of N. The respective process steps are as follows.
(1) BOF converter process: the molten iron fed into the furnace is required to have P less than or equal to 0.110wt%, S less than or equal to 0.030wt%, Si 0.20-0.60 wt% and temperature 1300-1450 ℃; and (4) leaving 2-5 t of steel slag in the converter after the previous smelting is finished. Performing slag splashing protection by blowing nitrogen at the bottom, wherein the slag splashing time is 3-5 min, and the nitrogen flow is 23000-26000 m during slag splashing3H is used as the reference value. The converter molten iron scrap steel proportion is: the amount of the molten iron is 80-85 wt%, the amount of the scrap steel is 15-20 wt%, and high-quality Cr and Mo scrap steel is used. Before smelting, converter slag near a converter mouth and a converter cap is cleaned, if splashing occurs in the blowing process, the converter slag remained on the converter cap needs to be cleaned for the second time, and the steel can be tapped after the converter cap is cleaned up and has no residue. Pouring out early-stage slag after blowing for 3-5 minutes by a converter, slagging again to perform double-slag smelting operation, adding 45-60 kg/t of lime steel, 20-30 kg/t of light-burned dolomite steel and 40-50 kg/t of limestone steel in the whole process of converter smelting, and consuming 50-60 m of oxygen3And t, the oxygen supply time is 15-22 min. The smelting period of the converter is 40-50 min, and the nitrogen consumption is 25-35 m3T is calculated. Tapping required for converter tapping [ C ]]Not less than 0.08wt%, tapping [ P ]]Not more than 0.008wt% and 1590-1620 deg.C; the blowing end point of the converter realizes double hit of components and temperature, and molten steel peroxidation is avoided. 1.5-2.0 kg/t of steel, 1.5-20 kg/t of steel, 16-8 kg/t of low-carbon ferrochrome, 6-8 kg/t of silicon-manganese alloy and 5.5-7.0 kg/t of ferromolybdenum are sequentially added in the tapping process; in order to ensure that the Al content of a finished product meets the standard requirement, slagging is carried out on converter tapping in a lime and fluorite mode, and refining composite slag is not used, wherein the addition amount of lime is 5-6 kg/t of steel, and the addition amount of fluorite is 0.8-1.2 kg/t of steel; slag is strictly forbidden to be discharged in the tapping process, and an aluminum wire is forbidden to be fed after tapping, so that good conditions can be created for smelting in the refining process. The lime is high-quality refined lime, and the main components and performance indexes of the lime are as follows: CaO more than or equal to 90 wt%, MgO less than or equal to 5.0wt%, SiO2Less than or equal to 2.0 wt%, less than or equal to 0.030wt% of S, less than or equal to 4% of ignition loss, more than or equal to 320% of activity and more than or equal to 90% of granularity of 10-50 mm.
The deoxidation alloying is carried out after the converter tapping, the components of the molten steel are preliminarily adjusted, the low content of [ Al ] in the molten steel can be ensured by adjusting a slag system, the deoxidation is enhanced in the refining process, the components and the gas content of the finished product can be ensured to meet the standard requirements, and particularly, the P is controlled to be less than or equal to 0.012wt%, the S is controlled to be less than or equal to 0.005wt%, the Al is controlled to be less than or equal to 0.010wt%, and the Ti is controlled to be less than or equal to 0.005 wt%. The specific process of the BOF converter of each example is shown in tables 1-3.
Table 1: specific process of BOF converter in each embodiment
Table 2: specific process of BOF converter in each embodiment
Table 3: specific process of BOF converter in each embodiment
(2) An LF refining procedure: and after LF is in place, feeding a calcium wire according to 0.05-0.07 kg/t steel, wherein double air bricks are used for a steel ladle. Adding lime, fluorite and quartz sand for slagging according to the melting condition and the fluidity of the refining furnace slag without using refining composite slag; in the refining process, the consumption of lime is 6-8 kg/t steel, the consumption of fluorite is 0.5-1.0 kg/t steel and the consumption of quartz sand is 0.8-1.2 kg/t steel, the refining time is more than or equal to 90min, and the holding time of white slag is more than or equal to 50 min. In the LF refining process, silicon carbide is added in an amount of 3-5 kg/t steel for diffusion deoxidation, so that a good deoxidation effect is ensured. The flow rate of argon gas in the LF process is controlled to 300-800 NL/min, and the argon gas consumption is 0.3 &0.5m3And/t, so as to ensure good air permeability and stirring effect and promote the progress of metallurgical reactions such as deoxidation and desulfurization, component adjustment, uniform temperature, inclusion floating and the like. In the LF refining process, the alloy content is adjusted according to target components, and 3.0-4.0 kg/t of low-aluminum silicon iron and other required alloys are used. The low-aluminum silicon iron comprises the following main component indexes: more than or equal to 75 wt% of Si, less than or equal to 0.5 wt% of Al, less than or equal to 0.035 wt% of P and 10-80 mm of granularity.
Controlling range of LF slag system: 52-56 wt% of CaO and Al2O3 15～20wt％、SiO213-18 wt%, 5-10 wt% of MgO, (TFe + MnO) is less than or equal to 0.5 wt%, and R is 3.2-3.6. LF slag system can control lower molten steel [ Al ]]The content of the slag meets the desulfurization requirement of steel grade, and the slag has good adsorbability to floating impurities, thereby ensuring good purity of molten steel. The specific process of LF refining in each example is shown in Table 4, and the LF slag system components are shown in Table 5.
Table 4: specific Process for LF refining in Each example
Table 5: LF slag composition of each example
(3) VD vacuum treatment process: the VD high vacuum degassing treatment (below 67 Pa) is kept for 25-30 min, the argon flow in the VD process is controlled to be 150-500 NL/min, and the argon consumption is 0.06-0.10 m3And/t, steam consumption is 35-42 kg/t steel. After the VD is broken, adding a pre-melted steel cladding covering agent according to the proportion of 1.0-1.5 kg/t; the soft blowing time is controlled to be 35-50 min, the argon flow is less than or equal to 17L/min during soft blowing, impurities are promoted to float sufficiently, the superheat degree of a ladle is 43-50 ℃, and the superheat degree of a steel ingot during pouring is guaranteed to be 43-47 ℃. The pre-melting ladle covering agent has the main component requirements that: caO 9～17％、SiO2 29～39％、Al2O3 6～14％、MgO≤6.0％、Fe2O3Less than or equal to 5.0 percent and 20 to 35 percent of C solid. The specific process of VD process for each example is shown in Table 6.
Table 6: specific process of VD vacuum treatment in each example
(4) Pouring: and controlling the mold temperature to be 50-80 ℃ when the steel ingot is poured. The pouring speed of the ingot body of the steel ingot is 1.2-1.5 t/min, the pouring speed of the cap opening of the steel ingot is 0.3-0.7 t/min, the stable rising of the liquid level of the molten steel in the ingot mould is ensured, and the argon protection is well carried out during pouring, so that the secondary oxidation and the nitrogen increase caused by the air suction of the molten steel are avoided. The raw and auxiliary materials contacting with the molten steel must be dried in a drying chamber for more than or equal to 48 hours. The covering slag is hung in a mode of combining hanging and process supplementing according to 1.5-1.8 kg/t, the hanging height is 250-300 mm, the rest is supplemented in bulk (the whole bag cannot be added, and the casting cannot be added), and the total amount of hanging and process supplementing is 1.5-2.5 kg/t. Adding a heating agent at a ratio of 1.5-1.8 kg/t when the molten steel reaches 60% -70% of an upper riser line, and adding carbonized rice hulls at a ratio of 1.5-2.0 kg/t after open fire does not exist. The residual molten steel amount in the ladle after pouring is more than or equal to 6 tons, and the ladle slag discharging in the pouring process is avoided. And cooling the steel ingot strip mold for 9-12 hours after pouring, demolding the steel ingot when the surface of the steel ingot is completely solidified and the surface temperature is 650-750 ℃, and performing hot-conveying forging on the steel ingot to perform subsequent forging production of a Cr5 supporting roll. The main component indexes of the die casting protective slag are as follows: c17 +/-5.0 wt%, CaO 14 +/-5.0 wt%, and SiO2 36±5.0wt％，Al2O3≤13wt％，MgO≤8.0wt％，Fe2O3Less than or equal to 7.0 percent. The concrete pouring process of each example is shown in Table 7, and the indexes of the main components of the mold powder of each example are shown in Table 8.
Table 7: concrete process of pouring in each embodiment
Table 8: indexes of main components of mold powder for each example
| Examples | C/％ | CaO/％ | SiO2/％ | Al2O3/％ | MgO/％ | Fe2O3/％ |
| 1 | 17.0 | 16.3 | 33.6 | 12.4 | 6.7 | 6.4 |
| 2 | 20.2 | 13.1 | 36.0 | 11.8 | 7.4 | 6.7 |
| 3 | 15.4 | 17.8 | 37.2 | 12.7 | 7.8 | 5.8 |
| 4 | 12.0 | 14.0 | 38.4 | 12.2 | 6.9 | 7.0 |
| 5 | 18.6 | 19.0 | 37.2 | 13.0 | 7.3 | 6.5 |
| 6 | 16.5 | 10.7 | 41.0 | 10.5 | 6.2 | 6.0 |
| 7 | 22.0 | 12.9 | 31.0 | 11.3 | 7.5 | 6.2 |
| 8 | 19.7 | 9.0 | 35.1 | 12.2 | 8.0 | 5.5 |
(5) The specific components of the Cr5 steel ingots obtained in the examples are shown in Table 9, the gas conditions are shown in Table 10, and the low-magnification test conditions of the steel ingots are shown in Table 11. The obtained Cr5 steel ingot was used as a backup roll, and the high power test condition of the backup roll and the flaw detection condition of the backup roll are shown in Table 12 and Table 13, respectively.
Table 9: concrete composition of Cr5 steel ingot
Table 10: ingot gas condition of the obtained Cr5
Table 11: low power detection condition of obtained Cr5 steel ingot
Table 12: high power detection condition of obtained Cr5 supporting roller
Table 13: flaw detection condition of obtained Cr5 supporting roller
Claims (5)
1. A production method of a steel ingot with low aluminum content Cr5 for a supporting roll is characterized by comprising the working procedures of BOF converter, LF refining, VD vacuum treatment and pouring;
the BOF converter process comprises the following steps: the molten iron entering the furnace is required to have P less than or equal to 0.110wt%, S less than or equal to 0.030wt%, Si 0.20-0.60 wt% and the temperature of 1300-1450 ℃; after the smelting of the previous furnace is finished, leaving 2-5 t of steel slag in the converter, and blowing nitrogen at the bottom to perform slag splashing and furnace protection; pouring out early-stage slag after blowing for 3-5 minutes by the converter, and slagging again to carry out double-slag smelting operation; in the whole smelting process of the converter, 45-60 kg/t of steel lime, 20-30 kg/t of light-burned dolomite and 40-50 kg/t of steel limestone are added, and the oxygen consumption is 50-60 m3T, oxygen supply time is 15-22 min; the smelting period of the converter is 40-50 min, and the nitrogen consumption is 25-35 m3T; tapping C of the converter is more than or equal to 0.08wt%, tapping P is less than or equal to 0.008wt%, and the temperature is 1590-1620 ℃; steel sand aluminum, low-carbon ferrochromium, silicon-manganese alloy and ferromolybdenum are added in sequence in the tapping process; slagging is carried out on converter steel tapping by adopting lime and fluorite, wherein the addition amount of the lime is 5-6 kg/t of steel, and the addition amount of the fluorite is 0.8-1.2 kg/t of steel; deoxidizing and alloying after converter tapping, and controlling P to be less than or equal to 0.012wt%, S to be less than or equal to 0.005wt%, Al to be less than or equal to 0.010wt% and Ti to be less than or equal to 0.005 wt%;
the LF refining process comprises the following steps: after LF is in place, feeding a calcium wire according to 0.05-0.07 kg/t steel, and adding lime, fluorite and quartz sand for slagging according to the melting condition and the fluidity of the refined slag; in the refining process, the consumption of lime is 6-8 kg/t steel, the consumption of fluorite is 0.5-1.0 kg/t steel and the consumption of quartz sand is 0.8-1.2 kg/t steel, the refining time is more than or equal to 90min, and the white slag holding time is more than or equal to 50 min; in the LF refining process, the consumption of silicon carbide is 3-5 kg/t of steel for diffusion deoxidation; the flow rate of argon in the LF process is controlled to be 300-800 NL/min, and the argon consumption is 0.3-0.5 m3T; adjusting the alloy content according to the target components in the LF refining process;
controlling range of LF slag system: 52-56% of CaO and Al2O3 15～20%、SiO2 13～18%、MgO 5～10%、(TFe+MnO)≤0.5%、R 3.2-3.6；
The VD vacuum treatment process comprises the following steps: VD high vacuum degassing treatment is carried out for 25-30 min; the flow rate of argon in the VD process is controlled to be 150-500 NL/min, and the argon consumption is 0.06-0.10 m3T, steam consumption is 35-42 kg/t steel; after the VD is broken, adding a pre-melted steel cladding covering agent, controlling the soft blowing time for 35-50 min, and controlling the argon flow to be less than or equal to 17L/min during soft blowing; the superheat degree of the ladle is 43-50 ℃, and the superheat degree of 43-47 ℃ during steel ingot casting is guaranteed;
the casting process comprises the following steps: controlling the mold temperature to be 50-80 ℃ when the steel ingot is poured; the pouring speed of the ingot body of the steel ingot is 1.2-1.5 t/min, and the pouring speed of the cap opening of the steel ingot is 0.3-0.7 t/min; the covering slag is hung in a mode of combining hanging and process supplementing according to 1.5-1.8 kg/t, the hanging height is 250-300 mm, the rest is supplemented in bulk, and the total amount of hanging and process supplementing is 1.5-2.5 kg/t; adding a heating agent at a ratio of 1.5-1.8 kg/t when the molten steel reaches 60% -70% of an upper riser line, and adding carbonized rice hulls at a ratio of 1.5-2.0 kg/t after open fire does not exist; the residual molten steel amount in the ladle after casting is more than or equal to 6 tons; and cooling the steel ingot strip mold for 9-12 hours after pouring, and demolding the steel ingot and carrying out hot-conveying forging when the surface temperature of the steel ingot is 650-750 ℃.
2. A method for producing a steel ingot low in aluminum content Cr5 for a backup roll according to claim 1, characterized in that the BOF converter process: when bottom blowing nitrogen is carried out to slag splashing and furnace protection, the slag splashing time is 3-5 min, and the nitrogen flow rate is 23000-26 during slag splashing000m3H; the converter molten iron scrap steel proportion is: the iron water amount is 80-85 wt%, and the scrap steel amount is 15-20 wt%; 1.5-2.0 kg/t of steel, 1.5-20 kg/t of steel, 16-20 kg/t of low-carbon ferrochromium, 6-8 kg/t of silicon-manganese alloy and 5.5-7.0 kg/t of ferromolybdenum are added in sequence in the tapping process.
3. A method for producing a steel ingot low in aluminum content Cr5 for a backup roll according to claim 1, characterized in that the LF refining process: in the LF refining process, 3.0-4.0 kg/t of low-aluminum silicon iron and other required alloys are adopted to adjust the alloy content according to target components.
4. A method for producing a steel ingot low in aluminum content Cr5 for a backup roll according to claim 1, wherein the VD vacuum treatment process comprises: and after the VD is broken, adding a pre-melted steel cladding covering agent according to the proportion of 1.0-1.5 kg/t.
5. A method for producing a steel ingot low in aluminum content Cr5 for a supporting roll according to any one of claims 1 to 4, wherein the main component indexes of the mold flux in the casting process are as follows: c17 +/-5.0 wt%, CaO 14 +/-5.0 wt%, and SiO2 36±5.0wt%，Al2O3≤13wt%，MgO≤8.0wt%，Fe2O3≤7.0wt%。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010839049.1A CN112126743B (en) | 2020-08-19 | 2020-08-19 | Production method of low-aluminum-content Cr5 steel ingot for supporting roll |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010839049.1A CN112126743B (en) | 2020-08-19 | 2020-08-19 | Production method of low-aluminum-content Cr5 steel ingot for supporting roll |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112126743A true CN112126743A (en) | 2020-12-25 |
| CN112126743B CN112126743B (en) | 2021-12-14 |
Family
ID=73850503
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010839049.1A Active CN112126743B (en) | 2020-08-19 | 2020-08-19 | Production method of low-aluminum-content Cr5 steel ingot for supporting roll |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112126743B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104858616A (en) * | 2014-02-26 | 2015-08-26 | 鞍钢股份有限公司 | Manufacturing method of A4Cr5MoSiV1 high-alloy core rod |
| CN106435353A (en) * | 2016-08-24 | 2017-02-22 | 营口市特殊钢锻造有限责任公司 | Cr5 series hot work die steel |
| CN106734805A (en) * | 2016-12-05 | 2017-05-31 | 东北特钢集团北满特殊钢有限责任公司 | Φ 500~650mm Cr6 swaged forging Electro Slag Remelting Steel cold roll blank forging deformation techniques |
| CN109536673A (en) * | 2018-11-06 | 2019-03-29 | 石钢京诚装备技术有限公司 | A kind of production method of 2Cr12NiMoWV steel ingot |
| CN110055450A (en) * | 2019-04-18 | 2019-07-26 | 石钢京诚装备技术有限公司 | A kind of smelting process of non-hardened and tempered steel |
| US20190284654A1 (en) * | 2016-11-15 | 2019-09-19 | Jiang Yin Xing Cheng Special Steel Works Co., Ltd | High-hardenability, medium-carbon, low-alloy round steel for fasteners and the manufacturing method thereof |
| CN110592461A (en) * | 2019-08-30 | 2019-12-20 | 石钢京诚装备技术有限公司 | Smelting method of alloy structural steel 45CrNi |
-
2020
- 2020-08-19 CN CN202010839049.1A patent/CN112126743B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104858616A (en) * | 2014-02-26 | 2015-08-26 | 鞍钢股份有限公司 | Manufacturing method of A4Cr5MoSiV1 high-alloy core rod |
| CN106435353A (en) * | 2016-08-24 | 2017-02-22 | 营口市特殊钢锻造有限责任公司 | Cr5 series hot work die steel |
| US20190284654A1 (en) * | 2016-11-15 | 2019-09-19 | Jiang Yin Xing Cheng Special Steel Works Co., Ltd | High-hardenability, medium-carbon, low-alloy round steel for fasteners and the manufacturing method thereof |
| CN106734805A (en) * | 2016-12-05 | 2017-05-31 | 东北特钢集团北满特殊钢有限责任公司 | Φ 500~650mm Cr6 swaged forging Electro Slag Remelting Steel cold roll blank forging deformation techniques |
| CN109536673A (en) * | 2018-11-06 | 2019-03-29 | 石钢京诚装备技术有限公司 | A kind of production method of 2Cr12NiMoWV steel ingot |
| CN110055450A (en) * | 2019-04-18 | 2019-07-26 | 石钢京诚装备技术有限公司 | A kind of smelting process of non-hardened and tempered steel |
| CN110592461A (en) * | 2019-08-30 | 2019-12-20 | 石钢京诚装备技术有限公司 | Smelting method of alloy structural steel 45CrNi |
Non-Patent Citations (1)
| Title |
|---|
| 黄永建 等: ""石钢转炉GCr15轴承钢生产实践"", 《河北冶金》 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112126743B (en) | 2021-12-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109252097B (en) | Non-quenched and tempered steel of high-strength expansion-fracture connecting rod and continuous casting production process thereof | |
| CN101717893B (en) | 55Si2MnVNbN spring steel and production process thereof | |
| CN102021488B (en) | Steel for nuclear-island seamless steel tube and production method thereof | |
| CN111910045B (en) | Smelting method of high-purity austenitic stainless steel | |
| CN112359279B (en) | Alloy structure steel wire rod for shaft and preparation method thereof | |
| CN113145807B (en) | Rare earth bearing steel ingot for shield machine and production method thereof | |
| CN108893682B (en) | Die steel billet and preparation method thereof | |
| CN113073272A (en) | High-strength Q690D steel plate and production method thereof | |
| CN108677084B (en) | Production method of low-inclusion clean steel | |
| CN113215476A (en) | Method for producing industrial pure iron | |
| CN114892094B (en) | Pre-hardened mirror plastic die steel and production method thereof | |
| CN114672723A (en) | 46MnVS series steel for expansion-fracture connecting rod and manufacturing method thereof | |
| CN114959415A (en) | Manufacturing method of microalloyed wind power transmission gear steel | |
| CN114381672B (en) | Smelting and continuous casting manufacturing method of martensite high-wear-resistance steel plate | |
| CN114015936B (en) | High-nitrogen gear steel and preparation method thereof | |
| CN111334718A (en) | European standard R260Mn steel rail and production method thereof | |
| CN117230376B (en) | Electrode for producing 300M steel and preparation method and application thereof | |
| CN112981233B (en) | Low-silicon medium-carbon gear steel suitable for cold forging processing and manufacturing method thereof | |
| CN111945062B (en) | Smelting method of low-carbon steel for mechanical structure pipe | |
| CN111893382B (en) | Food chain stainless steel and preparation method thereof | |
| CN117026092A (en) | High-strength spring steel and preparation method thereof | |
| CN115491575B (en) | High-carbon chromium wind power bearing steel and production process thereof | |
| CN116657043A (en) | Steel for low-alkalinity bead wire and production process thereof | |
| CN112126743B (en) | Production method of low-aluminum-content Cr5 steel ingot for supporting roll | |
| CN116397159A (en) | Steel H08MnSiCuCrNi II for gas-shielded welding wire and production and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |