A production quality control process for high carbon and high chromium steel ∮150 continuous casting round tube casting machine

Abstract

The invention discloses a high carbon high chromium steel ∮150 continuous casting round tube billet casting machine production quality control process, through the vibration table amplitude frequency, electromagnetic stirring parameters, protective slag model, secondary cooling water distribution, superheat and drawing speed matching parameters, casting machine full process protection pouring, drawing and straightening machine pressure setting, covering agent and other parameter settings, to obtain high carbon high chromium steel ∮150 continuous casting round tube billet with stable quality. Through the process parameter setting of the invention, there are no visible scars, slag inclusions, pores, pinholes, and cracks with a depth of more than 0.5mm on the surface of the high carbon high chromium steel ∮150 continuous casting round tube billet, and the out-of-roundness is ≤6.75mm; there are no visible white spots, stratification, and inclusions on the low-power acid leaching sample of the casting billet; the center looseness is ≤2 levels, and the center shrinkage cavity is ≤2 levels; after testing, the oxygen and nitrogen contents in the high carbon high chromium steel ∮150 continuous casting round tube billet are: oxygen content ≤12ppm, nitrogen content ≤60ppm.

Description

Technical Field

[0001] The invention belongs to the technical field of iron and steel metallurgy, and in particular relates to a production quality control process for a high-carbon and high-chromium steel ∮150 continuous casting round tube billet casting machine. Background Art

[0002] GCr15 bearing steel has a long history of research and development, and its uses are also very extensive. The core components of various mechanical equipment cannot do without bearings. Such bearings face complex and changeable environments in practical applications. Some bearings have a small contact area with the ring track during service, which leads to a large contact pressure stress between the two. Data show that the contact pressure can reach up to 5000MPa. The components of the bearing should have a high deformation resistance to slow down the occurrence of plastic deformation, thereby reducing its accuracy. Some bearing steels sometimes rotate tens of thousands of times per minute, and the relative sliding between the bearing and the track will also produce friction. When subjected to large contact stress or long wear time, some bearing tissues will change, which will cause changes in the mechanical properties of some bearing components and lead to bearing failure. In my country, bearings face a variety of working conditions. When they are subjected to large impact forces, large-sized hard inclusions and carbide particles protrude from the surface of the bearing steel, or the processing residue is uneven and fatigue falls off, the bearing steel may suffer from impact fracture failure, which is more harmful.

[0003] Over the past half century, GCr15 bearing steel has gradually formed a high-carbon and high-manganese series of bearing steel with a relatively complete production system. Because of its widespread application, it must undergo various strict inspections before it works, and after passing different heat treatment processes, it can be used in different working environments. This type of steel has a relatively wide range of applications and excellent performance; depending on the use environment and service status, the requirements for its various properties are also very different.

[0004] After searching, it was found that there are two literature patents that are most relevant to the technology of the present invention, and the specific contents are described as follows:

[0005] After searching, similar background technologies include: "A method for producing GCr15 bearing steel billet" (patent application number: 201410811222.1), which is different from the present invention in that: in terms of cross-sectional design, the present invention adopts a 150mm round tube billet, while the similar patents searched use a 150×150mm billet, and the production billet shape is inconsistent;

[0006] After searching, similar background technologies include: "A method for producing GCr15 bearing steel small square billets" (patent application number: 201711312719.9), which is different from the present invention in that: in terms of cross-sectional design, the present invention adopts Ф150mm round tube billets, while the retrieved similar patents adopt 150×150mm small square billets, and the production billet shapes are inconsistent. Summary of the invention

[0007] The purpose of the present invention is to provide a high-carbon high-chromium steel ∮150 continuous casting round tube casting machine production quality control process to obtain high-carbon high-chromium steel ∮150 continuous casting round tube billets with stable quality.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0009] The present invention discloses a high carbon high chromium steel ∮150 continuous casting round tube casting machine production quality control process, comprising:

[0010] (1) The temperature of the continuous casting ladle is 1531℃~1561℃, and the temperature of the continuous casting ladle is 1481℃~1511℃;

[0011] (2) Using weak cooling process, the crystallizer vibrates at high frequency and low amplitude;

[0012] (3) The superheat control range is 30℃~60℃, and the superheat is matched with the casting speed control;

[0013] (4) Carry out argon blowing operation on the tundish, long water inlet graphite sealing protection + protective slag + long water inlet argon protection pouring + tundish covering agent, keep the crystallizer protective slag and black slag covering throughout the process, and the water distribution coefficient and crystallizer cooling water are controlled as follows:

[0014] Specific water volume: Zone 1 30.1~38.44L / kg; Zone 2 49.21~61.05L / kg; Zone 3 27.02~32.43L / kg; Zone 4 12~20L / kg;

[0015] Crystallizer water: 1800~2400L / min;

[0016] (5) Adopting crystallizer electromagnetic stirring technology; the tensioning and straightening machine uses low-pressure tensioning and straightening, and the electromagnetic stirring parameters are: clockwise stirring, current 80-150A, and frequency 3;

[0017] (6) Requirements for mold slag composition: SiO 2 28~33%, CaO 20~30%, MgO 3.5~4.5%, A l 2 O 3 4.5~7%,Fe 2 O 3 0.5~1.5%, R 2O 5.0~7.0%, F 2.0~4.0%, C~tot.10~15%, moisture <1.0%;

[0018] (7) Hot billet pressure parameters of the straightening machine: 2 to 5 bar for 1 straightening machine, 2 to 5 bar for 2 straightening machines, 3 to 8 bar for 3 straightening machines, and 3 to 8 bar for 4 straightening machines.

[0019] Furthermore, the crystallizer vibration control is specifically as follows: the vibration mode is mechanical sine, the vibration fundamental frequency is 30 to 300 times / minute, and the vibration amplitude is 4 to 5 mm.

[0020] Furthermore, the matching of superheat and pulling speed control is specifically as follows: when the superheat control range is 30°C to 40°C, the pulling speed is 2.4 to 2.6 m / min; when the superheat control range is 40°C to 60°C, the pulling speed is 2.0 to 2.2 m / min.

[0021] Furthermore, the composition of the covering agent is calculated by mass percentage as follows: TC 5.0-8.5%, CaO 25.0-35.0%, SiO 2 35~45%,Al 2 O 3 15~20%, MgO 2.0~4.0%.

[0022] Furthermore, the surface of the high-carbon and high-chromium steel ∮150 continuous casting round tube billet produced has no visible scars, slag inclusions, pores, pinholes, and cracks with a depth exceeding 0.5 mm, and the out-of-roundness is ≤6.75 ​​mm; there are no visible white spots, stratification, or inclusions on the low-magnification acid immersion sample of the ingot; the central looseness is ≤level 2, and the central shrinkage cavity is ≤level 2.

[0023] Furthermore, the oxygen and nitrogen contents in the high carbon and high chromium steel ∮150 continuous casting round tube billet were tested: oxygen content ≤12ppm, nitrogen content ≤60ppm.

[0024] Compared with the prior art, the beneficial technical effects of the present invention are:

[0025] By setting the process parameters of the present invention, there are no visible scars, slag inclusions, pores, pinholes, and cracks with a depth exceeding 0.5 mm on the surface of the high-carbon high-chromium steel ∮150 continuous casting round tube billet, and the out-of-roundness is ≤6.75 ​​mm; there are no visible white spots, stratification, or inclusions on the low-magnification acid leaching sample of the ingot; the center looseness is ≤2 levels, and the center shrinkage cavity is ≤2 levels;

[0026] After testing, the oxygen and nitrogen contents in high carbon and high chromium steel ∮150 continuous casting round tube billet are as follows: oxygen content ≤12ppm, nitrogen content ≤60ppm. DETAILED DESCRIPTION

[0027] The chemical composition design of high carbon and high chromium steel ∮150 continuous casting round tube billet is shown in Table 1.

[0028] Table 1 Chemical composition test results of high carbon high chromium steel ∮150 continuous casting round tube billet (Wt%)

[0029]

[0030] The temperature of the continuous casting ladle is 1541℃~1578℃, and the temperature of the continuous casting ladle is 1491℃~1521℃.

[0031] A weak cooling process is adopted, and the crystallizer vibrates at high frequency and low amplitude. The crystallizer vibration control is shown in Table 2.

[0032] Table 2 Crystallizer vibration control of high carbon high chromium steel ∮150 continuous casting round tube billet

[0033] Vibration mode Fundamental frequency of vibration, times / minute Vibration amplitude, mm Mechanical sine 30～300 4～5

[0034] The superheat control range is 30℃~55℃, and the superheat and pulling speed control are shown in Table 3.

[0035] Table 3 Superheat and casting speed control of high carbon high chromium steel ∮150 continuous casting round tube billet

[0036] Superheat℃ 30～40 40～50 Pulling speed(m / min) 2.3～2.6 2.0～2.3

[0037] The tundish argon blowing operation was carried out, with long shroud graphite sealing protection + protective slag + long shroud argon protection pouring + tundish low-carbon covering agent. The crystallizer protective slag and black slag were covered throughout the process. The water distribution coefficient and crystallizer cooling water control were shown in Table 4.

[0038] Table 4 Crystallizer vibration control of high carbon high chromium steel ∮150 continuous casting round tube billet

[0039]

[0040] The crystallizer electromagnetic stirring technology is used; the tensioning and leveling machine uses low-pressure tensioning and leveling. The electromagnetic stirring parameters are shown in Table 5.

[0041] Table 5 Electromagnetic stirring parameter control of high carbon and high chromium steel ∮150 continuous casting round tube billet

[0042] Mixing method Current frequency Clockwise 80～150 3

[0043] The protective slag composition control is shown in Table 6.

[0044] Table 6 Requirements for the composition of protective slag for high carbon and high chromium steel ∮150 continuous casting round tube billet

[0045]

[0046] The hot billet pressure parameters of the tension and straightening machine are shown in Table 7.

[0047] Table 7 Hot billet pressure parameter control of high carbon high chromium steel ∮150 continuous casting round tube billet straightening machine

[0048] Tension leveling machine 1 tensioning and leveling machine 2 tensioning and leveling machines 3 tensioning and leveling machines 4 tensioning and leveling machines Hot billet pressure (bar) 3～5 3～5 4～8 4～8

[0049] The composition of the covering agent is shown in Table 8

[0050] Table 8 Requirements for low carbon covering agent composition of high carbon high chromium steel ∮150 continuous casting round tube billet (Wt%)

[0051]

[0052] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention.

[0053] Example 1

[0054] The liquidus temperature of high carbon and high chromium steel is about 1451℃, the temperature of continuous casting ladle is 1555℃, and the temperature of continuous casting ladle is 1510℃.

[0055] Chemical composition test results:

[0056] Table 9 Chemical composition test results of high carbon high chromium steel ∮150 continuous casting round tube billet (Wt%)

[0057]

[0058] The crystallizer vibration control is shown in Table 10:

[0059] Table 10 Example 1 Crystallizer Vibration Control

[0060] Vibration mode Fundamental frequency of vibration, times / minute Vibration amplitude, mm Mechanical sine 130 4.5

[0061] The superheat and casting speed control are shown in Table 11:

[0062] Table 11 Superheat and casting speed control of Example 1

[0063] Superheat℃ 59 45 Pulling speed, m / min 2.1 2.3

[0064] The water distribution coefficient and crystallizer cooling water control are shown in Table 12:

[0065] Table 12 Example 1 Crystallizer Vibration Control

[0066]

[0067] The electromagnetic stirring parameters are shown in Table 13:

[0068] Table 13 Electromagnetic stirring parameter control of Example 1

[0069] Mixing method Current frequency Clockwise 50 3

[0070] The mold slag composition control table 14 is shown as follows:

[0071] Table 14 Example 1 slag composition control

[0072]

[0073] The hot billet pressure parameters of the tension and straightening machine are shown in Table 15:

[0074] Table 15 Example 1 Hot billet pressure parameters Parameter control of the straightening machine

[0075] Tension leveling machine 1 tensioning and leveling machine 2 tensioning and leveling machines 3 tensioning and leveling machines 4 tensioning and leveling machines Hot billet pressure (bar) 4.2 4.2 7.2 6.9

[0076] The composition of low carbon covering agent is shown in Table 16:

[0077] Table 16 Example 1 Covering agent composition control (Wt%)

[0078] Main Elements TC CaO <![CDATA[SiO 2 ]]> <![CDATA[Al 2 THE 3 ]]> MgO Low carbon covering agent 8.4 34.08 36.06 15.09 3.88

[0079] Example 1 Continuous Casting Round Tube Billet Casting Quality Control:

[0080] 1. Surface quality: There are no visible scars, slag inclusions, pores, pinholes, or cracks with a depth exceeding 0.5 mm on the surface of the continuous casting billet, and the out-of-roundness is less than 6.75 mm;

[0081] 2. Low magnification of continuous casting billet: There are no visible white spots, stratification, or inclusions on the low magnification acid leaching sample of the continuous casting billet; the center looseness is level 1.5, and the center shrinkage cavity is level 1.5;

[0082] 3. Hydrogen, oxygen and nitrogen content in steel: [H]: 1.2ppm; [O]: 9ppm, [N] 52ppm;

[0083] 4. The chemical composition test results of the continuous casting round tube billet in Example 1 are shown in Table 17.

[0084] Table 17 Melting composition test results of Example 1 (Wt%)

[0085]

[0086]

[0087] 5. As shown in Table 18, the results of the spot check of the out-of-roundness of the casting are in line with the national standard YB / T 4149-2008, with a diameter of ≤150mm and an out-of-roundness of <4.5%d (6.75mm).

[0088] Table 18 Out-of-roundness control of continuous casting round tube billet in Example 1

[0089] Runner 1 stream 2 Stream 3 Stream 4 Stream 5. Stream Inner and outer arc (mm) 148 149 148 147.5 148 North and south (mm) 152 153 153 153.5 152 Out-of-roundness value (mm) 4 4 5 6 4

[0090] Example 2

[0091] (1) The temperature of the continuous casting ladle is 1533℃, and the temperature of the continuous casting ladle is 1496℃;

[0092] (2) Crystallizer vibration control is shown in Table 19:

[0093] Table 19 Crystallizer vibration control of continuous casting round tube billet in Example 2

[0094] Vibration mode Fundamental frequency of vibration, times / minute Vibration amplitude, mm Mechanical sine 160 4.5

[0095] (3) Superheat and casting speed control are shown in Table 20:

[0096] Table 20 Superheat and casting speed control of continuous casting round tube billet in Example 2

[0097] Superheat℃ 45 36 Pulling speed, m / min 2.3 2.6

[0098] (4) The water distribution coefficient and the crystallizer cooling water control are shown in Table 21:

[0099] Table 21 Crystallizer vibration control of continuous casting round tube billet in Example 2

[0100]

[0101] (5) Electromagnetic stirring parameters are shown in Table 22:

[0102] Table 22 Electromagnetic stirring parameter control of continuous casting round tube billet in Example 2

[0103] Mixing method Current frequency Clockwise 50 3

[0104] (6) The mold slag composition control table 23 shows

[0105] Table 23 Control of the protective slag composition of the continuous casting round tube billet in Example 2

[0106]

[0107] (7) The hot billet pressure parameters of the straightening machine are shown in Table 24:

[0108] Table 24 Parameter control of hot billet pressure parameters of the straightening machine for continuous casting round tube billet in Example 2

[0109] Tension leveling machine 1 tensioning and leveling machine 2 tensioning and leveling machines 3 tensioning and leveling machines 4 tensioning and leveling machines Hot billet pressure (bar) 4.5 4.5 7.4 7.3

[0110] (8) Covering agent composition is shown in Table 25:

[0111] Table 25 Carbon coating composition control of continuous casting round tube billet in Example 2 (Wt%)

[0112] Main Elements TC CaO <![CDATA[SiO 2 ]]> <![CDATA[Al 2 THE 3 ]]> MgO Low carbon covering agent 8.6 34.24 36.12 15.21 3.96

[0113] (9) Example 2 Continuous Casting Round Tube Billet Casting Quality Control

[0114] 1. Surface quality: There are no visible scars, slag inclusions, pores, pinholes, or cracks with a depth exceeding 0.5 mm on the surface of the continuous casting billet, and the out-of-roundness is less than 6.75 mm;

[0115] 2. Low magnification of continuous casting billet: There are no visible white spots, stratification, or inclusions on the low magnification acid leaching sample of the continuous casting billet; the center looseness is 1.5 level, and the center shrinkage cavity is 1.0 level;

[0116] 3. Hydrogen, oxygen and nitrogen content in steel: [H]: 1.3ppm; [O]: 8ppm, [N] 46ppm;

[0117] 4. The chemical composition test results of the continuous casting round tube billet in Example 2 are shown in Table 26.

[0118] Table 26 Melting composition test results of Example 2 (Wt%)

[0119]

[0120]

[0121] 5. As shown in Table 27, the results of the spot check of the out-of-roundness of the casting are in line with the national standard YB / T 4149-2008, diameter ≤150mm, out-of-roundness <4.5%d (6.75mm).

[0122] Table 27 Out-of-roundness control of continuous casting round tube billet in Example 2

[0123] Runner 1 stream 2 Stream 3 Stream 4 Stream 5. Stream Inner and outer arc (mm) 149 148 147 148 147 North and south (mm) 152 153 152 152 152.5 Out-of-roundness value (mm) 3 5 5 4 5.5

[0124] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A high carbon and high chromium steel ∮150 continuous casting round tube casting machine production quality control process, characterized in that: include: (1) The temperature of the continuous casting ladle is 1531℃~1561℃, and the temperature of the continuous casting ladle is 1481℃~1511℃; (2) Using weak cooling process, the crystallizer vibrates at high frequency and low amplitude; (3) The superheat control range is 30℃~60℃, and the superheat is matched with the casting speed control; (4) Carry out argon blowing operation on the tundish, long water inlet graphite sealing protection + protective slag + long water inlet argon protection pouring + tundish covering agent, keep the crystallizer protective slag and black slag covering throughout the process, and the water distribution coefficient and crystallizer cooling water are controlled as follows: Specific water volume: Zone 1 30.1~38.44L / kg; Zone 2 49.21~61.05L / kg; Zone 3 27.02~32.43L / kg; Zone 4 12~20L / kg; Crystallizer water: 1800~2400L / min; (5) Adopting crystallizer electromagnetic stirring technology; the tensioning and straightening machine uses low-pressure tensioning and straightening, and the electromagnetic stirring parameters are: clockwise stirring, current 80-150A, and frequency 3; (6) Requirements for mold slag composition: SiO2 28-33%, CaO 20-30%, MgO 3.5-4.5%, Al2O3 4.5-7%, Fe2O3 0.5-1.5%, R2O 5.0-7.0%, F 2.0-4.0%, C tot. 10-15%, moisture <1.0%; (7) Hot billet pressure parameters of the straightening machine: 2 to 5 bar for 1 straightening machine, 2 to 5 bar for 2 straightening machines, 3 to 8 bar for 3 straightening machines, and 3 to 8 bar for 4 straightening machines.

2. The high carbon and high chromium steel ∮150 continuous casting round tube casting machine production quality control process according to claim 1 is characterized in that: The crystallizer vibration control is specifically as follows: the vibration mode is mechanical sine, the vibration fundamental frequency is 30 to 300 times / minute, and the vibration amplitude is 4 to 5 mm.

3. The high carbon and high chromium steel ∮150 continuous casting round tube casting machine production quality control process according to claim 1 is characterized in that: The matching of superheat and pulling speed control is as follows: when the superheat control range is 30℃~40℃, the pulling speed is 2.4~2.6m / min; when the superheat control range is 40℃~60℃, the pulling speed is 2.0~2.2m / min.

4. The high carbon and high chromium steel ∮150 continuous casting round tube casting machine production quality control process according to claim 1 is characterized in that: The components of the covering agent are calculated by mass percentage as follows: T.C 5.0-8.5%, CaO 25.0-35.0%, SiO 2 35-45%, Al 2 O 3 15-20%, and MgO 2.0-4.0%.

5. The high carbon and high chromium steel ∮150 continuous casting round tube casting machine production quality control process according to claim 1 is characterized in that: The surface of the high-carbon and high-chromium steel ∮150 continuous casting round tube billet produced has no visible scars, slag inclusions, pores, pinholes, and cracks with a depth exceeding 0.5mm, and the out-of-roundness is ≤6.75mm; there are no visible white spots, stratification, or inclusions on the low-magnification acid immersion samples of the ingot; the central looseness is ≤level 2, and the central shrinkage cavity is ≤level 2.

6. The high carbon and high chromium steel ∮150 continuous casting round tube casting machine production quality control process according to claim 1 is characterized in that: After testing, the oxygen and nitrogen contents in high carbon and high chromium steel ∮150 continuous casting round tube billet are as follows: oxygen content ≤12ppm, nitrogen content ≤60ppm.

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