CN114231705A - Normalizing heat treatment method for large-thickness P460NH steel - Google Patents
Normalizing heat treatment method for large-thickness P460NH steel Download PDFInfo
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- CN114231705A CN114231705A CN202111582051.6A CN202111582051A CN114231705A CN 114231705 A CN114231705 A CN 114231705A CN 202111582051 A CN202111582051 A CN 202111582051A CN 114231705 A CN114231705 A CN 114231705A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 87
- 239000010959 steel Substances 0.000 title claims abstract description 87
- 238000010438 heat treatment Methods 0.000 title claims abstract description 50
- 238000000034 method Methods 0.000 title claims abstract description 25
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 43
- 238000001816 cooling Methods 0.000 claims abstract description 32
- 238000004321 preservation Methods 0.000 claims abstract description 25
- 238000007599 discharging Methods 0.000 claims abstract description 20
- 239000003034 coal gas Substances 0.000 claims abstract description 18
- 238000003756 stirring Methods 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
- C21D1/28—Normalising
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/005—Heat treatment of ferrous alloys containing Mn
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0081—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for slabs; for billets
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatments In General, Especially Conveying And Cooling (AREA)
Abstract
A normalizing heat treatment method for large-thickness P460NH steel comprises the following steps of heating, heat preservation and cooling in a vehicle bottom furnace: (1) the heating of the vehicle bottom furnace: slowly heating the steel plate in a vehicle bottom furnace for 4-5h, controlling the pressure of a hearth, the pressure of hot air, the pressure of coal gas, the flow of coal gas and the flow of hot air, and ensuring the uniform heating of the steel plate; (2) and (3) heat preservation: slowly raising the temperature of the steel plate to 890-910 ℃ and keeping the temperature for 2-2.5 min/mm; (3) and (3) cooling: and (3) discharging the steel plate at the temperature, putting the steel plate into a water tank for cooling, controlling the time from discharging to water inlet to be 3-4min, the water temperature to be 35-40 ℃, the water cooling time to be 5-7min, naturally cooling the steel plate after water outlet, and controlling the temperature of red returning to be 450-550 ℃. The normalizing process is optimized, so that the heat treatment efficiency of the steel plate is improved, the stable performance of the steel plate is ensured, and the use requirement of equipment is met.
Description
Technical Field
The invention belongs to the technical field of metallurgy, and particularly relates to a normalizing heat treatment method for large-thickness P460NH steel.
Background
The P460NH steel is EN 10028-3: 2017, in recent years, because the requirements of national large-scale equipment are gradually increased by using steel, the thickness of the steel plate is required to be gradually increased, the production process of the steel plate with the thickness less than 100mm is relatively stable, and the performance requirements of the equipment cannot be met by adopting the traditional heat treatment method along with the increase of the thickness of the steel plate, so that the production and manufacturing process of the steel plate needs to be optimized, the low-cost high-performance requirements are met, and greater benefits are created.
The invention mainly combines the current situation of the existing equipment, realizes the stable performance of the steel plate by optimizing the heat treatment process parameters, the steel structure characteristics, and the like through technological measures such as adjusting the heating system, controlling the heating temperature, adjusting the cooling mode and the like, and meets the requirement of domestic equipment manufacturing.
Disclosure of Invention
The invention aims to provide a normalizing heat treatment method for large-thickness P460NH steel.
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
a normalizing heat treatment method for large-thickness P460NH steel comprises the steps of vehicle bottom furnace heating, heat preservation and cooling, wherein:
(1) heating a vehicle bottom furnace: placing the steel plate on a trolley of the vehicle bottom furnace, driving the trolley into the vehicle bottom furnace, slowly heating for 4-5h, controlling the pressure of a hearth, the pressure of hot air, the pressure of coal gas, the flow of coal gas and the flow of hot air, and ensuring the uniform heating of the steel plate;
(2) and (3) heat preservation: slowly raising the temperature of the steel plate to 890-910 ℃ and keeping the temperature for 2-2.5 min/mm;
(3) and (3) cooling: and (3) discharging the steel plate from the furnace at a warm temperature, putting the steel plate into a water tank for cooling by adopting a crown block hook mode, controlling the time from discharging to water inlet to be 3-4min, controlling the water temperature to be 35-40 ℃, controlling the water cooling time to be 5-7min, controlling the temperature of red returning to be 450-550 ℃, independently placing the steel plate on a fixed rack after discharging water, and naturally cooling.
Specifically, in the step (1), the pressure of the hearth is 9-11Pa, the pressure of the hot air is 5-7KPa, the pressure of the coal gas is 3-5KPa, and the flow rate of the coal gas is 900-1000 Nm-3The flow rate of the hot air is 1700-1800Nm3/h。
Specifically, the heat preservation time in the step (2) is calculated from the time when all the thermocouples are displayed to the time when the heat preservation time is started.
Specifically, after the steel plate enters water, the air stirring device is started, and water is discharged quickly after time.
Specifically, the thickness of the steel plate is 150-200 mm.
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: the steel plate performance stability is ensured through the adjustment of normalizing process parameters, and the performance of the steel plate after heat treatment is as follows: yield strength ReH is more than or equal to 400MPa, tensile strength Rm: 530 ℃ and 690MPa, the low-temperature impact energy at minus 20 ℃ is more than or equal to 80J, and the elongation after fracture is more than or equal to 20 percent, thereby meeting the use requirement of equipment.
Detailed Description
The present invention will be described in further detail with reference to specific examples.
Example 1
The thickness of the large-thickness P460NH steel plate of the embodiment is 150mm, and the heat treatment process is as follows:
(1) heating a vehicle bottom furnace: placing the steel plate on a vehicle bottom furnace trolley, driving the trolley into the vehicle bottom furnace, slowly heating for 4h, controlling the pressure of a hearth 9Pa, the pressure of hot air 5KPa, the pressure of coal gas 3KPa and the flow of the coal gas 900Nm3Flow rate of hot air/h 1700Nm3And h, ensuring that the temperature of the steel plate is uniformly raised.
(2) And (3) heat preservation: the steel plate is slowly heated to 890 ℃, all thermocouples display the heat preservation time, and the heat preservation time is calculated according to the speed of 2 min/mm.
(3) And (3) cooling: and (3) discharging the steel plate from the furnace at a temperature, putting the steel plate into a water tank by adopting a crown block hook mode for cooling, controlling the time from discharging to water entering for 3min, controlling the water temperature for 35 ℃, controlling the water cooling time for 5min, starting an air stirring device after the steel plate enters the water, rapidly discharging the water after the time, controlling the temperature of red returning to 450 ℃, independently placing the steel plate on a fixed rack after the steel plate is discharged, and naturally cooling.
The properties of the heat treated steel sheet were: yield strength ReH410MPa, tensile strength Rm: 535MPa, low-temperature impact energy of-20 ℃ is 85J, and the elongation after fracture is 26 percent, thereby meeting the use requirement of equipment.
Example 2
The thickness of the large-thickness P460NH steel plate of the embodiment is 170mm, and the heat treatment process is as follows:
(1) heating a vehicle bottom furnace: placing the steel plate on a vehicle bottom furnace trolley, driving the trolley into the vehicle bottom furnace, slowly heating for 5h, controlling the hearth pressure to be 11Pa, the hot air pressure to be 7KPa, the coal gas pressure to be 5KPa and the coal gas flow to be 1000Nm3Flow rate of hot air/h 1800Nm3And h, ensuring that the temperature of the steel plate is uniformly raised.
(2) And (3) heat preservation: and slowly heating the steel plate to 910 ℃, displaying the heat preservation time by all thermocouples, and starting to calculate the heat preservation, wherein the heat preservation time is 2.5 min/mm.
(3) And (3) cooling: and (3) discharging the steel plate from the furnace at a temperature, cooling the steel plate in a water tank by adopting a crown block hook mode, controlling the time from discharging to water inlet for 4min, controlling the water temperature for 40 ℃, controlling the water cooling time for 7min, starting an air stirring device after the steel plate enters the water, rapidly discharging the water after the time, controlling the temperature of reddening to be 550 ℃, independently placing the steel plate on a fixed rack after the steel plate is discharged, and naturally cooling the steel plate.
The properties of the heat treated steel sheet were: yield strength ReH520MPa, tensile strength Rm: 685MPa, impact energy at-20 ℃ and low temperature of 130J, and elongation after fracture of 21 percent, and meets the use requirement of equipment.
Example 3
The thickness of the large-thickness P460NH steel plate of the embodiment is 190mm, and the heat treatment process is as follows:
(1) heating a vehicle bottom furnace: placing the steel plate on a bogie hearth furnace trolley, driving the trolley into the bogie hearth furnace, slowly heating for 4.5h, and controlling the pressure of a hearth 10Pa, the pressure of hot air 6KPa, the pressure of coal gas 4KPa and the flow of the coal gas 950Nm3The flow rate of hot air is 1750Nm3And h, ensuring that the temperature of the steel plate is uniformly raised.
(2) And (3) heat preservation: and slowly heating the steel plate to 900 ℃, displaying the heat preservation time by all thermocouples, and starting to calculate the heat preservation, wherein the heat preservation time is 2.3 min/mm.
(3) And (3) cooling: and (3) discharging the steel plate from the furnace at a temperature, putting the steel plate into a water tank by adopting a crown block hook mode for cooling, controlling the time from discharging to water entering for 3.5min, controlling the water temperature for 37 ℃, controlling the water cooling time for 6min, starting an air stirring device after the steel plate enters the water, discharging water quickly after the time, controlling the temperature of red returning to 500 ℃, independently placing the steel plate on a fixed rack after the steel plate is discharged, and naturally cooling.
The properties of the heat treated steel sheet were: yield strength ReH470MPa, tensile strength Rm: 600MPa, impact energy at-20 ℃ and low temperature of 100J, and elongation after fracture of 23 percent, thereby meeting the use requirements of equipment.
Example 4
The thickness of the large-thickness P460NH steel plate of the embodiment is 200mm, and the heat treatment process is as follows:
(1) heating a vehicle bottom furnace: steelThe plate is placed on a vehicle bottom furnace trolley, the trolley is driven into the vehicle bottom furnace, the temperature is slowly raised for 4.6 hours, the pressure of a hearth is controlled to be 10.5Pa, the pressure of hot air is controlled to be 6.5KPa, the pressure of coal gas is controlled to be 4.6KPa, and the flow of the coal gas is controlled to be 970Nm3Flow rate of hot air 1770Nm3And h, ensuring that the temperature of the steel plate is uniformly raised.
(2) And (3) heat preservation: and slowly heating the steel plate to 905 ℃, displaying the heat preservation time by all thermocouples, and starting to calculate the heat preservation, wherein the heat preservation time is 2.4 min/mm.
(3) And (3) cooling: and (3) discharging the steel plate from the furnace at a high temperature, putting the steel plate into a water tank by adopting a crown block hook mode for cooling, controlling the time from discharging to water inlet for 3.6min, controlling the water temperature to be 37 ℃ and the water cooling time to be 6.5min, starting an air stirring device after the steel plate enters water, discharging water quickly after the time, controlling the temperature of red returning to be 470 ℃, independently placing the steel plate on a fixed rack after the steel plate is discharged, and naturally cooling.
The properties of the heat treated steel sheet were: yield strength ReH490MPa, tensile strength Rm: the impact energy is 110J at the low temperature of-20 ℃ under 610MPa, the elongation after fracture is 22 percent, and the use requirement of equipment is met.
Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and it is intended to cover in the claims the invention as defined in the appended claims.
Claims (6)
1. The normalizing heat treatment method for the large-thickness P460NH steel comprises heating, heat preservation and cooling of a vehicle bottom furnace, and is characterized in that:
(1) the heating of the vehicle bottom furnace: slowly heating the steel plate in a vehicle bottom furnace for 4-5h, controlling the pressure of a hearth, the pressure of hot air, the pressure of coal gas, the flow of coal gas and the flow of hot air, and ensuring the uniform heating of the steel plate;
(2) and (3) heat preservation: slowly raising the temperature of the steel plate to 890-910 ℃ and keeping the temperature for 2-2.5 min/mm;
(3) and (3) cooling: and (3) discharging the steel plate at the temperature, putting the steel plate into a water tank for cooling, controlling the time from discharging to water inlet to be 3-4min, the water temperature to be 35-40 ℃, the water cooling time to be 5-7min, naturally cooling the steel plate after water outlet, and controlling the temperature of red returning to be 450-550 ℃.
2. The normalizing heat treatment method for the large-thickness P460NH steel according to claim 1, wherein the normalizing heat treatment method comprises the following steps: step (1), the pressure of the hearth is 9-11Pa, the pressure of the hot air is 5-7KPa, the pressure of the coal gas is 3-5KPa, and the flow rate of the coal gas is 900-1000 Nm-3The flow rate of the hot air is 1700-1800Nm3/h。
3. The normalizing heat treatment method for the large-thickness P460NH steel according to claim 1, wherein the normalizing heat treatment method comprises the following steps: and (3) calculating the heat preservation time from the display of all the thermocouples to the heat preservation time in the step (2).
4. The normalizing heat treatment method for the large-thickness P460NH steel according to claim 1, wherein the normalizing heat treatment method comprises the following steps: and (4) starting an air stirring device after the steel plate enters water, and quickly discharging water after time.
5. The normalizing heat treatment method for the large-thickness P460NH steel according to claim 1, wherein the normalizing heat treatment method comprises the following steps: the thickness of the steel plate is 150-200 mm.
6. The normalizing heat treatment method for the large-thickness P460NH steel according to claim 1, wherein the normalizing heat treatment method comprises the following steps: the properties of the steel plate after heat treatment are as follows: yield strength ReH is more than or equal to 400MPa, tensile strength Rm: 530 ℃ and 690MPa, the low-temperature impact energy at-20 ℃ is more than or equal to 80J, and the elongation after fracture is more than or equal to 20 percent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202111582051.6A CN114231705A (en) | 2021-12-22 | 2021-12-22 | Normalizing heat treatment method for large-thickness P460NH steel |
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| CN202111582051.6A CN114231705A (en) | 2021-12-22 | 2021-12-22 | Normalizing heat treatment method for large-thickness P460NH steel |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102732696A (en) * | 2012-06-05 | 2012-10-17 | 舞阳钢铁有限责任公司 | Normalization heat treatment method of heavy-gauge low-alloy steel plates |
| CN107326162A (en) * | 2017-06-08 | 2017-11-07 | 舞阳钢铁有限责任公司 | A kind of production method of normalized steel |
| CN109295289A (en) * | 2018-09-20 | 2019-02-01 | 舞阳钢铁有限责任公司 | A method of mitigating hydrogen sulfide corrosion resistant sheet metal banded structure |
-
2021
- 2021-12-22 CN CN202111582051.6A patent/CN114231705A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102732696A (en) * | 2012-06-05 | 2012-10-17 | 舞阳钢铁有限责任公司 | Normalization heat treatment method of heavy-gauge low-alloy steel plates |
| CN107326162A (en) * | 2017-06-08 | 2017-11-07 | 舞阳钢铁有限责任公司 | A kind of production method of normalized steel |
| CN109295289A (en) * | 2018-09-20 | 2019-02-01 | 舞阳钢铁有限责任公司 | A method of mitigating hydrogen sulfide corrosion resistant sheet metal banded structure |
Non-Patent Citations (1)
| Title |
|---|
| 秦晓钟: "《世界压力容器用钢手册》", 机械工业出版社, pages: 789 * |
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