US20220025473A1 - On-line Solution Heat Treatment Process for Austenitic Stainless Steel Plates - Google Patents

On-line Solution Heat Treatment Process for Austenitic Stainless Steel Plates Download PDF

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Publication number
US20220025473A1
US20220025473A1 US17/021,386 US202017021386A US2022025473A1 US 20220025473 A1 US20220025473 A1 US 20220025473A1 US 202017021386 A US202017021386 A US 202017021386A US 2022025473 A1 US2022025473 A1 US 2022025473A1
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Prior art keywords
rolling
heating
steel plates
stainless steel
cooling
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US17/021,386
Inventor
Haijun Li
Yi Han
Tianliang Fu
Jiadong LI
Yong Li
Zhaodong WANG
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Northeastern University China
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Northeastern University China
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Assigned to NORTHEASTERN UNIVERSITY reassignment NORTHEASTERN UNIVERSITY ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: FU, TIANLIANG, HAN, YI, Li, Haijun, LI, Jiadong, LI, YONG, WANG, ZHAODONG
Publication of US20220025473A1 publication Critical patent/US20220025473A1/en
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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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
    • B24C1/00—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods
    • B24C1/10—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods for compacting surfaces, e.g. shot-peening
    • 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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • 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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/021—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular fabrication or treatment of ingot or slab
    • 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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/021—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular fabrication or treatment of ingot or slab
    • C21D8/0215—Rapid solidification; Thin strip casting
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
    • C23G1/08—Iron or steel
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/001—Austenite

Definitions

  • the present invention belongs to the field of stainless steel heat treatment production processes, and particularly relates to a green on-line solution heat treatment process for austenitic stainless steel plates which makes full use of residual rolling temperature, saves energy and reduces emission.
  • China ranks first in the crude steel output in the world for a long term but still has a gap compared with the world advanced steel production countries mainly in aspects such as high carbon emission and energy consumption per ton of steel and unreasonable product structure.
  • the steel industry of China has the CO 2 emission accounting for more than 15% of the total emissions of the whole country and thus will bear huge pressure to reduce emissions for a long time. Facing the increasingly drastic competition of the world steel industry, the steel industry of China must constantly adapt to green, intelligent and high-end demands and adjust the development direction of the industry.
  • Austenitic stainless steel is the most widely used type of stainless steel, has good heat resistance, stain resistance and thermal processing performance, and can be used in kitchen and bathroom supplies, auto parts, medical equipment, building materials, chemistry, food industry, agriculture, ship parts and other fields. Austenitic stainless steel plates are usually delivered in a solid solution state.
  • the solution heat treatment methods for austenitic stainless steel plates adopt an off-line solution heat treatment process, which requires to heat hot-rolled stainless steel plates from the room temperature to the solid solution temperature (usually 1050-1100° C.), preserve heat for a certain period of time to make carbides and various alloying elements fully and uniformly dissolved in austenite, then quickly conduct quenching to improve the stain resistance of stainless steel, soften the structure and eliminate work hardening, as shown in FIG. 1 .
  • the heating process of the off-line solution heat treatment process needs to consume a large amount of energy and emits harmful gases such as CO 2 , which pollutes the environment.
  • the present invention proposes a green on-line solution heat treatment process for austenitic stainless steel plates which makes full use of residual rolling temperature and has the characteristics of energy saving and emission reduction, reducing the production cost of austenitic stainless steel plates and the environmental pollution.
  • FIG. 2 The main process flow of the on-line solution heat treatment process for austenitic stainless steel plates proposed by the present invention is shown in FIG. 2 : continuous casting billet heating ⁇ high pressure water dephosphorization ⁇ rough rolling ⁇ finish rolling ⁇ softening process ⁇ ultra fast cooling ⁇ straightening ⁇ cutting to length ⁇ shot peening ⁇ pickling. It should be pointed out that the present invention is also applicable to a stainless steel medium and heavy plate hot-rolling production line with only one rolling mill, and is also within the protection scope of the patent.
  • An on-line solution heat treatment process for austenitic stainless steel plates comprises the following steps:
  • Step 1 heating stainless steel continuous casting billets to 1200-1250° C. in a heating furnace, and preserving heat for 2-3 h to fully dissolve alloying elements and carbides;
  • Step 2 heating and preserving heat for the austenitized continuous casting billets, performing high pressure water dephosphorization after tapping to remove the surface iron scale, and then using a rolling mill to conduct multi-pass rolling to reach the target thickness required for a finished product;
  • Step 3 fully softening the steel plates which are work-hardened after rolling deformation to ensure that the product hardness does not exceed the standard requirements because hot-rolled stainless steel plates will be work-hardened; when heating and heat preservation conditions are available, heating the rolled steel plates to the solid solution temperature and preserving heat for 10-100 s; and when heating and heat preservation conditions are not available, to shorten the steel swinging time, improve the production efficiency and ensure the starting cooling temperature, selecting thin-gauge continuous casting billets with the thickness of ⁇ 220 mm as raw materials in step 1, reducing rolling passes, ensuring that the finishing rolling temperature is above 1050° C., and swinging steel for 10-200 s after rolling;
  • Step 4 putting the stainless steel plates softened in step 3 in a cooling zone for ultra fast cooling to make the stainless steel plates quickly pass the temperature range of high chromium carbide precipitation; and inhibiting the precipitation of M 23 C 6 to improve the stain resistance of stainless steel;
  • Step 5 putting the cooled steel plates with shape defect of strips such as warpage in a straightener for straightening;
  • Step 6 cutting the cooled and straightened steel plates to length according to the finished size requirements, and then transporting to a cooling bed for cooling;
  • Step 7 putting the steel plates cooled to the room temperature in a shot blasting machine for shot blasting, and then putting in a pickling tank for pickling to remove the surface iron scale and impurities.
  • heating and heat preservation equipment is arranged between a finishing mill and a cooling zone or beside a steel rolling bay, and the heating and heat preservation method is one of induction heating, direct-fire heating or roller hearth type heating furnace.
  • step 3 when heating and heat preservation conditions are not available, steel is swung on the front mill table of the cooling zone after rolling; and to shorten the steel swinging time required for softening after rolling and improving the production efficiency, the deformation in the rough rolling process in step 2 accounts for more than 80% of the total deformation, and the deformation in the finish rolling process does not exceed 20% of the total deformation to reduce work hardening in the rolling process.
  • a heat preservation hood is arranged in the steel swinging zone to reduce temperature drop in the steel swinging process.
  • step 4 for ultra fast cooling, the starting cooling temperature is not lower than 800° C., and the finishing cooling temperature is not higher than 430° C.
  • the starting cooling temperature is not lower than 850° C.
  • the finishing cooling temperature is 300-400° C.
  • the method for ultra fast cooling is high-pressure jet water cooling; and plates are cooled by passing the ultra fast cooling zone at one time or by swinging in the ultra fast cooling zone.
  • the mode of passing the ultra fast cooling zone at one time is preferred for cooling. For thick-gauge steel plates, if the one-time passing mode cannot meet the cooling temperature requirements, the swing mode can be selected.
  • the present invention has the following advantageous effects that: steel plates do not need reheating from the room temperature to the solid solution temperature, the deformed austenite structure is fully softened by making full use of the residual rolling temperature and then subjected to ultra fast cooling and quickly passes the high chromium carbide precipitation zone, and the precipitation of M 23 C 6 is inhibited to improve the stain resistance of steel plates.
  • the present invention realizes energy saving and emission reduction, and can shorten the manufacturing cycle of stainless steel solid solution plates and reduce the production cost.
  • the on-line solution heat treatment process for stainless steel proposed by the present invention can be conveniently realized by partially modifying the existing medium and heavy plate production line.
  • FIG. 1 is a flow chart of an off-line solution heat treatment process for stainless steel
  • FIG. 2 is a flow chart of the on-line solution heat treatment process of the present invention.
  • the softened stainless steel plates are put in a cooling zone for ultra fast cooling, the starting cooling temperature is about 860° C., and the finishing cooling temperature is about 400° C.;
  • the cooled steel plates are cut to length into a plurality of steel plates according to the finished size requirements, and the steel plates cooled to the room temperature on the cooling bed are transported to a shot blasting machine for shot blasting and then put in a pickling tank for pickling to remove surface impurities.
  • the steel plates treated by the on-line solution heat treatment process is tested for performance, and compared with steel plates treated by the off-line solution heat treatment process for analysis.
  • the grain sizes of the microstructures of steel plates treated by on-line and off-line solution heat treatment processes are respectively Grade 9.5 and 9.0, and the hardnesses are respectively 191 HB and 190 HB.
  • the stain resistance of steel plates is tested according to Corrosion of Metals and Alloys-Test Methods for Intergranular Corrosion of Stainless Steels (GB/T4334-2008), the corroded and bent samples are observed under a 10 ⁇ magnification microscope, and the surfaces of the samples are all intact without cracks.
  • the performance test result shows that the on-line solution heat treatment process can obtain the product performance similar to that obtained by the off-line solution heat treatment process under the conditions of saving the production cost and shortening the production cycle.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

An on-line solution heat treatment process for austenitic stainless steel plates is disclosed, which comprises continuous casting billet heating, high pressure water dephosphorization, rough rolling, finish rolling, softening process, ultra fast cooling, straightening, cutting to length, shot peening, pickling. The process of the present invention makes full use of the residual rolling temperature, without the need of reheating steel plates from the room temperature to the solid solution temperature. Compared with the conventional steel plate rolling process, the process needs to perform the softening process on the steel plates after rolling to ensure that the deformed austenite is fully softened before cooling. After the softening process, ultra fast cooling is performed to cool the steel plates from above 800° C. to below 430° C. so as to prevent intergranular chromium depletion caused by a large amount of precipitation of high chromium carbides from affecting the stain resistance of stainless steel.

Description

    TECHNICAL FIELD
  • The present invention belongs to the field of stainless steel heat treatment production processes, and particularly relates to a green on-line solution heat treatment process for austenitic stainless steel plates which makes full use of residual rolling temperature, saves energy and reduces emission.
    • BACKGROUND
  • China ranks first in the crude steel output in the world for a long term but still has a gap compared with the world advanced steel production countries mainly in aspects such as high carbon emission and energy consumption per ton of steel and unreasonable product structure. The steel industry of China has the CO2 emission accounting for more than 15% of the total emissions of the whole country and thus will bear huge pressure to reduce emissions for a long time. Facing the increasingly drastic competition of the world steel industry, the steel industry of China must constantly adapt to green, intelligent and high-end demands and adjust the development direction of the industry.
  • Austenitic stainless steel is the most widely used type of stainless steel, has good heat resistance, stain resistance and thermal processing performance, and can be used in kitchen and bathroom supplies, auto parts, medical equipment, building materials, chemistry, food industry, agriculture, ship parts and other fields. Austenitic stainless steel plates are usually delivered in a solid solution state. At present, the solution heat treatment methods for austenitic stainless steel plates adopt an off-line solution heat treatment process, which requires to heat hot-rolled stainless steel plates from the room temperature to the solid solution temperature (usually 1050-1100° C.), preserve heat for a certain period of time to make carbides and various alloying elements fully and uniformly dissolved in austenite, then quickly conduct quenching to improve the stain resistance of stainless steel, soften the structure and eliminate work hardening, as shown in FIG. 1. The heating process of the off-line solution heat treatment process needs to consume a large amount of energy and emits harmful gases such as CO2, which pollutes the environment.
    • SUMMARY
  • The present invention proposes a green on-line solution heat treatment process for austenitic stainless steel plates which makes full use of residual rolling temperature and has the characteristics of energy saving and emission reduction, reducing the production cost of austenitic stainless steel plates and the environmental pollution.
  • The main process flow of the on-line solution heat treatment process for austenitic stainless steel plates proposed by the present invention is shown in FIG. 2: continuous casting billet heating→high pressure water dephosphorization→rough rolling→finish rolling→softening process→ultra fast cooling→straightening→cutting to length→shot peening→pickling. It should be pointed out that the present invention is also applicable to a stainless steel medium and heavy plate hot-rolling production line with only one rolling mill, and is also within the protection scope of the patent.
  • The present invention adopts the following technical solutions:
  • An on-line solution heat treatment process for austenitic stainless steel plates, comprises the following steps:
  • Step 1, heating stainless steel continuous casting billets to 1200-1250° C. in a heating furnace, and preserving heat for 2-3 h to fully dissolve alloying elements and carbides;
  • Step 2, heating and preserving heat for the austenitized continuous casting billets, performing high pressure water dephosphorization after tapping to remove the surface iron scale, and then using a rolling mill to conduct multi-pass rolling to reach the target thickness required for a finished product;
  • Step 3, fully softening the steel plates which are work-hardened after rolling deformation to ensure that the product hardness does not exceed the standard requirements because hot-rolled stainless steel plates will be work-hardened; when heating and heat preservation conditions are available, heating the rolled steel plates to the solid solution temperature and preserving heat for 10-100 s; and when heating and heat preservation conditions are not available, to shorten the steel swinging time, improve the production efficiency and ensure the starting cooling temperature, selecting thin-gauge continuous casting billets with the thickness of ≤220 mm as raw materials in step 1, reducing rolling passes, ensuring that the finishing rolling temperature is above 1050° C., and swinging steel for 10-200 s after rolling;
  • Step 4, putting the stainless steel plates softened in step 3 in a cooling zone for ultra fast cooling to make the stainless steel plates quickly pass the temperature range of high chromium carbide precipitation; and inhibiting the precipitation of M23C6 to improve the stain resistance of stainless steel;
  • Step 5, putting the cooled steel plates with shape defect of strips such as warpage in a straightener for straightening;
  • Step 6, cutting the cooled and straightened steel plates to length according to the finished size requirements, and then transporting to a cooling bed for cooling;
  • Step 7, putting the steel plates cooled to the room temperature in a shot blasting machine for shot blasting, and then putting in a pickling tank for pickling to remove the surface iron scale and impurities.
  • Preferably, in step 3, when heating and heat preservation conditions are available, heating and heat preservation equipment is arranged between a finishing mill and a cooling zone or beside a steel rolling bay, and the heating and heat preservation method is one of induction heating, direct-fire heating or roller hearth type heating furnace.
  • Preferably, in step 3, when heating and heat preservation conditions are not available, steel is swung on the front mill table of the cooling zone after rolling; and to shorten the steel swinging time required for softening after rolling and improving the production efficiency, the deformation in the rough rolling process in step 2 accounts for more than 80% of the total deformation, and the deformation in the finish rolling process does not exceed 20% of the total deformation to reduce work hardening in the rolling process.
  • Preferably, in step 3, when heating and heat preservation conditions are not available, a heat preservation hood is arranged in the steel swinging zone to reduce temperature drop in the steel swinging process.
  • In step 4, for ultra fast cooling, the starting cooling temperature is not lower than 800° C., and the finishing cooling temperature is not higher than 430° C.
  • Preferably, in step 4, for ultra fast cooling, the starting cooling temperature is not lower than 850° C., and the finishing cooling temperature is 300-400° C.
  • Preferably, in step 4, the method for ultra fast cooling is high-pressure jet water cooling; and plates are cooled by passing the ultra fast cooling zone at one time or by swinging in the ultra fast cooling zone. In order to ensure the uniformity of cooling and the shape of plates after cooling, the mode of passing the ultra fast cooling zone at one time is preferred for cooling. For thick-gauge steel plates, if the one-time passing mode cannot meet the cooling temperature requirements, the swing mode can be selected.
  • The present invention has the following advantageous effects that: steel plates do not need reheating from the room temperature to the solid solution temperature, the deformed austenite structure is fully softened by making full use of the residual rolling temperature and then subjected to ultra fast cooling and quickly passes the high chromium carbide precipitation zone, and the precipitation of M23C6 is inhibited to improve the stain resistance of steel plates. The present invention realizes energy saving and emission reduction, and can shorten the manufacturing cycle of stainless steel solid solution plates and reduce the production cost. The on-line solution heat treatment process for stainless steel proposed by the present invention can be conveniently realized by partially modifying the existing medium and heavy plate production line.
    • DESCRIPTION OF DRAWINGS
  • FIG. 1 is a flow chart of an off-line solution heat treatment process for stainless steel;
  • FIG. 2 is a flow chart of the on-line solution heat treatment process of the present invention.
    •  DETAILED DESCRIPTION
  • The following specific embodiment is intended to further describe the present invention. It should be pointed out that the protection scope of the present invention includes but is not limited to the specific embodiment listed below, and some non-essential modifications and adjustments made by others according to the present invention still belong to the protection scope of the present invention.
    • Embodiment
  • (1) 304 austenitic stainless steel continuous casting billets with the size of 180 mm×1536 mm (thickness×width) are heated to 1250° C. in a heating furnace and discharged after heat preservation for 2.5 h;
  • (2) The continuous casting billets discharged from the heating furnace are rolled after high pressure water dephosphorization, the initial rolling temperature is about 1220° C., the roughing mill reciprocates rolling for five passes, and the thickness of intermediate billets at the rough rolling exit is 26.0 mm; and the finishing mill conducts rolling for one pass to roll the intermediate billets to the end thickness, the finished size is 20.0 mm×1535 mm (thickness×width), and the finishing rolling temperature is about 1030° C.;
  • (3) The rolled steel plates are swung slowly on the front and back mill tables of the finishing mill for 150 s so as to fully soften the steel plates which are work-hardened after rolling deformation;
  • (4) The softened stainless steel plates are put in a cooling zone for ultra fast cooling, the starting cooling temperature is about 860° C., and the finishing cooling temperature is about 400° C.;
  • (5) The cooled steel plates are cut to length into a plurality of steel plates according to the finished size requirements, and the steel plates cooled to the room temperature on the cooling bed are transported to a shot blasting machine for shot blasting and then put in a pickling tank for pickling to remove surface impurities.
  • (6) The steel plates treated by the on-line solution heat treatment process is tested for performance, and compared with steel plates treated by the off-line solution heat treatment process for analysis. The grain sizes of the microstructures of steel plates treated by on-line and off-line solution heat treatment processes are respectively Grade 9.5 and 9.0, and the hardnesses are respectively 191 HB and 190 HB. The stain resistance of steel plates is tested according to Corrosion of Metals and Alloys-Test Methods for Intergranular Corrosion of Stainless Steels (GB/T4334-2008), the corroded and bent samples are observed under a 10× magnification microscope, and the surfaces of the samples are all intact without cracks. The performance test result shows that the on-line solution heat treatment process can obtain the product performance similar to that obtained by the off-line solution heat treatment process under the conditions of saving the production cost and shortening the production cycle.

Claims (6)

1. An on-line solution heat treatment process for austenitic stainless steel plates, comprising the following steps:
step 1, heating stainless steel continuous casting billets to 1200-1250° C. in a heating furnace, and preserving heat for 2-3 h to fully dissolve alloying elements and carbides;
step 2, heating and preserving heat for the austenitized continuous casting billets, performing high pressure water dephosphorization after tapping to remove the surface iron scale, and then using a rolling mill to conduct multi-pass rolling to reach the target thickness required for a finished product;
step 3, fully softening the steel plates which are work-hardened after rolling deformation; when heating and heat preservation conditions are available, heating the rolled steel plates to the solid solution temperature and preserving heat for 10-100 s;
and when heating and heat preservation conditions are not available, selecting thin-gauge continuous casting billets with the thickness of ≤220 mm as raw materials in step 1, reducing rolling passes, ensuring that the finishing rolling temperature is above 1050° C., and swinging steel for 10-200 s after rolling;
step 4, putting the stainless steel plates softened in step 3 in a cooling zone for ultra fast cooling to make the stainless steel plates quickly pass the temperature range of high chromium carbide precipitation;
step 5, putting the cooled steel plates with shape defect of strips such as warpage in a straightener for straightening;
step 6, cutting the cooled and straightened steel plates to length according to the finished size requirements, and then transporting to a cooling bed for cooling;
step 7, putting the steel plates cooled to the room temperature in a shot blasting machine for shot blasting, and then putting in a pickling tank for pickling to remove the surface iron scale and impurities.
2. The on-line solution heat treatment process for austenitic stainless steel according to claim 1, wherein in step 3, when heating and heat preservation conditions are available, heating and heat preservation equipment is arranged between a finishing mill and a cooling zone or beside a steel rolling bay, and the heating and heat preservation method is one of induction heating, direct-fire heating or roller hearth type heating furnace.
3. The on-line solution heat treatment process for austenitic stainless steel according to claim 1, wherein in step 3, when heating and heat preservation conditions are not available, steel is swung on the front mill table of the cooling zone after rolling; and to shorten the steel swinging time required for softening after rolling and improving the production efficiency, the deformation in the rough rolling process in step 2 accounts for more than 80% of the total deformation, and the deformation in the finish rolling process does not exceed 20% of the total deformation to reduce work hardening in the rolling process.
4. The on-line solution heat treatment process for austenitic stainless steel according to claim 1, wherein in step 3, when heating and heat preservation conditions are not available, a heat preservation hood is arranged in the steel swinging zone to reduce temperature drop in the steel swinging process.
5. The on-line solution heat treatment process for austenitic stainless steel according to claim 1, wherein in step 4, for ultra fast cooling, the starting cooling temperature is not lower than 800° C., and the finishing cooling temperature is not higher than 430° C.
6. The on-line solution heat treatment process for austenitic stainless steel according to claim 1, wherein in step 4, the method for ultra fast cooling is high-pressure jet water cooling; and plates are cooled by passing the ultra fast cooling zone at one time or by swinging in the ultra fast cooling zone.
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CN114654176A (en) * 2022-04-21 2022-06-24 贵州航天精工制造有限公司 Thin-wall sleeve thread machining method
CN114891994A (en) * 2022-03-29 2022-08-12 江阴兴澄特种钢铁有限公司 Grain size control method for rolling 316H austenitic stainless steel medium plate for nuclear power
CN115029531A (en) * 2022-06-14 2022-09-09 山西太钢不锈钢股份有限公司 Online solution treatment method for stainless steel medium plate
CN115141920A (en) * 2022-07-06 2022-10-04 大冶特殊钢有限公司 Induction heating heat treatment method of austenitic stainless steel bar
WO2024120207A1 (en) * 2022-12-09 2024-06-13 中冶南方工程技术有限公司 Endless continuous casting and rolling production unit and production method for hot-rolled ultra-thin strip steel

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Cited By (6)

* Cited by examiner, † Cited by third party
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CN114310198A (en) * 2022-02-14 2022-04-12 丽水市隆信不锈钢线材有限公司 High-cleanness, corrosion-resistant and high-strength stainless steel wire processing technology for ship and processing equipment thereof
CN114891994A (en) * 2022-03-29 2022-08-12 江阴兴澄特种钢铁有限公司 Grain size control method for rolling 316H austenitic stainless steel medium plate for nuclear power
CN114654176A (en) * 2022-04-21 2022-06-24 贵州航天精工制造有限公司 Thin-wall sleeve thread machining method
CN115029531A (en) * 2022-06-14 2022-09-09 山西太钢不锈钢股份有限公司 Online solution treatment method for stainless steel medium plate
CN115141920A (en) * 2022-07-06 2022-10-04 大冶特殊钢有限公司 Induction heating heat treatment method of austenitic stainless steel bar
WO2024120207A1 (en) * 2022-12-09 2024-06-13 中冶南方工程技术有限公司 Endless continuous casting and rolling production unit and production method for hot-rolled ultra-thin strip steel

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