CN115198074A - Heat treatment method for improving flaw detection rescue yield of low-alloy steel plate - Google Patents

Heat treatment method for improving flaw detection rescue yield of low-alloy steel plate Download PDF

Info

Publication number
CN115198074A
CN115198074A CN202210911656.3A CN202210911656A CN115198074A CN 115198074 A CN115198074 A CN 115198074A CN 202210911656 A CN202210911656 A CN 202210911656A CN 115198074 A CN115198074 A CN 115198074A
Authority
CN
China
Prior art keywords
steel plate
equal
percent
less
heat treatment
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
Application number
CN202210911656.3A
Other languages
Chinese (zh)
Other versions
CN115198074B (en
Inventor
曲之国
张友建
刘振华
王博
王晓森
***
杨海峰
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rizhao Steel Yingkou Medium Plate Co Ltd
Original Assignee
Rizhao Steel Yingkou Medium Plate Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Rizhao Steel Yingkou Medium Plate Co Ltd filed Critical Rizhao Steel Yingkou Medium Plate Co Ltd
Priority to CN202210911656.3A priority Critical patent/CN115198074B/en
Publication of CN115198074A publication Critical patent/CN115198074A/en
Application granted granted Critical
Publication of CN115198074B publication Critical patent/CN115198074B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C21D1/28—Normalising
    • 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
    • C21D6/001—Heat treatment of ferrous alloys containing Ni
    • 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
    • C21D6/002—Heat treatment of ferrous alloys containing Cr
    • 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
    • C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/008—Heat treatment of ferrous alloys containing Si
    • 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
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • 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
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/20—Ferrous alloys, e.g. steel alloys containing chromium with copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • 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)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)

Abstract

The invention discloses a heat treatment method for improving the flaw detection rescue qualification rate of a low-alloy steel plate, which is characterized in that the condition that the flaw detection for the entry-into-furnace normalizing rescue is not matched with the low-alloy steel plate is determined, a roller-hearth continuous heat treatment segmented control mode is adopted, the temperature is set to 880-920 ℃ for the front-zone normalizing, the total time of a heating zone and a heat preservation zone is ensured to be more than or equal to 1.5T, wherein the heat preservation time is more than or equal to 10min, burners are closed in the rear zone, the steel plate is controlled to be slowly cooled in the rear zone in a furnace, and the opening and closing group number of the burners in the rear zone and the steel plate running time are controlled on the basis of controlling the steel plate tapping temperature to be less than or equal to T0. And (3) quickly stacking the steel plates off the line after the steel plates are discharged from the furnace, wherein the offline temperature is not lower than 250 ℃, the prepared bottom plate and cover plate are adopted to ensure that the whole stacking height is not lower than 800mm, and a heat preservation cover or heat preservation cloth is added for unstacking and flaw detection after more than 24 hours or the temperature of the steel plates reaches the room temperature. The method of the invention is adopted to carry out heat treatment rescue on the low alloy steel plate which is not qualified in flaw detection caused by center segregation, the rescue percent of pass can reach more than 90 percent, and the method has remarkable effect.

Description

Heat treatment method for improving flaw detection rescue yield of low-alloy steel plate
Technical Field
The invention belongs to the technical field of metal material processing, and particularly relates to a heat treatment method for improving the flaw detection rescue percent of low-alloy steel plates.
Background
Ultrasonic flaw detection is one of common technical requirements of hot rolling medium and heavy plates, particularly, ultrasonic flaw detection is usually required for low alloy steel plates applied to the fields of containers, ships, steel structures and the like, and the common flaw detection standards comprise GB/2970, NB/T47013 and the like. Once the steel plate is found to have the defects exceeding the standard in the ultrasonic flaw detection process, only judgment and reduction treatment can be carried out, so that the problems of benefit loss, repeated production and the like are caused. The root cause of the flaw detection failure of the low-alloy steel plate is the internal defects of the blank, including center segregation, cracks, inclusions, looseness and the like, and the defects fed back by the ultrasonic flaw detection of the steel plate include steel plate delamination, inclusions, segregation and the like. Aiming at the defect that the flaw detection of the steel plate is unqualified, many domestic production enterprises adopt normalizing treatment to rescue the flaw detection unqualified steel plate, and the normalizing treatment has the effects of uniform structure and reduction of internal segregation degree, and can play a role in reducing flaw detection defects to a certain extent. However, from the practical effect, the rescue percent of pass is lower, usually less than 65%, when the steel plate is thicker, the rescue percent of pass is lower, which not only causes the secondary waste of resources, but also is not beneficial to the production organization.
Therefore, the problem of low qualification rate of low-alloy steel plate flaw detection and heat treatment is solved, and the method has practical significance for reducing production consumption of steel enterprises and improving product supply capacity.
Disclosure of Invention
The invention aims to provide a heat treatment method for improving the flaw detection and rescue yield of a low-alloy steel plate so as to solve the problems in the prior art.
The invention is realized by the following technical scheme: a heat treatment method for improving flaw detection and rescue yield of a low-alloy steel plate is characterized by comprising the following steps:
the low alloy steel plate comprises the following components in percentage by mass: c:0.14 to 0.18 percent; si:0.15-0.35%; mn:1.35 to 1.55 percent; p is less than or equal to 0.025 percent; s is less than or equal to 0.008 percent; als is more than or equal to 0.015 percent; cr is less than or equal to 0.18 percent; ni is less than or equal to 0.08 percent; cu is less than or equal to 0.08 percent; mo is less than or equal to 0.06 percent; nb + V + Ti is less than or equal to 0.10 percent; CEV:0.38-0.45%; the balance of Fe and inevitable impurity elements;
the thickness of the low alloy steel plate is as follows: 8-80mm, the rolling compression ratio is more than or equal to 4.0, and the state is hot rolling or TMCP;
the heat treatment method comprises the following steps:
1) Selecting a steel plate satisfying the following conditions for processing:
point-like dense defects caused by center segregation; when the thickness of the steel plate is 8-50mm, the defect wave height is less than or equal to 85 percent, and when the thickness of the steel plate is 50-80mm, the defect wave height is less than or equal to 60 percent; the defect depth is 1/2 of the plate thickness;
2) Carrying out segmented normalizing treatment on the steel plate meeting the defects in the step 1 in a roller hearth type continuous heat treatment furnace, wherein the normalizing temperature is 880-920 ℃, the total in-furnace time is controlled to be 3.0-3.5T, and the minimum in-furnace time is more than or equal to 40min;
3) All burners in the front area of the heat treatment furnace are opened, the temperature of each section is set according to the normalizing temperature, and the total time of the heating section and the heat preservation section is ensured to be more than or equal to 1.5T, wherein the heat preservation time is more than or equal to 10min;
4) The nozzles in the rear zone of the heat treatment furnace are partially or completely closed, the steel plate is controlled to be slowly cooled in the rear zone of the furnace after being subjected to the normalization in the front zone, the number of the opening and closing groups of the nozzles in the rear zone and the steel plate traveling time are based on the control of the tapping temperature of the steel plate to be less than or equal to T0, wherein T0= 770-255C-85 Mn-35 (Ni + Cu) -70 Cr-83 Mo-0.4T;
5) Preparing thick steel plates with certain waste heat as a bottom and a cover, and ensuring that the total thickness of the steel plates of the bottom and the cover is not less than 150mm and the temperature is not less than 100 ℃;
6) After the steel plates are discharged from the furnace, the steel plates are quickly stacked off the line, the temperature of the off-line is not lower than 250 ℃, the steel plates are placed between the bottom plate and the cover plate, the whole stacking height is not lower than 800mm, and the treatment is finished after 24 hours or the steel plates are unstacked after the temperature reaches the room temperature;
wherein T is the thickness of the steel plate.
And further: and 6, arranging a heat-insulating cover or heat-insulating cloth outside the steel plate stack.
And further: the mechanical properties of the low-alloy steel plate before heat treatment are as follows: the yield strength is 315-440MPa, the tensile strength is 450-630MPa, and the elongation is more than or equal to 18 percent.
The invention has the advantages that: compared with the prior art, the method is suitable for enterprises with roller hearth heat treatment furnace conditions to implement, flaw detection of the low-alloy steel plate is unsure according to the method, the ultrasonic flaw detection qualification rate of the rescued steel plate is more than or equal to 90 percent and is far higher than that of conventional normalizing rescue treatment; meanwhile, the applicable specification is up to 80mm, and the conventional supply specification range of medium plate enterprises is basically met. The flaw detection misjudgment loss of medium plate enterprises caused by steel plate center segregation can be greatly reduced, and the resource utilization efficiency is improved.
Drawings
FIG. 1 illustrates a 40mmQ370R hot rolled flaw detection defective structure;
FIG. 2 40mmQ370R rescued post-flaw detection qualified tissue.
Detailed Description
The invention discloses a heat treatment method for improving flaw detection and rescue qualification rate of a low-alloy steel plate, which is applicable to the low-alloy steel plate and comprises the following components in percentage by mass: c:0.14-0.18%; si:0.15-0.35%; mn:1.35-1.55%; p is less than or equal to 0.025 percent; s is less than or equal to 0.008 percent; als is more than or equal to 0.015 percent; cr is less than or equal to 0.18 percent; ni is less than or equal to 0.08 percent; cu is less than or equal to 0.08 percent; mo is less than or equal to 0.06 percent; microalloy elements Nb, V and Ti are added according to the mechanical property requirement, but Nb + V + Ti is less than or equal to 0.10 percent; CEV:0.38-0.45%; the balance of Fe and inevitable impurity elements.
The steel plate has the following effects:
c: carbon is a main strengthening element of the low alloy steel plate, and the method controls the following steps: 0.14-0.18%, which considers the segregation sensitivity and avoids the defect of insufficient strength after normalizing the steel plate; si: silicon plays a role in solid solution strengthening, and Si:0.15-0.35%, ensuring that the strength of the steel plate is not reduced after normalizing; mn: manganese is an easily segregated element and is difficult to completely diffuse at high temperature, and the invention limits Mn:1.35-1.55%, and the problems of generation of banded structures and strength after normalizing are both considered; p, S: phosphorus and sulfur are harmful elements in steel, but P generally has no obvious influence on flaw detection and can meet various standards and performance requirements; the sulfur and the manganese are easy to form MnS plastic inclusions which usually exist together with segregation, and the flaw detection caused by the MnS inclusions is not easy to be saved under the condition that the S is more than 0.008 percent, so that the S is limited to be less than or equal to 0.008 percent; cr, ni, cu, mo: the alloy is a solid solution strengthening element, has the function of compensating the strength reduction after normalizing, is easy to cause segregation even if the alloy is too high, particularly, mo element is easy to form a more serious abnormal bainite zone or a blocky MA structure to cause adverse effect on flaw detection, so that the alloy limits that Cr is less than or equal to 0.18 percent, ni is less than or equal to 0.08 percent, cu is less than or equal to 0.08 percent and Mo is less than or equal to 0.06 percent; nb, V, ti: the microalloy elements are mainly used for compensating the effect of strength reduction after normalizing through precipitation strength, are normally added properly according to the performance requirement of low alloy steel, and the limitation that Nb + V + Ti is less than or equal to 0.10 percent is mainly considered that under the condition of temperature control in the stage of the invention, the precipitates of the microalloy elements are easy to aggregate and precipitate near a segregation zone, so that the risk of abnormal structure crack propagation is increased.
CEV: the carbon equivalent of the low-alloy steel plate is controlled, on one hand, the low CEV is considered to be low, which easily causes the strength after normalizing, on the other hand, the CEV is too high, which increases the segregation risk and reduces the rescue percent of pass, so the invention limits the CEV to 0.38-0.45%.
The low-alloy steel plate is produced by adopting the procedures of converter, LF (+ RH) refining, continuous casting production, heating, rolling, ACC, straightening and the like, and the thickness of the steel plate is as follows: 8-80mm, the rolling compression ratio is more than or equal to 4.0, the state is hot rolling or TMCP, and the mechanical property range before heat treatment is as follows: the yield strength is less than or equal to 440MPa, the tensile strength is less than or equal to 630MPa, and the elongation is more than or equal to 18 percent. The thickness of the steel plate is limited to 8-80mm, the rolling compression ratio is more than or equal to 4.0, on one hand, the thin-specification flaw detection qualification rate is high, and the problems are not related basically; on the other hand, if the compression ratio of the thick steel plate is lower than 4.0, the defects of internal looseness and the like can not be completely rolled and welded, and the internal defects caused by the method can not achieve ideal effects even if the method is adopted.
The heat treatment method for improving the rescue percent of pass comprises the following steps:
1) Adjusting the sensitivity of a flaw detector by adopting a flat bottom hole with the diameter of 5mm, classifying flaw detection defects of the steel plates, and eliminating the steel plates with layered and mixed defects without rescue; the point-like dense defects caused by center segregation are distributed on the local or whole plate surface of the steel plate, the wave height of the defects with the thickness of 8-50mm of the steel plate is less than or equal to 85 percent, the wave height of the defects with the thickness of 50-80mm of the steel plate is less than or equal to 60 percent, and the depth of the defects is 1/2 of the plate thickness, so that the heat treatment is carried out according to the conditions.
2) The steel plate is subjected to segmented normalizing treatment in roller hearth type continuous heat treatment, wherein the normalizing set temperature is 880-920 ℃, and the thin specification can be set according to the upper limit; the thickness gauge may be set at a lower limit in view of the subsequent temperature drop. The total furnace time (minutes, min) of the steel plate is controlled to be 3.0-3.5T (T is the thickness of the steel plate, mm), and the minimum furnace time of the steel plate with the thickness of 14mm or less is more than or equal to 40min.
3) All burners in the front area of the heat treatment furnace are opened, the temperature of each section is set according to the normalizing target temperature, the total time of the heating section and the heat preservation section is ensured to be more than or equal to 1.5T, and the heat preservation time is more than or equal to 10min. The part has the same mechanism as the conventional normalizing, namely, the components are uniformly diffused and the segregation is reduced through solute elements in the processes of temperature rise and heat preservation, and the preparation is made for the components and the tissues of the subsequent phase change; in addition, during recrystallization and austenitization, some fine cracks may be eliminated due to changes in phase structure and volume.
4) All the burners in the rear zone of the heat treatment furnace are closed, the steel plate is controlled to be slowly cooled in the rear zone of the furnace after being normalized by the front zone, the number of open-close groups of the burners in the rear zone and the running time of the steel plate are controlled according to the condition that the tapping temperature of the steel plate is not more than T0, wherein T0 (° C) = 770-255C-85 × Mn-35 (Ni + Cu) -70 × Cr-83 Mo-0.4 × T. The temperature at which the steel plate finishes phase transformation is measured and calculated through the formula T0, and the empirical formula considers the influence of phase transformation delay caused by segregation and different steel plate thicknesses. The steel plate is subjected to phase change under the condition of slow cooling in the furnace by controlling the tapping temperature of the steel plate to be less than or equal to T0, the phase change structure is more in a balance state, and the phase change stress is lowest. And when the temperature is higher than T0, discharging, the phase change of the steel plate, particularly the core phase change with serious component segregation is not completely finished, bainite phase change occurs under the condition of higher cooling speed after discharging, the phase change stress is higher, and the risk of cracking of a weak interface of the core exists. Meanwhile, by controlling the slow cooling in the furnace, the precipitation strengthening effect of elements such as microalloy and the like in the cooling process can be improved, and the loss of the strength caused by normalizing is partially compensated.
5) Preparing a thick steel plate with certain waste heat as a bottom and a cover, ensuring that the total thickness of the bottom and cover steel plates is not less than 150mm, ensuring that the temperature is not less than 200 ℃, and preparing a heat-insulating cover under the condition of permission.
6) And (3) after the steel plates are taken out of the furnace, offline stacking is carried out at the highest speed, the offline temperature is not lower than 250 ℃, the prepared bottom plate and cover plate are adopted to ensure that the whole stack height is not lower than 800mm, a heat-insulating cover or heat-insulating cloth is buckled, and unstacking and flaw detection are carried out after more than 24 hours or the temperature of the steel plates reaches the room temperature. The purpose of the part is to prevent the crack of the weak interface of the abnormal structure or the further propagation of the existing micro-crack caused by the stress concentration in the steel plate caused by the rapid cooling in the air by controlling the steel plate to be cooled at an extremely slow cooling speed.
The invention has the advantages that: compared with the prior art, the method is suitable for enterprises with the roller hearth type heat treatment furnace condition to implement, the flaw detection qualification rate of the low-alloy steel plate is not rescued according to the method, and the ultrasonic flaw detection qualification rate of the steel plate after rescue is more than or equal to 90 percent and is far higher than the conventional normalizing rescue treatment; meanwhile, the applicable specification is up to 80mm, and the conventional supply specification range of medium plate enterprises is basically met. The flaw detection misjudgment loss caused by steel plate center segregation in medium and heavy plate enterprises can be greatly reduced, and the resource utilization efficiency is improved.
The present solution is further illustrated by the following specific examples.
Examples 1 to 4
The heat treatment and the rescue of 4 low alloy steel plates with flaw detection defects are carried out according to the scheme of the invention, and the rescue of similar 2 steel plates is carried out in a common mode. Wherein, the embodiment 1 is Q345qD bridge steel, the embodiment 2 is DH32 ship plate, the embodiment 3 is Q370R container steel, and the embodiment 4 is Q355ND wind power steel; comparative example 1 was a DH36 boat plate and comparative example 2 was Q355B structural steel.
The contents of the components of the steel sheet are shown in Table 1.
Table 1 examples and comparative examples actual ingredients, wt%
- C Si Mn P S Als Ni Cr Cu Mo Nb+V+Ti CEV
Example 1 0.14 0.20 1.45 0.017 0.003 0.031 0.03 0.02 0.010 - 0.029 0.386
Example 2 0.17 0.25 1.36 0.020 0.006 0.035 0.03 0.03 0.012 - 0.012 0.40
Example 3 0.17 0.25 1.55 0.016 0.005 0.045 0.05 0.05 0.02 0.05 0.035 0.445
Example 4 0.155 0.30 1.55 0.014 0.003 0.028 0.03 0.03 0.012 - 0.05 0.42
Comparative example 1 0.18 0.35 1.38 0.018 0.006 0.028 - 0.03 0.012 - 0.025 0.418
Comparative example 2 0.16 0.25 1.35 0.020 0.003 0.030 - 0.16 0.014 - 0.025 0.42
The conditions of the steel plate production process and the performance before treatment and other condition information are as follows:
TABLE 2 Steel plate production conditions
- Specification, mm Thickness of steel billet in mm Compression ratio Yield strength, MPa Tensile strength, MPa Elongation percentage of%
Example 1 8-16 167、250 ≥15 376-426 524-576 ≥26.5
Example 2 24-40 250 6.2-10.4 355-396 499-550 ≥28
Example 3 34-40 250 6.2-7.3 378-428 555-620 ≥22.5
Example 4 50-80 328 4.1-6.5 384-418 525-597 ≥25.5
Comparative example 1 24-32 250 7.8-10.4 403-421 527-596 ≥20
Comparative example 2 42-60 328 5.4-7.8 375-411 528-567 ≥23
And adjusting the sensitivity of the flaw detector by adopting a flat bottom hole with the diameter of 5mm, classifying flaw detection defects of the steel plate and determining that the heat treatment conditions are met.
TABLE 3 Steel plate flaw detection information
- Specification, mm Not including total number of steel plates, sheet Range of defect wave height Satisfies the heat treatment conditions, sheet Actual heat treatment, sheet
Example 1 8-16 18 60-80% 18 18
Example 2 24-40 12 40-100% 10 10
Example 3 34-40 12 40-65% 12 12
Example 4 50-80 9 30-70% 7 7
Comparative example 1 24-32 12 60-80% 9 12
Comparative example 2 42-60 9 40-60% 9 9
The steel plate is subjected to segmented normalizing treatment in roller hearth type continuous heat treatment, the normalizing set temperature is 880-920 ℃, the steel plate is treated according to a conventional normalizing process in a comparative example, and the specific information is as follows:
TABLE 4 Heat treatment information of Steel plates
- Specification, mm Normalizing temperature, DEG C Heating time, min Incubation time, min Cooling method
Example 1 8-16 910 20-30 10-15 Slow cooling in furnace
Example 2 24-40 900 30-48 10-30 Slow cooling in furnace
Example 3 34-40 900 40-48 20-30 Slow cooling in furnace
Example 4 50-80 890 60-95 30-50 Slow cooling in furnace
Comparative example 1 24-32 890 30-35 10-20 Air cooling after tapping
Comparative example 2 42-60 890 55-68 20-40 Air cooling after tapping
All burners in the rear zone of the hot furnace are closed, the steel plate is controlled to be slowly cooled in the rear zone of the furnace after being normalized by the front zone, the opening and closing group number of the burners in the rear zone and the running time of the steel plate are based on controlling the tapping temperature of the steel plate to be less than or equal to T0, wherein T0 (° C) = 770-255C-85 × Mn-35 (Ni + Cu) -70 × Cr-83 Mo-0.4 × T. And (4) taking the steel plate of the comparative example out of the furnace, controlling the temperature to room temperature, and then directly carrying out flaw detection and finishing treatment. The specific information is as follows:
TABLE 5 Steel plate furnace Back zone control Process
- Specification, mm Furnace time of slow cooling section min T0，℃ The measured tapping temperature is lower than Off-line stacking temperature,. Degree.C
Example 1 8-16 15-25 601-604 590-600 365-385
Example 2 24-40 35-60 591-597 585-590 380-420
Example 3 34-40 45-60 574-576 562-570 375-410
Example 4 50-80 75-120 562-574 548-558 377-420
And (3) after the steel plates are taken out of the furnace, the steel plates are off-line stacked at the highest speed, the prepared bottom plate and the prepared cover plate are adopted, the total thickness of the bottom plate and the cover plate is not less than 150mm, the temperature is not less than 200 ℃, the whole stack height is not less than 800mm, a heat-insulating cover or heat-insulating cloth is added, and unstacking and flaw detection are carried out after 24 hours or the temperature of the steel plates reaches the room temperature. The actual flaw detection and performance conditions of the steel plate after the rescue are shown in the following table:
TABLE 6 rescue of posterior zone conditions by steel plates
Figure DEST_PATH_IMAGE002
From the processing results of the examples, by implementing the heat treatment rescue method of sectional controlled cooling, the flaw detection rescue percent of pass of different types of low alloy steel plates is 85.7 percent at the lowest, the average rate is more than or equal to 90 percent, and the flaw detection rescue percent of pass of comparative example steel plates rescued by adopting a common normalizing process is less than 50 percent. The method has remarkable effect on flaw detection rescue of the low-alloy steel plate. The performance of the steel plate after saving meets the requirement.
A Q370R steel plate with a thickness of 40mm was selected for the test. The photographs of the hot-rolled flaw detection incompetent tissue and the flaw detection qualified tissue after the rescue are respectively shown in fig. 1 and fig. 2, and it can be seen from the figures that the positions of the flaw detection incompetent tissue and the thickness 1/2 of the steel plate in fig. 1, abnormal tissue strips caused by segregation and micro-crack defects distributed in the abnormal tissue strips are obviously reduced, and the treatment effect is obvious, wherein the positions of the thickness 1/2 of the steel plate after the rescue in fig. 2 are abnormal strip-shaped tissues caused by segregation.

Claims (3)

1. A heat treatment method for improving the flaw detection rescue qualification rate of a low-alloy steel plate is characterized by comprising the following steps of:
the low alloy steel plate comprises the following components in percentage by mass: c:0.14-0.18%; si:0.15-0.35%; mn:1.35 to 1.55 percent; p is less than or equal to 0.025 percent; s is less than or equal to 0.008 percent; als is more than or equal to 0.015 percent; cr is less than or equal to 0.18 percent; ni is less than or equal to 0.08 percent; cu is less than or equal to 0.08 percent; mo is less than or equal to 0.06 percent; nb + V + Ti is less than or equal to 0.10 percent; CEV:0.38 to 0.45 percent; the balance of Fe and inevitable impurity elements;
the thickness of the low alloy steel plate is as follows: 8-80mm, the rolling compression ratio is more than or equal to 4.0, and the state is hot rolling or TMCP;
the heat treatment method comprises the following steps:
1) Selecting a steel plate satisfying the following conditions for processing:
point-like dense defects caused by center segregation; when the thickness of the steel plate is 8-50mm, the defect wave height is less than or equal to 85 percent, and when the thickness of the steel plate is 50-80mm, the defect wave height is less than or equal to 60 percent; the defect depth is 1/2 of the plate thickness;
2) Carrying out segmented normalizing treatment on the steel plate meeting the defects in the step 1 in a roller hearth type continuous heat treatment furnace, wherein the normalizing temperature is 880-920 ℃, the total in-furnace time is controlled to be 3.0-3.5T, and the minimum in-furnace time is more than or equal to 40min;
3) All burners in the front area of the heat treatment furnace are opened, the temperature of each section is set according to the normalizing temperature, and the total time of the heating section and the heat preservation section is ensured to be more than or equal to 1.5T, wherein the heat preservation time is more than or equal to 10min;
4) Each burner in the rear zone of the hot furnace is partially or completely closed, the steel plate is controlled to be slowly cooled in the rear zone of the furnace after being subjected to front zone normalizing, the opening and closing group number of the burners in the rear zone and the steel plate traveling time are based on controlling the tapping temperature of the steel plate to be less than or equal to T0, wherein T0= 770-255C-85 Mn-35 (Ni + Cu) -70 Cr-83 Mo-0.4T;
5) Preparing thick steel plates with certain waste heat as a bottom and a cover, and ensuring that the total thickness of the steel plates of the bottom and the cover is not less than 150mm and the temperature is not less than 100 ℃;
6) After the steel plates are discharged from the furnace, the steel plates are quickly stacked in an offline manner, the offline temperature is not lower than 250 ℃, the steel plates are placed between the bottom plate and the cover plate, the whole stacking height is not lower than 800mm, and the treatment is finished after 24 hours or after the temperature of the steel plates reaches the room temperature and unstacking is carried out;
wherein T is the thickness of the steel plate.
2. The heat treatment method according to claim 1, characterized in that: and 6, arranging a heat-insulating cover or heat-insulating cloth outside the steel plate stack.
3. The heat treatment method according to claim 1, characterized in that: the mechanical properties of the low-alloy steel plate before heat treatment are as follows: the yield strength is 315-440MPa, the tensile strength is 450-630MPa, and the elongation is more than or equal to 18 percent.
CN202210911656.3A 2022-07-30 2022-07-30 Heat treatment method for improving flaw detection and rescue qualification rate of low-alloy steel plate Active CN115198074B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210911656.3A CN115198074B (en) 2022-07-30 2022-07-30 Heat treatment method for improving flaw detection and rescue qualification rate of low-alloy steel plate

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210911656.3A CN115198074B (en) 2022-07-30 2022-07-30 Heat treatment method for improving flaw detection and rescue qualification rate of low-alloy steel plate

Publications (2)

Publication Number Publication Date
CN115198074A true CN115198074A (en) 2022-10-18
CN115198074B CN115198074B (en) 2023-06-20

Family

ID=83585755

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210911656.3A Active CN115198074B (en) 2022-07-30 2022-07-30 Heat treatment method for improving flaw detection and rescue qualification rate of low-alloy steel plate

Country Status (1)

Country Link
CN (1) CN115198074B (en)

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102367538A (en) * 2011-12-21 2012-03-07 南阳汉冶特钢有限公司 Super-thick low alloy high strength Q345C steel plate and production method thereof
CN102766806A (en) * 2012-07-11 2012-11-07 莱芜钢铁集团有限公司 Ultrawide and ultrafine gauge structural steel plate for bridges and production method thereof
CN106011626A (en) * 2016-07-04 2016-10-12 湖南华菱湘潭钢铁有限公司 Production method for hydrogenation medium-thickness steel plate
CN107937811A (en) * 2017-08-16 2018-04-20 新疆八钢铁股份有限公司 Low temperature resistant 410MPa grades of steel plate for tall building of normalizing state
CN108330398A (en) * 2018-05-22 2018-07-27 湖南华菱湘潭钢铁有限公司 A kind of production method of special thick antiacid tank plate
US20180298463A1 (en) * 2016-04-19 2018-10-18 Jiangyin Xingcheng Special Steel Works Co., Ltd Pressure vessel steel plate resistant against hydrogen-induced cracking and manufacturing method thereof
CN110184528A (en) * 2018-06-11 2019-08-30 江阴兴澄特种钢铁有限公司 With the Q345R steel plate and its manufacturing method of excellent properties under the conditions of a kind of High Temperature Simulation post weld heat treatment
CN111440930A (en) * 2020-03-18 2020-07-24 江阴兴澄特种钢铁有限公司 AS NZS 3678-350L 15Z15-Z35 normalized steel plate and manufacturing method thereof
CN113186452A (en) * 2021-03-30 2021-07-30 湖南华菱湘潭钢铁有限公司 Production method of steel for thermal forming end socket
WO2021189621A1 (en) * 2020-03-25 2021-09-30 南京钢铁股份有限公司 S355g10+n-thickness steel plate for offshore structure and production method therefor

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102367538A (en) * 2011-12-21 2012-03-07 南阳汉冶特钢有限公司 Super-thick low alloy high strength Q345C steel plate and production method thereof
CN102766806A (en) * 2012-07-11 2012-11-07 莱芜钢铁集团有限公司 Ultrawide and ultrafine gauge structural steel plate for bridges and production method thereof
US20180298463A1 (en) * 2016-04-19 2018-10-18 Jiangyin Xingcheng Special Steel Works Co., Ltd Pressure vessel steel plate resistant against hydrogen-induced cracking and manufacturing method thereof
CN106011626A (en) * 2016-07-04 2016-10-12 湖南华菱湘潭钢铁有限公司 Production method for hydrogenation medium-thickness steel plate
CN107937811A (en) * 2017-08-16 2018-04-20 新疆八钢铁股份有限公司 Low temperature resistant 410MPa grades of steel plate for tall building of normalizing state
CN108330398A (en) * 2018-05-22 2018-07-27 湖南华菱湘潭钢铁有限公司 A kind of production method of special thick antiacid tank plate
CN110184528A (en) * 2018-06-11 2019-08-30 江阴兴澄特种钢铁有限公司 With the Q345R steel plate and its manufacturing method of excellent properties under the conditions of a kind of High Temperature Simulation post weld heat treatment
CN111440930A (en) * 2020-03-18 2020-07-24 江阴兴澄特种钢铁有限公司 AS NZS 3678-350L 15Z15-Z35 normalized steel plate and manufacturing method thereof
WO2021189621A1 (en) * 2020-03-25 2021-09-30 南京钢铁股份有限公司 S355g10+n-thickness steel plate for offshore structure and production method therefor
CN113186452A (en) * 2021-03-30 2021-07-30 湖南华菱湘潭钢铁有限公司 Production method of steel for thermal forming end socket

Also Published As

Publication number Publication date
CN115198074B (en) 2023-06-20

Similar Documents

Publication Publication Date Title
CN111363973B (en) Super-thick container steel plate with excellent core low-temperature impact toughness and manufacturing method thereof
WO2021036272A1 (en) High-strength and low-yield-ratio 9ni steel plate for ship lng storage tanks and manufacturing method therefor
CN108034885B (en) Steel plate for low-crack-sensitivity pipe fitting used under low-temperature condition and manufacturing method thereof
WO2021196820A1 (en) Method for manufacturing low remanence 5ni steel plate with excellent surface quality
CN109266958B (en) F-grade steel for series ship and ocean engineering and flexible production method thereof
CN110499448A (en) high-N austenitic stainless steel medium plate with excellent performance and manufacturing method thereof
WO2022022066A1 (en) Steel board for polar marine engineering and preparation method therefor
CN108048733B (en) Economical steel plate for low-temperature high-toughness self-tempering pipe fitting and manufacturing method thereof
CN108070789B (en) Ultrafine grain super-thick steel with yield strength not less than 480MPa and preparation method thereof
CN108624744B (en) Q500qE bridge steel plate and production method thereof
CN110106322B (en) High-strength steel for thin engineering machinery and plate shape control method
CN109913750B (en) High-strength thin steel sheet having high surface quality and method for manufacturing the same
CN108754321B (en) Super-thick normalized high-strength pressure vessel steel plate and production method thereof
CN110423949B (en) Copper-containing steel without surface peeling defect and production method thereof
CN101578381A (en) Processes for production of steel sheets for cans
CN113564464A (en) 25.4mm hot continuous rolling limit specification pipeline steel plate coil and manufacturing method thereof
CN109136759B (en) 1300 MPa-grade thick-specification hot forming steel for spoke and preparation method thereof
CN111996462B (en) Longitudinal variable-thickness ultrahigh-strength ship board and production method thereof
CN110983182B (en) 800 MPa-grade hot rolled steel and preparation method and application thereof
CN115198074B (en) Heat treatment method for improving flaw detection and rescue qualification rate of low-alloy steel plate
CN111575602A (en) 1500 MPa-grade hot-formed steel plate for wheel and production method thereof
CN114892105B (en) Marine 5Ni steel plate with excellent brittle failure resistance and manufacturing method thereof
CN111321340A (en) Hot rolled steel plate with yield strength of 450MPa and manufacturing method thereof
CN116162864A (en) 09MnNiDR steel plate with low-temperature impact of-70 ℃ and manufacturing method thereof
CN110983181B (en) 700 MPa-grade hot rolled steel and preparation method and application 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