CN100546762C - A kind of cold-rolled non-oriented electrical steel and production method thereof - Google Patents
A kind of cold-rolled non-oriented electrical steel and production method thereof Download PDFInfo
- Publication number
- CN100546762C CN100546762C CNB2006100249645A CN200610024964A CN100546762C CN 100546762 C CN100546762 C CN 100546762C CN B2006100249645 A CNB2006100249645 A CN B2006100249645A CN 200610024964 A CN200610024964 A CN 200610024964A CN 100546762 C CN100546762 C CN 100546762C
- Authority
- CN
- China
- Prior art keywords
- normalizing
- straightening
- temperature
- cold
- iron loss
- 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.)
- Active
Links
Images
Abstract
A kind of production method of cold-rolled non-oriented electrical steel; its production stage is: strand → heating → hot rolling → straightening → normalizing → pickling → cold rolling → annealing → coating → finished product; wherein; elongation control is in 0.5～4% scope in the straightening step, and temperature was controlled at 800 ℃～1050 ℃ scopes interior 60～90 seconds in the normalizing step.The present invention through the straightening distortion, increases the hot rolled plate energy storage before normalizing, and ferrite crystal grain is thick after the normalizing, and cold rolling and annealing back texture is improved.The iron loss of finished product reduces, magnetic strength improves; Make normalizing temperature subsequently to reduce by 10～50 ℃ simultaneously, thereby reduced the requirement of normalizing equipment and cut down the consumption of energy in process of production, and, help pickling subsequently because temperature reduces the iron scale minimizing than the normalizing temperature of prior art.
Description
Technical field
The present invention relates to a kind of cold-rolled non-oriented electrical steel and production method thereof, is a kind of cold-rolled non-oriented electrical steel and production method thereof of high-magnetic induction, low-iron loss specifically.
Background technology
The high-magnetic induction, low-iron loss cold rolling non-oriented electrical steel is a non-oriented electrical steel hot of research and development in recent years, and it is adapted in recent years the requirement of high efficiency such as all kinds of motors, electronic transformer iron core, miniaturization is developed.
The method that improves magnetic strength, reduction iron loss generally has following several: the content that 1. reduces Si, improve the degree of purity of steel, keep under the high magnetic strength condition when reaching low silicon content, obtain lower iron loss, open flat 8-3699 (inventor: TAKASHIMA MINORU etc. as the Chinese patent application of inventions such as harvesting by high island numbers 95105753.7, a day spy of the present invention; Open day: 09.01.1996) etc.; 2. in steel, add the element that improves finished product texture, add Sn, Sb, Cu etc. as using; As the clear 50-98425 of day disclosure laid-open patent (inventor: MAEDA YASUYUKI etc.; Open day: 1982-05-28), clear 55-158252 (inventor: MATSUMURA HIROSHI etc.; Open day: 09.12.1980) etc.; 3. hot rolled plate being carried out normalizing handles.Independent or the compound use of this several method.First method has proposed very high requirement to smelting, developed utmost point low-sulfur series of high efficiency rate non-oriented electrical steel as Japanese NKK company, the content requirement of S reaches below the 10ppm, reduce hindering the sulfide of grain growth, development product and manufacturing technology have description on document ま て り あ No. 2 (2002) P114～116 of the 41st volume and relevant tens patents.Second method has improved the cost of alloy of steel.Third party's method is very effective to improving magnetic strength, and cost is also very low, to such an extent as to first kind and second kind often also needs to be used in combination with the third method.
The technological process of producing cold-rolled non-oriented electrical steel is handled in existing increase normalizing: strand → heating → hot rolling → normalizing → pickling → cold rolling → annealing → coating → finished product.
The main technologic parameters control of this technological process is as follows:
The strand heating: heating and temperature control is at 1000 ℃～1200 ℃.The heating-up temperature height, hot rolling plasticity is good, but precipitate such as MnS and AlN solid solution in the steel, they are solid-solubilized in the course of hot rolling and descend owing to solid solubility reduces with steel billet temperature, separate out with the small and dispersed shape again and hinder when annealing grain growth, (111) component increases, and magnetic degenerates.Heating-up temperature is low, and plasticity is poor.
Hot rolling: hot rolled plate thickness is 1.8～2.6mm.
Normalizing: the normalizing temperature is controlled at 850 ℃～1050 ℃, and the time keeps 60～90s.Purpose is that hot rolled plate is organized is more even, and recrystal grain is increased, and makes crystal grain and precipitate alligatoring simultaneously, strengthens (100) and (110) component and weakens (111) component, with raising magnetic.
Pickling: remove scale on surface through pickling before cold rolling.
Cold rolling: as to be cold rolled to finished product thickness 0.5mm by the thick hot rolled plate of 1.8～2.6mm.
Annealing: annealing temperature is controlled at 850 ℃～1050 ℃.To be cold-reduced sheet eliminate the strain of cold rolling generation and impel grain growth by crystallization again the purpose of annealing, meets the demands with assurance magnetic, hardness and magnetic aging.
Coating: coating unit and continuous annealing furnace can be positioned on the lines, also can be two units, and the purpose of coating is to make to have insulating properties between the steel plate.
The hot rolled plate normalizing is the important measures that improve non-oriented electrical steel texture and magnetic; because normalizing can make hot rolled plate grain coarsening and more even, obtain high 0kl (a kind of easy magnetization family of crystal planes) texture of intensity (this technology is published in its " The SumitomoSearch " 120-125 page or leaf in December the 44th nineteen ninety) when making cold-reduced sheet annealing.Hot rolled plate crystal grain is thick more, and the finished product magnetic strength is high more.The normalizing temperature generally is no more than Ac1 (α-γ phase transition temperature line), changes mutually thereby avoid taking place in the normalizing process α → γ → α, and the grain structure refinement improves unfavorable (seeing clear 63-210238, clear 64-55338) to final finished texture on the contrary.Because of the restriction of normalizing temperature,, must increase the normalizing time, as utilize more than the cover annealing 1h, or in continuous annealing furnace, anneal more than the 2min for obtaining thicker grain structure.Nonetheless because the normalizing temperature is lower, and the grain coarsening effect is limited, the effect that magnetic strength improves is limited.
Summary of the invention
The objective of the invention is at the deficiencies in the prior art and defective; a kind of improved cold-rolled non-oriented electrical steel and production method thereof are provided; make the hot rolling grain structure thick by adding straightening technology before the normalizing, thereby reduce the normalizing temperature, make the low magnetic strength height of iron loss behind the final annealing.
For achieving the above object, the present invention at first provides a kind of production method of cold-rolled non-oriented electrical steel, and its production stage is:
Strand → heating → hot rolling → straightening → normalizing → pickling → cold rolling → annealing → coating → finished product, wherein, elongation control is in 0.5～4% scope in the straightening step, and temperature was controlled at 800 ℃～1050 ℃ scopes interior 60～90 seconds in the normalizing step.
Below be the key point of master operation:
Straightening: the straightening machine is set before normalizing furnace.Preceding 0.5～4% distortion (straightening) that hot rolled plate is implemented is handled in normalizing; purpose is by this distortion the energy storage of hot rolled plate to be increased; promote hot rolled plate ferrite crystal grain thickization in annealing process; and the magnetic property of electrical sheet and ferrite crystal grain have direct relation; the big more iron loss P of ferrite crystal grain can be low more; and magnetic strength B can be higher, helps the improvement of electrical sheet magnetic property.
Simultaneously, hot rolled plate is through the straightening of 0.5～4% percentage elongation, and then carries out normalizing and handle, and the normalizing temperature of this moment can reduce by 10～50 ℃ than prior art.Reason is that the increase of energy storage makes possessed the driving force that enough ferrites are grown up under low relatively temperature because hot rolled plate has been implemented the straightening distortion.With Si content is 0.65% to be example; normalizing is preceding without straightening; the normalizing system is 950 ℃ * 90s, and average grain size is 90 μ m, and iron loss P15/50 is 5.5W/Kg; magnetic strength B50 is 1.740T; through 3% straightening distortion, the normalizing system is 900 ℃ * 90s (reducing by 50 ℃) before the normalizing, and average grain size reaches 158 μ m; iron loss P15/50 is reduced to 4.7W/Kg, and magnetic strength B50 is elevated to 1.771T.
Through suitable straightening, not only can improve magnetic property significantly before the normalizing, and reduce the requirement of normalizing equipment and help the reduction of production process energy consumption.
All the other steps can utilize prior art to carry out.
According to cold-rolled non-oriented electrical steel of the present invention, the chemical composition of its strand is (percentage by weight): C≤0.0050%, 0.1%≤Si≤3.2%, Al≤1.0%, Mn:0.10%～1.0%, P≤0.2%, S≤0.005%, N≤0.0030%, all the other are iron and inevitable impurity.
Below be the effect and the qualification explanation thereof of essential element of the present invention:
C: harmful to magnetic, pass precipitation under the C normal temperature of gap in α-Fe in time and separate out and cause magnetic aging.C too high levels, decarburization time prolong and reduce unit production capacity, improve wet atmosphere and can increase surface of steel plate internal oxidation layer deterioration magnetic property.C is the element that hinders grain growth strongly, and C is the element that enlarges the γ phase region simultaneously, and α and γ two-phase section transformation amount increased when excessive C handled normalizing, reduced the Ac1 point greatly, and crystalline structure is played refining effect, causes that iron loss increases.C of the present invention≤0.005%, best C≤0.003%.
Si: can be dissolved in and form substitution solid solution in the ferrite, improve matrix resistivity, reduce iron loss, be the most important alloying element of electrical sheet, when Si content reached certain value, its content continued to increase, reducing the iron loss effect obviously weakens, the present invention 0.1%≤Si≤3.2%, silicone content surpasses 3.2% processing difficulties, will not have the effect that reduces iron loss and be lower than 0.1%.
Al: dissolve in ferrite and improve matrix resistivity, coarsened grain reduces iron loss, simultaneously all right deoxidation fixed nitrogen, but cause oxidation in the finished product steel plate top layer easily.Al content surpasses 1.0% will make smelting cast difficulty, and magnetic strength reduces, and processing difficulties, and when requiring high magnetic strength, Al is residual amount in the steel.
Mn: can form stable MnS with inevitable field trash S, eliminate the harm of S to magnetic, also can prevent hot-shortly, it also is dissolved in ferrite and forms substitution solid solution, and the effect that reduces iron loss is arranged.Mn of the present invention is 0.10%～1.0%, and it is not obvious that Mn content is lower than 0.1% advantageous effect, is higher than 1.0%, and the Ac1 temperature reduces, and recrystallization temperature reduces, and α-γ phase transformation, deterioration favorable texture take place during heat treatment.
P: in steel, add the processability that certain phosphorus can improve steel plate, make cold-rolling of steel plate processability deterioration on the contrary but surpass at 0.2% o'clock.
S: all harmful to processing and magnetic, itself and Mn form tiny MnS particle, hinder the finished products grain growth, and severe exacerbation magnetic forms low melting point FeS and FeS with Fe
2Or eutectic, easily cause hot-working fragility.S of the present invention≤0.005%.
N: easily form small and dispersed nitride such as AlN, hinder grain growth strongly, iron loss deterioration, N of the present invention≤0.003%, optimum range≤0.002%.
The present invention has following advantage:
1, the present invention through the straightening distortion, increases the hot rolled plate energy storage before normalizing, and ferrite crystal grain is thick after the normalizing, and cold rolling and annealing back texture is improved.The iron loss of finished product reduces, magnetic strength improves.
2, the present invention can carry out under relatively low temperature; promptly because the present invention has increased straightening technology before normalizing; make normalizing temperature subsequently to reduce by 10～50 ℃ than the normalizing temperature of prior art; thereby reduced the requirement of normalizing equipment and cut down the consumption of energy in process of production; and reduce because temperature reduces iron scale, help pickling subsequently.
Description of drawings
Fig. 1 shows the relation of hot rolled plate percentage elongation and hot rolled plate crystal size;
Fig. 2 shows the relation of hot rolled plate percentage elongation and iron loss P15/50;
Fig. 3 shows the relation of hot rolled plate percentage elongation and magnetic strength B50.
The specific embodiment
Below be that example 1 of the present invention specifies.
With C:0.0025%, Si:0.65%, Mn:0.25%, Al:0.25%, the continuous casting billet of P:0.015%, S:0.0035% and N:0.0020% composition carries out hot rolling, hot rolling thickness of slab 2.60mm.Hot rolled plate is carried out the stretching of different percentage elongation, carry out 950 ℃ * 90s, 100N then
2Normalizing is handled.Be cold rolled to 0.50mm then.Cold-reduced sheet is carried out 800 ℃ * 20s annealing, and carry out magnetic detection, result such as Fig. 1～shown in Figure 3.Fig. 1～Fig. 3 is respectively iron loss and the magnetic strength of implementing hot rolling lath particle size after the pairing normalizing of different percentage elongation straightenings, finished product.
As shown in Figure 1, along with the increase of straightening deformation rate before the normalizing, the crystallite dimension after the hot rolled plate normalizing is that 90um increases to 158um also along with increase from average grain size, and the magnetic property of electrical sheet and ferritic crystallite dimension have direct corresponding relation, and effect is seen Fig. 2 and Fig. 3;
As shown in Figure 2, along with the increase of straightening deformation rate before the normalizing, iron loss P15/50 reduces (iron loss is low more good more) gradually, is reduced to the 4.7W/Kg that implements behind the present invention by implementing 5.5W/Kg before the present invention, reduces 0.8W/Kg;
As shown in Figure 3, the increase of straightening deformation rate before the normalizing, magnetic strength B50 increases (magnetic strength is the bigger the better) gradually, increases to the 1.771T that implements behind the present invention, rising 310Gs by implementing 1.740T before the present invention.
From result of the test as seen, percentage elongation reaches at 0.5% o'clock just obvious effects.Percentage elongation improves, and the hot rolled plate crystallite dimension increases, and iron loss reduces, and magnetic strength further improves.Iron loss and magnetic strength reach best effect at percentage elongation about 3%, and with the increase of straightening percentage elongation, the hot rolled plate crystallite dimension reduces afterwards, and downward trend appears in iron loss and magnetic strength.Before the normalizing hot rolled plate is implemented the energy storage increase that certain deformation (stretching) can increase hot rolled plate, promote hot rolled plate crystal grain thickization in annealing process.Though the straightening percentage elongation still has effect preferably greater than 4%, but the load of straightening machine is very big in actual production, even surpassed the load of straightening machine, percentage elongation is excessive on the other hand, peeling off appears in the oxide skin on hot rolled plate surface, damages the roller of back, and a large amount of oxide skins are peeled off in stove, influence the operation of annealing furnace, therefore infeasible aborning.
Below be specifying of example 2-7 of the present invention.
The concrete chemical composition of example 2-7 sees Table 1:
Table 1Wt%
| Numbering | Si | Al | Mn | P | | S | N | |
| 2 | 1.72 | 0.66 | 0.10 | 0.005 | 0.005 | 0.003 | 0.0030 | |
| 3 | 3.02 | 0.48 | 1.00 | 0.005 | 0.003 | 0.005 | 0.0024 | |
| 4 | 0.65 | 0.35 | 0.45 | 0.100 | 0.002 | 0.004 | 0.0027 | |
| 5 | 0.10 | 1.00 | 0.20 | 0.200 | 0.001 | 0.003 | 0.0023 | |
| 6 | 1.72 | 0.48 | 0.64 | 0.005 | 0.004 | 0.005 | 0.0008 | |
| 7 | 3.20 | 0.10 | 0.85 | 0.005 | 0.003 | 0.001 | 0.0015 |
The technological parameter of example 2-7 and corresponding iron loss and magnetic the results are shown in Table 2:
Table 2 embodiment production method and magnetic result
Remarks: above comparative example is not for implementing the example of the prior art of straightening.
As seen from Table 2, in numbering 2 (examples 2), through the straightening of 0.5% percentage elongation, the normalizing temperature reduces by 20 ℃ before the normalizing, and iron loss P15/50 reduces 0.41W/Kg, magnetic strength B50 rising 160Gs.
Numbering 3, through the straightening of 1.0～4.0% percentage elongation, the normalizing temperature reduces by 10～40 ℃ before the normalizing, and iron loss P15/50 reduces by 0.35～0.76W/Kg, the magnetic strength B50 160～340Gs that raises.
Numbering 4, the normalizing temperature is not made change, and when extension straightening rate was 3%, iron loss P15/50 reduced 0.84W/Kg, magnetic strength B50 rising 320Gs.
Numbering 6,50 ℃ of reduction normalizing temperature, straightening rate are 3% o'clock, iron loss P15/50 reduces 0.40W/Kg, magnetic strength B50 rising 100Gs.
In sum,, can obviously reduce the normalizing temperature, reduce iron loss and improve magnetic strength by the straightening before the normalizing.
Claims (1)
1. the production method of a cold-rolled non-oriented electrical steel, its production stage is:
Strand → heating → hot rolling → straightening → normalizing → pickling → cold rolling → annealing → coating → finished product, wherein, elongation control is in 0.5～4% scope in the straightening step, and temperature was controlled at 800 ℃～1050 ℃ scopes interior 60～90 seconds in the normalizing step,
And its composition percentage by weight is:
C≤0.0050％；
Si≤3.2％；
Al：0.10％～1.0％；
Mn：0.10％～1.0％；
P≤0.2％；
S≤0.005％；
N≤0.0030％；
All the other are iron and inevitable impurity.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100249645A CN100546762C (en) | 2006-03-22 | 2006-03-22 | A kind of cold-rolled non-oriented electrical steel and production method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100249645A CN100546762C (en) | 2006-03-22 | 2006-03-22 | A kind of cold-rolled non-oriented electrical steel and production method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101041222A CN101041222A (en) | 2007-09-26 |
| CN100546762C true CN100546762C (en) | 2009-10-07 |
Family
ID=38807127
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2006100249645A Active CN100546762C (en) | 2006-03-22 | 2006-03-22 | A kind of cold-rolled non-oriented electrical steel and production method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100546762C (en) |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101654757B (en) * | 2008-08-20 | 2012-09-19 | 宝山钢铁股份有限公司 | Coated semi-processed non-oriented electrical steel sheet and manufacturing method thereof |
| CN102373367A (en) * | 2010-08-26 | 2012-03-14 | 宝山钢铁股份有限公司 | Cold-rolled electromagnetic steel plate for rapid cycling synchrotron and manufacturing method thereof |
| CN102373366A (en) * | 2010-08-26 | 2012-03-14 | 宝山钢铁股份有限公司 | Method for improving coarse grains on surface of non-oriented silicon steel |
| CN102453837B (en) * | 2010-10-25 | 2013-07-17 | 宝山钢铁股份有限公司 | Method for preparing non-oriented silicon steel with high magnetic induction |
| CN102560239A (en) * | 2010-12-17 | 2012-07-11 | 鞍钢股份有限公司 | Production method of high-grade electrical steel product |
| CN102560235B (en) * | 2010-12-17 | 2014-01-01 | 鞍钢股份有限公司 | Manufacturing method of high-magnetic-inductive oriented silicon steel |
| CN102758150A (en) * | 2011-04-28 | 2012-10-31 | 宝山钢铁股份有限公司 | High-yield-strength non-oriented electrical steel plate and manufacturing method thereof |
| CN102260822B (en) * | 2011-07-27 | 2013-06-05 | 攀钢集团有限公司 | Smelting method of high-phosphorus low-sulfur non-oriented electrical steel |
| CN103031424B (en) * | 2011-09-29 | 2015-10-07 | 鞍钢股份有限公司 | The production method of non-oriented electrical steel coated semi handicraft product |
| CN103031423A (en) * | 2011-09-29 | 2013-04-10 | 鞍钢股份有限公司 | Method for improving performance of high-efficiency and high-grade non-oriented electrical steel product |
| CN103290190A (en) | 2012-03-02 | 2013-09-11 | 宝山钢铁股份有限公司 | Non-oriented silicon steel and manufacturing method thereof |
| RU2489500C1 (en) * | 2012-05-03 | 2013-08-10 | Открытое акционерное общество "Новолипецкий металлургический комбинат" | Manufacturing method of cold-rolled electrical isotropic steel with improved flatness |
| BR112015026904B1 (en) * | 2013-05-01 | 2020-04-07 | Nippon Steel & Sumitomo Metal Corp | steel plate resistant to spot welding and with low specific weight |
| CN104726763B (en) * | 2013-12-23 | 2017-04-12 | 鞍钢股份有限公司 | Hot rolling method of electrical steel |
| CN110468352A (en) * | 2019-09-25 | 2019-11-19 | 江苏沙钢集团有限公司 | A kind of non-orientation silicon steel and its production method |
| CN113403455B (en) * | 2021-06-17 | 2024-03-19 | 张家港扬子江冷轧板有限公司 | Production method of unoriented silicon steel |
| CN113897543A (en) * | 2021-08-31 | 2022-01-07 | 中冶南方工程技术有限公司 | Non-oriented electrical steel and method of manufacture |
-
2006
- 2006-03-22 CN CNB2006100249645A patent/CN100546762C/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN101041222A (en) | 2007-09-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100546762C (en) | A kind of cold-rolled non-oriented electrical steel and production method thereof | |
| CN102453837B (en) | Method for preparing non-oriented silicon steel with high magnetic induction | |
| CN102453844B (en) | Method for preparing non-oriented silicon steel with excellent magnetic property and high efficiency | |
| CN100567545C (en) | A kind of high grade non-oriented silicon steel and manufacture method thereof | |
| CN100446919C (en) | Production process of cold rolled orientation-free electrical steel plate with low iron loss and high magnetic induction | |
| CN100999050A (en) | Production method of low iron loss high magnetic sensing cold milling orientation less electrical steel plate | |
| CN101654757B (en) | Coated semi-processed non-oriented electrical steel sheet and manufacturing method thereof | |
| CN109097677B (en) | High magnetic induction oriented high silicon steel sheet thin strip and preparation method thereof | |
| CN1258608C (en) | Method for manufacturing cold-rolled orientation-free electrical sheet | |
| EP3719160B1 (en) | Non-oriented electrical steel sheet with excellent magnetism and manufacturing method therefor | |
| CN109022703A (en) | A kind of non-orientation silicon steel that magnetic anisotropy is low and its manufacturing method | |
| EP4001450A1 (en) | 600mpa grade non-oriented electrical steel sheet and manufacturing method thereof | |
| CN1796015A (en) | Method for manufacturing cold rolling non oriented electrical steel through continuous casting and tandem rolling sheet bar | |
| CN104328342A (en) | Non-oriented silicon steel used for frequency conversion high efficiency compressor and production method thereof | |
| CN112143964A (en) | Non-oriented electrical steel plate with extremely low iron loss and continuous annealing process thereof | |
| CN112430780B (en) | Cu-containing high-cleanliness non-oriented electrical steel plate and manufacturing method thereof | |
| CN1131333C (en) | Serial high-magnetic induction non-orieted electrical steel and its production process | |
| CN109182907B (en) | Method for producing semi-process non-oriented electrical steel by endless rolling | |
| CN110819879A (en) | Non-oriented silicon steel with excellent magnetic property and manufacturing method thereof | |
| CN113621774B (en) | High-silicon non-oriented electrical steel and production method thereof | |
| CN101348852A (en) | Method for producing oriented electrical steel by low temperature slab heating | |
| CN101586180A (en) | A kind of method that improves property of non-oriented electric steel | |
| CN113969371B (en) | Non-oriented electrical steel plate for simultaneously cutting stator and rotor iron core and manufacturing method thereof | |
| CN116790999A (en) | High-grade non-oriented silicon steel with low magnetic anisotropy and preparation method thereof | |
| CN111593262A (en) | Low-cost non-coating non-oriented silicon steel and production method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |