US3895974A - Process for producing a grain-oriented electrical steel sheet having excellent magnetic characteristic - Google Patents

Process for producing a grain-oriented electrical steel sheet having excellent magnetic characteristic Download PDF

Info

Publication number
US3895974A
US3895974A US402908A US40290873A US3895974A US 3895974 A US3895974 A US 3895974A US 402908 A US402908 A US 402908A US 40290873 A US40290873 A US 40290873A US 3895974 A US3895974 A US 3895974A
Authority
US
United States
Prior art keywords
sheet
steel sheet
electrical steel
rolling
grain
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.)
Expired - Lifetime
Application number
US402908A
Other languages
English (en)
Inventor
Shozo Watanabe
Kiyoshi Tanaka
Yozo Suga
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.)
Nippon Steel Corp
Original Assignee
Nippon Steel Corp
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 Nippon Steel Corp filed Critical Nippon Steel Corp
Application granted granted Critical
Publication of US3895974A publication Critical patent/US3895974A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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
    • C21D8/12—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • C21D8/1216—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the working step(s) being of interest
    • C21D8/1222—Hot rolling

Definitions

  • the present invention relates to a process for producing so-called grain-oriented electrical steel sheets having a magnetizable axis l in the rolling direction.
  • Silicon steels widely used presently as materials for the grain-oriented electrical steel sheets are composed of grains having a body-centred cubic lattice, and it is well known that the direction 100 along the three tetragonal axis is most easily magnetized.
  • the grainoriented electrical steel sheet is a steel sheet in which this magnetizable axis l 00 is arranged in the rolling direction and the plane ⁇ 110 ⁇ is arranged in parallel to the rolling plane, and crystallographically it is referred to as (ll0)[00l] orientation by the Miller indices.
  • the grain-oriented electrical steel sheet is composed of the grains having the specific selective orientation, and such grain orientation is attained by the secondary recrystallization phenomenon during the final annealing of the cold rolled steel sheet of final thickness.
  • the grain-oriented electrical steel sheets are used mainly as iron cores for transformers and other electrical appliances, and they must have good exitation and low watt loss characteristics as magnetic properties.
  • the magnetic flux density B (Wb/m produced in the iron core at an intensity of the magnetic field H 800A'T/m (ampere per meter) is used, and the value for representing the energy loss caused when predetermined A.C magnetic flux density is given to the iron core, namely the watt loss, the watt loss at A.C magnetic flux density of 1.7 Wb/m and 50 Hz frequency is used.
  • one of the objects of the present invention is to provide a process for producing an electrical sheel sheet which satisfies the above requirements.
  • the present invention is to provide a process for producing grain-oriented electrical steel sheet having excellent magnetic characteristics by hot rolling a silicon steel material comprising not less than 2% preferably 2.0 to 4.5% silicon, 0.010 to 0.045% preferably 0.027 to 0.045% acid soluble aluminium (soLAl), 0.0030 to 0.0095% preferably 0.0065 to 0.0095% nitrogen, with the balance being iron and unavoidable impurities, cold rolling the hot rolled material to the final sheet thickness and subjecting the cold rolled sheet to a high temperature annealing, which is characterized in that the hot rolled material is subjected to light hot working of 3 to 20% preferably to 16% at a temperature between 700 and 900C preferably 720 and 830C and held in the temperature Table 1 Elements Contents C 0.025 0.060% Si more than 2% Mn
  • the silicon content is defined as not less than 2%.
  • MN is mainly utilized, and thus the amounts of acid soluble aluminium and total nitrogen which form AlN are particularly defined.
  • the content of acid soluble aluminium with less than 0.010% acid soluble aluminium, the amount of AlN is not enough to be utilized as the dispersed precipitates. On the other hand, if the content of acid soluble aluminium is beyond 0.045%, uniformity in the refinement of the dispersed precipitates of AIN is damaged. Therefore the content of acid soluble aluminium is limited to 0.010 to 0.045%.
  • the content of the total nitrogen if the total nitrogen is less than 0.0030%, the amount of MN is not enough as in the case of the acid soluble aluminium and if the total nitrogen is over 0.0095%, there will be caused in the final product surface defects such as commonly called blisters. Therefore, the total nitrogen content is limited to 0.0030 to 0.0095%.
  • the silicon steel as shown in Table l is used as starting material, and is subjected to a light hot working immediately after the hot rolling or prior to the cold rolling to obtain appropriate precipitation of AlN, thereby a high magnetic flux density grain-oriented electrical steel sheet having at least more than 1.85 ⁇ Vb/m of flux density B can be produced.
  • the precipitation treatment of AlN in the above prior art is conducted by a high temperature heat treatment between 900 and l,200C for 30 seconds to 30 minutes. This is completely different from the present invention in which the precipitation of AlN is made uniform by the light hot working.
  • the light hot working is conducted in a temperature range in which the precipitation of AlN takes place suddenly to disperse the precipitation sites thereby finely and uniformly dispersed precipitates of AlN most suitable to the secondary recrystallization is rapidly obtained.
  • the present invention is based on technical thought completely different from the precipitation treatment of AlN conducted after the light cold working, or the simple precipitation treatment of AlN without a light working.
  • FlG. l is a graph showing the relation among the light hot rolling temperature the rolling reduction rate and the 8, value.
  • FIG. 2 is a graph showing the relation among the bending ratio, the bending temperature and the B value.
  • FIG. 3 is a graph showing the relation between the holding time after the light hot working and the B value.
  • FIG. 4 to FIGv 6 are electron microscopic photographs showing the precipitation of AlN.
  • FIG. 1 shows the magnetic flux density ofa specimen which was prepared by heating rapidly hot rolled steel plate of 2.3mm thickness containing 2.95% Si, 0.025% soLAl. 0.0058% total N to a temperature between 700 and l,lC, giving the plate a light rolling of 0 to about 26%. holding the plate for 4 seconds, quenching the plate in a salt water, cold rolling the plate to 030mm thickness, decarburizing the sheet in a wet hydrogen atmosphere. and subjecting the sheet to a high temperature annealing for the secondary recrystallization.
  • a grain-oriented electrical steel sheet having high magnetic flux density can be obtained by conducting the light hot working at a temper ature between 700 and l.l00C with a reduction rate between 3 and and the light hot working conditions of the present invention have been defined on the basis of the above experiments.
  • the results shown in FIG. 1 were obtained by adopting the hot rolling as the light hot working, but the light hot working can be conducted by any of other equipments which can give the specified reduction rate such as roller levellers, stretcher levellers and so on.
  • FIG. 2 shows the magnetic flux density of a specimen prepared by rapidly heating the hot rolled steel sheet as used in FIG. 1 to a temperature between 500 and 1,000C, bending the sheet with bending radius of mm and 50mm, holding the sheet for 4 seconds, quenching the sheet in a salt water and then treating the sheet in a similar way as in HO 1.
  • the maximum working ratios corresponding to the bending ratios of 25mm and 50mm are 4.4% and 2.3% respectively, and it is understood that the desired re sults of the present invention can be obtained if the temperature and the working ratio for the light hot working are satisfied irrespective to the kind of the light hot working.
  • the other feature of the present invention is to obtain an appropriate precipitation of AlN by the light hot working, and for this purpose a certain holding time is required for changing the AlN precipitation.
  • FIG. 3 shows magnetic flux densities of five specimens prepared by rapidly heating to 800C five hot rolled steel sheets of 2.3mm thickness containing 2.5 to 3.2% Si. 0.015 to 0.025% sol.Al, and 0.0050 to 0.0070% total N, subjecting the sheets to light hot rolling of 9.5 to 10.5%, holding the sheets at various times after the light hot rolling to the quenching in a salt water (the temperature of the sheets after the light hot rolling was about 750C), quenching the sheets in a salt water, cold rolling the sheets to 030mm thickness and subjecting the sheets to decarburization annealing and high temperature annealing.
  • the results show that the object of the present invention is attained by the holding times not shorter than 2 seconds.
  • MN is utilized as the dispersed precipitates for the secondary recrystallization and the light hot working is utilized for rendering the AlN precipitates into an appropriate form.
  • the present inventors have conducted studies on effects of the light hot working on the form of AlN precipitates.
  • FIG. 4 shows the distribution of AlN in the hot rolled sheet
  • FIG. 5 shows the sheet which was heated rapidly to 800C and cooled without the light hot rolling
  • FIG. 6 shows AIN in the sheet which was heated rapidly to 800C and subjected to light hot rolling of 11%.
  • MN precipitates finely and uniformly when the light hot rolling is conducted.
  • the AlN precipitates are in flocks, resulting in irregular distribution of AlN.
  • a process for producing a goss texture. grainoriented electrical steel sheet having excellent magnetic characteristics greater than I .85 Wb/m comprising hot rolling a silicon sheet material consisting essentially of not less than 2% silicon, 0.0! to 0.45% acid soluble aluminium, 0.003 to 0.0095% nitrogen with the balance being iron and unavoidable impurities, cold rolling the hot rolled material to a final sheet thickness.
  • the hot rolled sheet is subjected to a light hot working of 3 to 20% in a temperature range between steel material consists essentially of 2.0 to 4.5% silicon, 0.027 to 0.045% acid soluble aluminium, 0.0065 to 0.0095% nitrogen. and the light hot working is performed with a reduction rate between [0 and 16% at a temperature between 720 and 830C.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Thermal Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Electromagnetism (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing Of Steel Electrode Plates (AREA)
  • Soft Magnetic Materials (AREA)
US402908A 1972-10-11 1973-10-03 Process for producing a grain-oriented electrical steel sheet having excellent magnetic characteristic Expired - Lifetime US3895974A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP47101795A JPS5037134B2 (enrdf_load_stackoverflow) 1972-10-11 1972-10-11

Publications (1)

Publication Number Publication Date
US3895974A true US3895974A (en) 1975-07-22

Family

ID=14310080

Family Applications (1)

Application Number Title Priority Date Filing Date
US402908A Expired - Lifetime US3895974A (en) 1972-10-11 1973-10-03 Process for producing a grain-oriented electrical steel sheet having excellent magnetic characteristic

Country Status (9)

Country Link
US (1) US3895974A (enrdf_load_stackoverflow)
JP (1) JPS5037134B2 (enrdf_load_stackoverflow)
BE (1) BE805861A (enrdf_load_stackoverflow)
BR (1) BR7307945D0 (enrdf_load_stackoverflow)
FR (1) FR2202943B1 (enrdf_load_stackoverflow)
GB (1) GB1430434A (enrdf_load_stackoverflow)
IT (1) IT995734B (enrdf_load_stackoverflow)
SE (1) SE387131B (enrdf_load_stackoverflow)
SU (1) SU682142A3 (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4204891A (en) * 1978-11-27 1980-05-27 Nippon Steel Corporation Method for preventing the edge crack in a grain oriented silicon steel sheet produced from a continuously cast steel slab
EP0125653A1 (en) * 1983-05-12 1984-11-21 Nippon Steel Corporation Process for producing a grain-oriented electrical steel sheet
US5609696A (en) * 1994-04-26 1997-03-11 Ltv Steel Company, Inc. Process of making electrical steels
US6068708A (en) * 1998-03-10 2000-05-30 Ltv Steel Company, Inc. Process of making electrical steels having good cleanliness and magnetic properties
US6217673B1 (en) 1994-04-26 2001-04-17 Ltv Steel Company, Inc. Process of making electrical steels

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0730397B2 (ja) * 1990-04-13 1995-04-05 新日本製鐵株式会社 磁気特性の優れた一方向性電磁鋼板の製造方法
JP3319898B2 (ja) * 1994-12-20 2002-09-03 川崎製鉄株式会社 コイル内で磁気特性の均一な無方向性電磁鋼帯の製造方法
KR101149792B1 (ko) * 2009-10-01 2012-06-08 주식회사 포스코 저철손 고자속밀도 방향성 전기강판 및 그 제조방법

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2084337A (en) * 1934-12-01 1937-06-22 Allegheny Steel Co Method of rolling magnetic material
US3144363A (en) * 1961-12-14 1964-08-11 Westinghouse Electric Corp Process for producing oriented silicon steel and the product thereof
US3671337A (en) * 1969-02-21 1972-06-20 Nippon Steel Corp Process for producing grain oriented electromagnetic steel sheets having excellent magnetic characteristics
US3764406A (en) * 1971-11-04 1973-10-09 Armco Steel Corp Hot working method of producing cubeon edge oriented silicon iron from cast slabs

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2084337A (en) * 1934-12-01 1937-06-22 Allegheny Steel Co Method of rolling magnetic material
US3144363A (en) * 1961-12-14 1964-08-11 Westinghouse Electric Corp Process for producing oriented silicon steel and the product thereof
US3671337A (en) * 1969-02-21 1972-06-20 Nippon Steel Corp Process for producing grain oriented electromagnetic steel sheets having excellent magnetic characteristics
US3764406A (en) * 1971-11-04 1973-10-09 Armco Steel Corp Hot working method of producing cubeon edge oriented silicon iron from cast slabs

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4204891A (en) * 1978-11-27 1980-05-27 Nippon Steel Corporation Method for preventing the edge crack in a grain oriented silicon steel sheet produced from a continuously cast steel slab
EP0125653A1 (en) * 1983-05-12 1984-11-21 Nippon Steel Corporation Process for producing a grain-oriented electrical steel sheet
US5609696A (en) * 1994-04-26 1997-03-11 Ltv Steel Company, Inc. Process of making electrical steels
USRE35967E (en) * 1994-04-26 1998-11-24 Ltv Steel Company, Inc. Process of making electrical steels
US6217673B1 (en) 1994-04-26 2001-04-17 Ltv Steel Company, Inc. Process of making electrical steels
US6068708A (en) * 1998-03-10 2000-05-30 Ltv Steel Company, Inc. Process of making electrical steels having good cleanliness and magnetic properties

Also Published As

Publication number Publication date
GB1430434A (en) 1976-03-31
JPS5037134B2 (enrdf_load_stackoverflow) 1975-12-01
BR7307945D0 (pt) 1974-07-11
SE387131B (sv) 1976-08-30
IT995734B (it) 1975-11-20
DE2350774A1 (de) 1974-04-18
BE805861A (fr) 1974-02-01
DE2350774B2 (de) 1975-07-03
SU682142A3 (ru) 1979-08-25
JPS4959029A (enrdf_load_stackoverflow) 1974-06-07
FR2202943B1 (enrdf_load_stackoverflow) 1978-02-17
FR2202943A1 (enrdf_load_stackoverflow) 1974-05-10

Similar Documents

Publication Publication Date Title
KR100266552B1 (ko) 자속밀도가 높으면서 철손이 낮은 일방향성 전자강판 및 그 제조방법
KR970008162B1 (ko) 입자 방향성 전기강의 초고속 열처리
CN107109552B (zh) 低铁损取向性电磁钢板及其制造方法
US3287183A (en) Process for producing single-oriented silicon steel sheets having a high magnetic induction
US3770517A (en) Method of producing substantially non-oriented silicon steel strip by three-stage cold rolling
KR930001948B1 (ko) 무방향성 전기강 스트립 제조방법
US3841924A (en) Method for producing a high magnetic flux density grain oriented electrical steel sheet
US2307391A (en) Art of producing magnetic material
KR100336661B1 (ko) 매우철손이낮은방향성전자강판과그제조방법
KR102742671B1 (ko) 무방향성 전자 강판
EP0234443B1 (en) Process for producing a grain-oriented electrical steel sheet having improved magnetic properties
JPH02274815A (ja) 磁気特性の優れた一方向性電磁鋼板の製造方法
US3895974A (en) Process for producing a grain-oriented electrical steel sheet having excellent magnetic characteristic
NO141723B (no) Fremgangsmaate for fremstilling av krystallorientert magnetplate
US3180767A (en) Process for making a decarburized low carbon, low alloy ferrous material for magnetic uses
US3892605A (en) Method of producing primary recrystallized textured iron alloy member having an open gamma loop
JPH032932B2 (enrdf_load_stackoverflow)
EP0588342B1 (en) Grain-oriented electrical steel sheet and material having very high magnetic flux density and method of manufacturing same
EP3760746A1 (en) Grain-oriented electromagnetic steel sheet
CN113366125B (zh) 方向性电磁钢板和使用该方向性电磁钢板的铁芯
US2939810A (en) Method for heat treating cube-on-edge silicon steel
US3833431A (en) Process for continuously annealed silicon steel using tension-producing glass
KR20000001997A (ko) 수요가 열처리후 자성이 우수한 무방향성 전기강판의 제조방법
CN112313358B (zh) 磁特性优异的方向性电磁钢板
US3802936A (en) Method of making grain oriented electrical steel sheet