GB2146567A - Production of grain orientated steel - Google Patents
Production of grain orientated steel Download PDFInfo
- Publication number
- GB2146567A GB2146567A GB08423012A GB8423012A GB2146567A GB 2146567 A GB2146567 A GB 2146567A GB 08423012 A GB08423012 A GB 08423012A GB 8423012 A GB8423012 A GB 8423012A GB 2146567 A GB2146567 A GB 2146567A
- Authority
- GB
- United Kingdom
- Prior art keywords
- strip
- sheet
- discharge
- probe
- ablation
- 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
Links
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
- C21D8/1294—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties involving a localized treatment
-
- 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
- C21D1/06—Surface hardening
- C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
- H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
- H01F1/16—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of sheets
Description
1 GB 2 146 567 A 1
SPECIFICATION
Improvements in or relating to the production of grain orientated steel This invention relates to the production of grain orientated steel.
Sheet or strip of grain orientated steel for electrical purposes is of course well known. Such sheet or strip is used for electromagnetic applications eg. to form a magnetic circuit in electric machines. The sheet or strip is typically produced from steel containing silicon typically in concentrations within the range 2 - 4% weight. Processing of the silicon steel by working and thermal treatment in known manner promotes preferential growth of some grains within the steel in order to obtain large grains having predominantly (110) [001]Miller10 Indices and to inhibit the growth of the remaining grains. This of course leads to strong orientation of the grains with strongly enhanced magnetic characteristics for the purposes for which the steel is intended.
A problem associated with the production of such grain orientated steel is that production of optimum alignment of the grain leads at the same time to grains of a larger than optimum size. Such large grain size leads to significant power loss problems. Magnetic domain wall spacing within the grains becomes large so 15 that in use rapid movement of the domain walls (caused by the greater distance to be moved by the domain walls in unit time) create severe micro-eddy currents, in turn causing power losses.
It has been proposed to overcome this problem by the provision of artificial barriers intended to simulate the effect of grain boundaries in the steel sheet or strip and therefore to refine, or reduce, the domain spacing so as to reduce movement of the domain walls.
It is an object of the present invention to provide an improved method of and apparatus for creating such artificial barriers.
In accordance with one aspect of the invention there is provided a method of treating grain orientated steel sheet or strip to refine domain spacing by subjecting the steel sheet or strip to electrical discharge to create a line of surface ablation and stress thereacross.
In accordance with another aspect of the present invention there is provided apparatus for treating grain orientated steel sheet or strip to refine the domain spacing comprising an electric discharge probe adapted to be located above the surface of a grain orientated sheet or strip and means for causing the probe to discharge so as to create a line of surface ablation and stress on the sheet or strip.
The line of ablation can be constituted by a succession of discharge spots, or alternatively a continuous line of ablation can be created. We have found that with electrical steel sheet or strip of the kind to which this invention relates, typically having a thickness of between 0.20 to 0.35 mm, the line of ablation created by the discharge provides a simulated grain boundary effect through the thickness of the metal. Thus the discharge creates atomic magnitude disruption at and below the metal surface, and in addition a thermal stress field is set up below the surface through the thickness of the sheet or strip effective as a simulated grain boundary. 35 In order that the invention may be more readily understood one embodiment thereof will now be described by way of example with reference to the accompanying drawing which shows diagrammatically the arrangement of a discharge probe above a grain orientated steel sheet.
The probe 1 is located with a gap 2 of between 2 and 3 mm above the surface of the sheet 3 which is of a thickness between 0.20 and 0.35 mm (although the gap 2 can be less, for example down to 0.5 mm) and is raised to a high voltage supply of -12 KV with respect to the sheet in order to cause a sparkto discharge from the probe to the sheet. The voltage for discharge will be of the order of 3000 to 10,000 volts. It is to be observed that although grain orientated electrical steel carries an insulating coating as a matter of course, high voltage of this magnitude, necessary forthe sparkto traverse the air gap between the probe and the steel sheet, will also be quite adequate to effect thp breakdown of the insulating coating. A gap of between 1 45 to 3 mm is sufficiently large to enable a relative constancy of spacing between the probe and the sheet to be maintained during movement of the probe relative to the sheet.
A capacitor 4 is connected between the probe and the sheet, the capacitor being of a moderate size, for example somewhere between 1000 and 10,000 pf. In this case then the energy delivered is of the order of 1/2 CV2 joules where C is the capacitance of the capacitor and V is the voltage across the gap between the probe 50 and the sheet. It is to be noted that regulation of the gap between the probe and the sheet (and thus the discharge voltage) or the capacitance of the capacitor will enable regulation of the delivered energy.
A circuit of the kind illustrated in the Figure will act in practise as a relaxation oscillator so that spark discharge will occur at the rate related to a time constant R, where R is the resistance of a resistor 5 connected in the power supply line, and the relaxation between the power supply of 12 KV and the breakdown potential of the gap between the probe and the sheet. Regulation of the energy delivery rate can also be controlled by regulation of the value given to a low value resistor 6 connected in series with the capacitor 4.
Adjustment of the gap between probe 1 and sheet 2, the value of the capacitor 4, the value of the large resistor 5, the value of the power supply, and the value of the small resistor 6 give a very wide control of the 60 production of ablation spots from the discharge. If the probe is moving in line along or across the sheet a line of ablation spots, producing a barrier wall simulating the effect of a grain boundary will be produced, this barrier wall acting as a domain spacing refining system. Clearly the probe can be moved successively across the sheet to produce a succession of such lines and a domain spacing refining system throughout the sheet.
2 GB 2 146 567 A 2 In an alternative arrangement a continuous arc discharge can be produced so that a continuous line of ablation can be drawn across the surface of the sheet.
Again, if desired as an alternative the discharge spots can be provided at a fixed power supply by use of a trigger mechanism to discharge the capacitor rather than rely on the natural breakdown voltage of the gap between the probe and the sheet.
It is to be noted that in practise it is desirable, as illustrated, to utilise a negative potential on the probe so as to reduce probe erosion, which otherwise could be quite severe.
A multiple array of probes can be utilised for simultaneous actuation, the probes being spaced a predetermined distance apart and moved together across the sheet. The spacing of the probes in this case would be such as to apply lines of barrier walls at a spacing found to be most suitable for the particular grain 10 orientated steel concerned.
We have found that the arrangement according to the invention herein described enables an inexpensive and simple creation of artificial grain boundaries. We believe that improvements to the core loss properties of electrical steels with good grain orientation can be up to 15% as indicated by the data given in the Table set out below, and the examples therefollowing.
The losses referred to in the following table 1 part B are measured at an induction of 1.7 Tesla and 50 Hertz.
TABLE 1 Part A Data related to ablated samples 20 Ablation conditions Electrodelstrio Traverse rate of Resistance Capitance Example gap (mm) electrode across (M) (p F) strip (cmIsec) 25 1 1.81 0.5 1000 2500 1A 113 30 2 0.86 0.5 1000 2500 2A 213 3 1.14 0.5 5000 2500 35 3A 313 4 1.14 0.5 200 2500 4A 40 413 1.14 5.0 1000 2500 5A 5B 45 5C 6 1.14 10.0 1000 5000 6A 11 10.0 1000 2500 7 0.42 2.5 1000 2500 8 2.2 2.5 1000 2500 50 Note: The above date relates to Epstein samples of HiB type material 3 TABLE 1 Part B Data related to ablated samples GB 2 146 567 A 3 Permeability Initial Loss after scribing % change in % change in 5 loss at 0.5cm line spacing loss at 1. Ocm loss at 0.5 cm Example (Wlkg) (Wlkg) 1 1.96 1.276 1.148 7.1 10.0 1A 1,93 1.301 1.173 8.1 9.8 10 1 B 1.93 1.200 1.131 4.8 5.8 2 1.96 1.242 1.044 11.9 15.9 2A 1.96 1.216 1.077 9.3 11.4 213 1.93 1.247 1.125 7.1 9.8 15 3 1.96 1.314 1.170 6.7 11.0 3A 1.96 1.105 1.019 5.0 7.8 313 1.93 1.175 1.069 6.8 9.0 20 4 1,96 1.288 1.137 8.9 11.7 4A 1.96 1.111 1.022 6.9 8.0 4B 1.96 1.075 1.027 2.9 4.5 5 1.93 1.143 1.043 9.1 25 5A 1.93 1.340 1.180 11.9 513 1.93 1.270 1.173 - 7.7 5C 1.93 1.250 1.155 5.6 7.6 6 1.96 1.172 1.086 - 7.3 6A 1.93 1.249 1.130 5.8 8.9 30 7 1.93 1.190 1.134 - 7.0 8 1.93 1.320 1.230 6.8 Note: The above data relates to Epstein samples of HiB type material Example 1
An Epstein sample of Hi B type grain oriented silicon steel wasscribed bythe method described above using an electrode/strip gap of 1.81 mm, a resistor of value 1 Mfl, a capacitor of value 25OOpF, and a traverse rate of electrode across the strip of 0.5cm/sec.
Prior to treatment the permeability of the sample was 1.96 and the power loss was 1.276W/kg. After 40 treatment the loss value was reduced by 10.0% to a value of 1.1 48W/kg.
Other samples treated under similar conditions exhibited loss reduction values of 9.8 and 5.8% (Examples 1A and 16 in Table 1).
Example 2
An Epstein sample of Hi B type grain oriented silicon steel was scribed by the method described above using an electrode/strip gap of 0.86mm, a resistor of value 1 MQ, a capacitor of value 2500pF, and a traverse rate of electrode across the strip of 0.5cm/sec.
Prior to treatment the permeability of the sample was 1.96 and the power loss was 1.242W/kg. After treatment the loss value was reduced by 15.9% to a value of 1.044W/kg.
Other samples treated under similar conditions exhibited loss reduction values of 11.4 and 9.8% (Examples 2A and 2B in Table 1).
The ablation energy in this case was lowerthan that employed in Example 1 as indicated by the lower electrode/strip gap (0.86mm compared to 1.81 mm).
In the following Examples 3 - 6, an ablation energy between those employed in Examples 1 and 2 was utilised as indicated by the electrode/strip gap of 1.1 4mm. In addition, diff erent pulse rates were employed from that used in Examples 1 and 2, as indicated by the use of different resistor values, capacitor values and traverse rates of electrode across the strip.
4 GB 2 146 567 A 4 Example 3
An Epstein sample of Hi B type grain oriented silicon steel was scribed bythe method described above using an electrode/strip gap of 1.14mm, a resistor of value 5Mn, a capacitor of value 25OOpF, and a traverse rate of electrode across the strip of 0.5cm/sec.
Prior to treatment the permeability of the sample was 1.96 and the power loss was 1.314 W/kg. After 5 treatment the loss value was reduced by 11.0% to a value of 1.170W/kg.
Other samples treated under similar conditions exhibited loss reduction values of 7.8 and 9.0% (Examples 3A and 3B in Table 1).
Example 4
An Epstein sample of Hi B type grain oriented silicon steel was scribed by the method described above using an electrode/strip gap of 1.1 4mm, a resistor of value 200kfl, a capacitor of value 25OOpF and a traverse rate of electrode across the strip of 0.5cm/sec.
Prior to treatment the permeability of the sample was 1.96 and the power loss was 1.288W/kg. After 15 treatment the loss value was reduced by 11. 7% to a value of 1.137W/kg.
Other samples treated under similar conditions exhibited loss reduction values of 8.0, and 4.5% (Examples 4A and 4B in Table 1).
Example 5
An Epstein sample of Hi B type grain oriented silicon steel was scribed by the method described above 20 using an electrode/strip gap of 1.14mm, a resistor of value 1 Mfl, a capacitor of value 25OOpF, and a traverse rate of electrode across the strip of 0.5cm/sec.
Prior to treatment the permeability of the sample was 1.93 and the power loss was 1.148W/kg. After treatment the loss value was reduced by 9.1 % to a value of 1.043W/kg.
Other samples treated under similar conditions exhibited loss reduction values of 11.9 and 7.6% (Examples 5A, 5B and 5C in Table 1).
Example 6
An Epstein sample of Hi B type grain oriented silicon steel was scribed by the method described above using an electrode/strip gap of 1.1 4mm, a resistor of value 1 Mfl, a capacitor of value 25OOpF, and a traverse 30 rate of electrode across the strip of 1 Ocm/sec.
Prior to treatment the permeability of the sample was 1.96 and the power loss was 1.172W/kg. After treatment the loss value was reduced by 7.3% to a value of 1.086W/kg.
Another sample treated under similar conditions exhibited a loss reduction value of 8.9% (Example 6A in Table 1).
The following Examples 7 and 8 give data for higher and lower ablation energies than employed in Examples 1 - 6, as indicated by the values of electrode/strip gap, 0.42 and 2.2mm compared to 0.86 - 1.81 mm.
Example 7
An Epstein sample of Hi B type grain oriented silicon steel was scribed by the method described above 40 using an eleGtrodefstrip gap of 0.42mm, a resistor of value 1 MfII a capacitor of value 25OOpF, and a traverse rate of electrode across the strip of 2.5cm/sec.
Prior to treatment the permeability of the sample was 1.93 and the power loss was 1.190 W/kg. After treatment the loss value was reduced by 7.0% to a value of 1.1 34W/kg.
Example 8
An Epstein sample of Hi B type grain oriented silicon steel was scribed by the method described above using an electrode/strip gap of 2.2mm, a resistor of value 1 Mil, a capacitor of value 25OOpF, and a traverse rate of electrode across the strip of 2.5cm/sec.
Prior to treatment the permeability of the sample was 1.93 and the power loss was 1.320W/kg. After 50 treatment the loss value was reduced by 6.8% to a value of 1.230W/kg.
GB 2 146 567 A 5
Claims (11)
1. A method of treating grain orientated steel sheet or strip to refine domain spacing by subjecting the steel sheet or strip to electrical discharge to create a line of surface ablation and stress thereacross.
2. A method as claimed in claim 1 wherein the line of ablation is constituted by a succession of discharge 5 spots.
3. A method as claimed in claim 1 or 2 wherein a succession of spark discharges is created by a probe separated from the sheet or strip by between 1 and 3mm, having a voltage for each discharge applied thereto of the order of 3,000 to 10,000 volts.
4. A method as claimed in claim 3 wherein the probe is moved relatively across the sheet or strip to 10 produce a line of ablation spots.
5. A method as claimed in claim 4 wherein the probe is moved successively relatively across the sheet or strip to produce a succession of lines of ablation spots and thereby a domain spacing refining system throughout the sheet or strip.
6. A method as claimed in claim 1 wherein a continuous line of ablation is created.
7. A method as claimed in claim 6 wherein the electrical discharge is provided by a continuous arc discharge.
8. Apparatus for treating grain orientated steel or strip to refine the domain spacing comprising an electric discharge probe adapted to be located above the surface of a grain orientated sheet or strip and means for causing the probe to discharge so as to create a line of surface ablation and stress on the sheet or 20 strip.
9. Apparatus as claimed in claim 8 including a multiple array of probes arranged for simultaneous discharge actuation, the probes being spaced a predetermined distance apart and moved together across the sheet or strip.
10. A method of treating grain orientated steel sheet or strip substantially as hereinbefore described with reference to the accompanying drawing and in the accompanying examples.
11. Apparatus for treating grain orientated steel substantially as shown in and as hereinbefore described with reference to the accompanying drawings.
Printed in the UK for HMSO, D8818935, 2185, 7102.
Published by The Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB838324643A GB8324643D0 (en) | 1983-09-14 | 1983-09-14 | Production of grain orientated steel |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8423012D0 GB8423012D0 (en) | 1984-10-17 |
| GB2146567A true GB2146567A (en) | 1985-04-24 |
| GB2146567B GB2146567B (en) | 1987-09-09 |
Family
ID=10548790
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB838324643A Pending GB8324643D0 (en) | 1983-09-14 | 1983-09-14 | Production of grain orientated steel |
| GB08423012A Expired GB2146567B (en) | 1983-09-14 | 1984-09-12 | Production of grain orientated steel |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB838324643A Pending GB8324643D0 (en) | 1983-09-14 | 1983-09-14 | Production of grain orientated steel |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4652316A (en) |
| EP (1) | EP0137747B1 (en) |
| JP (1) | JPS6089523A (en) |
| DE (1) | DE3476897D1 (en) |
| GB (2) | GB8324643D0 (en) |
| NO (1) | NO163785C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0228157A2 (en) * | 1985-12-16 | 1987-07-08 | Allegheny Ludlum Corporation | Method and apparatus for scribing grain oriented silicon steel strip |
| CN109202192A (en) * | 2018-10-31 | 2019-01-15 | 清华大学 | Fine electric spark servo scanning machined parameters preferred method and system |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0772300B2 (en) * | 1985-10-24 | 1995-08-02 | 川崎製鉄株式会社 | Method for manufacturing low iron loss grain oriented silicon steel sheet |
| US4772338A (en) * | 1985-10-24 | 1988-09-20 | Kawasaki Steel Corporation | Process and apparatus for improvement of iron loss of electromagnetic steel sheet or amorphous material |
| JPS62151511A (en) * | 1985-12-26 | 1987-07-06 | Kawasaki Steel Corp | Method for decreasing iron loss of grain oriented silicon steel sheet |
| JPH0672264B2 (en) * | 1985-12-26 | 1994-09-14 | 川崎製鉄株式会社 | Method for manufacturing low iron loss grain-oriented silicon steel sheet |
| JPH0772301B2 (en) * | 1985-12-26 | 1995-08-02 | 川崎製鉄株式会社 | Iron loss reduction method for grain-oriented silicon steel sheet |
| JPH0672265B2 (en) * | 1985-12-26 | 1994-09-14 | 川崎製鉄株式会社 | Iron loss improvement method for grain-oriented silicon steel sheet |
| US4909864A (en) * | 1986-09-16 | 1990-03-20 | Kawasaki Steel Corp. | Method of producing extra-low iron loss grain oriented silicon steel sheets |
| US4931613A (en) * | 1987-05-08 | 1990-06-05 | Allegheny Ludlum Corporation | Electrical discharge scribing for improving core loss of grain-oriented silicon steel |
| US4780155A (en) * | 1987-05-08 | 1988-10-25 | Allegheny Ludlum Corporation | Capacitive electrical discharge scribing for improving core loss of grain-oriented silicon steel |
| US4767469A (en) * | 1987-05-08 | 1988-08-30 | Allegheny Ludlum Corporation | Electrical discharge scribing for improving core loss of grain-oriented silicon steel |
| GB2208871B (en) * | 1987-08-22 | 1991-03-27 | British Steel Plc | Processing grain-oriented "electrical" steel |
| US4915750A (en) * | 1988-03-03 | 1990-04-10 | Allegheny Ludlum Corporation | Method for providing heat resistant domain refinement of electrical steels to reduce core loss |
| GB8805296D0 (en) * | 1988-03-05 | 1988-04-07 | British Steel Corp | Processing grain-oriented electrical steel |
| US5123977A (en) * | 1989-07-19 | 1992-06-23 | Allegheny Ludlum Corporation | Method and apparatus for refining the domain structure of electrical steels by local hot deformation and product thereof |
| RU2405841C1 (en) * | 2009-08-03 | 2010-12-10 | Открытое акционерное общество "Новолипецкий металлургический комбинат" | Manufacturing method of plate anisotropic electric steel |
| DE102014102033B4 (en) * | 2014-02-18 | 2016-09-22 | Gottfried Wilhelm Leibniz Universität Hannover | Method for conductive heating of a sheet and heating device therefor |
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| GB1094394A (en) * | 1964-05-28 | 1967-12-13 | Ritzerfeld Gerhard | Electrostatic printing |
| GB1112259A (en) * | 1966-02-22 | 1968-05-01 | Agemaspark Holdings Ltd | Spark erosion machines |
| GB1206578A (en) * | 1968-06-15 | 1970-09-23 | Philips Electronic Associated | Improvements in or relating to spark erosion |
| GB1253115A (en) * | 1968-10-17 | 1971-11-10 | ||
| GB1476895A (en) * | 1974-04-25 | 1977-06-16 | Nippon Steel Corp | Method of producing grain oriented electromagnetic steel sheet |
| GB1548737A (en) * | 1975-11-27 | 1979-07-18 | Siemens Ag | Production of predetermined patterns in metal layers on electrically insulating foils |
| GB2104432A (en) * | 1981-07-17 | 1983-03-09 | Nippon Steel Corp | Method and apparatus for reducing the watt loss of a grain-oriented electromagnetic steel sheet and a grain-oriented electromagnetic steel sheet having a low watt loss |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB817408A (en) * | 1956-12-13 | 1959-07-29 | Sparcatron Ltd | Improvements in and relating to apparatus for the production of hardened surfaces |
| DE696739C (en) * | 1937-10-21 | 1940-09-27 | Metallgesellschaft Akt Ges | ical workpieces |
| CH381717A (en) * | 1957-01-12 | 1964-09-15 | Lihl Franz Prof Dr | Process for high hardening of non-austenitic steels |
| GB893233A (en) * | 1958-10-24 | 1962-04-04 | Ass Elect Ind | Improvements relating to the surface heating of metals |
| FR1265272A (en) * | 1960-05-18 | 1961-06-30 | Citroen Sa Andre | Apparatus for surface hardening of metals by sparks |
| US3281289A (en) * | 1964-07-31 | 1966-10-25 | Daniel I Gordon | Method of producing magnetic cores |
| SU652230A1 (en) * | 1977-10-04 | 1979-03-15 | Институт физики металлов УНЦ АН СССР | Method of thermal treatment of electrical engineering steel |
| JPS5518566A (en) * | 1978-07-26 | 1980-02-08 | Nippon Steel Corp | Improving method for iron loss characteristic of directional electrical steel sheet |
| JPS57188810A (en) * | 1981-05-18 | 1982-11-19 | Nippon Steel Corp | Improving method for magnetic characteristic of directional electromagnetic steel plate |
| JPS57198217A (en) * | 1981-05-27 | 1982-12-04 | Nippon Steel Corp | Magnetic characteristic improvidng method of directional electrical sheet |
| JPS58144424A (en) * | 1982-02-19 | 1983-08-27 | Kawasaki Steel Corp | Manufacture of directional electromagnetic steel sheet having low iron loss |
| US4554029A (en) * | 1982-11-08 | 1985-11-19 | Armco Inc. | Local heat treatment of electrical steel |
-
1983
- 1983-09-14 GB GB838324643A patent/GB8324643D0/en active Pending
-
1984
- 1984-08-31 US US06/645,834 patent/US4652316A/en not_active Expired - Lifetime
- 1984-09-12 GB GB08423012A patent/GB2146567B/en not_active Expired
- 1984-09-13 EP EP84306258A patent/EP0137747B1/en not_active Expired
- 1984-09-13 DE DE8484306258T patent/DE3476897D1/en not_active Expired
- 1984-09-13 NO NO843625A patent/NO163785C/en unknown
- 1984-09-13 JP JP59192441A patent/JPS6089523A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1094394A (en) * | 1964-05-28 | 1967-12-13 | Ritzerfeld Gerhard | Electrostatic printing |
| GB1112259A (en) * | 1966-02-22 | 1968-05-01 | Agemaspark Holdings Ltd | Spark erosion machines |
| GB1206578A (en) * | 1968-06-15 | 1970-09-23 | Philips Electronic Associated | Improvements in or relating to spark erosion |
| GB1253115A (en) * | 1968-10-17 | 1971-11-10 | ||
| GB1476895A (en) * | 1974-04-25 | 1977-06-16 | Nippon Steel Corp | Method of producing grain oriented electromagnetic steel sheet |
| GB1548737A (en) * | 1975-11-27 | 1979-07-18 | Siemens Ag | Production of predetermined patterns in metal layers on electrically insulating foils |
| GB2104432A (en) * | 1981-07-17 | 1983-03-09 | Nippon Steel Corp | Method and apparatus for reducing the watt loss of a grain-oriented electromagnetic steel sheet and a grain-oriented electromagnetic steel sheet having a low watt loss |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0228157A2 (en) * | 1985-12-16 | 1987-07-08 | Allegheny Ludlum Corporation | Method and apparatus for scribing grain oriented silicon steel strip |
| US4728083A (en) * | 1985-12-16 | 1988-03-01 | Allegheny Ludlum Corporation | Method and apparatus for scribing grain-oriented silicon steel strip |
| EP0228157A3 (en) * | 1985-12-16 | 1988-04-06 | Allegheny Ludlum Corporation | Method and apparatus for scribing grain oriented silicon steel strip |
| CN109202192A (en) * | 2018-10-31 | 2019-01-15 | 清华大学 | Fine electric spark servo scanning machined parameters preferred method and system |
| CN109202192B (en) * | 2018-10-31 | 2019-09-17 | 清华大学 | Fine electric spark servo scanning machined parameters preferred method and system |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0137747A3 (en) | 1985-09-25 |
| NO843625L (en) | 1985-03-15 |
| US4652316A (en) | 1987-03-24 |
| NO163785C (en) | 1990-07-18 |
| EP0137747B1 (en) | 1989-03-01 |
| JPS6089523A (en) | 1985-05-20 |
| NO163785B (en) | 1990-04-09 |
| GB8324643D0 (en) | 1983-10-19 |
| EP0137747A2 (en) | 1985-04-17 |
| GB2146567B (en) | 1987-09-09 |
| DE3476897D1 (en) | 1989-04-06 |
| GB8423012D0 (en) | 1984-10-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732 | Registration of transactions, instruments or events in the register (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19990912 |