US1932307A - Silicon steel and method of making the same - Google Patents

Silicon steel and method of making the same Download PDF

Info

Publication number
US1932307A
US1932307A US632917A US63291732A US1932307A US 1932307 A US1932307 A US 1932307A US 632917 A US632917 A US 632917A US 63291732 A US63291732 A US 63291732A US 1932307 A US1932307 A US 1932307A
Authority
US
United States
Prior art keywords
rolling
strain
silicon
furnace
steel
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
US632917A
Other languages
English (en)
Inventor
Edward M Freeland
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Priority to US632917A priority Critical patent/US1932307A/en
Priority to FR761955D priority patent/FR761955A/fr
Priority to BE398582D priority patent/BE398582A/xx
Application granted granted Critical
Publication of US1932307A publication Critical patent/US1932307A/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
    • 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
    • C21D8/1244—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest
    • C21D8/1261—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties the heat treatment(s) being of interest following hot rolling
    • 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
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/30—Foil or other thin sheet-metal making or treating
    • Y10T29/301—Method

Definitions

  • the present invention relates broadly to the art of metal working, -and more particularly to that branch of the art having to do with the subjecting of a predetermined composition or alloy to a treatment of such nature that the electrical properties thereof are materially modified, thereby enabling the production of an improved article having such properties as to better adapt it to electrical uses.
  • the treatment include as one of the steps thereof a heat-treating operation under such conditions as to insure a film of oxidized metal on the surface of the steels.
  • a film where closely adhering and of relatively minute thickness, provided an insulating layer between adjacent laminae in such manner that the disadvantages, such as objectionable heating, which usually characterize lamin free of any insulation, or a solid core, are obviated.
  • the electrical properties are improved as the silicon content is increased.
  • the electrical properties may be improved by certain characteristic treatment steps preferably in a certain order.
  • the invention preferably contemplates the production of electrical steels from material which at least at some time during the treatment to which it is subjected has been in the form of a hot rolled strip.
  • the only known method of reducing a hot rolled strip to certain of the gauges required for electrical steels has been by cold rolling, and it has been a commonly accepted belief that the excessive strain incident to the cold rolling operation would preclude the use of such a material from the electrical field.
  • My invention not only provides a method of treatment wherein the objections incident to such excessive strain may be completely obviated, but whereby the material when delivered in the form of a one-piece strip wound in successive convolutions to provide a coil to facilitate handling and transportation thereof, may be substantially free from coil set. Elimination of coil set, from a coiled strip of electrical steel which, in itself, constitutes a new article of manufacture, enables lamin to be cut from the metal of the coil and assembled without introducing strain in the lamin by the attening operation usually incident to the assembly of the laminas.,
  • the production of the hot rolled strip which is used in the present invention may be effected by suitable hot rolling in a succession of passes to a desired gauge while always rolling the metal in the direction only in which the ingot was rolled.
  • Such a succession of passes may obviously be obtained by repeatedly subjecting. the metal to rolling operations in the same mill, or to repeated rolling operations in a succession of mill stands such as afforded by a continuous or tandem mill. While the last mentioned procedure is desirable from the standpoint of production and the comparatively few handling operations involved, it will be apparent to those skilled in the art that my invention is not limited to the constructional or operating characteristics of the mills, or the number of stands utilized in perfecting the production of the hot rolled strip.
  • the last hot rolling operation be accomplished at a temperature which bears a definite and predetermined relationship to the recalescence point of the particular material undergoing treatment. If the material, during the last hot rolling pass, is at a temperature higher than the recalescence temperature, the finished material, with a given silicon content, will be characterized by an absence of re-crystallization and by certain electrical properties. If the last rolling operation in the hot mill is accomplished atsubstantially the recalescence temperature, the material while characterized likewise by the absence of recrystallization will have-generally superior electrical properties to the product before referred to. In like manner, final rolling at a temperature slightly below the recalescence temperature will further improve the electrical properties.
  • the grain growth is not a determining factor in the electrical characteristics. If the-last hot rolling step is -accomplished at a temperature suilclently below the recalescence point to cause re-crystallization upon subsequent heat treatment, the resulting product will have electrical properties which are generally inferior to-the corresponding properties characteristic of material wherein the last hot rolling was at a temperature above, equal toor but slightly below the recalescence point.
  • a material rolled with the last pass appreciably below the recalescence point may have electrical ⁇ properties superior to metal of a lower silicon content rolled at slightly below or above the recalescence point.
  • Figures l to l5, inclusive are diagrammatic views illustrating different characteristic operations both as to sequence and type, each operation, however, being characterized by a rolling of the material throughout in the direction only in which the material is reduced from the ingot in the blooming mill.
  • I have used descriptive legends for the purpose of facilitating a reading and understanding of the operations diagrammatically illustrated.
  • a suitable silicon steel ingot having the desired silicon content is subjected to the usual back and forth roughy rolling in the blooming mill 2 for reducing it to a billet 3.
  • This billet in turn may be subjected to suitable hot rolling in a succession of passes in a hot mill herein illustrated as comprising four roll stands l effective for producing a hot rolled strip 5.
  • This hot rolled strip may be subjected to a suitable pickling operation in a pickling bath 6, effective for producing a pickled hot rolled strip 7.
  • This hot rolled strip may then be heated in any suitable furnace 8 up to a temperature bearing a predetermined relationship to the recalescence temperature of the metal and previously determined upon by reason of the silicon content and the grade of steel to be produced.
  • the product may be sold directly, or it may be reheated and allowed to cool in the at to remove coil set.
  • normalizing the product may be' immediately coiled, or it may .be allowed to cool in the flat before coiling, in
  • box anneal or normalized product so produced may be subjected to a suitable leveling operation, as by a roller leveller, then sheared and either box annealed or normalized.
  • the roll stands 4 may be considered as only effective for rolling to an intermediate gauge, and the stand 9 effective for' producing the finished gauge.
  • FIG 2 there is illustrated a slightly modified embodiment of the invention wherein parts corresponding to the parts shown in Figure 1 are designated by the same reference characters having the suffix a added thereto.
  • the pickled hot rolled strip 7a is sheared by a suitable shear 14 to provide a plurality of pieces of sheared hot roll strip 15. These individual pieces 15 may then be raised to the predetermined temperature in the heating furnace 8a, hot rolled at that temperature in the roll stand 9a to provide sheets 16, which are then box annealed or normalized in a suitable furnace or box 17. If desired, there may be both an anneal and normalizing.
  • sheets after having been box annealed or normalized in theifurnace or box 17h are subjected to a cold rolling operation in a rollstand 21, preferably so adjusted as to introduce a strain in the sheets corresponding to that represented by an elongation of somewhere in the range of from approximately 1 to 5%.
  • a strain introduction a strain introduced and subsequently removed therefrom.
  • FIG 4 there is illustrated another embodiment of my invention in which parts corresponding to the parts illustrated in Figure l are designated by the same reference characters having the suflix c added thereto.
  • the coiled strip after having been subjected to a box annealing or normalizing 12o is given a cold rolling treatment in one or more cold rolling stands 21o, corresponding in function to the stand 21 of Figure 3, but effective for producing a strip 24 having va desirable strain component of the character indicated therein.
  • This strip may then be coiled in a suitable coiler 25 after which it may be placed in an annealing box 26 and subjected to an annealing temperature of the order indicated for effecting substantially complete strain removal, or may be normalized for this purpose. In either case, coil set may be eliminated as referred to in connection with Figure l.
  • Figure 6 shows an embodiment generally similar to Figure 5 with the parts desfgnated by the same refere e characters as those used in Figure 1, but with the suix e added thereto.
  • a strip coiled in the coiler 11e is passed through either a normalizing or an annealing furnace. 29 and either normalized or annealed, and thereafter passed through an annealing or normaliz'ng furnace 30, wherein the operation which was not performed in the furnace 29 is carried out. Thereafter, the material in strip form which has been subjected to both an annealing and normalizing operation is coiled in a suitable coiler 28e. ⁇ Suitable shearing and heat treating may follow the unit 20, or the treatment may be as before described, to remove or prevent coil set.
  • the annealed coil may be relili? heated and then cooled in the flat before coiling.
  • Figure 8 The lay-out of Figure 8 is similar to that of Figure 7, and the same system of reference numerals has been followed with the suffix changed.
  • the material after having been subjected to strain introduction in the cold rolling stand 21g and either before or after having been coiled in a suitable coiler 31g is subjected to normalizing in a furnace 30g. Upon leaving the furnace it is carried an appreciable distance in fiat form, and permitted to cool in this form so as to remove coil set, after which it is coiled in a suitable coiler 32g.
  • the strain introduction involves only a very small reduction in thickness, and while relied upon to give some reduction, is yprimarily for the purpose of introducing a desirable strain component of the order referred to.
  • the hot rolling operat'on and particularly where carried out in a continuous mill is customarily relied upon for producing a hot rolled strip substantially free from any cold Working strains, having a thickness of approximately .0625 inch, corresponding to 16 gauge, and having any desired width.
  • Electrical sheets customarily have a thickness lying within and including 22to 30 gauge (United States standard).
  • This material in strip form can most effectively be reduced by cold rolling in a continuous mill, but such a continuous mill has heretofore been considered impracticable for the production of electrical steels by reason of the excessive strain introducedinto the metal thereby, the cold rolling effecting a very appreciable reduction. If this reduction is from .0625 inch to 024 inch, there is a ,reduction of .0385 inch, equal to approximately 61%.
  • These figures are representative of thicknesses frequently produced in the cold rolling of steel for purposes other than the production of electrical steels. While such a cold rolling operation is effective for reducing the hot rolled strip to the desired nished gauge, the strain introduced by reason of the reduction effected is far in excess of the strain heretofore though permissible in the production of electrical steels.
  • material for example, after having been normalized or annealed at 27h and after being coiled in a suitable coiler 28h, is passed to a continuous cold mill 33 comprising a plurality of 4stands in tandem effective for giving the desired reduction in thickness.
  • a continuous cold mill 33 comprising a plurality of 4stands in tandem effective for giving the desired reduction in thickness.
  • the excessive strain referred to is introduced.
  • This material may then be coiled in a coiler 34 and subjected to a partial annealing in a suitable furnace 35 after which it may or may not be coiled in a suitable coiler 36 and then subjected to a normalizing operation in a furnace 37, after which it may be coiled for shipment in a suitable coiler 38.
  • it after leaving the coiler 34, it may be partially normalized in the furnace 35 and then, after coiling in the coiler.
  • the undesirable strain component wiil vary with changes in the reduction effected lby the cold rolling operation, the strain increasing with increased reductions, and decreasing with smaller reductions. While the actual strain introduced under varyes'I ing reductions is not a straight line function,
  • the undesirable strain component increases in amount as the silicon content of the material undergoing treatment increases, with any given percentage of reduction by the cold mill. 4
  • the total timetemperature treatment for effecting removal of the undesirable strain component varies directly as the thickness of the material undergoing treatment, assuming a predetermined silicon content and a predetermined reduction.
  • This treatment may be considered as involving the two factors of time and temperature. If it is desired to decrease the time of treatment, it is necessary to increase the temperature, while if it is desired to increase the time, there should be a corresponding reduction in temperature.
  • the furnace 35 may be used for partial strain removal only, with definite assurance that a desirable strain will be retained in the material.
  • Figure 10 illustrates an operation generally similar to that of Figure 9, but differing in that the material coiled in the'coiler 381 is heated in a suitable furnace 39 and then cooled in the flat to remove coil set before being subsequently coiled in the coiler 321.
  • the material after having been cold rolled in the continuous mill 331 and after having been coiled in the collar 34j may be either annealed or normalized in a furnace 40. Thereafter it may be coiled in a coiler 41, passed through a cold rolling stand 21j effective for introducing a desirable strain component only, thereafterrecoiled in a coiler 42 with subsequent annealing or normalizing in a furnace 375 followed by coiling in a collar 383.
  • the heat treating furnace 40 is effective for completely removing all of the strain introduced by cold rolling, and that thereafter, only a desirable strain component is introduced.
  • Figure 12 shows a lay-out generally similar to that of Figure 9, but differing principally in that the material,.usually after having been coiled in a coiler 36k, is passed through anormalizing furnace 43 and thereafter cooled in the fiat to remove coil set and then coiled in a suitable coiler 32k.
  • a roller leveler 44 may pass through a roller leveler 44 to a suitable shear 14m effective for producing sheets 45 which may thereafter be box annealed in an annealing box 19m.
  • Figure 15 the operation of Figure 9 is followed up to the coiling in the coiler 341 after which the material may pass through a roller leveler 44 to a shear 14n eiective for forming sheets 45n which may be partially annealed in a box 46 to remove only the undesirable strain component and thereafter again anneal in a suitable box anneal 47 to complete the strain removal.
  • an annealing or normalizing step may be introduced following the hot rolling to intermediate gauge and prior to any subsequent rolling.
  • the pickling step illustrated may be varied as to its time of performance, as desired, its function being only to eiect removal of scale or oxide.
  • shearing step may be practiced without roller leveling, if desired, although I have found the leveling operation to be generally more satisfactory.
  • the material is annealed in coils, -it may be reheated and cooled in the fiat to remove coil set, and wherever it is normalized in strip form, it may be cooled in the flat before being recoiled, in order that coil set may be eliminated.
  • Another feature of my invention relates to the accomplishing of the last hot rolling pass in definite predetermined relationship to the recalescence point ofthe metal for reasons pointed out in detail.
  • My invention further contemplates taking advantage of the variable factors hereinbefore referred to and using them either individually or combined to produce superior electrical properties.
  • these variables it is possible to meet guarantees as shown below in the table containing seven different grades of electrical steels, each with an identifying title, together with' the Watt loss per pound at frequencies of both 50 and 60 cycles at the assumed specific gravities indicated, the maximum watt losses in the case of some of the grades being shown for a plurality of different gauges, these ranges covering the gauges ordinarily manufactured.
  • the Wattloss is figured at a ux density of 10,000-B and determined in Laccordance with the specification A-34-28 of the American Society for Testing Materials. ⁇
  • My invention further contemplates the production of superior electrical steel in either sheet or coil form, and in the case of coil strip either with or without the coil set removed therefrom.
  • the steps consisting in casting a steel ingot of the desired silicon content andhot rolling the ingot to reduce it, all the hot rolling passes in which any substantial reduction is effected being in the direction in which the ingot was rolled, thereby to improve the electrical properties ofthe material.
  • the steps consisting in casting a steel ingot of the desired silicon content and hot rolling the ingot to reduce it, all the hot rolling passes in which any substantial reduction is effected being in the direction in which the meot was rolled, thereby to improve the electrical properties of the material, and further controlling the electrical properties of the steel by varying the temperature at whichthe last hot rolling is effected.
  • the steps consisting in casting a steel ingot of the desired silicon content, hot rolling the ingot to reduce it, all the hot rolling passes in which any substantial reduction is ef- MG fected being in the direction in which the ingot was rolled, thereby to improve the electrical properties of the material, raising the temperature of the material sumciently to eect elimination of part but not all of the strains therein, allowing the material to cool, and then annealing it.
  • the steps consisting in 'casting a. steel ingot of the desired silicon content, hot roll- 150 ing the ingot to reduce it, all the hot rolling passes in which any substantial reduction is eiected being in the direction in which the ingot was rolled, thereby t'o improve the electrical properties of the material, then raising the temperature of the material sufliciently to effect substantial elimination of the strains therein, then so working the material as to introduce strain therein, and then annealing it to remove such strain.
  • the steps consisting in castinga steel ingot of the desired silicon content, hot rolling the ingot to reduce it, all the hot rolling passes in which any substantial reduction is effected being in the direction in which the ingot was rolled, thereby to improve the electrical properties of the material, then raising the temperature of the material sufficiently to effect substantial elimination of the strains therein, cold rolling the material, and then annealing it.
  • the steps consisting in casting a steel ingot of lthe desired silicon content and reducing the ingot to sheet-like form by hot rolling passes and subsequent cold rolling passes, all of the rolling passes in ⁇ which any substantial reduction' is effected being in the direction in which the ingot was rolled, thereby to improve the electrical properties of the material.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Manufacturing & Machinery (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing Of Steel Electrode Plates (AREA)
US632917A 1932-09-13 1932-09-13 Silicon steel and method of making the same Expired - Lifetime US1932307A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US632917A US1932307A (en) 1932-09-13 1932-09-13 Silicon steel and method of making the same
FR761955D FR761955A (fr) 1932-09-13 1933-09-12 Perfectionnements relatifs aux aciers au silicium et aux procédés de fabrication desdits aciers
BE398582D BE398582A (enrdf_load_html_response) 1932-09-13 1933-09-13

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US632917A US1932307A (en) 1932-09-13 1932-09-13 Silicon steel and method of making the same

Publications (1)

Publication Number Publication Date
US1932307A true US1932307A (en) 1933-10-24

Family

ID=24537510

Family Applications (1)

Application Number Title Priority Date Filing Date
US632917A Expired - Lifetime US1932307A (en) 1932-09-13 1932-09-13 Silicon steel and method of making the same

Country Status (3)

Country Link
US (1) US1932307A (enrdf_load_html_response)
BE (1) BE398582A (enrdf_load_html_response)
FR (1) FR761955A (enrdf_load_html_response)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2585277A (en) * 1946-06-27 1952-02-12 Drever Co Apparatus for annealing strip
US3099176A (en) * 1957-11-06 1963-07-30 Westinghouse Electric Corp Rolling silicon-iron

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2585277A (en) * 1946-06-27 1952-02-12 Drever Co Apparatus for annealing strip
US3099176A (en) * 1957-11-06 1963-07-30 Westinghouse Electric Corp Rolling silicon-iron

Also Published As

Publication number Publication date
BE398582A (enrdf_load_html_response) 1933-10-31
FR761955A (fr) 1934-03-31

Similar Documents

Publication Publication Date Title
US3770517A (en) Method of producing substantially non-oriented silicon steel strip by three-stage cold rolling
US2867557A (en) Method of producing silicon steel strip
EP0684320B1 (en) Process of making electrical steels
US3415696A (en) Process of producing silicon steel laminations having a very large grain size after final anneal
US2113537A (en) Method of rolling and treating silicon steel
US1932307A (en) Silicon steel and method of making the same
US6217673B1 (en) Process of making electrical steels
US2088440A (en) Magnetic sheet steel and process for making the same
US4291558A (en) Process of rolling iron-silicon strip material
JPH06220537A (ja) 無方向性電磁鋼板の製造方法
US2602034A (en) Method of making enameling sheets
US1867818A (en) Method of treating silicon steel sheets
US2666722A (en) Metal treatment
DE68921478T2 (de) Verfahren zur herstellung nicht-orientierter elektrobleche mit ausgezeichneten magnetischen eigenschaften.
US6068708A (en) Process of making electrical steels having good cleanliness and magnetic properties
US2305615A (en) Sheet metal and method of manufacture
US2042124A (en) Electric sheet
US1992039A (en) Method of producing high silicon steel articles
US2084336A (en) Magnetic material and method of manufacture
DE1433733A1 (de) Verfahren zur Herstellung eines kornorientierten Siliziumeisenblech-Stahls durch Warmwalzen
US3874954A (en) Method of preparing iron silicon alloys with high silicon content for cold working requiring ductility
US2358788A (en) Production of silicon steel of uniformly low core loss
JP7276502B2 (ja) 方向性電磁鋼板の製造方法及び設備列
JPS5830936B2 (ja) 繰返し曲げ特性の優れた方向性珪素鋼板の製造方法
US3130091A (en) Non-oriented silicon-iron sheet stock and process of making it