US3678571A - Method for the production of sheets - Google Patents

Method for the production of sheets Download PDF

Info

Publication number
US3678571A
US3678571A US3678571DA US3678571A US 3678571 A US3678571 A US 3678571A US 3678571D A US3678571D A US 3678571DA US 3678571 A US3678571 A US 3678571A
Authority
US
United States
Prior art keywords
bar
slabs
temperature
steel
cast
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
Inventor
Rudolf Schoffmann
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.)
Voestalpine AG
Voest AG
Original Assignee
Voestalpine AG
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
Priority to AT444569A priority Critical patent/AT293315B/en
Application filed by Voestalpine AG filed Critical Voestalpine AG
Application granted granted Critical
Publication of US3678571A publication Critical patent/US3678571A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21BROLLING OF METAL
    • B21B1/00Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/46Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226Hot rolling
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/021Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular fabrication or treatment of ingot or slab
    • YGENERAL 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
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00Metal working
    • Y10T29/49Method of mechanical manufacture
    • Y10T29/49972Method of mechanical manufacture with separating, localizing, or eliminating of as-cast defects from a metal casting [e.g., anti-pipe]
    • YGENERAL 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
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00Metal working
    • Y10T29/49Method of mechanical manufacture
    • Y10T29/4998Combined manufacture including applying or shaping of fluent material
    • Y10T29/49988Metal casting
    • Y10T29/49989Followed by cutting or removing material
    • YGENERAL 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
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00Metal working
    • Y10T29/49Method of mechanical manufacture
    • Y10T29/4998Combined manufacture including applying or shaping of fluent material
    • Y10T29/49988Metal casting
    • Y10T29/49991Combined with rolling

Abstract

The disclosure proposes a method for the production of sheets from the slabs cut from a bar of unkilled steel cast by the continuous casting method, wherein the cast bar, after it has solidified completely and as soon as its cross section has an equalized temperature in the range of 900* to 1,200* C., preferably 1,000* to 1,100* C., is shaped in one step so as to reduce its cross section by about 10 to 20 percent, whereupon it is shorn to length, and the slabs are then heated to rolling temperature and shaped in a plurality of passes. Owing to this method the bubble wreath which is characteristic for unkilled steel slabs is eliminated so that the heat transition from the surface to the core is improved.

Description

United States Patent Schoffmann [451 July 25, 1972 54] METHOD FOR THE PRODUCTION OF 3,491,823 1/1970 Tarmann et al ..l64/76 SHEETS [72] lnventor: Rudolf Schoffmann, Linz, Austria OTHER PUBLICATIONS 1 Assignee: Vminigte oster-reichische Eisen-und The Making Shaping and Treating of Steel, 1964. p. 550.
Stahlwerke Aktiengesellschaft, Linz, Ausi Primary E.taminer-J. Spencer Overholser [22] Filed: April 27 1970 Assistant Examiner-John E. Roethel Atmrne v-Brumbaugh. Graves, Donohue & Raymond [2]] Appl. No.: 32,230
57] ABSTRACT [30] Foreign Applicafim Prim'ity Data The disclosure proposes a method for the production of sheets May 9, 1969 Austria; ..A 4445/69 l the 81-395 cm mm a bar Steel by tinuous casting method, wherein the cast bar, after it has solidified completely and as soon as its cross section has an [52] U.S. Cl ..29/527.6,29/527.7, 148/2, equalized temperature in the range of 9000 to 12000 C. 148/12, 164/76 preferably 1,000 to l,l00 C., is shaped in one step so as to 5 l Int. Cl ..B23p 25/00 reduce its cross section by about 10 to 20 percent, whereupon Fleld 0t search-w it is shorn to length, and the slabs are then heated to rolling 164/76; 148/2, 12 temperature and shaped in a plurality of passes. Owing to this method the bubble wreath which is characteristic for unkilled [56] References Cited steel slabs is eliminated so that the heat transition from the i surface to the core is improved.
UNITED STATES PATENTS 4 Claims, 1 Drawing Figure 3,317.994 5/1967 Coferetal ..l64/76 PATENTEUJUL2SI9I2 3.678.571
INVENTOR. RUDOLF SCHOFFMANN ATTORNEYS METHOD FOR THE PRODUCTION OF SHEETS The invention relates to a method for the production of sheets from slabs cut from a cast bar of unkilled steel which was cast by the continuous casting method.
There are various problems when sheets are produced from unkilled steel slabs. At first a steel has to be produced whosei oxygen content and temperature are closely adapted to the chemical composition. Furthermore, the cross section of the bar, particularly the thickness of the bar, the casting speed and the cooling conditions in the continuous casting plant are important factors which have an influence upon the quality of the product.
When unkilled steel slabs are to be processed to sheets in a train of rolls they have to be subjected to a preliminary treatment. Their surface has to be examined and surface defects, have to be removed. When the slabs are completely cooled,l they are heated to rolling temperature in continuous type furnaces before they are rolled out to sheets in a plurality of passes. When the slabs are heated to rolling temperature the: wreath of bubbles which is characteristic for unkilled steel; slabs provides great difficulties because it impairs the heat transition from the surface of the slabs into the core of the slabs when they are heated up in gas or oil heated furnaces. As i a result, the surface is overheated and heavy scaling occurs,
whereas the core is not sufficiently heated. This again makes for qualitative and technological disadvantages in the rollingof slabs. The heavy scaling and overheating of the surface may lead to a connection between the bubble wreath and the atmosphere which exerts an oxidizing effect so that welding of the gas bubble hollow spaces is rendered difficult or impossi-j ble; only waste products will be obtained when such a starting material is used.
ln order to avoid the difficulties which arise when heating unkilled steel slabs because of the presence of a bubble wreath it has already been proposed to heat the slabs to rolling temperature in electrical induction furnaces instead of in gas or oil heated furnaces. When electrical induction is used, the slabs are heated more evenly over their entire cross section, i.e. the insulating effect of the bubble wreath does not make itself noticeable in such a disadvantageous manner with this kind of heating, and qualitative flaws which are unavoidable in gas or oil heated furnaces i.e. from the surface occur to a lesser degree. However, the prime costs and the operation costs are rather high for induction furnaces, so that for economical reasons it is rather improbable that induction heating for slabs will be generally used.
The thickness of unkilled steel slabs usually amounts to 250 to 300 mm; the slabs are about l,250 mm broad and up to 12 m long. Thus the cross sections and the piece weights are considerable. Attempts are being made to find a solution for the economical and qualitative problems in the rolling of unkilled steel slabs but up to now the heating problem which presents itself owing to the presence of the bubble wreath has remained unsolved.
The invention is aimed at avoiding the described disadvantages and difficulties and, in a method for the production of sheets from slabs cut from a cast bar of unkilled steel which was cast by the continuous casting method, wherein the slabs are heated to rolling temperature and shaped in a plurality of passes, resides in that the cast bar, prior to being shorn to length, is shaped in one step after complete solidification and' HS soon as the solidified bar has over its entire cross section a uniform temperature in the range of 900 to l,200 C., preferably l,000 to l,l C.
Suitably, the temperature is equalized over the entire cross section of the bar by arranging behind the secondary cooling zone a non-cooled or heated equalization zone, respectively, through which the bar is passed prior to being shaped in one step.
Shaping according to the invention is effected to a degree which about corresponds to the volume of the hollow spaces of the bubbles in the bar so that the material is densified. The cross section of the bar is reduced in the one step haping process by about "to to 20 percent without any noticeable cogging down. Instead, re-shaping is effected.
The attached drawing shows the cross section of a bar of unkilled steel before being shaped according to the invention. The macroscopic structure of a slab is schematically shown. In the bar cross section three zones may clearly be distinguished, namely zone 1 which is free from bubbles, which zone is also called bacon layer," or skin the marginal bubble zone 2 proper, and the core zone 3 of the bar cross section. The thickness of the marginal layer 1 which is free from bubbles in unkilled steel slabs depends on the withdrawal speed and the intensity of gas evolution and motion (boiling) of the metal in the casting mould and in general does not amount to less than 10 mm.
When the slabs are heated to rolling temperature, it is essential to keep the dense zone 1 as intact as possible so as to prevent oxidizing gases from entering into the marginal bubbles. When this condition is fulfilled, the marginal bubbles bond completely during rolling.
As has been mentioned, according to the invention the marginal bubbles are pressed together already when the bar is slightly shaped after its solidification so that they are welded together and a densification of the bar in the area of the marginal bubble zone 2 is effected so that the heat insulating bubble wreath is removed. A bar of unkilled steel which has been densified according to this method may be heated to rolling temperature in gas or oil heated furnaces exactly as a bar of killed steel.
The expenses for a roll stand in connection with a continuous casting plant are small. For the one step reshaping process the latent heat of the bar is used; the rolling pressure is rela tively small because a small energy will suffice for pressing the hollow spaces of the bubbles together. Owing to the fact that the bubble wreath may relatively easily be removed the remaining zones of the bar cross section are hardly shaped at all. Prior to carrying out the method :it is only necessary to determine the bubble volume which depends on the steel quality and the bar cross section, but otherwise remains within narrow limits. Thus this examination will have to be carried out only once and then the reduction of the cross section may .be settled for the densification according to the invention of the material.
The aim of the invention, i.e. an improvement of the quality of the slabs with regard to their heat technological properties so that an essentially improved heat transition is achieved, will also be obtained when not all bubbles are welded together completely. The heating process is hardly impaired by individual bubbles which may be present still after shaping. Thus the method according to the invention. does not require high accuracy in the determination of the bubble hollow spaces, which fact simplifies its application in practice.
What 1 claim is 1. A method for the production of a steel product comprismg,
continuously casting a steel bar,
solidifying the cast bar,
equalizing the temperature of the cast bar over its entire cross-section to a temperature in the range of 900-] ,200 C., reducing the cross-sectional area of the cast bar by 10 to 20 percent by means of a one-step shaping operation, shearing the bar to form individual slabs, heating the slabs to rolling temperature, and shaping and working the slabs to produce the steel product.
2. The method as defined by claim 1 wherein the cast bar is solidified by passing it through a cooling zone and the bar temperature is equalized by passing it through a non-cooled zone.
3. The method as defined by claim ll wherein the bar temperature is equalized by passing it through a heated zone.
4. The method as defined by claim 1. wherein the temperature of the bar is equalized to approximately 1,000 to 1,100 C.
1 i i i l

Claims (4)

1. A method for the production of a steel product comprising, continuously casting a steel bar, solidifying the cast bar, equalizing the temperature of the cast bar over its entire cross-section to a temperature in the range of 900*-1,200* C., reducing the cross-sectional area of the cast bar by 10 to 20 percent by means of a one-step shaping operation, shearing the bar to form individual slabs, heating the slabs to rolling temperature, and shaping and working the slabs to produce the steel product.
2. The method as defined by claim 1 wherein the cast bar is solidified by passing it through a cooling zone and the bar temperature is equalized by passing it through a non-cooled zone.
3. The method as defined by claim 1 wherein the bar temperature is equalized by passing it through a heated zone.
4. The method as defined by claim 1 wherein the temperature of the bar is equalized to approximately 1,000* to 1,100* C.
US3678571D 1969-05-09 1970-04-27 Method for the production of sheets Expired - Lifetime US3678571A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT444569A AT293315B (en) 1969-05-09 1969-05-09 Process for processing an unquenched cast steel strand

Publications (1)

Publication Number Publication Date
US3678571A true US3678571A (en) 1972-07-25

Family

ID=3564105

Family Applications (1)

Application Number Title Priority Date Filing Date
US3678571D Expired - Lifetime US3678571A (en) 1969-05-09 1970-04-27 Method for the production of sheets

Country Status (13)

Country Link
US (1) US3678571A (en)
JP (1) JPS4820691B1 (en)
AT (1) AT293315B (en)
BE (1) BE750120A (en)
CA (1) CA939174A (en)
CH (1) CH504257A (en)
CS (1) CS152474B2 (en)
DE (1) DE2019699B2 (en)
ES (1) ES379081A1 (en)
FR (1) FR2046436A5 (en)
GB (1) GB1306135A (en)
SE (1) SE364197B (en)
SU (1) SU361543A3 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4204884A (en) * 1978-08-11 1980-05-27 Ingersoll Steel Company Method of conditioning cast steel for hot working
US4256516A (en) * 1978-12-26 1981-03-17 Nippon Kokan Kabushiki Kaisha Method of manufacturing non-magnetic Fe-Mn steels having low thermal expansion coefficients and high yield points
US4422884A (en) * 1977-10-20 1983-12-27 Concast Ag Method of treating a continuously cast strand formed of stainless steel

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2545935C2 (en) * 1975-10-14 1984-04-26 Mannesmann Ag, 4000 Duesseldorf, De
DE2851875C2 (en) * 1978-11-30 1983-11-10 Heinz Wilhelm 8000 Muenchen De Becker
JPS6233009B2 (en) * 1981-07-24 1987-07-17 Nippon Steel Corp
TW297788B (en) * 1994-12-15 1997-02-11 Sumitomo Metal Ind

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3317994A (en) * 1964-08-19 1967-05-09 Southwire Co Method of conditioning metal for hot forming
US3491823A (en) * 1966-04-22 1970-01-27 Boehler & Co Ag Geb Process for the manufacture of continuous castings

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3317994A (en) * 1964-08-19 1967-05-09 Southwire Co Method of conditioning metal for hot forming
US3491823A (en) * 1966-04-22 1970-01-27 Boehler & Co Ag Geb Process for the manufacture of continuous castings

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
The Making, Shaping and Treating of Steel, 1964, p. 550. *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4422884A (en) * 1977-10-20 1983-12-27 Concast Ag Method of treating a continuously cast strand formed of stainless steel
US4204884A (en) * 1978-08-11 1980-05-27 Ingersoll Steel Company Method of conditioning cast steel for hot working
US4256516A (en) * 1978-12-26 1981-03-17 Nippon Kokan Kabushiki Kaisha Method of manufacturing non-magnetic Fe-Mn steels having low thermal expansion coefficients and high yield points

Also Published As

Publication number Publication date
SE364197B (en) 1974-02-18
DE2019699B2 (en) 1975-09-04
CS152474B2 (en) 1973-12-19
DE2019699A1 (en) 1970-11-19
CH504257A (en) 1971-03-15
SU361543A3 (en) 1972-12-07
CA939174A1 (en)
FR2046436A5 (en) 1971-03-05
BE750120A1 (en)
JPS4820691B1 (en) 1973-06-22
GB1306135A (en) 1973-02-07
CA939174A (en) 1974-01-01
AT293315B (en) 1971-10-11
BE750120A (en) 1970-10-16
ES379081A1 (en) 1972-09-01

Similar Documents

Publication Publication Date Title
JP2738934B2 (en) Method and apparatus for manufacturing steel strip
KR101204479B1 (en) Process and plant for manufacturing steel plates without interruption
US3678571A (en) Method for the production of sheets
US3491823A (en) Process for the manufacture of continuous castings
US3680623A (en) Improvements in or relating to processes of manufacturing rolled stock from products of continuous casting processes
US4962808A (en) Method of producing a steel strip having a thickness of less than 10 mm
US7025118B2 (en) Method and device for continuously casting ingots, slabs or thin slabs
US3710436A (en) Method for the production of plates
CA2228445C (en) Method and device for operating a continuous casting plant
US3589429A (en) Method for continuous casting, cooling and shaping of metal bars
JPH06106205A (en) Method of producing roll material consisting of oxygen-free copper
US4709572A (en) Method of processing continuously cast slabs
JP2004237291A (en) Method of manufacturing continuous casting slab and steel material obtained by working the cast slab
US3650314A (en) Apparatus for manufacturing stretch-formed products of high-melting metals
JP2004074233A (en) Method for reducing center segregation in continuously cast slab
GB1318703A (en) Continuous casting plant for slabs
RU1839682C (en) Method of manufacture of metal band
US3743005A (en) Process for producing hot rolled three layer steel products from continuously cast hollow tubes
JP3218361B2 (en) Continuous casting of steel and continuous casting and rolling
JP2001191158A (en) Continuous casting method of steel
CA1110822A (en) Continuous casting
JPH11221651A (en) Method for making forged product subjected to coating and apparatus therefor
GB1174849A (en) A Method of Producing Continuous Steel Castings
FI88591C (en) Foerfarande Foer framstaellning av ett staolband med en tjocklek under 10 mm
JPH07276020A (en) Continuous casting method