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EP0347512A1 - A bimetal construction roll for reducing and finishing stands in a rolling mill train - Google Patents

A bimetal construction roll for reducing and finishing stands in a rolling mill train Download PDF

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Publication number
EP0347512A1
EP0347512A1 EP88830267A EP88830267A EP0347512A1 EP 0347512 A1 EP0347512 A1 EP 0347512A1 EP 88830267 A EP88830267 A EP 88830267A EP 88830267 A EP88830267 A EP 88830267A EP 0347512 A1 EP0347512 A1 EP 0347512A1
Authority
EP
European Patent Office
Prior art keywords
alloy
construction roll
bimetal construction
niobium
titanium
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.)
Withdrawn
Application number
EP88830267A
Other languages
German (de)
French (fr)
Inventor
Ferruccio Camplani
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.)
INNSE CILINDRI Srl
Original Assignee
INNSE CILINDRI Srl
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 INNSE CILINDRI Srl filed Critical INNSE CILINDRI Srl
Priority to EP88830267A priority Critical patent/EP0347512A1/en
Publication of EP0347512A1 publication Critical patent/EP0347512A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • C21D9/00Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/38Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for roll bodies
    • 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
    • C21D6/00Heat treatment of ferrous alloys
    • C21D6/002Heat treatment of ferrous alloys containing Cr

Definitions

  • This invention relates to a bimetal construction roll for reducing and finishing stands in a rolling mill train, being of a type having a table formed from an alloy including 1% to 2% carbon and 8% to 16% chromium.
  • a bimetal construction roll as indicated being characterized in that metallic carbides of at least one element from the group comprising vanadium, niobium, and titanium are present in said alloy.
  • a bimetal construction roll of steel for reducing and finishing stands in a hot rolling mill train comprises a table formed from an alloy which includes 1% to 2% carbon and 8% to 16% chromium.
  • the table is formed from an alloy steel, specifically an alloy including, additionally to iron, the following composition of alloying elements: C Si Mn Cr Ni Mo V 1.5 .8 .8 12 .5 3.5 1
  • the table of the bimetallic roll for rolling mills according to this invention is subjected to the following heat treatment steps: austenitization at temperatures in the 950° to 1050°C range; hardening in either still or blown air, with the cooling rate set to suit the roll size, and a pause followed by homogenizing at about 500°C; and two-step tempering to convert the residual austenite, at temperatures in the 450° to 550°C range to be selected according to the hardness sought.
  • Additional elements such as molybdenum, are provided in the alloy whose content is determined in a manner known per se contingent on individual specific requirements.
  • the bimetal construction roll of this invention has tested successfully as regards wear, thermal fatigue, and the banding phenomenon, while affording the added advantage of retaining the table shape characteristics unaltered as a result of the presence of secondary and tertiary vanadium, niobium, and titanium metallic carbides.
  • these carbides affect the table deformability at working temperatures and impart a high resistance to hot plastic state flowing, thereby preventing surface deformation of the table.
  • the net result is that the bimetal construction rolls according to the invention yield high quality rolled products.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Reduction Rolling/Reduction Stand/Operation Of Reduction Machine (AREA)

Abstract

In a bimetal construction roll for reducing and finishing stands in a rolling mill train, the table is composed of an alloy comprising 1% to 2% carbon, 8% to 16% chromium, and secondary and tertiary metallic carbides of at least one element selected from the group including vanadium, niobium, and titanium; a table such as this performs well both with respect to wear and thermal fatigue, and retains the surface shape characteristics unaltered.

Description

  • This invention relates to a bimetal construction roll for reducing and finishing stands in a rolling mill train, being of a type having a table formed from an alloy including 1% to 2% carbon and 8% to 16% chromium.
  • In relation to bimetallic steel rolls in reducing and finishing stands for hot rolling strip and sheet metal, the need is particularly felt to prevent formation of hard oxide deposits from the rolled, which phenomenon is better known by the term "banding", to control both the amount and the type of the oxides which form on the surface of the roll tables, and to minimize the occurrence of wear, thermal fatigue, and cracking phenomena which affect the tables. In fact, all of the above-noted phenomena contribute toward deteriorating the roll tables so as to shorten their life and lower their performance; also for these reasons, the rolled product may lack uniformity and fall short of the expected quality levels.
  • To meet such demands, it is known to use bimetallic rolls the tables whereof are formed from an alloy having a carbon content within the range of 0.9% to 1.9%, a chromium content within 6% to 15%, and molybdenum additions which may be as high as 5%.
  • While being on the whole satisfactory in the respect of the banding phenomenon, resistance to thermal fatigue and to wear, such conventional bimetallic rolls exhibit the well-recognized drawback of their tables being prone to undergo surface deformation, such as in the form of wrinkles.
  • The problem that underlies this invention is to provide a bimetal construction roll of the type specified above, which has such structural and operational features as to overcome the cited drawback affecting the prior art.
  • This problem is solved according to the invention by a bimetal construction roll as indicated being characterized in that metallic carbides of at least one element from the group comprising vanadium, niobium, and titanium are present in said alloy.
  • Further features and the advantages of a bimetal construction roll of steel according to the invention will be apparent from the following detailed description of a preferred embodiment given herein below by way of illustrative example and not of limitation. A bimetal construction roll of steel for reducing and finishing stands in a hot rolling mill train comprises a table formed from an alloy which includes 1% to 2% carbon and 8% to 16% chromium.
  • Advantageously present in the alloy are metallic carbides of at least one element selected from the group including vanadium, niobium, and titanium, provided therein to a proportion between 0.20% and 4%.
  • In accordance with a preferred embodiment of this invention, the table is formed from an alloy steel, specifically an alloy including, additionally to iron, the following composition of alloying elements:
    C Si Mn Cr Ni Mo V
    1.5 .8 .8 12 .5 3.5 1
  • Shown in the following table is the composition of another exemplary alloy for a bimetal construction roll table according to this invention:
    C Si Mn Cr Ni Mo Nb Ti
    1.8 .8 .8 12 .5 3.5 1 .5
  • Advantageously, the table of the bimetallic roll for rolling mills according to this invention is subjected to the following heat treatment steps:
    austenitization at temperatures in the 950° to 1050°C range;
    hardening in either still or blown air, with the cooling rate set to suit the roll size, and a pause followed by homogenizing at about 500°C; and
    two-step tempering to convert the residual austenite, at temperatures in the 450° to 550°C range to be selected according to the hardness sought.
  • It is to be noted that in the aforesaid alloy there are present vanadium, niobium, and titanium, which elements are sure to trigger, in the course of the heat treatment, formation of the so-called secondary and tertiary metallic carbides, which will precipitate during the hardening step and the tempering steps, respectively.
  • The above-noted secondary and tertiary metallic carbides will form within the grain, and practically constitute actual anchoring points, to impart the grain with superior hardness and resistance.
  • Additional elements, such as molybdenum, are provided in the alloy whose content is determined in a manner known per se contingent on individual specific requirements.
  • The bimetal construction roll of this invention has tested successfully as regards wear, thermal fatigue, and the banding phenomenon, while affording the added advantage of retaining the table shape characteristics unaltered as a result of the presence of secondary and tertiary vanadium, niobium, and titanium metallic carbides. In fact, these carbides affect the table deformability at working temperatures and impart a high resistance to hot plastic state flowing, thereby preventing surface deformation of the table. The net result is that the bimetal construction rolls according to the invention yield high quality rolled products.

Claims (7)

1. A bimetal construction roll for reducing and finishing stands in a rolling mill train, being of a type having a table formed from an alloy including 1% to 2% carbon and 8% to 16% chromium, and characterized in that metallic carbides of at least one element from the group comprising vanadium, niobium, and titanium are present in said alloy.
2. A bimetal construction roll according to Claim 1, characterized in that it comprises metallic carbides of at least one element selected from the vanadium, niobium, and titanium group as caused to precipitate by means of a heat treatment process including a hardening step and at least one tempering step.
3. A bimetal construction roll according to Claim 2, characterized in that it comprises secondary metallic carbides as precipitated by means of said hardening step.
4. A bimetal construction roll according to Claim 2, characterized in that it comprises tertiary metallic carbides as precipitated by means of said at least one tempering step.
5. A bimetal construction roll according to Claim 1, characterized in that said at least one element selected from the vanadium, niobium, and titanium group is present in said alloy in amounts ranging from 0.2% to 4%.
6. A bimetal construction roll according to Claim 1, characterized in that in said alloy there are present metallic vanadium carbides as precipitated by means of a heat treatment process including a hardening step and at least one tempering step, wherein vanadium is in the amount of 1%, said alloy being substantially austenite-free.
7. A bimetal construction roll according to Claim 1, characterized in that in said alloy there are present metallic carbides of niobium and titanium as precipitated by means of a heat treatment process including a hardening step and at least one tempering step, wherein niobium and titanium are in the respective amounts of 1% and 0.5%, said alloy being substantially austenite-free.
EP88830267A 1988-06-23 1988-06-23 A bimetal construction roll for reducing and finishing stands in a rolling mill train Withdrawn EP0347512A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP88830267A EP0347512A1 (en) 1988-06-23 1988-06-23 A bimetal construction roll for reducing and finishing stands in a rolling mill train

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP88830267A EP0347512A1 (en) 1988-06-23 1988-06-23 A bimetal construction roll for reducing and finishing stands in a rolling mill train

Publications (1)

Publication Number Publication Date
EP0347512A1 true EP0347512A1 (en) 1989-12-27

Family

ID=8200640

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88830267A Withdrawn EP0347512A1 (en) 1988-06-23 1988-06-23 A bimetal construction roll for reducing and finishing stands in a rolling mill train

Country Status (1)

Country Link
EP (1) EP0347512A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5419973A (en) * 1990-06-13 1995-05-30 Nippon Steel Corporation Composite roll for rolling and process for producing the same

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3725050A (en) * 1970-03-02 1973-04-03 Bethlehem Steel Corp Cold work die steel
EP0051511A1 (en) * 1980-10-31 1982-05-12 UNION SIDERURGIQUE DU NORD ET DE L'EST DE LA FRANCE par abréviation "USINOR" Cast roll for cold rolling, and method for its production

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3725050A (en) * 1970-03-02 1973-04-03 Bethlehem Steel Corp Cold work die steel
EP0051511A1 (en) * 1980-10-31 1982-05-12 UNION SIDERURGIQUE DU NORD ET DE L'EST DE LA FRANCE par abréviation "USINOR" Cast roll for cold rolling, and method for its production

Non-Patent Citations (9)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, vol. 104, no. 14, 7th April 1986, page 240, abstract no. 113711s, Columbus, Ohio, US; H. BERNS et al.: "New cold-working tool steels", & PROC. CONF. MATER. ENG., 2ND 1985, 71-7 *
CHEMICAL ABSTRACTS, vol. 105, no. 12, 22nd October 1986, page 217, abstract no. 100939t, Columbus, Ohio, US; H. BERNS et al.: "New cold-working tool steel", & MET. MATER. (INST. MET.) 1986, 2(7), 421-5 *
IRON AND STEEL ENGINEER, vol. 59, no. 3, March 1982, pages 53-58, Pittsburgh, Penns., US; J. DODD: "Recent advances in roll metallurgy and technology" *
METALS ABSTRACTS, vol. 13, no. 12, December 1980, page 176, column 1, abstract no. 56-0995, Foxton, Cambridge, GB; J. ZLATNIKOVA et al.: "Study on properties of high-carbon chromium, molybdenum and vanadium alloyed steel in conditions of surface hardening of rolls", & HUTN. LISTY. 1980, 35(3), 174-179 *
PATENT ABSTRACTS OF JAPAN, vol. 11, no. 192 (C-429)[2639], 19th June 1987; & JP-A-62 13 529 (KAWASAKI STEEL CORP.) 22-01-1987 *
PATENT ABSTRACTS OF JAPAN, vol. 11, no. 214 (C-434)[2661], 10th July 1987; & JP-A-62 30 854 (NIPPON STEEL CORP.) 09-02-1987 *
PATENT ABSTRACTS OF JAPAN, vol. 6, no. 122 (C-112)[1000], 7th July 1982; & JP-A-57 47 849 (KOBE SEIKOSHO K.K.) 18-03-1982 *
PATENT ABSTRACTS OF JAPAN, vol. 6, no. 197 (C-128)[1075], 6th October 1982; & JP-A-57 108 248 (KANTOU TOKUSHIYU SEIKOU K.K.) 06-07-1982 *
PATENT ABSTRACTS OF JAPAN, vol. 6, no. 35 (C-93)[913], 3rd March 1982; & JP-A-56 152 945 (SHIN NIPPON SEITETSU K.K) 26-11-1981 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5419973A (en) * 1990-06-13 1995-05-30 Nippon Steel Corporation Composite roll for rolling and process for producing the same

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