US3660174A - Method in the manufacture of stainless, hardenable chromium-steel strip and sheet - Google Patents

Method in the manufacture of stainless, hardenable chromium-steel strip and sheet Download PDF

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Publication number
US3660174A
US3660174A US827355A US3660174DA US3660174A US 3660174 A US3660174 A US 3660174A US 827355 A US827355 A US 827355A US 3660174D A US3660174D A US 3660174DA US 3660174 A US3660174 A US 3660174A
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steel
percent
sheet
weight
strip
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US827355A
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Klas-Erik Jakenberg
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Uddeholms AB
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Uddeholms AB
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    • 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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips

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  • the material has then been cold-rolled in a large number of passes, alternating with anneals and intermediate anneals, until the desired dimensions are obtained.
  • This method is a lengthy one, and thus expensive, it is still applied in practice, since it is considered the only conceivable method by which a high-quality product can be obtained.
  • Cold rolling namely increases the properties of the steel in several respects; for instance its hardness and mechanical strength. The surface of the metal becomes bright and thus, among other things, more resistant to corrosion.
  • the cold-rolling technic is accompanied with marked disadvantages.
  • One such disadvantage is the longdrawn process required by the technic; which plays a dominating role in the final price of the product.
  • When concerning stainless steels there are also difficult problems to resolve in connection with the annealing operations rendered necessary by the cold hardening of the steel. Those factors which influence the quality of the final product, are, in addition to the nature of the starting material, primarily the number of anneals necessary, the manner in which the anneals are effected and the annealing temperatures and times.
  • the first object of the invention is to produce a stainless, strip or sheet steel which is highly resistant to corrosion and having improved hardness in relation to known steels of corresponding composition.
  • improved hardening is meant an increased ability of the carbon to rapidly solubilize during austenitizing of the steel.
  • Another object of the invention is to produce sheet or strip steel of homogeneous structure.
  • a further object of the invention is to produce stainless, strip or sheet having a relatively high degree of flatness.
  • One object of the invention is also to produce a material having a high yield point ultimate strength ratio in an unhardened state.
  • Still another object of the invention is to produce a steel with fewer variations in hardness after hardening than has previously been possible.
  • the invention is mainly characterized by using as a starting material a material whose main structure is pearlite, by heating the material to a temperature of between 600 and 790 C and rolling the material in this temperature range, by adapting the working temperature and degree of reduction so that the pearlite structure is broken down and transformed to a structure substantially comprising finely-divided spheroidized carbidesin a ferritic matrix having at least 40, preferably at least 60, and in certain cases more than carbide grains per l00,u,m
  • hardenable, stainless chromium-steel such hardenable, stainless steels which in addition to iron contain chromium as the dominating alloying constituent.
  • the carbon content of these steels varies from between about 0.1 percent and about 1.0 percent.
  • Remaining alloying constituents are present in moderate percentages (each at a maximum of about 2 percent) and may, for example, comprise silicon, manganese, molybdenum, nickel and copper. Other elements, such as boron, beryllium, nitrogen etc, may also be present in small quantities.
  • the starting material is hotrolled strip which has been cooled to room temperature and surface treated by, for example, pickling, grinding, blasting or like processes.
  • the strip is preferably cooled while well coated in insulating ashes, to ensure the pearlitic structure.
  • the steel can normally be worked direct, without prior annealing being necessary, and to unlimited reduction, by which is meant that the reduction is so extensive that the desired final dimension can be obtained in the absence of intermediate anneals.
  • area reduction is understood the ratio between the reduction in area of the strip or sheet at right angles to the direction of stretch and the corresponding starting area. In spite of the comparitively high working temperature bright surfaces are obtained and scale formation is negligible. A protective atmosphere which is conceivable in principle has not proven necessary.
  • the material can also be rolled at room temperature, for the purpose of achieving certain tolerances for instance.
  • EXAMPLE The test was concerned with the production of stainless steel strip having properties which in several respects were superior to those of material produced by cold rolling according to conventional methods.
  • the analysis of the steel was 0.66 percent C, 0.38 percent Si, 0.45 percent Mn, 13.8 percent Cr, 0.06 percent Ni, 0.04 percent Mo and 0.063 percent N.
  • the material had been first hot rolled in a conventional manner, down to a thickness of 6 mm, slowly cooled, buried in ashes, to room temperature and then pickled.
  • the material was heated in anelectric furnace provided with a movable hard bottom positioned as close as possible to the roll gap.
  • the temperature of the furnace was varied from between, 600 and 750 C.
  • the basic structure of the steel is still ferritic at these temperatures.
  • the material was rolled direct to the final dimension without intermediate anneals.
  • ductility it was discovered that there was a temperature limit range between 600 and 650 C.
  • the lower limit can be taken as being about 620 C.
  • Ductility was good from 650 C up to and including 750 C, and strong reductions were obtained at each pass, and hence only a few passes were necessary.
  • FIGS. 1, 2 and 3 1,200 X show the starting structure of the steel and the structures after a 67 percent and 76 total area reduction at a rolling temperature of 750 C.
  • Rolling should be continued to an extentwhereby finely-divided spheroidized carbides are obtained with at least 40 and preferably at least 60 carbide grains per 100 um
  • the structure should be homogenous, without appreciable rests of pearlite.
  • the carbide content was satisfactory after a 67 percent reduction in area (FIG. 2), although small portions containing pearlitic residues were still present. Subsequent to rolling down to a 76 percent reduction (FIG. 3) no pearlitic portions could be observed.
  • the carbidecontent was very high; well in excess of the highest value, 80 carbides per 100 [1.111 of the carbide scale.
  • FIG. 4 1,200 X a starting material of the same analysis as the previous material but with a mixed structure
  • FIG. 5 (1,200 X) shows the same material rolled to an approximate 78 percent total reduction at 700 C.
  • the starting structure, FIG. 4 is comprised of a mixed structure of complex character
  • the final structure, FIG. 5, hereby obtains an uneven carbide distribution.
  • the Figure clearly shows sweeps of material having fewer carbides.
  • FIG. 6 (1,200 X) illustrates a starting material which is partly spheroidized and has an uneven structure.
  • FIG. 7 shows the same material rolled to a total area reduction of 77 percent at 750 C. Undesired sweeps of portions containing fewer carbides are also present in this instance. The spheroidizing, however, is sufiicient.
  • the strip is preferably further reduced in thickness by a conventional cold rolling process.
  • This operation is normally necessary to give desired tolerances, although it also improves the quality of the steel insofar as the yield point ultimate strength ratio rises to a value which is difficult to achieve when using solely conventional technics.
  • This operation is not carried out in this example, however, but instead the strip is hardened directly after rolling at said high temperature.
  • Hardening of the strip is effected in a simulator, adapted to simulate operational conditions in continuous hardening processes.
  • the strip is subjected to solubilizing treatment continuously upon passage through a furnace heated to a temperature of l,l00 C.
  • the time at disposal with the existing strip speeds is 45 seconds.
  • the strip is then cooled continuously at 70 C.
  • the hardness was tested for material according to the invention which had been rolled at 650, 700 and 750 C and which was then hardened at varying stay times during the austenitizing treatment process.
  • the reference material comprised two samples of the same composition as the material of the invention but produced by conventional cold rolling technics.
  • the reference material was also hardened under the same conditions as the material produced according to the invention. It was discovered that as opposed to the reference material the materials produced according to the invention showed very little spread while at the same time they lay on a higher level. These circumstances can be attributed to the fine, readily solubilizable and homogeneous structure of the material according to the invention, but are nevertheless remarkable. The following values were obtained.
  • the steel compositions are only to be considered conceivable examples of types of analyses which can be used in accordance with the invention.
  • the steel should have a carbon content in excess of 0.1 percent and preferably in excess of 0.2 percent.
  • carbon and chromium other additives usually used in stainless steel may be employed.
  • Material which contains such elements as those which favor the occurrence of graphite, e.g. silicon, nickel or aluminium,
  • a method for the manufacture of hardenable steel strip and sheet which comprises, hot rolling a billet of the steel in the austenite condition, slowly cooling the hot-rolled strip or sheet to room temperature to produce a structure in the rolled material containing at least 80 percent pearlite, heating the material to a temperature between 600 and 790 C, and rolling in the ferritic state of the steel matrix to a total area reduction of at least 70 percent, so that the pearlite is broken down and transformed to a structure of finely-divided spheroidized carbides in a ferritic matrix having at least 40 carbide grains per 100 m 2.
  • a method according to claim 1 wherein the hot-rolled material is cooled to room temperature in an insulating medi- 3.
  • a method according to claim 1, in which the steel is a stainless, hardenable chromium steel in which rolling of the material with the pearlitic structure is effected in the temperature range from 700 to 780 C.
  • an alloying composition essentially consisting of from 0.2 to 1.5 weight-percent carbon, 5 to 20 weight-percent chromium, O to 4 weight-percent of an alloying metal selected from the group consisting of Ni, Mo, ,Mn, Cu and Co, 0 to 3 weight-percent of an alloying element of the group consisting of W and Si, 0 to 2 weight-percent of V, and 0 to 1 weight-percent of Ti, Ta, Nb, B and

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  • 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)
  • Heat Treatment Of Sheet Steel (AREA)
  • Heat Treatment Of Steel (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
US827355A 1968-05-31 1969-05-23 Method in the manufacture of stainless, hardenable chromium-steel strip and sheet Expired - Lifetime US3660174A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE6807333A SE330900C (sv) 1968-05-31 1968-05-31 Sett att vermebehandla band eller plat av rostfritt, herdbart kromstal

Publications (1)

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US3660174A true US3660174A (en) 1972-05-02

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US (1) US3660174A (de)
AT (1) AT326166B (de)
DE (1) DE1927381B2 (de)
FR (1) FR2009792A1 (de)
GB (1) GB1279481A (de)
SE (1) SE330900C (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3859147A (en) * 1972-03-10 1975-01-07 Carpenter Technology Corp Hot hard stainless steel
DE2602007A1 (de) 1975-01-22 1976-07-29 Uddeholms Ab Verfahren zur herstellung von bandstahl oder streifenblech
US5055253A (en) * 1990-07-17 1991-10-08 Nelson & Associates Research, Inc. Metallic composition
US5139583A (en) * 1992-01-21 1992-08-18 Kawasaki Steel Corporation Graphite precipitated hot-rolled steel plate having excellent bending workability and hardenability and method therefor
US5182079A (en) * 1990-07-17 1993-01-26 Nelson & Associates Research, Inc. Metallic composition and processes for use of the same
US5505798A (en) * 1994-06-22 1996-04-09 Jerry L. Nelson Method of producing a tool or die steel
US6488787B1 (en) * 1999-06-30 2002-12-03 Nippon Steel Corporation Cold workable steel bar or wire and process
US20100291407A1 (en) * 2008-01-21 2010-11-18 Hitachi Metals, Ltd. Alloy to be surface-coated and sliding members

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6037849B2 (ja) * 1979-07-12 1985-08-28 動力炉・核燃料開発事業団 クロム・モリブデン鋼の耐脱炭処理方法
DE102011079955B4 (de) 2011-07-28 2023-10-19 Aktiebolaget Skf Stahl, Bauteil und Verfahren zum Herstellen von Stahl
FR3114683B1 (fr) 2020-09-25 2025-10-17 Semco Smartech France Support pour substrats semiconducteurs pour traitement PECVD avec forte capacité de chargement de substrats

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2801916A (en) * 1954-08-24 1957-08-06 Jessop William & Sons Ltd Ferrous alloys for high temperature use
US2905577A (en) * 1956-01-05 1959-09-22 Birmingham Small Arms Co Ltd Creep resistant chromium steel
US3116180A (en) * 1957-04-27 1963-12-31 Neuzeughammer Ambosswerk Messe Method of producing articles having a cutting edge portion and consisting of stainless chromium steel
US3216868A (en) * 1961-03-06 1965-11-09 Lasalle Steel Co Elevated temperature working and heat treatment of stainless steel
US3281287A (en) * 1962-02-27 1966-10-25 Sandvikens Jernverks Ab Corrosion resistant edge tool and method of making the same
US3425877A (en) * 1965-10-22 1969-02-04 Wilkinson Sword Ltd Safety razor blades

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2801916A (en) * 1954-08-24 1957-08-06 Jessop William & Sons Ltd Ferrous alloys for high temperature use
US2905577A (en) * 1956-01-05 1959-09-22 Birmingham Small Arms Co Ltd Creep resistant chromium steel
US3116180A (en) * 1957-04-27 1963-12-31 Neuzeughammer Ambosswerk Messe Method of producing articles having a cutting edge portion and consisting of stainless chromium steel
US3216868A (en) * 1961-03-06 1965-11-09 Lasalle Steel Co Elevated temperature working and heat treatment of stainless steel
US3281287A (en) * 1962-02-27 1966-10-25 Sandvikens Jernverks Ab Corrosion resistant edge tool and method of making the same
US3425877A (en) * 1965-10-22 1969-02-04 Wilkinson Sword Ltd Safety razor blades

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3859147A (en) * 1972-03-10 1975-01-07 Carpenter Technology Corp Hot hard stainless steel
DE2602007A1 (de) 1975-01-22 1976-07-29 Uddeholms Ab Verfahren zur herstellung von bandstahl oder streifenblech
US4046598A (en) * 1975-01-22 1977-09-06 Uddehoms Aktiebolag Procedure for manufacture of steel band or strip
US5055253A (en) * 1990-07-17 1991-10-08 Nelson & Associates Research, Inc. Metallic composition
US5182079A (en) * 1990-07-17 1993-01-26 Nelson & Associates Research, Inc. Metallic composition and processes for use of the same
US5139583A (en) * 1992-01-21 1992-08-18 Kawasaki Steel Corporation Graphite precipitated hot-rolled steel plate having excellent bending workability and hardenability and method therefor
US5505798A (en) * 1994-06-22 1996-04-09 Jerry L. Nelson Method of producing a tool or die steel
US5616187A (en) * 1994-06-22 1997-04-01 Nelson; Jerry L. Tool steel
US6488787B1 (en) * 1999-06-30 2002-12-03 Nippon Steel Corporation Cold workable steel bar or wire and process
US20100291407A1 (en) * 2008-01-21 2010-11-18 Hitachi Metals, Ltd. Alloy to be surface-coated and sliding members
US8409712B2 (en) * 2008-01-21 2013-04-02 Hitachi Metals Ltd. Alloy to be surface-coated and sliding members

Also Published As

Publication number Publication date
DE1927381A1 (de) 1972-03-23
ATA504069A (de) 1975-02-15
SE330900B (de) 1970-12-07
FR2009792A1 (de) 1970-02-06
SE330900C (sv) 1978-12-18
GB1279481A (en) 1972-06-28
AT326166B (de) 1975-11-25
DE1927381B2 (de) 1973-10-11

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