EP0400031A1 - Cold-rolled sheet or strip and process for manufacturing them. - Google Patents

Cold-rolled sheet or strip and process for manufacturing them.

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Publication number
EP0400031A1
EP0400031A1 EP19890901844 EP89901844A EP0400031A1 EP 0400031 A1 EP0400031 A1 EP 0400031A1 EP 19890901844 EP19890901844 EP 19890901844 EP 89901844 A EP89901844 A EP 89901844A EP 0400031 A1 EP0400031 A1 EP 0400031A1
Authority
EP
European Patent Office
Prior art keywords
titanium
epsilon
strip
cold
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.)
Granted
Application number
EP19890901844
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German (de)
French (fr)
Other versions
EP0400031B1 (en
EP0400031B2 (en
Inventor
Klaus Freier
Walter Zimnik
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Salzgitter AG
Original Assignee
Preussag Stahl AG
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Priority to AT89901844T priority Critical patent/ATE97169T1/en
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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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0421—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the working steps
    • C21D8/0426—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • 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
    • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0421—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the working steps
    • C21D8/0436—Cold 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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0447—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the heat treatment
    • C21D8/0473—Final recrystallisation annealing

Definitions

  • the invention relates to a method for producing a sheet or strip and a sheet or strip suitable for deep-drawing according to the preambles of claims 1 and 6.
  • Texture-free cold-rolled strip or sheet is used for deep-drawing rotationally symmetrical steel parts, so that quasi-isotropic forming is possible and the drawn part is free of lobes. This means that a z. B. cylindrical deep-drawn part has no wavy edge.
  • the value for the flat anisotropy is calculated from the anisotropy r for different expansion behavior of the material in the rolling direction as well as at 45 degrees and 90 degrees. Different r values can be set for different deep-drawing properties.
  • tip-free material can only be achieved by normalizing the cold-rolled strip - in a continuous annealing at about 1000 degrees Celsius, the sheet in the final state having an ASTM 8 grain size with a relative tip height of about 0.3 to 0. 4% and Delta r approx. ⁇ 0.1.
  • the final rolling temperatures should be approximately 750 degrees Celsius and the cold rolling degrees should either be below 25% or above 80% and are said to be unfavorable for the cornering
  • Recrystallization temperatures of over 600 degrees Celsius can be worked.
  • DE-OS 3234 574 discloses a generic cold-rolled steel sheet or steel strip suitable for deep drawing. Depending on the content of carbon, oxygen, sulfur and nitrogen, the titanium content should rise to values of up to 0.15%, the reel temperature should be over 700 degrees Celsius or at least 580 degrees Celsius with subsequent hot strip heating to over 700 degrees Celsius . We also recommend a cold rolling degree of 70 - 85% and a continuous annealing at 700 - 900 degrees Celsius with a maximum holding time of two minutes. No information is given on the formation of the material.
  • EP-A1-101 740 recommends a slab heating temperature of less than 1100 degrees Celsius, a final rolling temperature of less than Ar 3 , coiling temperatures of 320-600 degrees Celsius and cold rolling degrees of 50-95% and recrystallizing continuous annealing for a generic cold-rolled steel.
  • a steel with a maximum of 0.005% carbon, a maximum of 0.004% nitrogen and a maximum of 0.02% niobium should be used in combination with one or more of the elements aluminum, chromium, boron or tungsten. High average r values above 1.2 are achieved. There are no indications that the material is tricky after deep-drawing.
  • hot-rolled strip has good quasi-isotropic deformability, but has an inadequate surface quality and tolerances that are too large, and is also not produced in thicknesses below 1.2 mm.
  • the invention is therefore based on the object of proposing a sheet-free or at least low-corner deep-drawing suitable sheet made of steel strip and a corresponding manufacturing process in which continuous annealing at temperatures above A 1 is dispensed with, but can nevertheless be produced inexpensively.
  • the object is achieved by claims 1 and 6.
  • the values of the grain size of at best ASTM 8 corresponding to 490 ⁇ m 2 which are usually achieved in the state of the art for steel St 4 NZ or RSt 14 by normal annealing, can be undercut by recrystallizing annealing using the method according to the invention, wherein additional low yield strength values can be maintained by choosing appropriate ones Cold rolling degrees depending on the titanium content. This has the advantage that high investments in continuous annealing for normalizing treatment can be dispensed with.
  • any desired degree of cold rolling can be set for the production of tip-free material and / or likewise a yield strength between 175 and 450 N / mm 2 with tensile strengths of 310 to 520 N / mm 2 .
  • a particular advantage of the hot strip produced in this way is that there is in principle no restriction with regard to the subsequent cold rolling, provided that the degree of cold rolling is at least approx. 5%, i.e. remains above the known critical weak cold deformation, which leads to coarse grain during recrystallization annealing. So far, the production of almost strip-free cold strip was tied to certain cold rolling degrees, unless normal annealing was to be carried out.
  • the variation of the cold rolling degrees as a function of the amount of titanium alloyed is limited to cold rolling degrees of 45 to 85% with the simultaneous addition of niobium within the specified limits.
  • niobium does not hinder the early formation of titanium nitride, so that even with this steel alloy according to the invention, a pan-cake structure cannot arise during the recrystallizing annealing.
  • a serious technical and economic significance of the invention lies in the use of the thin sheet for rotationally symmetrical deep-drawn parts such as needle bearing cages, pulley halves etc.
  • the sheet according to the invention can be used in these cases without substantial reworking such as cutting off the tips.
  • the low-end point also prevents the formation of sectoral wall weaknesses during deep drawing, so that the drawn parts do not have any imbalance during rotation. Further advantages of low-lobe or lobe-free cold strip are known, so that a further description is unnecessary.
  • FIG. 1 shows three different wells, which are to define the terms used in the following, pointed (Fig. 1a), low-pointed (Fig. 1b) and free (Fig. 1c), since the measurement of the height of the corners with the conventional corner measuring devices, in particular of corner-poor and Tip-free wells with small height differences are problematic even with the smallest deep-drawing burrs on the edge of the well.
  • the cells showed a different deep-drawing result depending on the titanium content at different degrees of cold rolling:
  • Table 2 shows the grain size achieved according to the invention in ASTM units; The achievable grain refinement compared to steels without titanium addition according to the state of the art is considerable and extends up to ASTM 11.
  • the coarsest grain was obtained with a small addition of Ti and a low degree of cold rolling (ASTM 7).
  • ASTM 7 For steel A - D, the hot strip values for the grain size (ASTM 9-10) were compared in FIG. 12.
  • FIGS. 2a, 2b, 2c show corresponding results on cups made from 180 mm round blanks, which were deep-drawn using 100 mm stamps at a retention force of 50 kN.
  • Table 1 also lists the melt analyzes of the steel G with 0.01% titanium, H with 0.02% titanium and I with 0.03% titanium with 0.05% and 0.06% addition of niobium in the process , a comparative steel K with
  • Slabs 220 mm thick were cast in the strand from the melts G - I according to the invention and the comparative melt K. After heating in the pusher furnace to 1250 degrees Celsius, the slab was rolled out into hot strip of 4 mm thickness and coiled and cooled to room temperature. The final roll temperature was 880 degrees Celsius and the reel temperature was 510 degrees Celsius. After pickling, the strips were reduced by cold rolling in different stages from 10 to 80% to sheet thickness and reeled. After coiling, the tightly wound coil was heated to 700 degrees Celsius in the Ludwig annealing furnace and recrystallized annealing at throughput rates of 1.1 tons or 1.8 tons per hour, then cooled to 120 degrees Celsius in the annealing furnace. After tempering with a degree of deformation of 1.1%, the strip was made into sheet metal. Sheet rounds of 90 mm in diameter were deep-drawn into cups using drawing dies of 50 mm in diameter (FIGS. 13-16).
  • FIG. 16 clearly shows that deep-drawing without tipping was not possible with any of the tried and tested degrees of cold rolling.
  • the wells showed a slightly different deep-drawing result depending on the titanium content at different degrees of cold rolling:
  • Corner arm in the range of 60 to 70% cold rolling degrees.
  • yield strength and tensile strength values were found to be more than 50 N / mm 2 above the characteristic values of the only titanium-alloyed material.
  • the melts L and M according to the invention listed in Table 1 with phosphorus contents at the upper analysis limit were treated like steels A - F.
  • the reel temperature was 510 and 500 degrees Celsius, respectively.
  • the consistency of the results was checked over the entire strip length in order to confirm the effectiveness of the annealing.
  • the wells from the deep-drawing test are shown in FIGS. 17 and 18, respectively. They show that tip-free material was produced both at the beginning of the tape (position 0) and after every further quarter of the length of the tape up to the end of the tape (position 1).

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
  • Continuous Casting (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

Pour produire une tôle présentant de bonnes caractéristiques de formage, notamment pour l'emboutissage profond à symétrie de rotation, on allie un acier pauvre en carbone contenant au maximum 0,009 % de N, avec 0,01-0,04 % de Ti et dans certains cas également avec 0,01 à 0,06 % de Niob, on effectue une coulée continue, on réchauffe les brames au-dessus de 1120 degrés Celsius, on lamine pour obtenir un feuillard à chaud au-dessus du point d'Ar3 et on bobine à 520 U 100 degrés Celsius. Après laminage à froid pour obtenir l'épaisseur de tôle mince souhaitée, le feuillard acier subit un recuit de recristallisation avant de subir pour finir une passe de dressage et d'être confectionné en tôles.To produce sheet with good forming characteristics, especially for rotationally symmetric deep drawing, a low carbon steel containing a maximum of 0.009% N is alloyed with 0.01-0.04% Ti and in some cases also with 0.01 to 0.06% Niob, continuous casting is carried out, the slabs are heated above 1120 degrees Celsius, rolled to obtain a hot strip above the point of Ar3 and we coil at 520 U 100 degrees Celsius. After cold rolling to obtain the desired thin sheet thickness, the steel strip undergoes recrystallization annealing before finally undergoing a straightening pass and being made into sheets.

Description

Kaltgewalztes Blech oder Band und Verfahren zu seiner HerstellungCold rolled sheet or strip and process for its manufacture
Beschreibungdescription
Die Erfindung betrifft ein Verfahren zur Herstellung eines Bleches oder Bandes sowie ein zum Tiefziehen geeignetes Blech oder Band gemäß den Oberbegriffen der Ansprüche 1 und 6.The invention relates to a method for producing a sheet or strip and a sheet or strip suitable for deep-drawing according to the preambles of claims 1 and 6.
Zum Tiefziehen von rotationssymmetrischen Stahlteilen wird möglichst texturfreies kaltgewalztes Band oder Blech eingesetzt, damit ein quasiisotropes Umformen möglich und das gezogene Teil zipfelfrei ist. Damit ist gemeint, daß ein z. B. zylindrisch tiefgezogenes Teil keinen welligen Rand aufweist.Texture-free cold-rolled strip or sheet is used for deep-drawing rotationally symmetrical steel parts, so that quasi-isotropic forming is possible and the drawn part is free of lobes. This means that a z. B. cylindrical deep-drawn part has no wavy edge.
Eine vollkommene Zipfelfreiheit ist nur von isotropem Material ohne Seigerungen, ohne nichtmetallische Einschlüsse, ohne perlschnurartige Zementitausscheidungen und bei pan-cake-freiem Gefüge zu erwarten. Daher wird in der folgenden Beschreibung nur der Begriff "zipfelarmes" auch für nach dem Stand der Technik "zipfelfreies" Band verwendet.A perfect tip freedom can only be expected from isotropic material without segregations, without non-metallic inclusions, without pearlite-like cementite precipitates and with a pan-cake-free structure. Therefore, in the following description, only the term "low-corner" is also used for "corner-free" tape according to the prior art.
In "Blech, Rohre, Profile" 9/1977, S. 341 - 346 wird detailliert die Ursache für die Zipfelbildung beschrieben und ein Maß für die relative Zipfelhöhe Z sowie die ebene Anisotropie Delta r definiert. Ideal wären jeweils Ergebnisse mit dem Wert Null (zipfelfreies Material).In "Blech, Rohr, Profiles" 9/1977, pp. 341 - 346 the cause of the tip formation is described in detail and a measure for the relative tip height Z and the flat anisotropy Delta r are defined. In each case, results with the value zero (tip-free material) would be ideal.
Der Wert für die ebene Anisotropie errechnet sich aus der Anisotropie r für unterschiedliches Ausdehnungsverhalten des Materials in Walzrichtung sowie unter 45 Grad und 90 Grad dazu. Für unterschiedliche Tiefzieheigenschaften sind verschiedene r-Werte einstellbar. Für die in der Veröffentlichung erwähnten Stähle läßt sich zipfelfreies Material nur durch Normalglühen des kaltgewalzten Bandes-in einer Durchlaufglühe bei etwa 1000 Grad Celsius erreichen, wobei das Blech im Endzustand eine Korngröße ASTM 8 bei einer relativen Zipfelhöhe von ca. 0,3 bis 0,4 % und Delta r ca. ± 0,1 erreichen.The value for the flat anisotropy is calculated from the anisotropy r for different expansion behavior of the material in the rolling direction as well as at 45 degrees and 90 degrees. Different r values can be set for different deep-drawing properties. For the steels mentioned in the publication, tip-free material can only be achieved by normalizing the cold-rolled strip - in a continuous annealing at about 1000 degrees Celsius, the sheet in the final state having an ASTM 8 grain size with a relative tip height of about 0.3 to 0. 4% and Delta r approx. ± 0.1.
Für nicht normalisierend geglühtes Band sei nur ein zipfelarmer Zustand durch Kompromisse in der Verfahrensführung bei der Blechherstellung zu erreichen. Dabei sollen die Walzendtemperaturen ca. 750 Grad Celsius und die Kaltwalzgrade entweder unter 25 % oder über 80 % liegen und mit als für die Zipfeligkeit ungünstig bezeichnetenFor non-normalizing annealed strip, only a low-tip condition can be achieved through compromises in the process control in sheet metal production. The final rolling temperatures should be approximately 750 degrees Celsius and the cold rolling degrees should either be below 25% or above 80% and are said to be unfavorable for the cornering
Rekristallisationstemperaturen von über 600 Grad Celsius gearbeitet werden.Recrystallization temperatures of over 600 degrees Celsius can be worked.
Beschrieben wird weiterhin, daß ein Normalisieren nicht im Bund, sondern nur in einer Durchlaufglühe erfolgen kann, weil bei den hohen Temperaturen die Bänder zusammenkleben würden.It is also described that normalization cannot take place in the bundle, but only in a continuous annealing line, because at the high temperatures the strips would stick together.
Aus der DE-OS 3234 574 ist ein gattungsgemäßes zum Tiefziehen geeignetes kaltgewalztes Stahlblech oder Stahlband bekannt. Der Titangehalt soll, in Abhängigkeit der Gehalte an Kohlenstoff, Sauerstoff, Schwefel und Stickstoff, auf Werte bis 0,15 % steigen können, die Haspeltemperatur über 700 Grad Celsius oder mindestens jedoch 580 Grad Celsius mit anschließender Warmband-Erwärmung auf über 700 Grad Celsius betragen. Weiterhin wird ein Kaltwalzgrad von 70 - 85 % sowie ein Durchlaufglühen bei 700 - 900 Grad Celsius mit maximal zwei Minuten Haltezeit empfohlen. Hinweise zur Zipfelbildung des Materials werden nicht gegeben. Aus der EP-A1-101 740 wird für einen gattungsgemäßen kaltgewalzten Stahl eine Brammenerwärmungstemperatur kleiner als 1100 Grad Celsius, eine Walzendtemperatur von unter Ar3, Haspeltemperaturen von 320 - 600 Grad Celsius und Kaltwalzgrade von 50 - 95 % sowie rekristallisierendes Durchlaufglühen empfohlen. Dabei soll ein Stahl mit maximal 0,005 % Kohlenstoff, maximal 0,004 % Stickstoff und maximal 0,02 % Niob in Kombination mit einem oder mehreren der Elemente Aluminium, Chrom, Bor oder Wolfram Verwendung finden. Erzielt werden hohe mittlere r-Werte oberhalb 1,2. Hinweise auf die Zipfligkeit des Materials nach dem Tiefziehen sind nicht offenbart.DE-OS 3234 574 discloses a generic cold-rolled steel sheet or steel strip suitable for deep drawing. Depending on the content of carbon, oxygen, sulfur and nitrogen, the titanium content should rise to values of up to 0.15%, the reel temperature should be over 700 degrees Celsius or at least 580 degrees Celsius with subsequent hot strip heating to over 700 degrees Celsius . We also recommend a cold rolling degree of 70 - 85% and a continuous annealing at 700 - 900 degrees Celsius with a maximum holding time of two minutes. No information is given on the formation of the material. EP-A1-101 740 recommends a slab heating temperature of less than 1100 degrees Celsius, a final rolling temperature of less than Ar 3 , coiling temperatures of 320-600 degrees Celsius and cold rolling degrees of 50-95% and recrystallizing continuous annealing for a generic cold-rolled steel. A steel with a maximum of 0.005% carbon, a maximum of 0.004% nitrogen and a maximum of 0.02% niobium should be used in combination with one or more of the elements aluminum, chromium, boron or tungsten. High average r values above 1.2 are achieved. There are no indications that the material is tricky after deep-drawing.
Ein weiteres Verfahren zur Herstellung tiefziehgeeigneter Stähle mit Brammenglühtemperatur kleiner 1100 Grad Celsius, Endwalztemperatur max. 780 Grad Celsius und Haspeltemperaturen von mindestens 450 Grad Celsius sowie Kaltbandglühen im Haubenoder Durchlaufglühofen sind in der EP-B1-120 976 offenbart. Das Verfahren soll r-Werte um 2 erzielen; Werte für die Zipfelbildung sind nicht offenbart.Another process for producing deep-drawing steels with a slab annealing temperature of less than 1100 degrees Celsius, final rolling temperature max. 780 degrees Celsius and reel temperatures of at least 450 degrees Celsius as well as cold strip annealing in the hood or continuous annealing furnace are disclosed in EP-B1-120 976. The method should achieve r values around 2; Values for tip formation are not disclosed.
Es ist allgemein bekannt, daß Warmband eine gute quasiisotrope Unforrribarkeit besitzt, jedoch eine nicht ausreichende Oberflächengüte und zu große Toleranzen aufweist und zudem nicht in Dicken unter 1,2 mm hergestellt wird.It is generally known that hot-rolled strip has good quasi-isotropic deformability, but has an inadequate surface quality and tolerances that are too large, and is also not produced in thicknesses below 1.2 mm.
Von daher liegt der Erfindung die Aufgabe zugrunde, ein zipfelfreies oder zumindest zipfelarmes tiefziehgeeignetes Blech aus Stahlband und ein entsprechendes Herstellverfahren vorzuschlagen, bei dem auf das Durchlaufglühen bei Temperaturen oberhalb A1 verzichtet, aber trotzdem kostengünstig produziert werden kann. Die Aufgabe wird erfindungsgemäß durch die Ansprüche 1 und 6 gelöst.The invention is therefore based on the object of proposing a sheet-free or at least low-corner deep-drawing suitable sheet made of steel strip and a corresponding manufacturing process in which continuous annealing at temperatures above A 1 is dispensed with, but can nevertheless be produced inexpensively. The object is achieved by claims 1 and 6.
Vorteilhafte Weiterbildungen der Erfindung sind in denAdvantageous developments of the invention are in the
Unteransprüchen erfaßt.Subclaims recorded.
Überraschenderweise hat sich gezeigt, daß bei Anwendung der erfindungsgemäßen Brammen-, Glüh-, Walz- und Haspeltemperaturen für den genannten Stahl ein rekristallisierendes Glühen eines Bundes im Haubenofen ausreicht, um dem Stahlband oder demkonfektionierten Stahlblech hervorragende Tiefzieheigenschaften, insbesondere eine extreme Zipfelarmut, zu geben.Surprisingly, it has been shown that when the slab, annealing, rolling and coiling temperatures according to the invention are used, a recrystallizing annealing of a coil in the bell-type furnace is sufficient to give the steel strip or the prefabricated steel sheet excellent deep-drawing properties, in particular an extreme low angle.
Die üblicherweise beim Stand der Technik für den Stahl St 4 NZ oder RSt 14 durch Normalglühen erreichten Werte der Korngröße von bestenfalls ASTM 8 entsprechend 490 μm2 können durch das erfindungsgemäße Verfahren durch rekristallisierendes Glühen unterschritten werden, wobei zusätzlich niedrige Streckgrenzenwerte beibehalten werden können durch Wahl entsprechender Kaltwalzgrade in Abhängigkeit vom Titangehalt. Dies ergibt den Vorteil, daß auf hohe Investitionen für eine Durchlaufglühe für eine Normalglühbehandlung verzichtet werden kann.The values of the grain size of at best ASTM 8 corresponding to 490 μm 2 , which are usually achieved in the state of the art for steel St 4 NZ or RSt 14 by normal annealing, can be undercut by recrystallizing annealing using the method according to the invention, wherein additional low yield strength values can be maintained by choosing appropriate ones Cold rolling degrees depending on the titanium content. This has the advantage that high investments in continuous annealing for normalizing treatment can be dispensed with.
Durch Variation der Zulegierung von Titan in den angegebenen Grenzen läßt sich praktisch jeder gewünschte Kaltwalzgrad für die Erzeugung zipfelfreien Materials einstellen und/oder genauso ebenfalls eine Streckgrenze zwischen 175 und 450 N/mm2 bei Zugfestigkeiten von 310 bis 520 N/mm2.By varying the addition of titanium within the specified limits, practically any desired degree of cold rolling can be set for the production of tip-free material and / or likewise a yield strength between 175 and 450 N / mm 2 with tensile strengths of 310 to 520 N / mm 2 .
Eine der Ursachen für die günstigen Eigenschaften des erzeugten Bleches ist in der frühzeitigen Bildung von Titannitrid zu sehen, so daß ein pan-cake-Gefüge während des rekristallisierenden Glühens durch die Aluminium-Nitrid-Ausscheidungen nicht entstehen kann. Durch die Wahl niedriger Haspel temper aturen um 520 Grad Celsius wurden überraschend Warmbandqualitäten erzielt, die nach dem Kaltwalzen ein zipfelfreies Material gewährleisteten und eine zusätzliche Kornverfeinerung ermöglichten.One of the reasons for the favorable properties of the sheet produced is the early formation of titanium nitride, so that a pan-cake structure cannot arise during the recrystallizing annealing due to the aluminum nitride precipitates. By choosing low reel temperatures of around 520 degrees Celsius, hot strip qualities were surprisingly achieved, which ensured cold-rolled material and made it possible to further refine the grain.
Ein besonderer Vorteil des so hergestellten Warmbandes liegt darin, daß im Grundsatz keinerlei Restriktion hinsichtlich des anschließenden Kaltwalzens besteht, sofern der Kaltwalzgrad mindestens ca. 5 % beträgt, d.h. oberhalb der bekannten kritischen schwachen Kaltverformung bleibt, die beim Rekristallisationsglühen zu grobem Korn führt. Bisher war man bei der Erzeugung annähernd zipfelfreien Kaltbandes an bestimmte Kaltwalzgrade gebunden, sofern nicht normalgeglüht werden sollte.A particular advantage of the hot strip produced in this way is that there is in principle no restriction with regard to the subsequent cold rolling, provided that the degree of cold rolling is at least approx. 5%, i.e. remains above the known critical weak cold deformation, which leads to coarse grain during recrystallization annealing. So far, the production of almost strip-free cold strip was tied to certain cold rolling degrees, unless normal annealing was to be carried out.
Es wurde überraschend gefunden, daß zwar ein gewisser Titangehalt in der Stahllegierung unerlässlich ist, um das erfindungsgemäße Verfahren durchführen zu können und erfindungsgemäße Materialeingenschaften zu erzielen, aber diese Verfahrensparameter zumindest hinsichtlich des Kaltwalzgrades dann anzupassen sind, wenn der Stahllegierung das festigkeitssteigernde Element Niob hinzugefügt wird.It has surprisingly been found that, although a certain titanium content is essential in the steel alloy in order to be able to carry out the process according to the invention and to achieve material properties according to the invention, these process parameters must be adapted, at least with regard to the degree of cold rolling, when the strength-increasing element niobium is added to the steel alloy.
Die Variation der Kaltwalzgrade in Abhängigkeit von der Menge des zulegierten Titans ist bei gleichzeitiger Zulegierung von Niob in den angegebenen Grenzen auf Kaltwalzgrade von 45 bis 85 % beschränkt.The variation of the cold rolling degrees as a function of the amount of titanium alloyed is limited to cold rolling degrees of 45 to 85% with the simultaneous addition of niobium within the specified limits.
Die Zulegierung von Niob behindert nicht die frühzeitige Bildung von Titannitrid, so daß auch bei dieser erfindungsgemäßen Stahllegierung ein pan-cake-Gefüge während des rekristallisierenden Glühens nicht entstehen kann. Eine gravierende technische und wirtschaftliche Bedeutung der Erfindung liegt in der Verwendung des Feinbleches für rotationssymmetrisch tiefgezogene Teile wie Nadellagerkäfige, Riemenscheibenhälften usw. Das erfindungsgemäße Blech kann in diesen Fällen ohne wesentliche Nacharbeit wie Abschneiden der Zipfel eingesetzt werden. Die Zipfelarmut verhindert beim Tiefziehen auch das Entstehen sektoraler Wandschwächungen, so daß die gezogenen Teile bei Rotation keine Unwucht aufweisen. Weitere Vorteile zipfelarmen oder zipfelfreien Kaltbandes sind bekannt, so daß sich eine weitere Beschreibung erübrigt.The addition of niobium does not hinder the early formation of titanium nitride, so that even with this steel alloy according to the invention, a pan-cake structure cannot arise during the recrystallizing annealing. A serious technical and economic significance of the invention lies in the use of the thin sheet for rotationally symmetrical deep-drawn parts such as needle bearing cages, pulley halves etc. The sheet according to the invention can be used in these cases without substantial reworking such as cutting off the tips. The low-end point also prevents the formation of sectoral wall weaknesses during deep drawing, so that the drawn parts do not have any imbalance during rotation. Further advantages of low-lobe or lobe-free cold strip are known, so that a further description is unnecessary.
Einige Ausführungsbeispiele sollen das Ergebnis des erfindungsgemäßen Verfahrens verdeutlichen.Some exemplary embodiments are intended to clarify the result of the method according to the invention.
Aus den erfindungsgemäßen Schmelzen A - D sowie den Vergleichsschmelzen E - F (Tabelle 1) werden Brammen von 210 mm Dicke im Strang vergossen. Nach Erwärmung im Stoßofen auf 1250 Grad Celsius wurde die Bramme zu Warmband von 3 mm Dicke ausgewalzt, gehaspelt und auf Raumtemperatur abgekühlt. Die Walzendtemperaturen und Haspeltemperaturen zeigt Tabelle 2. Nach dem Beizen wurden Bänder durch Kaltwalzen in unterschiedlichen Stufen von 10 % bis zu 80 % auf Feinblechdicke reduziert und erneut gehaspelt. Das Bund wurde im Haubenglühofen der Bauart Fa. Ludwig auf 700 Grad Celsius erwärmt, mit einem Durchsatz von 1 , 1 t/h bis 1, 9 t/h rekristallisierend geglüht und anschließend im Ofen auf 120 Grad Celsius abgekühlt. Nach dem Dressieren mit Umformgraden von 1 - 1, 2 % wurde das Band zu Blechtafeln konfektioniert.From the melts A - D according to the invention and the comparative melts E - F (Table 1), slabs 210 mm thick are cast in the strand. After heating in the pusher furnace to 1250 degrees Celsius, the slab was rolled out into 3 mm thick hot strip, coiled and cooled to room temperature. The final roll temperatures and reel temperatures are shown in Table 2. After the pickling, strips were reduced by cold rolling in various stages from 10% to 80% to the thickness of the sheet and rewound. The coil was heated to 700 degrees Celsius in a bell annealer of the Ludwig company, recrystallized at a throughput of 1.1 t / h to 1.9 t / h and then cooled in the furnace to 120 degrees Celsius. After the tempering with degrees of deformation of 1 - 1, 2%, the strip was made into sheet metal.
Blechronden von 90 bzw. 180 mm Durchmesser wurden mit Ziehstempeln von 50 bzw. 100 mm Durchmesser bei Haltekräften von 50 kN zu Näpfchen tiefgezogen. Figur 1 zeigt drei verschiedene Näpfchen, die die im folgenden verwendeten Begriffe zipfelig (Fig. 1a), zipfelarm (Fig. 1b) und zipfelfrei (Fig. 1c) definieren sollen, da die Messung der Zipfelhöhe mit den handelsüblichen Zipfelmeßgeräten, insbesondere von zipfelarmen und zipfelfreien Näpfchen mit geringen Höhendifferenzen bereits bei kleinsten Tiefziehgraten auf dem Näpfchenrand problematisch ist.Sheet rounds of 90 or 180 mm in diameter were deep-drawn into cups using drawing dies of 50 or 100 mm in diameter and holding forces of 50 kN. Figure 1 shows three different wells, which are to define the terms used in the following, pointed (Fig. 1a), low-pointed (Fig. 1b) and free (Fig. 1c), since the measurement of the height of the corners with the conventional corner measuring devices, in particular of corner-poor and Tip-free wells with small height differences are problematic even with the smallest deep-drawing burrs on the edge of the well.
Diese Definition wurde für Figur 10 zur Darstellung der Zipfeligkeit von Näpfchen aus den verschiedenen Schmelzen übernommen. Bestätigt wurde die Erkenntnis, daß der bei 710 Grad Celsius gehaspelte Stahl E nur bei Kaltwalzgraden kleiner ca. 25 % zipfelfrei ist und im Bereich 30 - 50 % Kaltwalzgrad allenfalls als zipfelarm bezeichnet werden kann. Für den Vergleichsstahl F der gemäß Stand der Technik bei 500 Grad Celsius gehaspelt wurde, wurde Zipfeligkeit bei Kaltwalzgraden größer 30 % festgestellt. Die Fotos in den Figuren 8 und 9 belegen dies eindrucksvoll.This definition was adopted for Figure 10 to represent the lobes of wells from the different melts. The finding was confirmed that the steel E coiled at 710 degrees Celsius is free of flakes only at cold rolling degrees of less than approx. 25% and in the range of 30 - 50% cold rolling degrees can at best be described as flake-free. For the comparative steel F which was coiled at 500 degrees Celsius according to the state of the art, cornering was found at degrees of cold rolling greater than 30%. The photos in Figures 8 and 9 demonstrate this impressively.
Bei Verwendung der erfindungsgemäß gewalzten und geglühten Stähle A - D zeigten die Näpfchen in Abhängigkeit vom Titangehalt bei verschiedenen Kaltwalzgraden ein unterschiedliches Tiefziehergebnis:When using the steels A - D rolled and annealed according to the invention, the cells showed a different deep-drawing result depending on the titanium content at different degrees of cold rolling:
Stahl A mit 0,01 % Ti:Steel A with 0.01% Ti:
Die Näpfchen waren bei Kaltwalzgraden von Epsilon = 30 - 50 % absolut zipfelfrei, während Kaltwalzgrade von 20 % bzw. 60 % nur zipfelarmes Näpfchen-Ziehen ermöglichte.The cups were absolutely spot-free at cold rolling degrees of Epsilon = 30 - 50%, while cold rolling degrees of 20% or 60% only made it possible to pull wells with little tips.
Stahl B mit 0,02 % Ti:Steel B with 0.02% Ti:
Zipfelfrei bei Epsilon = 10 % sowie 50 - 80 % Zipfelarm bei Epsilon = 20 %; 40 %Point-free at Epsilon = 10% and 50 - 80% Tip arm at Epsilon = 20%; 40%
Stähle C1/C2 mit 0,03 % Ti, wobei C1 mit 500 Grad Celsius und C2 mit 450 Grad Celsius gehaspelt wurde:Steels C1 / C2 with 0.03% Ti, whereby C1 was coiled at 500 degrees Celsius and C2 at 450 degrees Celsius:
Zipfelfrei bei Epsilon = 10 - 20 % sowie 60 - 80 %Point-free at Epsilon = 10 - 20% and 60 - 80%
Zipfelarm bei Epsilon = 30 %; 50 %Tip arm at Epsilon = 30%; 50%
Stahl D mit 0,04 % Ti:Steel D with 0.04% Ti:
Zipfelfrei bei Epsilon = 60 - 70 % bzw. 20 %Point-free at Epsilon = 60 - 70% or 20%
Zipfelarm bei Epsilon = 15 %, 25 % ; 55 %; 80 %Pointed arm at Epsilon = 15%, 25%; 55%; 80%
Aus dem Vergleich der Kurven für die Stähle A - D lassen sich Tendenzen ablesen, die für Zwischenwerte des Legierungselementes Titeln beispielsweise 0,025 % Ti - ausgehend von Stahl B - zipfelfreies Näpfchenziehen bei Kaltwalzgraden bis 15 % oder 20 % und bis 85 % erwarten lassen, also eine Kurvenverschiebung nach rechts; bei Werten zwischen 0,01 % und 0,02 % umgekehrt eine Verschiebung der "zipfelfreien" Kaltwalzgrade zu niedrigeren Umformverhältnissen nahelegen.From the comparison of the curves for steels A - D, tendencies can be read which, for intermediate values of the alloying element titles, for example 0.025% Ti - starting from steel B - tip-free cell pulling at cold rolling grades of up to 15% or 20% and up to 85% can be expected a curve shift to the right; conversely, values between 0.01% and 0.02% suggest a shift in the "corner-free" cold rolling degrees to lower forming ratios.
Die zu den Stählen gemäß Figur 10 und Tabelle 1 bzw. 2 korrespondierenden Fotos der Figuren 3 bis 7 von tiefgezogenen Näpfchen veranschaulichen das Ergebnis deutlich.The photos of FIGS. 3 to 7 of deep-drawn cells corresponding to the steels according to FIG. 10 and Tables 1 and 2 clearly illustrate the result.
Überraschend zeigte sich, daß den "zipfelfreien" Umformgraden jeweils ein bestimmtes Zugfestigkeits- und Streckgrenzenniveau zugeordnet werden konnte (Figur 11 ) und die größte Zipfeligkeit gleichzeitig bei der niedrigsten Streckgrenze/Zugfestigkeit festzustellen war.Surprisingly, it was found that a certain level of tensile strength and yield strength could be assigned to the "corner-free" degrees of deformation (FIG. 11) and that the greatest cornering was found at the same time with the lowest yield strength / tensile strength.
Beispiel: Stahl B a) Zipfelfreiheit beim Kaltwalzgrad 10 % - 15 % ≙ Streckgrenzenniveau Rp0,2= 400 - 350 N/mm2 Zugfestigkeitsniveau Rm = 450 - 400 N/mm2 Example: Steel B a) Point free at cold rolling degree 10% - 15% ≙ yield point level R p 0.2 = 400 - 350 N / mm 2 tensile strength level R m = 450 - 400 N / mm 2
b) Zipfeligkeit beim Kaltwalzgrad 30 % ≙ Rp0,2= 180 N/mm2 und Rm = 320 N/mm2 b) Pointedness at the degree of cold rolling 30% ≙ Rp 0.2 = 180 N / mm 2 and R m = 320 N / mm 2
c) Zipfelfreiheit beim Kaltwalzgrad 50 - 80 % ≙ Rp0, 2= 250 - 280 N/mm2 und Rm = 360 - 370 N/mm2 c) Point freedom with cold rolling degree 50 - 80% ≙ R p0, 2 = 250 - 280 N / mm 2 and R m = 360 - 370 N / mm 2
Diese Erkenntnis ermöglicht eine bauteil- oder funktionsangepaßte Wahl der Festigkeit für ein und dasselbe Bauteil durch Änderung der Parameter Titangehalt und Kaltwalzgrad.This knowledge enables a component or function-adapted choice of strength for one and the same component by changing the parameters titanium content and cold rolling degree.
Tabelle 2 zeigt korrespondierend zu Figur 12 die erfindungsgemäß erzielte Korngröße in ASTM-Einheiten; die erzielbare Kornverfeinerung gegenüber Stählen ohne Titanzusatz nach dem Stand der Technik ist erheblich und reicht bis ASTM 11.Corresponding to FIG. 12, Table 2 shows the grain size achieved according to the invention in ASTM units; The achievable grain refinement compared to steels without titanium addition according to the state of the art is considerable and extends up to ASTM 11.
Das gröbste Korn wurde bei geringem Ti-Zusatz und geringem Kaltwalzgrad erzielt (ASTM 7). Vergleichsweise wurden bei den Stählen A - D die Warmband-Werte für die Korngröße (ASTM 9-10) in die Figur 12 aufgenommen.The coarsest grain was obtained with a small addition of Ti and a low degree of cold rolling (ASTM 7). For steel A - D, the hot strip values for the grain size (ASTM 9-10) were compared in FIG. 12.
Für einen Stahl C (Varianten C3 - C5) wurden Versuche mit variabler Haspeltemperatur Th und Glühdurchsatz Pg durchgeführt (Tabelle 3) . Während Schwankungen in der Durchsatzmenge des Haubenglühofens von 1,1 - 1,9 t/h sowohl die Korngröße als auch die ebene Anisotropie Delta r nicht negativ beeinflußten, hatte eine Erhöhung der Haspeltemperaturen auf 710 Grad Celsius bei annähernd gleichen Walzendtemperaturen eine Kornvergroberung und eine Verschlechterung der ebenen Anisotropie zur Folge. Die Figuren 2a, 2b, 2c zeigen entsprechende Ergebnisse an Näpfchen aus 180 mm-Ronden, die mit 100 mm-Stempeln bei 50 kN Rückhaltekraft tiefgezogen wurden.For a steel C (variants C3 - C5) tests were carried out with variable coiling temperature Th and annealing throughput Pg (Table 3). While fluctuations in the throughput of the bell annealer from 1.1 - 1.9 t / h did not negatively affect the grain size or the flat anisotropy Delta r, an increase in the reel temperatures to 710 degrees Celsius with roughly the same roll temperatures resulted in grain coarsening and deterioration the plane anisotropy. FIGS. 2a, 2b, 2c show corresponding results on cups made from 180 mm round blanks, which were deep-drawn using 100 mm stamps at a retention force of 50 kN.
In Tabelle 1 sind auch die Schmelzanalysen des erfindungsgemäß bei dem Verfahren einzusetzenden Stahles G mit 0,01 % Titan, H mit 0,02 % Titan und I mit 0,03 % Titan bei 0,05 % bzw. 0,06 % Niobzugabe aufgelistet, dazu wurde ein Vergleichsstahl K mitTable 1 also lists the melt analyzes of the steel G with 0.01% titanium, H with 0.02% titanium and I with 0.03% titanium with 0.05% and 0.06% addition of niobium in the process , a comparative steel K with
0,05 % Niobzugabe, aber ohne Titangehalt aufgeführt.0.05% niobium added, but listed without titanium content.
Aus den erfindungsgemäßen Schmelzen G - I sowie der Vergleichsschmelze K wurden Brammen von 220 mm Dicke im Strang vergossen. Nach Erwärmung im Stoßofen auf 1250 Grad Celsius wurde die Bramme zu Warmband von 4 mm Dicke ausgewalzt und gehaspelt sowie auf Raumtemperatur abgekühlt. Die Walzendtemperatur betrug 880 Grad Celsius und die Haspeltemperatur 510 Grad Celsius. Nach dem Beizen wurden die Bänder durch Kaltwalzen in unterschiedlichen Stufen von 10 bis 80 % auf Feinblechdicke reduziert und erneut gehaspelt. Nach dem Haspeln wurde das festgewickelte Bund im Haubenglühofen der Bauart Fa. Ludwig auf 700 Grad Celsius erwärmt und bei Durchsatzraten von 1,1 Tonnen bzw. 1,8 Tonnen pro Stunde rekristallisierend geglüht, anschließend im Haubenglühofen auf 120 Grad Celsius abgekühlt. Nach dem Dressieren mit einem Umformgrad von 1,1 % wurde das Band zu Blechtafeln konfektioniert. Blechronden von 90 mm Durchmesser wurden mit Ziehstempeln von 50 mm Durchmesser zu Näpfchen tiefgezogen (Figuren 13 - 16).Slabs 220 mm thick were cast in the strand from the melts G - I according to the invention and the comparative melt K. After heating in the pusher furnace to 1250 degrees Celsius, the slab was rolled out into hot strip of 4 mm thickness and coiled and cooled to room temperature. The final roll temperature was 880 degrees Celsius and the reel temperature was 510 degrees Celsius. After pickling, the strips were reduced by cold rolling in different stages from 10 to 80% to sheet thickness and reeled. After coiling, the tightly wound coil was heated to 700 degrees Celsius in the Ludwig annealing furnace and recrystallized annealing at throughput rates of 1.1 tons or 1.8 tons per hour, then cooled to 120 degrees Celsius in the annealing furnace. After tempering with a degree of deformation of 1.1%, the strip was made into sheet metal. Sheet rounds of 90 mm in diameter were deep-drawn into cups using drawing dies of 50 mm in diameter (FIGS. 13-16).
Für den Vergleichsstahl K, der in der Legierung kein Titan enthält, ansonsten zu der gattungsgemäßen Stahlsorte gehört, zeigt Fig. 16 deutlich, daß bei keinem der erprobten Kaltwalzgrade zipfelfreies Tiefziehen möglich war. Bei Verwendung der erfindungsgemäß gewalzten und geglühten Stähle G bis I zeigten die Näpfchen in Abhängigkeit vom Titangehalt bei verschiedenen Kaltwalzgraden ein geringfügig unterschiedliches Tiefziehergebnis:For the comparative steel K, which contains no titanium in the alloy, otherwise belongs to the generic steel grade, FIG. 16 clearly shows that deep-drawing without tipping was not possible with any of the tried and tested degrees of cold rolling. When using the steels G to I rolled and annealed according to the invention, the wells showed a slightly different deep-drawing result depending on the titanium content at different degrees of cold rolling:
Stahl G mit 0,01 % Titan (Fig. 13):Steel G with 0.01% titanium (Fig. 13):
Die Näpfchen waren bei Kaltwalzgraden von Epsilon = 45 bis 85 % in der Kategorie zipfelarm und bei etwa 60 bis 80 % Kaltwalzgraden sogar zipfelfrei.The cups were low in cold rolled grades of epsilon = 45 to 85% in the category pointed and even roughly 60 to 80% cold rolled.
Stahl H mit 0,02 % Titan (Fig. 14):Steel H with 0.02% titanium (Fig. 14):
Zipfelarm im Bereich Epsilon = 55 bis 85 % fast zipfelfrei imTip arm in the area of epsilon = 55 to 85% almost tip free in
Bereich von 60 bis 75 %.Range from 60 to 75%.
Stahl I mit 0,03 % Titan (Fig. 15):Steel I with 0.03% titanium (Fig. 15):
Zipfelarm im Bereich von 60 bis 70 % Kaltwalzgraden.Corner arm in the range of 60 to 70% cold rolling degrees.
Bei den erfindungsgemäß hergestellten Stählen konnten beispielsweise bei einem Titangehalt von 0,01 % am tiefziehfertigen Blech Streckgrenz- und Zugfestigkeitswerte festgestellt werden, die um mehr als 50 N/mm2 über den Kennwerten des nur titanlegierten Materials lagen.In the steels produced according to the invention, for example, with a titanium content of 0.01% on the deep-drawn sheet, yield strength and tensile strength values were found to be more than 50 N / mm 2 above the characteristic values of the only titanium-alloyed material.
Die in Tabelle 1 aufgeführten erfindungsgemäßen Schmelzen L bzw. M mit Phosphorgehalten an der oberen Analysengrenze wurden behandelt wie die Stähle A - F. Die Haspeltemperatur betrug 510 bzw. 500 Grad Celsius. Bei einem Kaltwalzgrad von 66 % wurde die Konstanz der Ergebnisse über die gesamte Bandlänge geprüft, um die Effektivität des Bundglühens zu bestätigen. Die Näpfchen aus dem Tiefziehversuchen sind in Fig. 17 bzw. 18 dargestellt. Sie zeigen, daß zipfelfreies Material sowohl am Bandanfang (Position 0) als auch nach jedem weiteren Viertel des Bandlänge bis zum Bandende (Position 1) erzeugt wurde. The melts L and M according to the invention listed in Table 1 with phosphorus contents at the upper analysis limit were treated like steels A - F. The reel temperature was 510 and 500 degrees Celsius, respectively. At a cold rolling degree of 66%, the consistency of the results was checked over the entire strip length in order to confirm the effectiveness of the annealing. The wells from the deep-drawing test are shown in FIGS. 17 and 18, respectively. They show that tip-free material was produced both at the beginning of the tape (position 0) and after every further quarter of the length of the tape up to the end of the tape (position 1).
Tabe l l e 2 Table 2
Stahl Tw Th K Figur °C °C min / maxSteel Tw Th K figure ° C ° C min / max
A 860 490 10 / 7 3A 860 490 10/7 3
B 870 500 11 / 9 4B 870 500 11/9 4
C1 870 500 11 / 9 5C1 870 500 11/9 5
C2 880 450 11 / 9 6C2 880 450 11/9 6
D 890 430 11 / 9 7D 890 430 11/9 7
E 900 710 9 / 4 8E 900 710 9/4 8
F 890 500 9 / 6 9F 890 500 9/6 9
Tabe l l e 3Table 3
Stahl Tw Th Pg K Δ r FigurSteel Tw Th Pg K Δ r figure
°C °C t/h min /max° C ° C t / h min / max
C3 880 520 1,1 9 - 10 -0,07/+0,06 2aC3 880 520 1.1 9 - 10 -0.07 / + 0.06 2a
C4 915 540 1,9 9 - 10 -0,04/+0,08 2bC4 915 540 1.9 9 - 10 -0.04 / + 0.08 2b
C5 870 710 1,9 8 - 9 +0,09/+0,17 2cC5 870 710 1.9 8 - 9 + 0.09 / + 0.17 2c
In Tabelle 2 und 3 bedeutenIn tables 2 and 3 mean
Tw WalzendtemperaturTw final roll temperature
Th HaspeltemperaturTh reel temperature
K Korngröße nach ASTMK grain size according to ASTM
Pg GlühdurchsatzPg annealing throughput
Δr ebene Anisotropie Δr flat anisotropy

Claims

Kaltgewalztes Blech oder Band und Verfahren zu seiner HerstellungCold rolled sheet or strip and process for its manufacture
PatentansprücheClaims
1. Verfahren zur Herstellung eines kaltgewalzten Bleches oder Bandes mit guter önformbarkeit aus Stahl mit folgender Zusammensetzung in Gewichtsprozenten:1. Method for producing a cold-rolled sheet or strip with good ductility from steel with the following composition in percent by weight:
max. 0,10 % Kohlenstoff max. 0,40 % Silizium 0 , 10 bis 1 ,0 % Mangan max. 0,08 % Phosphor max. 0,02 % Schwefel max. 0,009 % StickstoffMax. 0.10% carbon max. 0.40% silicon 0.10 to 1.0% manganese max. 0.08% phosphorus max. 0.02% sulfur max. 0.009% nitrogen
0,015 bis 0,08 % Aluminium0.015 to 0.08% aluminum
0,01 bis 0,04 % Titan max. 0,15 % von einem oder mehreren der0.01 to 0.04% titanium max. 0.15% of one or more of the
Elementen aus der Gruppe Kupfer,Elements from the group copper,
Vanadium, Nickel, Rest Eisen und unvermeidbare Verunreinigungen,Vanadium, nickel, remainder iron and unavoidable impurities,
welches nach dem Warmwalzen und Kaltwalzen geglüht wird, dadurch gekennzeichnet, daß die Bramme auf oberhalb 1120 Grad Celsius erwärmt und zu Warmband bei einer Walzendtemperatur oberhalb des Ar3-Punktes ausgewalzt und bei 520 ± 100 Grad Celsius gehaspelt und nach dem Kaltwalzen rekristallisierend im Bund geglüht wird.which is annealed after hot rolling and cold rolling, characterized in that the slab is heated to above 1120 degrees Celsius and rolled into hot strip at a final rolling temperature above the Ar 3 point and coiled at 520 ± 100 degrees Celsius and annealed in the coil after cold rolling becomes.
2. Verfahren zur Herstellung eines kaltgewalzten Bleches oder Bandes gemäß Anspruch 1, dadurch gekennzeichnet, daß es in Abhängigkeit vom Titangehalt mit nachstehenden Umformgraden (Epsilon) kaltgewalzt wird: ca. 0,01 % Titan: Epsilon 20 - 60 %, vorzugsweise 30 - 50 %2. A process for producing a cold-rolled sheet or strip according to claim 1, characterized in that it is cold-rolled depending on the titanium content with the following degrees of deformation (epsilon): approx. 0.01% titanium: epsilon 20 - 60%, preferably 30 - 50%
ca. 0,02 % Titan: Epsilon 5 - 20 %, vorzugsweise 10 - 15 % oder Epsilon 40 - 85 %, vorzugsweise 50 - 80 %approx. 0.02% titanium: epsilon 5-20%, preferably 10-15% or epsilon 40-85%, preferably 50-80%
ca. 0,03 % Titan: Epsilon 5 - 25 %, vorzugsweise 10 - 20 % oder Epsilon 50 - 85 %. vorzugsweise 60 - 80 %approx. 0.03% titanium: epsilon 5 - 25%, preferably 10 - 20% or epsilon 50 - 85%. preferably 60 - 80%
ca. 0,04 % Titan: Epsilon 15 - 25 %, vorzugsweise 20 % oderabout 0.04% titanium: epsilon 15-25%, preferably 20% or
Epsilon 55 - 80 %, vorzugsweise 60 - 70 %Epsilon 55 - 80%, preferably 60 - 70%
und anschließend bei Temperaturen unterhalb A1 rekristallisierend geglüht und danach mit einem Umformgrad von ca. 1 % dressiert wird.and then annealed at temperatures below A 1, and then tempered with a degree of deformation of approximately 1%.
Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß ein Stahl eingesetzt wird, der zusätzlich 0,01 - 0,06 % Niob enthält.Method according to claim 1, characterized in that a steel is used which additionally contains 0.01-0.06% niobium.
Verfahren zur Herstellung eines kaltgewalzten Bleches oder Bandes gemäß Anspruch 1, dadurch gekennzeichnet, daß es in Abhängigkeit vom Titangehalt mit nachstehenden Umformgraden (Epsilon) kaltgewalzt wird: ca. 0,01 % Titan: Epsilon 45 bis 85 % ca. 0,02 % Titan: Epsilon 55 bis 85 % ca. 0,03 % Titan: Epsilon 60 bis 70 %A process for producing a cold-rolled sheet or strip according to claim 1, characterized in that it is cold-rolled depending on the titanium content with the following degrees of deformation (epsilon): approx. 0.01% titanium: epsilon 45 to 85% approx. 0.02% titanium: epsilon 55 to 85% approx. 0.03% titanium: epsilon 60 to 70%
und anschließend bei Temperaturen unterhalb A1 rekristallisierend geglüht und danach mit einem Umformgrad von ca. 1 % dressiert wird.and then annealed at temperatures below A 1, and then tempered with a degree of deformation of approximately 1%.
5. Verfahren nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß der Stahl nach dem Kaltwalzen im Festbund geglüht wird.5. The method according to any one of claims 1 to 4, characterized in that the steel is annealed in the tight coil after cold rolling.
6. Zum Tiefziehen geeignetes Blech oder Band aus Stahl in der angegebenen Zusammensetzung und hergestellt nach einem der in den Ansprüchen 1 bis 5 angegebenen Verfahren, gekennzeichnet durch ein rekristallisiertes Gefüge mit einer Ferritkorngröße feiner als ASTM 7 für einen Titangehalt von 0,01 % und feiner als ASTM 9 für Titangehalte von 0,015 bis 0,04 %.6. Suitable for deep drawing sheet or strip of steel in the specified composition and produced by one of the methods specified in claims 1 to 5, characterized by a recrystallized structure with a ferrite grain size finer than ASTM 7 for a titanium content of 0.01% and finer as ASTM 9 for titanium contents from 0.015 to 0.04%.
7. Zum Tiefziehen geeignetes Blech oder Band gemäß Anspruch 6, dadurch gekennzeichnet, daß der Titangehalt mindestens dem 3,5-fachen des Stickstoffgehaltes entspricht.7. Suitable for deep drawing sheet or strip according to claim 6, characterized in that the titanium content corresponds to at least 3.5 times the nitrogen content.
8. Verwendung eines gemäß einem der Verfahren nach Anspruch 1 bis 5 hergestellten Bleches oder Bandes für das zipfelarme Tiefziehen vorzugsweise von rotationssymmetrischen8. Use of a sheet or strip produced according to one of the methods according to claims 1 to 5 for low-corner deep drawing, preferably of rotationally symmetrical
Teilen. Share.
9. Verwendung eines Stahles gemäß Anspruch 1 oder 3 für die Herstellung tiefgezogener, vorzugsweise rotationssymmetrischer Teile. 9. Use of a steel according to claim 1 or 3 for the production of deep-drawn, preferably rotationally symmetrical parts.
EP89901844A 1988-01-29 1989-01-27 Cold-rolled sheet or strip and process for manufacturing them Expired - Lifetime EP0400031B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT89901844T ATE97169T1 (en) 1988-01-29 1989-01-27 COLD ROLLED SHEET OR STRIP AND PROCESS FOR ITS PRODUCTION.

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
DE3803064 1988-01-29
DE3803064A DE3803064C2 (en) 1988-01-29 1988-01-29 Cold rolled sheet or strip and process for its manufacture
DE3843732A DE3843732C2 (en) 1988-01-29 1988-12-22 Cold rolled sheet or strip and process for its manufacture
DE3843732 1988-12-22
PCT/DE1989/000057 WO1989007158A1 (en) 1988-01-29 1989-01-27 Cold-rolled sheet or strip and process for manufacturing them

Publications (3)

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EP0400031A1 true EP0400031A1 (en) 1990-12-05
EP0400031B1 EP0400031B1 (en) 1993-11-10
EP0400031B2 EP0400031B2 (en) 2002-01-02

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US (1) US5139580A (en)
EP (1) EP0400031B2 (en)
JP (1) JPH0814003B2 (en)
DD (1) DD285298B5 (en)
DE (3) DE3803064C2 (en)
ES (1) ES2018975A6 (en)
GR (1) GR1000537B (en)
WO (1) WO1989007158A1 (en)

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US5686194A (en) * 1994-02-07 1997-11-11 Toyo Kohan Co., Ltd. Resin film laminated steel for can by dry forming
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US5656102A (en) * 1996-02-27 1997-08-12 Bethlehem Steel Corporation Bake hardenable vanadium containing steel and method thereof
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Also Published As

Publication number Publication date
US5139580A (en) 1992-08-18
ES2018975A6 (en) 1991-05-16
EP0400031B1 (en) 1993-11-10
JPH0814003B2 (en) 1996-02-14
WO1989007158A1 (en) 1989-08-10
DE3803064C2 (en) 1995-04-20
GR1000537B (en) 1992-08-25
DE3843732C2 (en) 2001-05-10
DD285298A5 (en) 1990-12-12
JPH03503185A (en) 1991-07-18
DE3803064C1 (en) 1989-04-06
DE58906176D1 (en) 1993-12-16
DD285298B5 (en) 1999-01-28
DE3843732A1 (en) 1990-07-05
EP0400031B2 (en) 2002-01-02

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