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
  • C21D8/0447—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
  • C21D8/0468—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 between cold rolling steps
• • 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
  • 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

Definitions

• the invention relates to a method of manufacturing a sheet metal strip. steel for the production of metal packaging and the sheet obtained by the process.
• Sheets with strong characteristics may need to be obtained mechanical, in particular mechanical strength and high yield strength for making metal bodies or bodies with very good resistance, even in the case of very thin sheets for the production of certain packaging.
• the level of mechanical characteristics of the sheet which is obtained after the second cold rolling is a function of the reduction rate or the elongation of the sheet obtained during the two passes of the second rolling.
• the double reduction process which involves a second rolling cold in two passes after annealing the sheets, was applied to steel grades for packaging as well of the ultra low carbon type (ULC) whose carbon content is less than 0.008% than in steels other types, such as renitrided low aluminum steels containing from 8 to 16 thousandths percent of nitrogen.
• ULC ultra low carbon type
• Example 1 case of an ultra low carbon steel ULC.
• the blank was subjected to a second cold rolling in a rolling mill skin-pass.
• Sheet metal ref Allongt 1 passes era TT Re (MPa) Extension 2 * pass Total elongation Re (MPa) SP output Re (MPa) after 200 ° C / 20 min AT 43% 562 606 B 31% 527 9% 43% 558 610 VS 31% 20 ° C / 10d 568 9% 43% 594 648 D 31% 75 ° C / 30mn 561 9% 43% 605 648 E 31% 75 ° C / 3h 552 9% 43% 616 665 F 31% 200 ° C / 20mn 565 9% 43% 616 668 G 31% 20 ° C / 3d 560 9% 43% 589 621
• the sheets designated by the references A and B have not been submitted to a treatment according to the invention.
• the sheets A and B obtained after second cold rolling with skin-pass are designated as comparative sheets.
• the sheets designated under the references C to G have been subjected, according to the method of the invention, to a second cold rolling in two aging passes between the two skin-pass rolling passes.
• the total elongation of the sheet is 43%, this elongation being obtained in a single pass in the case of sheet A.
• the elongation is obtained in two passes (respectively 31 and 9% lengthening), without intermediate aging treatment between two passes, in the case of sheet B.
• Sheet C is subjected to 10 days aging at 20 ° C and sheet D to an aging treatment at 75 ° C for 30 minutes, between two passes of cold rolling.
• An aging treatment at 200 ° C for 20 minutes is carried out between the two passes from the final cold rolling to the skin-pass (extensions of 31 and 9%) in the case of sheet F and sheet G is subject three days aging at 20 ° C between the two rolling passes final.
• the elastic limit of the sheets was measured in MPa, at the end of the treatment thermal after the first pass from cold rolling to the skin-pass, when two rolling passes are made (sheets B to G); limits corresponding elastics are reported in the fourth column of the table I.
• the elastic limits of the sheets were also measured immediately after leaving the skin-pass (7 th column of table I) and after holding the sheet for 20 minutes at 200 ° C. after leaving the skin-pass (8 th column of the table I).
• Sheet B which is made with a second rolling in two passes therefore has mechanical characteristics, after 20 minutes at 200 ° C, slightly higher than sheet A produced by a second rolling in one pass.
• an additional improvement is brought about by an aging treatment between the two rolling passes of the rolling final.
• the elastic limits, immediately at the exit of the skin-pass or after 20 minutes at 200 ° C, are still increased due to the work hardening provided by the second rolling pass.
• the final elastic limits obtained on sheets C to G whose development is carried out according to the invention are significantly higher than the final elastic limits of sheets A and B obtained by a process of second rolling in one pass (sheet A) or second rolling in two passes (sheet B) according to the prior art, the total elongation rate being identical in all cases.
• the process according to the invention therefore makes it possible to obtain, for a total hardening of the identical sheet, superior mechanical characteristics. Because the ability to form sheet metal and in particular the ability at the drawing depend on the work hardening, one can obtain sheets with satisfactory forming characteristics at the same time and high mechanical characteristics.
• ultra low carbon steel can age at room temperature of the order of 20 ° C for a period of 3 to 10 days, at a moderate temperature included between 50 and 100 ° C for a period of 1 to 5 hours, or even a higher temperature, between 150 and 300 ° C, during a duration between 10 minutes and 1 hour.
• Sheet metal ref Allongt 1 passes era TT Re (MPa) Long 2nd pass Total elongation Re (MPa) SP output AT' 28% 570 B ' 20% 20 ° C / 3d 601 6% 28% 595 VS' 20% 75 ° C / 10 h 600 6% 28% 635 Of 20% 200 ° C / 20 min 630 6% 28% 625
• the sheet A ' is produced by a production process according to the prior art while the sheets B ', C' and D 'are produced by a process according to the invention.
• the second cold rolling is carried out in a single pass with an elongation rate of 28%.
• the elastic limit of the sheet at the exit of the skin-pass is 570 MPa.
• the sheets B ', C' and D' were produced by a process according to the invention in which the second cold rolling is carried out in two passes (20% and 6% elongation respectively) with a heat treatment of aging between the two passes.
• the manufacturing processes for sheets B ', C' and D ' are distinguished by the conditions under which the heat treatment between the two passes of the final rolling.
• Sheet B ' was aged at an ambient temperature of 20 ° C for three days.
• Sheet C ' has been aged at a moderate temperature of 75 ° C for 10 hours and the sheet metal D has been aged at a temperature higher than 200 ° C for 20 minutes.
• the elastic limits obtained at the exit of the skin-pass after the second rolling pass producing 6% elongation are all greater than the elastic limit of the sheet A 'obtained by rolling with skin pass in one pass.
• sheet B ' Although long-term aging at room temperature is satisfactory (sheet B '), it is preferable to carry out the aging at a higher temperature, for a shorter time.
• a new dislocation network or second dislocation network During the second skin pass pass, a new dislocation network or second dislocation network.
• This new configuration of the dislocation network explains obtaining a better formability for characteristics mechanical properties or obtaining mechanical characteristics maintaining good formability.
• the invention applies to all steels for Al-K sheets, that is to say steels calmed with aluminum, without carburogenic and / or ni scholarogenic elements, when these sheet steels are continuously annealed.
• the aging treatment can be carried out at a temperature close to 20 ° C, for a period of 3 to 10 days, or at a moderate temperature between 50 and 100 ° C for a period of 5 to 15 hours, or even at a higher temperature between 150 and 300 ° C for a period of between 10 minutes and 1 hour.
• the invention also applies to ultra low carbon steels, the general composition is given above.
• the sheets obtained by the process of the invention can be used in all applications for DR quality packaging sheets.
• the sheets can be cut to make blanks intended for the manufacture of bodies or bottoms of boxes two or three pieces with strong mechanical characteristics.
• the sheets obtained by the process of the invention can be used in thinner thicknesses.
• the total elongation rate during the second cold rolling can be different from the elongation rates indicated above.
• the distribution elongation percentages between the first and second pass of the second cold rolling may be different from the indicated distributions upper.
• the second cold rolling with an elongation rate of between 25% and 35% during the first rolling pass and with an elongation rate less than 15% and preferably between 5% and 10% for the second rolling phase.
• the second rolling is preferably carried out the second rolling with an elongation rate of between 15% and 25% during the first rolling pass and a rate of less than 10%, during the second pass of the second cold rolling.
• the process according to the invention can be applied to manufacturing thin metal strips for packaging metallic in different shades from ultra low carbon shades or low renitrided aluminum which have been described above.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Physics & Mathematics (AREA)
• Heat Treatment Of Sheet Steel (AREA)
• Package Frames And Binding Bands (AREA)
• Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
• Heat Treatment Of Steel (AREA)
• Manufacturing Of Steel Electrode Plates (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=9511822

Family Applications (1)

Country Status (8)

Cited By (4)

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Citations (6)

• 1997
  • 1997-10-03 FR FR9712375A patent/FR2769251B1/fr not_active Expired - Fee Related
• 1998
  • 1998-09-28 ES ES98402383T patent/ES2181143T3/es not_active Expired - Lifetime
  • 1998-09-28 DE DE69807617T patent/DE69807617T2/de not_active Expired - Lifetime
  • 1998-09-28 EP EP98402383A patent/EP0906961B1/de not_active Expired - Lifetime
  • 1998-09-28 AT AT98402383T patent/ATE223503T1/de not_active IP Right Cessation
  • 1998-09-28 PT PT98402383T patent/PT906961E/pt unknown
  • 1998-10-02 CA CA002246591A patent/CA2246591C/fr not_active Expired - Lifetime
  • 1998-10-05 US US09/166,126 patent/US6156131A/en not_active Expired - Lifetime

Patent Citations (6)

Non-Patent Citations (2)

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