Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/06—Alloys based on aluminium with magnesium as the next major constituent
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
  • C22F1/047—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon of alloys with magnesium as the next major constituent
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/06—Alloys based on aluminium with magnesium as the next major constituent
  • C22C21/08—Alloys based on aluminium with magnesium as the next major constituent with silicon

Definitions

• the invention relates to a method for producing a sheet or strip from an aluminum alloy and a sheet, strip or molded part produced thereby.
• Al-Mg-Mn alloys are therefore only suitable to a limited extent, for example, for outer skin parts in body construction, where ssf (strech strain free) quality or ffa (low flow figure) quality, i.e. freedom or reduction of type A flow figures, is required.
• the process should be easy to use and reproducible.
• the sheet or strip in the process is made of an aluminum alloy with the composition, namely from 2.0 to 5.5% by weight of magnesium (Mg), from 0.2 to 1.2% by weight of manganese (Mn), optionally up to 0.45% by weight silicon (Si), optionally up to 0.55% by weight iron (Fe), optionally up to 0.35% by weight chromium (Cr), optionally up to 0.2% by weight % Titanium (Ti), optionally up to 0.2% by weight silver (Ag), optionally up to 4.0% by weight zinc (Zn), optionally up to 0.8% by weight copper (Cu), optionally up to 0.8% by weight of zirconium (Zr), optionally up to 0.3% by weight of niobium (Nb), optionally up to 0.25% by weight of tantalum (Ta), optionally up to 0.05% by weight of vanadium (V) and the remainder aluminum and production-related inevitable impurities, each with a maximum of 0.05% by weight and a total of at most 0.15% by weight of magnesium (M
• the sheet or strip cold-rolled to the final thickness has at least one intermetallic phase with first particles with an average particle size of 5 ⁇ m to 10 ⁇ m (measured according to the line-cutting method ASTM E112) - by the process steps before the heat treatment.
• the at least casting and the cold rolling in particular after the intermediate annealing, are coordinated with one another in such a way that the sheet or strip has at least one intermetallic phase with first particles with an average particle size of 5 ⁇ m to 10 ⁇ m.
• a sheet or strip with high strength and formability as well as ssf quality or ffa quality can be produced - if this sheet or strip has a mean crystal grain size D of ⁇ 60 ⁇ m after heat treatment (measured according to the ASTM E112 line cutting method) ) and the average crystal grain size D in mm and the number A of the first particles per mm 2 in the aluminum alloy the condition D ⁇ A > 1 , 8th fulfilled - for example in which the recrystallization annealing of the heat treatment is carried out in this way.
• This method is also easy to use and, for example by means of water cooling for accelerated cooling, has the highest level of reproducibility in order to produce a sheet or strip in ssf quality or ffa quality.
• the number of dislocations in the sheet or strip can be increased further in the process if D ⁇ A > 2nd is. Especially if D ⁇ A > 2nd , 5 the sheet or strip can meet comparatively high quality standards without the fear of flow figures, for example Lüders lines of type A, on the surface of the formed sheet or strip, even in the case of comparatively complex geometries or unfavorable plastic deformations.
• the reproducibility of the method can be further improved if, in the heat treatment, the recrystallization annealing is carried out by holding at a temperature of 300 ° C. (degrees Celsius) or more, in particular up to 600 ° C. This can improve further if the recrystallization annealing at 450 ° C to 550 ° C he follows. In addition, this annealing temperature can be sufficient to prestress the structure sufficiently by accelerated cooling in order to produce those dislocations on the first particles which subsequently do not make it necessary to dislodge Lüders lines.
• the heated sheet is accelerated at a cooling rate of at least 10 K / s (Kelvin per second), in particular at least 20 K / s or at least 50 K / s, this accelerated cooling to in particular below 180 ° C. , especially at room temperature.
• K / s Kelvin per second
• the billet is solidified while maintaining a cooling rate (or cooling rate) of ⁇ 2.5 ° C./s.
• a cooling rate or cooling rate
• the cooling rate is ⁇ 2 ° C / s or ⁇ 1 ° C / s or ⁇ 0.75 ° C / s.
• a possible reduction in the average particle size can be absorbed by subsequent process steps, for example by cold rolling, to ensure an average particle size of 5 ⁇ m to 10 ⁇ m before the heat treatment.
• the optional homogenization can be done by holding at 450 ° C to 550 ° C for at least 0.5 h.
• Hot rolling can take place at 280 ° C to 550 ° C.
• the cold rolling to the final thickness can take place with a degree of rolling from 10% to 65%, in particular from 20% to 50%.
• a degree of rolling from 10% to 65%, in particular from 20% to 50%.
• the cold rolling takes place after the intermediate annealing with a rolling degree of 10% to 65%, in particular 20% to 50%, in order to improve the reproducibility of the average particle size from 5 ⁇ m to 10 ⁇ m.
• the optional intermediate annealing can be done by holding at 300 ° C to 500 ° C.
• the optional stabilization can be carried out by holding at 80 ° C to 120 ° C for at least 0.5 h.
• An average particle size of 5 ⁇ m to 10 ⁇ m before the heat treatment can be ensured in particular if the product of degree of rolling in% after intermediate annealing and cooling rate in ° C / s meets the condition 10 ⁇ degree of rolling * cooling rate ⁇ 50, in particular 20 ⁇ degree of rolling * Cooling rate ⁇ 45, fulfilled.
• the intermetallic phase has an Al-Mn base, those dislocations can be created in the aluminum alloy on the basis of which flow figures can be avoided in a particularly stable manner.
• the intermetallic phase is preferably of the Al 13 (Mn, Fe) 6 or Al 15 FeMn 3 Si 2 or Al 12 Mn or Al 6 Mn type. It is also conceivable that the primary phase forms the intermetallic phase in order to create a sufficient number of dislocations in cooperation with the heat treatment of the sheet or strip.
• the aluminum alloy (with an Al-Mg-Mn base) is from 4.0 to 5.0% by weight of magnesium (Mg) and / or Has 0.2 to 0.5 wt .-% manganese (Mn).
• the aluminum alloy additionally contains 2.0 to 4.0% by weight of zinc (Zn) (Al-Mg-Zn base).
• This aluminum alloy can optionally have up to 0.8% by weight of copper (Cu).
• the invention achieves the stated object with regard to the sheet or strip by the features of claim 8.
• zirconium (Zr) optionally up to 0.3% by weight of niobium (Nb), optionally up to 0.25% by weight of tantalum (Ta) and the rest aluminum and Due to production-related unavoidable impurities with a maximum of 0.05% by weight and a total of at most 0.15% by weight, an alloy composition is available with which sufficiently high strength and formability, an
• the mean crystal grain size D according to the invention of 60 60 ⁇ m leads to the fact that the comparatively fine crystal grain of the sheet or strip enables high strength and formability.
• the first particles present in the sheet or strip have a limited average particle size of 5 ⁇ m to 10 ⁇ m, the average crystal grain size D in mm and the number A of the first Particles in the aluminum alloy per mm 2 the condition D ⁇ A > 1 , 8th Fulfills.
• a sheet or strip made of an aluminum alloy preferably with an Al-Mg base (or Mg as one of the main alloy elements) in ssf-quality or ffa-quality, is created, which also has sufficient strength and formability, for example for outer skin parts in body construction can award.
• the number of dislocations in the sheet or strip can be increased further if D ⁇ A > 2nd is. Especially if D ⁇ A > 2nd , 5 the sheet or strip can meet comparatively high quality standards without the fear of flow figures, for example Lüders lines of type A, on the surface of the formed sheet or strip, even in the case of comparatively complex geometries or unfavorable plastic deformations.
• a sufficient number of dislocations in order to avoid flow figures on the formed sheet or strip can result if the crystal structure has more than 200, in particular more than 400, dislocations on each first particle. This can be achieved if the sheet or strip has been heat-treated by heating and then accelerated cooling such that the crystal structure has more than 200, in particular more than 400, dislocations for each first particle.
• the number A of the first particles is preferably 10 10 particles / mm 2 , which can enable a sufficient distribution of the dislocations in the sheet metal or strip to avoid flow figures. This is particularly the case if the number A of the first particles is 25 25 particles / mm 2 , preferably 35 35 particles / mm 2 .
• the intermetallic phase has an Al-Mn base, those dislocations can be created in the aluminum alloy that can be used to avoid stable flow figures.
• the intermetallic phase is preferably of the Al 13 (Mn, Fe) 6 or Al 15 FeMn 3 Si 2 or Al 12 Mn or Al 6 Mn type. It is also conceivable that the primary phase forms the intermetallic phase in order to create a sufficient number of dislocations through the subsequent heat treatment of the sheet or strip.
• the aluminum alloy contains 4.0 to 5.0% by weight of magnesium (Mg) and / or 0.2 to 0.5% by weight of manganese (Mn ) having.
• the aluminum alloy additionally contains 2.0 to 4.0% by weight of zinc (Zn) (with an Al-Mg-Zn base).
• This aluminum alloy can optionally have up to 0.8% by weight of copper (Cu).
• the sheet or strip according to the invention can also be particularly suitable for producing a molded part, in particular a vehicle part, preferably a body part, by sheet metal forming.
• a plate is preferably produced from the sheet or strip in order to be able to carry out a sheet metal forming process.
• the aluminum alloy preferably has an Al-Mg base.
• the sheet or strip can have an average crystal grain size D of ⁇ 50 ⁇ m, ⁇ 40 ⁇ m or ⁇ 30 ⁇ m.
• the cooling rate (or cooling rate) ⁇ 2.4 ° C / s, ⁇ 2.3 ° C / s, ⁇ 2.2 ° C / s, ⁇ 2.1 ° C / s, ⁇ 2.0 ° C / s, ⁇ 1.9 ° C / s, ⁇ 1.8 ° C / s, ⁇ 1.7 ° C / s, ⁇ 1.6 ° C / s, ⁇ 1.5 ° C / s, ⁇ 1.4 ° C / s, ⁇ 1.3 ° C / s, ⁇ 1.2 ° C / s, ⁇ 1.1 ° C / s, ⁇ 1.0 ° C / s, ⁇ 0.9 ° C / s, ⁇ 0.8 ° C / s, ⁇ 0.7 ° C / s or ⁇ 0.6 ° C / s.
• the strip can be separated into a split strip or into sheet metal or else cut off from the sheet or strip in order to form these semi-finished products, for example to form sheet metal.
• Forming can be deep drawing, roll profiling, etc.
• the aluminum alloy can be of the type, for example, EN AW-5083 or EN AW-5086 or EN AW-5182 or EN AW-5454 or EN AW-5457 or EN AW-5754.
• a fine sheet A1 with a sheet thickness of 1.2 mm was produced from an alloy of the type AA5182 (Al-Mg-Mn base) with the chemical composition C1.
• the production of the billet was solidified with a comparatively reduced cooling rate (or cooling rate), the rolling steps for hot and cold rolling were carried out according to the standard scheme.
• the last rolling pass during cold rolling was 63% (from 3.25 mm to 1.2 mm) and the final heat treatment was carried out at 500 ° C. with subsequent water quenching.
• the mean crystal grain size or final grain size of the thin sheet A1 was 15 ⁇ m (measured according to the line-cutting method ASTM E112) and in the intermetallic phase 44, the first having a mean particle size of 5 ⁇ m to 10 ⁇ m (measured according to the line-cutting method ASTM E112) Particles per mm 2 . These first particles were also comparatively rough.
• the condition 10 ⁇ degree of rolling * cooling rate ⁇ 50 is met.
• the criterion ( ⁇ D * A> 1.8) is met with a ⁇ D * A value of 5.4.
• a tensile test showed no lines of Lüders on the surface of the sheet A1.
• the intermetallic phase according to the invention with the first particles could therefore ensure a sufficient number of dislocations in order to prevent Lüders lines from being formed.
• a sheet A2 with a sheet thickness of 1.2 mm was made from an alloy of type AA5182 with the chemical composition C2.
• the billet was solidified at a cooling rate (or cooling rate) of 1.8 ° C / s and the rolling steps during hot and cold rolling were carried out according to the standard scheme.
• the last rolling pass during cold rolling was 15% (from 1.41 mm to 1.2 mm), the final heat treatment was carried out at 500 ° C subsequent water quenching.
• the condition 10 ⁇ degree of rolling * cooling rate ⁇ 50 is met.
• the average crystal grain size or final grain size of the fine sheet A1 after the heat treatment was found to be 35 ⁇ m and in the intermetallic phase there were 12 first particles per mm 2 having an average particle size of 5 ⁇ m to 10 ⁇ m. With a ⁇ D * A value of 2.24, the criterion ( ⁇ D * A> 1.8) is met. A tensile test showed no lines of Lüders on the surface of the sheet A2. The intermetallic phase according to the invention with the first particles could therefore ensure a sufficient number of dislocations in order to prevent Lüders lines from being formed.
• a sheet A3 with a sheet thickness of 1.2 mm was made from an alloy of type AA5182 with the chemical composition C3.
• the ingot was solidified at a cooling rate (or cooling rate) of 1.8 ° C / s and the rolling steps in hot and cold rolling were carried out according to the standard scheme.
• the last rolling pass during cold rolling was 18% (from 1.46 mm to 1.2 mm), the final heat treatment was carried out at 500 ° C with subsequent water quenching.
• the average crystal grain size or final grain size was 29 ⁇ m and in the intermetallic phase 14 first particles per mm 2 were found having an average particle size of 5 ⁇ m to 10 ⁇ m.
• the condition 10 ⁇ degree of rolling * cooling rate ⁇ 50 is met.
• Two sheets A4.1 and A4.2 with a sheet thickness of 1.2 mm were made from an alloy of type AA5182 with the chemical composition C4.
• the rolling ingot was solidified at a cooling rate (or cooling rate) of 1.8 ° C./s, and the rolling steps during hot and cold rolling were carried out according to the standard scheme.
• the last rolling pass during cold rolling was 25% (from 1.60 mm to 1.2 mm).
• the final heat treatment was carried out on sheet A4.1 at 500 ° C with subsequent water quenching.
• the sheet A4.2 was finally heat-treated at 370 ° C with subsequent cooling in still air.
• the average crystal grain size or final grain size of the two fine sheets A4.1 and A4.2 was 32 ⁇ m and in their intermetallic phase there were 12 first particles per mm 2 having an average particle size of 5 ⁇ m to 10 ⁇ m. With a ⁇ D * A value of 2.14, the criterion ( ⁇ D * A> 1.8) is met by both thin sheets A4.1 and A4.2.
• Lüders lines appear on A4.2 thin sheet after deep drawing.
• the slower cooling in still air did not allow a sufficient number of dislocations to form on the sheet A4.2 to prevent lines of wear.
• the accelerated water cooling of the sheet A4.1 therefore meant that the intermetallic phase with the first particles could provide a sufficient number of dislocations to prevent Lüders lines from being formed.
• a sheet A5 with a sheet thickness of 1.2 mm was made from an alloy of type AA5182 with the chemical composition C4.
• the billet was solidified at a cooling rate (or cooling rate) of 1.8 ° C / s and the rolling steps during hot and cold rolling were carried out according to the standard scheme.
• the last rolling pass during cold rolling was 63% (from 3.25 mm to 1.2mm), the final heat treatment was carried out at 500 ° C with subsequent water quenching.
• the average crystal grain size or final grain size was 10 ⁇ m and in the intermetallic phase there were 12 first particles per mm 2 having an average particle size of 5 ⁇ m to 10 ⁇ m.
• a sheet A6.1 with a sheet thickness of 1.2 mm was made from an alloy with an Al-Mg-Zn-Mn base with chemical composition D1.
• the billet was solidified at a cooling rate (or cooling rate) of 1.8 ° C / s and the rolling steps during hot and cold rolling were carried out according to the standard scheme.
• the last roll pass during cold rolling was 18% (from 1.46 mm to 1.2 mm).
• the final heat treatment was carried out at 500 ° C with subsequent water quenching. After the accelerated cooling, stabilization was carried out at 100 ° C for 3 h (hours).
• the mean crystal grain size or final grain size was 28 ⁇ m and in the intermetallic phase there were 14 first particles per mm 2 having an average particle size of 5 ⁇ m to 10 ⁇ m.
• the criterion ( ⁇ D * A> 1.8) is met with a ⁇ D * A value of 2.34.
• the condition 10 ⁇ degree of rolling * cooling rate ⁇ 50 is met.
• a tensile test showed no lines of Lüders on the surface of the sheet A6.1.
• the intermetallic phase according to the invention with the first particles could therefore ensure a sufficient number of dislocations in order to prevent Lüders lines from being formed.
• a sheet A6.2 with a sheet thickness of 1.2 mm was made from an alloy with an Al-Mg-Zn-Mn base of chemical composition D1.
• the billet was solidified at a cooling rate (or cooling rate) of 1.8 ° C / s and the rolling steps during hot and cold rolling were carried out according to the standard scheme.
• the last rolling pass during cold rolling was 63% (from 3.25 mm to 1.2 mm), the final heat treatment was carried out at 500 ° C with subsequent water quenching.
• the average crystal grain size or final grain size was 10 ⁇ m and in the intermetallic phase there were 14 first particles per mm 2 having an average particle size of 5 ⁇ m to 10 ⁇ m.
• All of the exemplary embodiments according to the invention namely A1, A2, A3, A4.1 and A6.1, have in common that their crystal structure has more than 200, in particular more than 400, dislocations on each first particle.

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• Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
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• Crystallography & Structural Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Metal Rolling (AREA)
• Continuous Casting (AREA)
• Heat Treatment Of Sheet Steel (AREA)
• Manufacturing Of Steel Electrode Plates (AREA)

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• 2019
  • 2019-01-30 EP EP19154632.4A patent/EP3690076A1/fr not_active Withdrawn
• 2020
  • 2020-01-30 JP JP2021544421A patent/JP2022519238A/ja active Pending
  • 2020-01-30 CA CA3128294A patent/CA3128294A1/fr active Pending
  • 2020-01-30 CN CN202080011029.3A patent/CN113474479B/zh not_active Expired - Fee Related
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