CA3128294A1 - Method for producing a sheet or strip from an aluminium alloy and a sheet, strip or molded part produced thereby - Google Patents
Method for producing a sheet or strip from an aluminium alloy and a sheet, strip or molded part produced thereby Download PDFInfo
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- CA3128294A1 CA3128294A1 CA3128294A CA3128294A CA3128294A1 CA 3128294 A1 CA3128294 A1 CA 3128294A1 CA 3128294 A CA3128294 A CA 3128294A CA 3128294 A CA3128294 A CA 3128294A CA 3128294 A1 CA3128294 A1 CA 3128294A1
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- 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
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- 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
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- 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
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- Heat Treatment Of Sheet Steel (AREA)
Abstract
The invention discloses a method for producing a sheet or strip from an aluminium alloy, and a sheet, strip or shaped part produced thereby. A rough surface and flow patterns can be avoided if the cold-rolled sheet or strip of a particular composition and microstructure is subjected to a heat treatment including recrystallization annealing with subsequent accelerated cooling.
Description
Method for Producing a Sheet or Strip from an Aluminum Alloy and a Sheet, Strip or Molded Part Produced Thereby Technical Field The invention relates to a method for producing a sheet or strip from an aluminum alloy and to a sheet, strip, or molded part produced thereby.
Prior Art In order to adjust the strength and formability or ductility, more particularly deep-draw-ing formability in a 5xxx-aluminum alloy or aluminum alloy with an Al-Mg basis, it is known to provide the sheet or strip or more precisely the metal structure of the alumi-num alloy sheet or strip with a finer average crystal grain size, namely of 60 pm or, according to EP0507411A1, of less than 50 pm. A finer crystal grain size of 60 pm or less of this kind disadvantageously involves the risk of the occurrence of type A
stretcher strain marks, namely LOders bands, on the surface of the plastically de-formed sheet or strip. Al-Mg-Mn alloys thus have only a limited suitability, for example, for outer shell components in vehicle body construction, which require ssf quality (stretcher strain free) or what is also known by its German abbreviation ffa quality (ffa = flief3figurenarme [low stretcher strain]), i.e. a freedom from or reduction in type A
stretcher strain marks.
Disclosure of the Invention The object of the invention, therefore, is to create a method for producing a sheet or strip from an aluminum alloy having Mg as one of the main alloying elements and to
Prior Art In order to adjust the strength and formability or ductility, more particularly deep-draw-ing formability in a 5xxx-aluminum alloy or aluminum alloy with an Al-Mg basis, it is known to provide the sheet or strip or more precisely the metal structure of the alumi-num alloy sheet or strip with a finer average crystal grain size, namely of 60 pm or, according to EP0507411A1, of less than 50 pm. A finer crystal grain size of 60 pm or less of this kind disadvantageously involves the risk of the occurrence of type A
stretcher strain marks, namely LOders bands, on the surface of the plastically de-formed sheet or strip. Al-Mg-Mn alloys thus have only a limited suitability, for example, for outer shell components in vehicle body construction, which require ssf quality (stretcher strain free) or what is also known by its German abbreviation ffa quality (ffa = flief3figurenarme [low stretcher strain]), i.e. a freedom from or reduction in type A
stretcher strain marks.
Disclosure of the Invention The object of the invention, therefore, is to create a method for producing a sheet or strip from an aluminum alloy having Mg as one of the main alloying elements and to
- 2 -create a sheet or strip of the type described above that has a comparatively high strength and formability and is of ssf quality or ffa quality The method should also be easy to use and reproducible.
The invention attains the stated object with regard to the method by means of the features of claim 1.
According to the invention, the sheet or strip in the method is composed of an alumi-num alloy, namely with the composition of from 2.0 to 5.5 wt% magnesium (Mg), from 0.2 to 1.2 wt% manganese (Mn), optionally up to 0.45 wt% silicon (Si), optionally up to 0.55 wt% iron (Fe), optionally up to 0.35 wt% chromium (Cr), optionally up to 0.2 wt% titanium (Ti), optionally up to 0.2 wt% silver (Ag), optionally up to 4 0 wt% zinc (Zn), optionally up to 0.8 wt% copper (Cu), optionally up to 0.8 wt% zirconium (Zr), optionally up to 0.3 wt% niobium (Nb), optionally up to 0.25 wt% tantalum (Ta), op-tionally up to 0.05 wt% vanadium (V), and the remainder comprised of aluminum and inevitable production-related impurities, with up to at most 0.05 wt% of each and all together totaling at most 0.15 wt%.
The method has the following method steps = casting of a rolling slab, = hot rolling of the rolling slab into a hot-rolled sheet or strip;
= cold rolling of the hot-rolled sheet or strip to a final thickness;
= heat treatment of the sheet or strip that has been cold-rolled to the final thick-ness, including recrystallization annealing with subsequent accelerated cool-ing;
Optionally, the method can have the following method steps:
= homogenization of the rolling slab;
= intermediate annealing of the sheet or strip in the cold rolling of the hot-rolled sheet or strip to a final thickness = stabilization of the sheet or strip, which has undergone accelerated cooling, in the heat treatment;
The invention attains the stated object with regard to the method by means of the features of claim 1.
According to the invention, the sheet or strip in the method is composed of an alumi-num alloy, namely with the composition of from 2.0 to 5.5 wt% magnesium (Mg), from 0.2 to 1.2 wt% manganese (Mn), optionally up to 0.45 wt% silicon (Si), optionally up to 0.55 wt% iron (Fe), optionally up to 0.35 wt% chromium (Cr), optionally up to 0.2 wt% titanium (Ti), optionally up to 0.2 wt% silver (Ag), optionally up to 4 0 wt% zinc (Zn), optionally up to 0.8 wt% copper (Cu), optionally up to 0.8 wt% zirconium (Zr), optionally up to 0.3 wt% niobium (Nb), optionally up to 0.25 wt% tantalum (Ta), op-tionally up to 0.05 wt% vanadium (V), and the remainder comprised of aluminum and inevitable production-related impurities, with up to at most 0.05 wt% of each and all together totaling at most 0.15 wt%.
The method has the following method steps = casting of a rolling slab, = hot rolling of the rolling slab into a hot-rolled sheet or strip;
= cold rolling of the hot-rolled sheet or strip to a final thickness;
= heat treatment of the sheet or strip that has been cold-rolled to the final thick-ness, including recrystallization annealing with subsequent accelerated cool-ing;
Optionally, the method can have the following method steps:
= homogenization of the rolling slab;
= intermediate annealing of the sheet or strip in the cold rolling of the hot-rolled sheet or strip to a final thickness = stabilization of the sheet or strip, which has undergone accelerated cooling, in the heat treatment;
- 3 -According to the invention, before the heat treatment, the sheet or strip that has been cold-rolled to the final thickness has at least one, more particularly primary, interme-tallic phase with first particles having an average particle size of 5 pm to 10 pm (meas-ured using the ASTM E112 linear intercept method) ¨ this by means of the method steps preceding the heat treatment For example in that at least the casting and the cold rolling, more particularly after the intermediate annealing, are adjusted relative to each other in such a way that the sheet or strip has at least one intermetallic phase with first particles having an average particle size of 5 pm to 10 pm. These first and thus primary particles are relatively coarse. These particles of the primary phase also have a high stability ¨ even relative to a subsequent recrystallization annealing or relative to a subsequent heat treatment With such a composition and microstructure, it is possible to produce a sheet or strip with a high strength and formability and of an ssf quality or ffa quality ¨
namely if after the heat treatment, this sheet or strip that has been cold-rolled to the final thickness also has an average crystal grain size D of 5 60 pm (measured using the ASTM
linear intercept method) and the average crystal grain size D in mm and the number A of first particles per mm2 in the aluminum alloy satisfy the condition -V75 * A > 1.8 ¨
for example in that the recrystallization annealing of the heat treatment is performed in such a way. Because of the different thermal expansion coefficients, an accelerated cooling following the recrystallization annealing causes internal stresses in the struc-ture to occur, namely between the aluminum matrix and the first particles of the inter-metallic phase, which ensures that there is a sufficient number of free dislocations at the first particles of the primary intermetallic phase As a result, LCiders band disloca-tions are not necessarily or inevitably produced during the forming of the sheet or strip. This is also true in the event of unfavorable deformations or complex geometries in the formed sheet or strip.
This method is also easy to use and has an extremely high reproducibility, for example due to a water cooling for the accelerated cooling, for producing a sheet or strip in ssf quality or ffa quality.
namely if after the heat treatment, this sheet or strip that has been cold-rolled to the final thickness also has an average crystal grain size D of 5 60 pm (measured using the ASTM
linear intercept method) and the average crystal grain size D in mm and the number A of first particles per mm2 in the aluminum alloy satisfy the condition -V75 * A > 1.8 ¨
for example in that the recrystallization annealing of the heat treatment is performed in such a way. Because of the different thermal expansion coefficients, an accelerated cooling following the recrystallization annealing causes internal stresses in the struc-ture to occur, namely between the aluminum matrix and the first particles of the inter-metallic phase, which ensures that there is a sufficient number of free dislocations at the first particles of the primary intermetallic phase As a result, LCiders band disloca-tions are not necessarily or inevitably produced during the forming of the sheet or strip. This is also true in the event of unfavorable deformations or complex geometries in the formed sheet or strip.
This method is also easy to use and has an extremely high reproducibility, for example due to a water cooling for the accelerated cooling, for producing a sheet or strip in ssf quality or ffa quality.
- 4 -The number of dislocations in the sheet or strip can be further increased in the method if al * A is > 2. More particularly, if NIT * A is > 2.5, then the sheet or strip can satisfy comparatively high quality requirements without having to also fear the occurrence of stretcher strain marks such as type A LOders bands on the surface of the formed sheet or strip, even in the case of comparatively complex geometries or unfavorable plastic deformations.
The method can be further improved in terms of reproducibility if in the heat treatment, the recrystallization annealing takes place by means of holding at a temperature of 300 C (degrees Celsius) or more, more particularly up to 600 C. This can improve even more if the recrystallization annealing takes place at 450 C to 550 C. In addition, this annealing temperature can be enough to pre-stress the structure by means of an accelerated cooling sufficiently to produce the dislocations at the first particles, which subsequently make LOders band dislocations unnecessary.
This is more particularly the case if the heated sheet is cooled in an accelerated man-ner at a cooling rate of at least 10 K/s (Kelvin per second), more particularly at least 20 K/s or at least 50 K/s, wherein this accelerated cooling can more particularly be carried out to below 180 C, more particularly to room temperature It is possible to ensure that first particles are embodied as large enough in the average particle size if the rolling slab is solidified by maintaining a cooling rate (or cooling speed) of < 2.5 C/s This can be further improved if the cooling rate is < 2 C/s or <
1 C/s or < 0.75 C/s. In addition, this can counteract a possible reduction in the aver-age particle size by means of subsequent method steps, for example by means of the cold rolling, in order to ensure an average particle size of 5 pm to 10 pm before the heat treatment.
In addition, the optional homogenization can take place by means of holding at to 550 C for at least 0.5 h.
The hot rolling can take place at 280 C to 550 C.
The method can be further improved in terms of reproducibility if in the heat treatment, the recrystallization annealing takes place by means of holding at a temperature of 300 C (degrees Celsius) or more, more particularly up to 600 C. This can improve even more if the recrystallization annealing takes place at 450 C to 550 C. In addition, this annealing temperature can be enough to pre-stress the structure by means of an accelerated cooling sufficiently to produce the dislocations at the first particles, which subsequently make LOders band dislocations unnecessary.
This is more particularly the case if the heated sheet is cooled in an accelerated man-ner at a cooling rate of at least 10 K/s (Kelvin per second), more particularly at least 20 K/s or at least 50 K/s, wherein this accelerated cooling can more particularly be carried out to below 180 C, more particularly to room temperature It is possible to ensure that first particles are embodied as large enough in the average particle size if the rolling slab is solidified by maintaining a cooling rate (or cooling speed) of < 2.5 C/s This can be further improved if the cooling rate is < 2 C/s or <
1 C/s or < 0.75 C/s. In addition, this can counteract a possible reduction in the aver-age particle size by means of subsequent method steps, for example by means of the cold rolling, in order to ensure an average particle size of 5 pm to 10 pm before the heat treatment.
In addition, the optional homogenization can take place by means of holding at to 550 C for at least 0.5 h.
The hot rolling can take place at 280 C to 550 C.
- 5 -The cold rolling to the final thickness can be carried out with a degree of rolling reduc-tion of from 10% to 65%, more particularly from 20% to 50%. More particularly, it can be advantageous if the cold rolling after the intermediate annealing is carried out with a degree of rolling reduction of from 10% to 65%, more particularly from 20%
to 50%, in order to improve the reproducibility of the average particle size of 5 pm to 10 pm The optional intermediate annealing can take place by means of holding at 300 C to 500 C.
The optional stabilization can take place by means of holding at 80 C to 120 C
for at least 0.5 h.
An average particle size of 5 pm to 10 pm before the heat treatment can more partic-ularly be assured if the product of the degree of rolling reduction in % after the inter-mediate annealing and the cooling rate in C/s satisfies the condition 10 <
degree of rolling reduction * cooling rate < 50, more particularly 20 <
degree of rolling reduction * cooling rate < 45.
If the intermetallic phase has an Al-Mn basis, then it is possible to produce the dislo-cations in the aluminum alloy that enable stretcher strain marks to be avoided in a particularly reliable way. Preferably, the intermetallic phase is of the A113(Mn,Fe)6 type or of the Al15FeMn3Si2 type or of the Al12Mn type or of the AlsMn type. These first particles of the primary phase are a particularly stable phase. It is also conceivable for the primary phase to constitute the intermetallic phase in order, in combination with the heat treatment of the sheet or strip, to produce a sufficient number of dislo-cations.
The method can achieve high strength and formability while avoiding orange peel and stretcher strain marks if the aluminum alloy (with an Al-Mg-Mn basis) has from 4.0 to 5.0 wt% magnesium (Mg) and/or from 0 2 to 0.5 wt% manganese (Mn) Particularly high strength can be achieved if the aluminum alloy also has from 2.0 to 4.0 wt% zinc (Zn) (Al-Mg-Zn basis). Optionally, this aluminum alloy can also has up to 0.8 wt% copper (Cu)
to 50%, in order to improve the reproducibility of the average particle size of 5 pm to 10 pm The optional intermediate annealing can take place by means of holding at 300 C to 500 C.
The optional stabilization can take place by means of holding at 80 C to 120 C
for at least 0.5 h.
An average particle size of 5 pm to 10 pm before the heat treatment can more partic-ularly be assured if the product of the degree of rolling reduction in % after the inter-mediate annealing and the cooling rate in C/s satisfies the condition 10 <
degree of rolling reduction * cooling rate < 50, more particularly 20 <
degree of rolling reduction * cooling rate < 45.
If the intermetallic phase has an Al-Mn basis, then it is possible to produce the dislo-cations in the aluminum alloy that enable stretcher strain marks to be avoided in a particularly reliable way. Preferably, the intermetallic phase is of the A113(Mn,Fe)6 type or of the Al15FeMn3Si2 type or of the Al12Mn type or of the AlsMn type. These first particles of the primary phase are a particularly stable phase. It is also conceivable for the primary phase to constitute the intermetallic phase in order, in combination with the heat treatment of the sheet or strip, to produce a sufficient number of dislo-cations.
The method can achieve high strength and formability while avoiding orange peel and stretcher strain marks if the aluminum alloy (with an Al-Mg-Mn basis) has from 4.0 to 5.0 wt% magnesium (Mg) and/or from 0 2 to 0.5 wt% manganese (Mn) Particularly high strength can be achieved if the aluminum alloy also has from 2.0 to 4.0 wt% zinc (Zn) (Al-Mg-Zn basis). Optionally, this aluminum alloy can also has up to 0.8 wt% copper (Cu)
- 6 -The invention attains the stated object with regard to the sheet or strip by means of the features of claim 8.
If the sheet or strip is composed of an aluminum alloy, namely with the alloy contents from 2.0 to 5 5 wt% magnesium (Mg), from 0.2 to 1.2 wt% manganese (Mn), optionally up to 0.45 wt% silicon (Si), optionally up to 0.55 wt% iron (Fe), optionally up to 0.35 wt% chromium (Cr), optionally up to 0.2 wt% titanium (Ti), optionally up to 0.2 wt%
silver (Ag), optionally up to 4.0 wt% zinc (Zn), optionally up to 0.8 wt%
copper (Cu), optionally up to 0.8 wt% zirconium (Zr), optionally up to 0.3 wt% niobium (Nb), option-ally up to 0.25 wt% tantalum (Ta), and the remainder comprised of aluminum and inevitable production-related impurities, with up to at most 0.05 wt% of each and all together totaling at most 0.15 wt%, then this provides an alloy composition with which it is possible to achieve a sufficiently high strength and formability/ductility ¨ of the kind that is required, for example, for outer shell components in vehicle body con-struction.
Freedom from orange peel and stretcher strain marks, among other things LOders bands, in the formed sheet or strip can be achieved if this sheet or strip has an aver-age crystal grain size D of 5 60 pm (measured using the ASTM E112 linear intercept method) and at least one, more particularly primary, intermetallic phase with first par-ticles having an average particle size of 5 pm to 10 pm (measured using the ASTM
E112 linear intercept method) and the average crystal grain size D in mm and the number A of first particles per mm2 in the aluminum alloy satisfy the condition V15 *
A > 1.8. It is also necessary for the sheet or strip to have been subjected to a heat treatment, including recrystallization annealing with subsequent accelerated cooling and optionally a stabilization of the sheet or strip that has undergone accelerated cooling. As a result, dislocations are produced at the first particles in the structure of the sheet or strip. These first and thus primary particles are also stable relative to the heat treatment that is used to further adjust the microstructure of the sheet or strip.
If the sheet or strip is composed of an aluminum alloy, namely with the alloy contents from 2.0 to 5 5 wt% magnesium (Mg), from 0.2 to 1.2 wt% manganese (Mn), optionally up to 0.45 wt% silicon (Si), optionally up to 0.55 wt% iron (Fe), optionally up to 0.35 wt% chromium (Cr), optionally up to 0.2 wt% titanium (Ti), optionally up to 0.2 wt%
silver (Ag), optionally up to 4.0 wt% zinc (Zn), optionally up to 0.8 wt%
copper (Cu), optionally up to 0.8 wt% zirconium (Zr), optionally up to 0.3 wt% niobium (Nb), option-ally up to 0.25 wt% tantalum (Ta), and the remainder comprised of aluminum and inevitable production-related impurities, with up to at most 0.05 wt% of each and all together totaling at most 0.15 wt%, then this provides an alloy composition with which it is possible to achieve a sufficiently high strength and formability/ductility ¨ of the kind that is required, for example, for outer shell components in vehicle body con-struction.
Freedom from orange peel and stretcher strain marks, among other things LOders bands, in the formed sheet or strip can be achieved if this sheet or strip has an aver-age crystal grain size D of 5 60 pm (measured using the ASTM E112 linear intercept method) and at least one, more particularly primary, intermetallic phase with first par-ticles having an average particle size of 5 pm to 10 pm (measured using the ASTM
E112 linear intercept method) and the average crystal grain size D in mm and the number A of first particles per mm2 in the aluminum alloy satisfy the condition V15 *
A > 1.8. It is also necessary for the sheet or strip to have been subjected to a heat treatment, including recrystallization annealing with subsequent accelerated cooling and optionally a stabilization of the sheet or strip that has undergone accelerated cooling. As a result, dislocations are produced at the first particles in the structure of the sheet or strip. These first and thus primary particles are also stable relative to the heat treatment that is used to further adjust the microstructure of the sheet or strip.
- 7 -Thus the average crystal grain size D of 60 pm according to the invention results in the fact that the comparatively fine crystal grain of the sheet or strip enables achieve-ment of a high strength and formability.
The latter, however, is not impaired by the presence of stretcher strain marks on the surface of the formed sheet or strip since according to the invention, the first particles that are present in the sheet or strip have a limited average particle size of 5 pm to pm and the average crystal grain size D in mm and the number A of first particles per mm2 in the aluminum alloy satisfy the condition VD * A > 1.8 To be precise, if in the method for producing the sheet or strip, a heat treatment is performed by means of recrystallization annealing and subsequent accelerated cool-ing, then based on the composition and the resulting microstructure, this can ensure a sufficiently high number of dislocations in the sheet or strip. This prevents the for-mation of LOders band dislocations even with complex geometries. According to the invention, this produces a sheet or strip composed of an aluminum alloy, preferably with an Al-Mg basis (or with Mg as one of the main alloying elements) in ssf quality or ffa quality, which due to its sufficient strength and formability can also excel when used, for example, for outer shell components in vehicle body construction.
The number of dislocations in the sheet or strip can be further increased if VD * A is > 2. More particularly, if -0* A is > 2.5, then the sheet or strip can satisfy compara-tively high quality requirements without having to also fear the occurrence of stretcher strain marks such as type A Luders bands on the surface of the formed sheet or strip, even in the case of comparatively complex geometries or unfavorable plastic defor-mations.
A sufficient number of dislocations in order to avoid stretcher strain marks in the formed sheet or strip can be achieved if the crystal structure has more than 200, more particularly more than 400, dislocations at each first particle This can be achieved if the sheet or strip has been heat treated by heating and subsequent accelerated cool-ing in such a way that the crystal structure has more than 200, more particularly more than 400, dislocations at each first particle.
The latter, however, is not impaired by the presence of stretcher strain marks on the surface of the formed sheet or strip since according to the invention, the first particles that are present in the sheet or strip have a limited average particle size of 5 pm to pm and the average crystal grain size D in mm and the number A of first particles per mm2 in the aluminum alloy satisfy the condition VD * A > 1.8 To be precise, if in the method for producing the sheet or strip, a heat treatment is performed by means of recrystallization annealing and subsequent accelerated cool-ing, then based on the composition and the resulting microstructure, this can ensure a sufficiently high number of dislocations in the sheet or strip. This prevents the for-mation of LOders band dislocations even with complex geometries. According to the invention, this produces a sheet or strip composed of an aluminum alloy, preferably with an Al-Mg basis (or with Mg as one of the main alloying elements) in ssf quality or ffa quality, which due to its sufficient strength and formability can also excel when used, for example, for outer shell components in vehicle body construction.
The number of dislocations in the sheet or strip can be further increased if VD * A is > 2. More particularly, if -0* A is > 2.5, then the sheet or strip can satisfy compara-tively high quality requirements without having to also fear the occurrence of stretcher strain marks such as type A Luders bands on the surface of the formed sheet or strip, even in the case of comparatively complex geometries or unfavorable plastic defor-mations.
A sufficient number of dislocations in order to avoid stretcher strain marks in the formed sheet or strip can be achieved if the crystal structure has more than 200, more particularly more than 400, dislocations at each first particle This can be achieved if the sheet or strip has been heat treated by heating and subsequent accelerated cool-ing in such a way that the crystal structure has more than 200, more particularly more than 400, dislocations at each first particle.
- 8 -Preferably, the number A of first particles is ?. 10 particles/mm2, which can enable a sufficient distribution of the dislocations in the sheet or strip in order to avoid stretcher strain marks. This is more particularly the case if the number A of first particles is 25 particles/mm2, preferably 35 particles/mm2.
If the intermetallic phase has an Al-Mn basis, then it is possible to produce the dislo-cations in the aluminum alloy that enable stretcher strain marks to be avoided in a particularly reliable way. Preferably, the intermetallic phase is of the A113(Mn,Fe)6 type or of the Al15FeMn3Si2 type or of the Al12Mn type or of the AlsMn type. These first particles of the primary phase are a particularly stable phase. It is also conceivable for the primary phase to constitute the intermetallic phase in order, through the sub-sequent heat treatment of the sheet or strip, to achieve a sufficient number of dislo-cations.
The method can achieve high strength and formability while avoiding orange peel and stretcher strain marks if the aluminum alloy has from 4 0 to 5.0 wt% magnesium (Mg) and/or from 0 2 to 0.5 wt% manganese (Mn).
Particularly high strength can be achieved if the aluminum alloy also has from 2.0 to 4.0 wt% zinc (Zn) (with an Al-Mg-Zn basis). Optionally, this aluminum alloy can also has up to 0 8 wt% copper (Cu).
The sheet or strip according to the invention can also be particularly well-suited for producing a molded part, more particularly a vehicle part, preferably a vehicle body part, by means of sheet-metal-forming. Preferably, the sheet or strip is used to pro-duce a sheet bar in order to be able to perform a sheet-metal-forming process.
In general, it should be mentioned that the average crystal grain size and the average particle size are measured using the ASTM E112 linear intercept method Preferably, the aluminum alloy has an Al-Mg basis.
In addition, the sheet or strip can have an average crystal grain size D of 5 50 pm, 5. 40 pm, or 5 30 pm.
If the intermetallic phase has an Al-Mn basis, then it is possible to produce the dislo-cations in the aluminum alloy that enable stretcher strain marks to be avoided in a particularly reliable way. Preferably, the intermetallic phase is of the A113(Mn,Fe)6 type or of the Al15FeMn3Si2 type or of the Al12Mn type or of the AlsMn type. These first particles of the primary phase are a particularly stable phase. It is also conceivable for the primary phase to constitute the intermetallic phase in order, through the sub-sequent heat treatment of the sheet or strip, to achieve a sufficient number of dislo-cations.
The method can achieve high strength and formability while avoiding orange peel and stretcher strain marks if the aluminum alloy has from 4 0 to 5.0 wt% magnesium (Mg) and/or from 0 2 to 0.5 wt% manganese (Mn).
Particularly high strength can be achieved if the aluminum alloy also has from 2.0 to 4.0 wt% zinc (Zn) (with an Al-Mg-Zn basis). Optionally, this aluminum alloy can also has up to 0 8 wt% copper (Cu).
The sheet or strip according to the invention can also be particularly well-suited for producing a molded part, more particularly a vehicle part, preferably a vehicle body part, by means of sheet-metal-forming. Preferably, the sheet or strip is used to pro-duce a sheet bar in order to be able to perform a sheet-metal-forming process.
In general, it should be mentioned that the average crystal grain size and the average particle size are measured using the ASTM E112 linear intercept method Preferably, the aluminum alloy has an Al-Mg basis.
In addition, the sheet or strip can have an average crystal grain size D of 5 50 pm, 5. 40 pm, or 5 30 pm.
- 9 -In addition, the cooling rate (or cooling speed) can be < 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.
In general, it should be mentioned that the strip can be cut into a slit strip or cut into sheets or also sheet bars can be cut out from the sheet or strip in order to form these semi-finished products, for example by means of sheet-metal-forming. The forming can be a deep-drawing, roll profiling, etc.
In general, it should be mentioned that the aluminum alloy can, for example, be of the EN AVV-5083 or EN AVV-5086 or EN AVV-5182 or EN AVV-5454 or EN AVV-5457 or EN
AVV-5754 type.
Ways to Implement the Invention To demonstrate the achieved effects, cold-rolled semi-finished products, namely thin sheets composed of an aluminum alloy with an Al-Mg-Mn basis and thin sheets com-posed of and aluminum alloy with an Al-Mg-Zn-Mn basis were produced. The follow-ing aluminum alloys were used, which were composed of Mg Mn Fe Si Zn Alloy wt% wt% wt% i wt% wt%
Cl 4.57 0.41 019 012 C2 4.71 041 0.23 0.12 C3 4.88 0.41 0 18 0.12 C4 4.74 0.44 0.24 0.12 D1 4.70 0.45 0.23 0.13 3.5 Table 1: Different aluminum alloys and the remainder comprised of aluminum and inevitable production-related impuri-ties, with up to at most 0.05 wt% of each and all together totaling at most 0.15 wt%
-The production of these thin sheets was carried out with the following process param-eters:
Casting Hot rolling Cold rolling Cooling Starting Degree of Intermediate rate temperature rolling re- annealing Heat Sheets Alloy [ C/s] [ C] duction after treatment the interme-diate an-nealing 0.7 530 C 63% 385 C 500 C
Al Cl 2h VVQ
1 8 530 C 15% 385 C 500 C
2h VVQ
1 8 530 C 18% 385 C 500 C
2h VVQ
1.8 530 C 25% 385 C 500 C
2h VVQ
1.8 530 C 25% 385 C 370 C
A4.2 04 2h AC
1.8 530 C 63% 385 C 500 C
2h VVQ
1.8 530 C 18% 385 C 500 C
A6.1 D1 2h VVQ
1 8 530 C 63% 385 C 500 C
2h VVQ
Table 2: Overview of the production processes VVa Water quenching (as an example of an accelerated cooling) AC: Cooling in stationary air These thin sheets were used to produce sheet bars ¨ i e sheet blanks ¨ which were formed, namely sheet-metal-formed, specifically deep-drawn, to produce a vehicle body part, namely a hood.
Grain size \ID A -\/ID. A 1 Stretcher strain Sheets Alloy D [pm] [mmo 5] [mm-2] [mm-15] marks Al Cl 15 0.12 44 5.4 No A2 02 35 0.19 12 2.24 No A3 03 29 0.17 14 2.38 No A4.1 04 32 018 12 214 No A4.2 04 32 0.18 12 2.14 Yes A5 04 10 010 12 1.2 Yes A6 1 D1 28 0.17 14 2.34 No A6.2 D1 10 0.1 14 1.4 Yes Table 3. Overview of the deep-drawn thin sheets Exemplary Embodiment 1:
An alloy of the AA5182 type (AI-Mg-Mn basis) with the chemical composition Cl was used to produce a thin sheet Al with a sheet thickness of 1.2 mm. The production of the rolling slab was solidified at a comparatively reduced cooling rate (or cooling speed) and the rolling steps in the hot rolling and cold rolling were carried out in ac-cordance with the standard scheme. The last rolling reduction pass in the cold rolling amounted to 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 average crystal grain size or final grain size of the thin sheet Al was 15 pm (measured using the ASTM E112 linear intercept method) and in the primary intermetallic phase, there were 44 first particles per mm2 having an average particle size of 5 pm to 10 pm (measured using the ASTM
E112 linear intercept method) These primary particles were also embodied as com-paratively coarse. In addition, with the product of the cooling rate after the intermedi-ate annealing and the degree of rolling reduction of 44, the condition 10 <
degree of rolling reduction * cooling rate < 50 is satisfied.
With a .\11:)*A value of 5.4, the criterion (\ILYA > 1.8) is satisfied. A
tensile test did not show any Leiders bands on the surface of the thin sheet Al. The intermetallic phase according to the invention with the first particles was therefore able to provide a suffi-cient number of dislocations to prevent the occurrence of LOders bands during the forming.
Exemplary Embodiment 2:
An alloy of the AA5182 type with the chemical composition 02 was used to produce a thin sheet A2 with a sheet thickness of 1.2 mm The rolling slab was solidified at a cooling rate (or cooling speed) of 1 8 C/s and the rolling steps in the hot rolling and cold rolling were carried out in accordance with the standard scheme. The last rolling reduction pass in the cold rolling amounted to 15% (from 1.41 mm to 1.2 mm) and the final heat treatment was carried out at 500 C with subsequent water quenching In addition, with the product of the cooling rate after the intermediate annealing and the degree of rolling reduction of 27, the condition 10 < degree of rolling reduction *
cooling rate < 50 is satisfied.
The average crystal grain size or final grain size of the thin sheet Al after the heat treatment was 35 pm and in the primary intermetallic phase, there were 12 first parti-cles per mm2 having an average particle size of 5 pm to 10 pm With a :AM value of 2.24, the criterion (iD*A > 1.8) is satisfied A tensile test did not show any LOders bands on the surface of the thin sheet A2. The intermetallic phase according to the invention with the first or primary particles was therefore able to provide a sufficient number of dislocations to prevent the occurrence of LOders bands during the forming.
Exemplary Embodiment 3:
An alloy of the AA5182 type with the chemical composition 03 was used to produce a thin sheet A3 with a sheet thickness of 1.2 mm The rolling slab was solidified at a cooling rate (or cooling speed) of 1.8 C/s and the rolling steps in the hot rolling and cold rolling were carried out in accordance with the standard scheme. The last rolling reduction pass in the cold rolling amounted to 18% (from 1.46 mm to 1.2 mm) and 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 pm and in the primary intermetallic phase, there were 14 first particles per mm2 having an average particle size of 5 pm to 10 pm. In addition, with the product of the cooling rate after the intermediate an-nealing and the degree of rolling reduction of 32, the condition 10 <
degree of rolling reduction * cooling rate < 50 is satisfied With a .VD*A value of 2.38, the criterion (VID*A > 1.8) is satisfied. A
tensile test did not show any LOders bands on the surface of the thin sheet A3 The intermetallic phase according to the invention with the first or primary particles was therefore able to pro-vide a sufficient number of dislocations to prevent the occurrence of LOders bands during the forming.
Exemplary Embodiment 4:
An alloy of the AA5182 type with the chemical composition C4 was used to produce two thin sheets A4.1 and A4.2 with a sheet thickness of 1.2 mm The rolling slab was solidified at a cooling rate (or cooling speed) of 1.8 C/s and the rolling steps in the hot rolling and cold rolling were carried out in accordance with the standard scheme. The last rolling reduction pass in the cold rolling amounted to 25% from 1 60 mm to 1.2 mm). The final heat treatment of the thin sheet A4 1 was carried out at 500 C
with subsequent water quenching. By contrast, the final heat treatment of the thin sheet A4.2 was carried out at 370 C with subsequent cooling in stationary air.
The average crystal grain size or final grain size of both of the thin sheets A4.1 and A4 2 was 32pm and in their primary intermetallic phase, there were 12 first particles per mm2 having an average particle size of 5 pm to 10 pm. With a -\/Di*A value of 2.14, the criterion (\trA > 1.8) is satisfied by both thin sheets A4.1 and A4 2.
In addition, with the product of the cooling rate after the intermediate annealing and the degree of rolling reduction of 45, the condition 10 < degree of rolling reduction *
cooling rate < 50 is satisfied by both thin sheets A4 1 and A4.2 By contrast with the thin sheet A4.1, the thin sheet A4.2 exhibits LOders bands after the deep-drawing. In the thin sheet A4.2, despite having the same composition and microstructure, because of the slower cooling in stationary air, it was not possible for a sufficient number of dislocations in the structure to form in order to prevent the oc-currence of alders bands. In other words, the accelerated water cooling of the thin sheet A4.1 resulted in the fact that the intermetallic phase with the first or primary particles was able to provide a sufficient number of dislocations to prevent the occur-rence of LOders bands during the forming.
Exemplary Embodiment 5:
An alloy of the AA5182 type with the chemical composition 04 was used to produce a thin sheet A5 with a sheet thickness of 1.2 mm. The rolling slab was solidified at a cooling rate (or cooling speed) of 1.8 C/s and the rolling steps in the hot rolling and cold rolling were carried out in accordance with the standard scheme. The last rolling reduction pass in the cold rolling amounted to 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 average crystal grain size or final grain size was 10 pm and in the primary intermetallic phase, there were 12 first particles per mm2 having an average particle size of 5 pm to 10 pm.
With a -Nil:VA value of 1.2, the criterion for freedom from LOders bands (-\/D*A > 1 8) is not satisfied. In addition, with the product of the cooling rate after the intermediate annealing and the degree of rolling reduction of 113, the condition 10 5_ degree of rolling reduction * cooling rate < 50 is not satisfied. After the deep-drawing, LOders bands were detected The intermetallic phase with the first or primary particles was therefore not able to provide a sufficiently high number of dislocations to prevent the occurrence of LOders bands during the forming Exemplary Embodiment 6.1:
An alloy with an Al-Mg-Zn-Mn basis and the chemical composition D1 was used to produce a thin sheet A6.1 with a sheet thickness of 1 2 mm The rolling slab was solidified at a cooling rate (or cooling speed) of 1 8 C/s and the rolling steps in the hot rolling and cold rolling were carried out in accordance with the standard scheme. The last rolling reduction pass in the cold rolling amounted to 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, a stabilization was carried out at 100 C for 3 h. The average crystal grain size or final grain size was 28 pm and in the primary intermetallic phase, there were 14 first particles per mm2 having an average particle size of 5 pm to 10 pm. With a =NlID*A value of 2.34, the criterion (\iLD*A > 1 8) is satisfied In addition, with the product of the cooling rate after the intermediate annealing and the degree of rolling reduction of 32, the condition 10 < degree of rolling reduction *
cooling rate < 50 is satisfied.
A tensile test did not show any LOders bands on the surface of the thin sheet A6.1 The intermetallic phase according to the invention with the first or primary particles was therefore able to provide a sufficient number of dislocations to prevent the occur-rence of Luders bands during the forming.
Exemplary Embodiment 6.2:
An alloy with an Al-Mg-Zn-Mn basis and the chemical composition D1 was used to produce a thin sheet A6.2 with a sheet thickness of 1 2 mm The rolling slab was solidified at a cooling rate (or cooling speed) of 1.8 C/s and the rolling steps in the hot rolling and cold rolling were carried out in accordance with the standard scheme The last rolling reduction pass in the cold rolling amounted to 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 average crystal grain size or final grain size was 10 pm and in the primary intermetallic phase, there were 14 first particles per mm2 having an average particle size of 5 pm to 10 pm With a \11-3*A value of 1 4, the criterion for freedom from LOders bands (\/D*A > 1.8) is not satisfied. In addition, with the product of the cooling rate after the intermediate annealing and the degree of rolling reduction of 113, the condition 10 < degree of rolling reduction * cooling rate 5 SO is not satisfied.
After the deep-drawing, LOders bands were detected. The intermetallic phase with the first or primary particles was therefore not able to provide a sufficiently high number of dislocations to prevent the occurrence of LUders bands during the forming All of the exemplary embodiments according to the invention, namely Al, A2, A3, A4.1, and A6.1 share the fact that their crystal structure has more than 200, more particularly more than 400, dislocations at each first particle.
In general, it should be noted that the German expression "insbesondere" can be translated into English as more particularly." A feature that is preceded by more particularly" is to be considered an optional feature that can be omitted and therefore does not constitute a limitation, for example of the claims. The same applies to the German term "vorzugsweise,"which is translated into English as "preferably."
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.
In general, it should be mentioned that the strip can be cut into a slit strip or cut into sheets or also sheet bars can be cut out from the sheet or strip in order to form these semi-finished products, for example by means of sheet-metal-forming. The forming can be a deep-drawing, roll profiling, etc.
In general, it should be mentioned that the aluminum alloy can, for example, be of the EN AVV-5083 or EN AVV-5086 or EN AVV-5182 or EN AVV-5454 or EN AVV-5457 or EN
AVV-5754 type.
Ways to Implement the Invention To demonstrate the achieved effects, cold-rolled semi-finished products, namely thin sheets composed of an aluminum alloy with an Al-Mg-Mn basis and thin sheets com-posed of and aluminum alloy with an Al-Mg-Zn-Mn basis were produced. The follow-ing aluminum alloys were used, which were composed of Mg Mn Fe Si Zn Alloy wt% wt% wt% i wt% wt%
Cl 4.57 0.41 019 012 C2 4.71 041 0.23 0.12 C3 4.88 0.41 0 18 0.12 C4 4.74 0.44 0.24 0.12 D1 4.70 0.45 0.23 0.13 3.5 Table 1: Different aluminum alloys and the remainder comprised of aluminum and inevitable production-related impuri-ties, with up to at most 0.05 wt% of each and all together totaling at most 0.15 wt%
-The production of these thin sheets was carried out with the following process param-eters:
Casting Hot rolling Cold rolling Cooling Starting Degree of Intermediate rate temperature rolling re- annealing Heat Sheets Alloy [ C/s] [ C] duction after treatment the interme-diate an-nealing 0.7 530 C 63% 385 C 500 C
Al Cl 2h VVQ
1 8 530 C 15% 385 C 500 C
2h VVQ
1 8 530 C 18% 385 C 500 C
2h VVQ
1.8 530 C 25% 385 C 500 C
2h VVQ
1.8 530 C 25% 385 C 370 C
A4.2 04 2h AC
1.8 530 C 63% 385 C 500 C
2h VVQ
1.8 530 C 18% 385 C 500 C
A6.1 D1 2h VVQ
1 8 530 C 63% 385 C 500 C
2h VVQ
Table 2: Overview of the production processes VVa Water quenching (as an example of an accelerated cooling) AC: Cooling in stationary air These thin sheets were used to produce sheet bars ¨ i e sheet blanks ¨ which were formed, namely sheet-metal-formed, specifically deep-drawn, to produce a vehicle body part, namely a hood.
Grain size \ID A -\/ID. A 1 Stretcher strain Sheets Alloy D [pm] [mmo 5] [mm-2] [mm-15] marks Al Cl 15 0.12 44 5.4 No A2 02 35 0.19 12 2.24 No A3 03 29 0.17 14 2.38 No A4.1 04 32 018 12 214 No A4.2 04 32 0.18 12 2.14 Yes A5 04 10 010 12 1.2 Yes A6 1 D1 28 0.17 14 2.34 No A6.2 D1 10 0.1 14 1.4 Yes Table 3. Overview of the deep-drawn thin sheets Exemplary Embodiment 1:
An alloy of the AA5182 type (AI-Mg-Mn basis) with the chemical composition Cl was used to produce a thin sheet Al with a sheet thickness of 1.2 mm. The production of the rolling slab was solidified at a comparatively reduced cooling rate (or cooling speed) and the rolling steps in the hot rolling and cold rolling were carried out in ac-cordance with the standard scheme. The last rolling reduction pass in the cold rolling amounted to 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 average crystal grain size or final grain size of the thin sheet Al was 15 pm (measured using the ASTM E112 linear intercept method) and in the primary intermetallic phase, there were 44 first particles per mm2 having an average particle size of 5 pm to 10 pm (measured using the ASTM
E112 linear intercept method) These primary particles were also embodied as com-paratively coarse. In addition, with the product of the cooling rate after the intermedi-ate annealing and the degree of rolling reduction of 44, the condition 10 <
degree of rolling reduction * cooling rate < 50 is satisfied.
With a .\11:)*A value of 5.4, the criterion (\ILYA > 1.8) is satisfied. A
tensile test did not show any Leiders bands on the surface of the thin sheet Al. The intermetallic phase according to the invention with the first particles was therefore able to provide a suffi-cient number of dislocations to prevent the occurrence of LOders bands during the forming.
Exemplary Embodiment 2:
An alloy of the AA5182 type with the chemical composition 02 was used to produce a thin sheet A2 with a sheet thickness of 1.2 mm The rolling slab was solidified at a cooling rate (or cooling speed) of 1 8 C/s and the rolling steps in the hot rolling and cold rolling were carried out in accordance with the standard scheme. The last rolling reduction pass in the cold rolling amounted to 15% (from 1.41 mm to 1.2 mm) and the final heat treatment was carried out at 500 C with subsequent water quenching In addition, with the product of the cooling rate after the intermediate annealing and the degree of rolling reduction of 27, the condition 10 < degree of rolling reduction *
cooling rate < 50 is satisfied.
The average crystal grain size or final grain size of the thin sheet Al after the heat treatment was 35 pm and in the primary intermetallic phase, there were 12 first parti-cles per mm2 having an average particle size of 5 pm to 10 pm With a :AM value of 2.24, the criterion (iD*A > 1.8) is satisfied A tensile test did not show any LOders bands on the surface of the thin sheet A2. The intermetallic phase according to the invention with the first or primary particles was therefore able to provide a sufficient number of dislocations to prevent the occurrence of LOders bands during the forming.
Exemplary Embodiment 3:
An alloy of the AA5182 type with the chemical composition 03 was used to produce a thin sheet A3 with a sheet thickness of 1.2 mm The rolling slab was solidified at a cooling rate (or cooling speed) of 1.8 C/s and the rolling steps in the hot rolling and cold rolling were carried out in accordance with the standard scheme. The last rolling reduction pass in the cold rolling amounted to 18% (from 1.46 mm to 1.2 mm) and 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 pm and in the primary intermetallic phase, there were 14 first particles per mm2 having an average particle size of 5 pm to 10 pm. In addition, with the product of the cooling rate after the intermediate an-nealing and the degree of rolling reduction of 32, the condition 10 <
degree of rolling reduction * cooling rate < 50 is satisfied With a .VD*A value of 2.38, the criterion (VID*A > 1.8) is satisfied. A
tensile test did not show any LOders bands on the surface of the thin sheet A3 The intermetallic phase according to the invention with the first or primary particles was therefore able to pro-vide a sufficient number of dislocations to prevent the occurrence of LOders bands during the forming.
Exemplary Embodiment 4:
An alloy of the AA5182 type with the chemical composition C4 was used to produce two thin sheets A4.1 and A4.2 with a sheet thickness of 1.2 mm The rolling slab was solidified at a cooling rate (or cooling speed) of 1.8 C/s and the rolling steps in the hot rolling and cold rolling were carried out in accordance with the standard scheme. The last rolling reduction pass in the cold rolling amounted to 25% from 1 60 mm to 1.2 mm). The final heat treatment of the thin sheet A4 1 was carried out at 500 C
with subsequent water quenching. By contrast, the final heat treatment of the thin sheet A4.2 was carried out at 370 C with subsequent cooling in stationary air.
The average crystal grain size or final grain size of both of the thin sheets A4.1 and A4 2 was 32pm and in their primary intermetallic phase, there were 12 first particles per mm2 having an average particle size of 5 pm to 10 pm. With a -\/Di*A value of 2.14, the criterion (\trA > 1.8) is satisfied by both thin sheets A4.1 and A4 2.
In addition, with the product of the cooling rate after the intermediate annealing and the degree of rolling reduction of 45, the condition 10 < degree of rolling reduction *
cooling rate < 50 is satisfied by both thin sheets A4 1 and A4.2 By contrast with the thin sheet A4.1, the thin sheet A4.2 exhibits LOders bands after the deep-drawing. In the thin sheet A4.2, despite having the same composition and microstructure, because of the slower cooling in stationary air, it was not possible for a sufficient number of dislocations in the structure to form in order to prevent the oc-currence of alders bands. In other words, the accelerated water cooling of the thin sheet A4.1 resulted in the fact that the intermetallic phase with the first or primary particles was able to provide a sufficient number of dislocations to prevent the occur-rence of LOders bands during the forming.
Exemplary Embodiment 5:
An alloy of the AA5182 type with the chemical composition 04 was used to produce a thin sheet A5 with a sheet thickness of 1.2 mm. The rolling slab was solidified at a cooling rate (or cooling speed) of 1.8 C/s and the rolling steps in the hot rolling and cold rolling were carried out in accordance with the standard scheme. The last rolling reduction pass in the cold rolling amounted to 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 average crystal grain size or final grain size was 10 pm and in the primary intermetallic phase, there were 12 first particles per mm2 having an average particle size of 5 pm to 10 pm.
With a -Nil:VA value of 1.2, the criterion for freedom from LOders bands (-\/D*A > 1 8) is not satisfied. In addition, with the product of the cooling rate after the intermediate annealing and the degree of rolling reduction of 113, the condition 10 5_ degree of rolling reduction * cooling rate < 50 is not satisfied. After the deep-drawing, LOders bands were detected The intermetallic phase with the first or primary particles was therefore not able to provide a sufficiently high number of dislocations to prevent the occurrence of LOders bands during the forming Exemplary Embodiment 6.1:
An alloy with an Al-Mg-Zn-Mn basis and the chemical composition D1 was used to produce a thin sheet A6.1 with a sheet thickness of 1 2 mm The rolling slab was solidified at a cooling rate (or cooling speed) of 1 8 C/s and the rolling steps in the hot rolling and cold rolling were carried out in accordance with the standard scheme. The last rolling reduction pass in the cold rolling amounted to 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, a stabilization was carried out at 100 C for 3 h. The average crystal grain size or final grain size was 28 pm and in the primary intermetallic phase, there were 14 first particles per mm2 having an average particle size of 5 pm to 10 pm. With a =NlID*A value of 2.34, the criterion (\iLD*A > 1 8) is satisfied In addition, with the product of the cooling rate after the intermediate annealing and the degree of rolling reduction of 32, the condition 10 < degree of rolling reduction *
cooling rate < 50 is satisfied.
A tensile test did not show any LOders bands on the surface of the thin sheet A6.1 The intermetallic phase according to the invention with the first or primary particles was therefore able to provide a sufficient number of dislocations to prevent the occur-rence of Luders bands during the forming.
Exemplary Embodiment 6.2:
An alloy with an Al-Mg-Zn-Mn basis and the chemical composition D1 was used to produce a thin sheet A6.2 with a sheet thickness of 1 2 mm The rolling slab was solidified at a cooling rate (or cooling speed) of 1.8 C/s and the rolling steps in the hot rolling and cold rolling were carried out in accordance with the standard scheme The last rolling reduction pass in the cold rolling amounted to 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 average crystal grain size or final grain size was 10 pm and in the primary intermetallic phase, there were 14 first particles per mm2 having an average particle size of 5 pm to 10 pm With a \11-3*A value of 1 4, the criterion for freedom from LOders bands (\/D*A > 1.8) is not satisfied. In addition, with the product of the cooling rate after the intermediate annealing and the degree of rolling reduction of 113, the condition 10 < degree of rolling reduction * cooling rate 5 SO is not satisfied.
After the deep-drawing, LOders bands were detected. The intermetallic phase with the first or primary particles was therefore not able to provide a sufficiently high number of dislocations to prevent the occurrence of LUders bands during the forming All of the exemplary embodiments according to the invention, namely Al, A2, A3, A4.1, and A6.1 share the fact that their crystal structure has more than 200, more particularly more than 400, dislocations at each first particle.
In general, it should be noted that the German expression "insbesondere" can be translated into English as more particularly." A feature that is preceded by more particularly" is to be considered an optional feature that can be omitted and therefore does not constitute a limitation, for example of the claims. The same applies to the German term "vorzugsweise,"which is translated into English as "preferably."
Claims (15)
Claims
1 A method for producing a sheet or strip from an aluminum alloy, having from 2.0 to 5.5 wt% magnesium (Mg), from 0.2 to 1.2 wt% manganese (Mn), optionally up to 0.45 wt% silicon (Si), up to 0 55 wt% iron (Fe), up to 0.35 wt% chromium (Cr), up to 0.2 wt% titanium (Ti), up to 0.2 wt% silver (Ag), up to 4.0 wt% zinc (Zn), up to 0.8 wt% copper (Cu), up to 0.8 wt% zirconium (Zr), up to 0 3 wt% niobium (Nb), up to 0.25 wt% tantalum (Ta), up to 0.05 wt% vanadium (V), and the remainder comprised of aluminum and inevitable production-related im-purities, with up to at most 0.05 wt% of each and all together totaling at most 0.15 wt%, wherein the method has the following method steps:
casting of a rolling slab;
optional homogenization of the rolling slab;
hot rolling of the rolling slab into a hot-rolled sheet or strip;
cold rolling of the hot-rolled sheet or strip to a final thickness, optionally with an intermediate annealing of the sheet or strip, wherein the sheet or strip that has been cold-rolled to the final thickness has at least one intermetallic phase with first particles having an average particle size of 5 pm to 10 pm;
heat treatment of the sheet or strip that has been cold-rolled to the final thickness, including recrystallization annealing with subsequent acceler--ated cooling and optionally a stabilization of the sheet or strip that has un-dergone accelerated cooling, wherein the heat-treated sheet or strip has an average crystal grain size D of 60 pm and the average crystal grain size D in mm and the number A of first particles per mm2 in the aluminum alloy satisfy the condition * A > 1.8.
casting of a rolling slab;
optional homogenization of the rolling slab;
hot rolling of the rolling slab into a hot-rolled sheet or strip;
cold rolling of the hot-rolled sheet or strip to a final thickness, optionally with an intermediate annealing of the sheet or strip, wherein the sheet or strip that has been cold-rolled to the final thickness has at least one intermetallic phase with first particles having an average particle size of 5 pm to 10 pm;
heat treatment of the sheet or strip that has been cold-rolled to the final thickness, including recrystallization annealing with subsequent acceler--ated cooling and optionally a stabilization of the sheet or strip that has un-dergone accelerated cooling, wherein the heat-treated sheet or strip has an average crystal grain size D of 60 pm and the average crystal grain size D in mm and the number A of first particles per mm2 in the aluminum alloy satisfy the condition * A > 1.8.
2. The method according to claim 1, characterized in that VC5 * A
is > 2, more particularly > 2.5.
is > 2, more particularly > 2.5.
3. The method according to one of claims 1 to 2, characterized in that the recrystallization annealing takes place at 300 C or more, more particularly at up to 600 C, preferably from 450 C to 550 C, and/or the accelerated cooling takes place at a cooling rate of at least 10 K/s, more par-ticularly at least 20 K/s or at least 50 K/s, more particularly to below 180 C, more particularly to room temperature.
4 The method according to one of claims 1 to 3, characterized in that the rolling slab is solidified by maintaining a cooling rate of < 2.5 C/s, more par-ticularly < 2 C/s or < 1 C/s or < 0 75 C/s.
5. The method according to one of claims 1 to 4, characterized in that the optional homogenization takes place at 450 C to 550 C for at least 0.5 h, and/or the hot rolling takes place at 280 C to 550 C, and/or the cold rolling to the final thickness, more particularly after the intermediate an-nealing, takes place with a degree of rolling reduction of 10% to 65%, more par-ticularly of 15% to 65%, and/or the optional intermediate annealing of the sheet or strip takes place at 300 C
to 500 C and/or ¨ a the optional stabilization takes place at 80 C to 120 C for at least 0 5 h.
to 500 C and/or ¨ a the optional stabilization takes place at 80 C to 120 C for at least 0 5 h.
6. The method according to one of claims 1 to 5, characterized in that the product of the degree of rolling reduction in % after the intermediate annealing and the cooling rate in C/s satisfies the condition 10 <
degree of rolling reduction * cooling rate < 50, more particularly 20 <
degree of rolling reduction * cooling rate < 45.
degree of rolling reduction * cooling rate < 50, more particularly 20 <
degree of rolling reduction * cooling rate < 45.
7. The method according to one of claims 1 to 6, characterized in that the preferably primary intermetallic phase has an Al-Mn basis, more particularly is of the A113(Mn,Fe)6 type or of the A15FeMn3Si2 type or of the Al12Mn type or of the Al6Mn type.
8. The method according to one of claims 1 to 7, characterized in that the aluminum alloy has from 4.0 to 5 0 wt% magnesium (Mg) and/or from 0.2 to 0.5 wt% manganese (Mn) and optionally from 2.0 to 4.0 wt% zinc (Zn).
9. A sheet or strip composed of an aluminum alloy having from 2.0 to 5 5 wt% magnesium (Mg), from 0.2 to 1.2 wt% manganese (Mn), optionally up to 0.45 wt% silicon (Si), up to 0.55 wt% iron (Fe), up to 0.35 wt% chromium (Cr), up to 0.2 wt% titanium (Ti), up to 0.2 wt% silver (Ag), up to 4,0 wt% zinc (Zn), up to 0.8 wt% copper (Cu), , =
up to 0.8 wt% zirconium (Zr), up to 0.3 wt% niobium (Nb), up to 0.25 wt% tantalum (Ta), up to 0.05 wt% vanadium (V), and the remainder comprised of aluminum and inevitable production-related im-purities, with up to at most 0.05 wt% of each and all together totaling at most 0.15 wt%, wherein the sheet or strip has an average crystal grain size D of 5. 60 pm and has at least one intermetallic phase with first particles having an average particle size of 5 pm to 10 pm, and wherein the average crystal grain size D
in mm and the number A of first particles per mm2 in the aluminum alloy satisfy the condition A > 1.8, wherein the sheet or strip has been subjected to a heat treatment, including re-crystallization annealing with subsequent accelerated cooling and optionally a stabilization of the sheet or strip that has undergone accelerated cooling.
up to 0.8 wt% zirconium (Zr), up to 0.3 wt% niobium (Nb), up to 0.25 wt% tantalum (Ta), up to 0.05 wt% vanadium (V), and the remainder comprised of aluminum and inevitable production-related im-purities, with up to at most 0.05 wt% of each and all together totaling at most 0.15 wt%, wherein the sheet or strip has an average crystal grain size D of 5. 60 pm and has at least one intermetallic phase with first particles having an average particle size of 5 pm to 10 pm, and wherein the average crystal grain size D
in mm and the number A of first particles per mm2 in the aluminum alloy satisfy the condition A > 1.8, wherein the sheet or strip has been subjected to a heat treatment, including re-crystallization annealing with subsequent accelerated cooling and optionally a stabilization of the sheet or strip that has undergone accelerated cooling.
10. The sheet or strip according to claim 9, characterized in that A
is > 2, more particularly > 2.5
is > 2, more particularly > 2.5
11. The sheet or strip according to one of claims 9 to 10, characterized in that the crystal structure has more than 200, more particularly more than 400, dislo-cations at each first particle.
12. The sheet or strip according to one of claims 9 to 11, characterized in that the number A of first particles in the aluminum alloy is ?. 10 particles/mm2, more particularly 25 particles/mm2, preferably ?. 35 particles/mm2.
13. The sheet or strip according to one of claims 9 to 12, characterized in that the preferably primary intermetallic phase has an Al-Mn basis, more particularly is of the A113(Mn,Fe)6 type or of the Al15FeMn3S12 type or of the Al12Mn type or of the AlsMn type
14. The sheet or strip according to one of claims 9 to 13, characterized in that the aluminum alloy has from 4 0 to 5.0 wt% magnesium (Mg) and/or from 0.2 to 0.5 wt% manganese (Mn) and optionally from 2.0 to 4.0 wt% zinc (Zn).
15. A molded part, more particularly a vehicle part, preferably a vehicle body part, composed of a sheet-metal-formed sheet or strip according to one of claims 9 to 14.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP19154632.4 | 2019-01-30 | ||
| EP19154632.4A EP3690076A1 (en) | 2019-01-30 | 2019-01-30 | Method for producing a metal sheet or strip made from aluminum alloy and a metal sheet, strip or moulded part produced thereby |
| PCT/EP2020/052375 WO2020157246A1 (en) | 2019-01-30 | 2020-01-30 | Method for producing a sheet or strip from an aluminium alloy, and a sheet, strip or shaped part produced thereby |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA3128294A1 true CA3128294A1 (en) | 2020-08-06 |
Family
ID=65268872
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA3128294A Pending CA3128294A1 (en) | 2019-01-30 | 2020-01-30 | Method for producing a sheet or strip from an aluminium alloy and a sheet, strip or molded part produced thereby |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US20220127708A1 (en) |
| EP (2) | EP3690076A1 (en) |
| JP (1) | JP2022519238A (en) |
| CN (1) | CN113474479B (en) |
| CA (1) | CA3128294A1 (en) |
| MX (1) | MX2021009093A (en) |
| WO (1) | WO2020157246A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3848476A1 (en) * | 2020-01-07 | 2021-07-14 | AMAG rolling GmbH | Sheet or strip made of a curable aluminium alloy, vehicle part manufactured from same, its use and a method for producing the sheet or strip |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH638243A5 (en) * | 1978-07-05 | 1983-09-15 | Alusuisse | METHOD FOR PRODUCING magnesium and zinc CONTAINING ALUMINUM ALLOY SHEETS. |
| JPH0668146B2 (en) * | 1986-09-09 | 1994-08-31 | スカイアルミニウム株式会社 | Method for manufacturing rolled aluminum alloy plate |
| NL9100565A (en) | 1991-04-02 | 1992-11-02 | Hoogovens Aluminium Nv | ALUMINUM PLATE AND METHOD FOR MANUFACTURING THAT. |
| DE10231422A1 (en) | 2001-08-13 | 2003-02-27 | Corus Aluminium Nv | Aluminum-magnesium alloy product |
| SE530437C2 (en) * | 2006-10-13 | 2008-06-03 | Sapa Heat Transfer Ab | Rank material with high strength and high sagging resistance |
| CA2990303C (en) * | 2015-06-25 | 2019-12-17 | Hydro Aluminium Rolled Products Gmbh | High-strength and easily formable almg-strip, and method for producing the same |
| CN106834825B (en) * | 2016-11-16 | 2018-08-31 | 广西南南铝加工有限公司 | 5182 aluminium alloys |
-
2019
- 2019-01-30 EP EP19154632.4A patent/EP3690076A1/en not_active Withdrawn
-
2020
- 2020-01-30 WO PCT/EP2020/052375 patent/WO2020157246A1/en unknown
- 2020-01-30 EP EP20706105.2A patent/EP3918102A1/en active Pending
- 2020-01-30 CN CN202080011029.3A patent/CN113474479B/en active Active
- 2020-01-30 JP JP2021544421A patent/JP2022519238A/en active Pending
- 2020-01-30 MX MX2021009093A patent/MX2021009093A/en unknown
- 2020-01-30 CA CA3128294A patent/CA3128294A1/en active Pending
- 2020-01-30 US US17/427,460 patent/US20220127708A1/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JP2022519238A (en) | 2022-03-22 |
| EP3918102A1 (en) | 2021-12-08 |
| CN113474479A (en) | 2021-10-01 |
| EP3690076A1 (en) | 2020-08-05 |
| WO2020157246A1 (en) | 2020-08-06 |
| MX2021009093A (en) | 2021-10-22 |
| CN113474479B (en) | 2023-06-06 |
| US20220127708A1 (en) | 2022-04-28 |
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