CA2454210A1 - Crash resistant aluminum alloy sheet products and method of making same - Google Patents
Crash resistant aluminum alloy sheet products and method of making same Download PDFInfo
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- CA2454210A1 CA2454210A1 CA002454210A CA2454210A CA2454210A1 CA 2454210 A1 CA2454210 A1 CA 2454210A1 CA 002454210 A CA002454210 A CA 002454210A CA 2454210 A CA2454210 A CA 2454210A CA 2454210 A1 CA2454210 A1 CA 2454210A1
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- aluminum alloy
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- alloy sheet
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- 229910000838 Al alloy Inorganic materials 0.000 title claims abstract description 63
- 238000004519 manufacturing process Methods 0.000 title description 2
- 238000010791 quenching Methods 0.000 claims abstract description 37
- 230000000171 quenching effect Effects 0.000 claims abstract description 15
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 11
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910045601 alloy Inorganic materials 0.000 claims description 34
- 239000000956 alloy Substances 0.000 claims description 34
- 238000000034 method Methods 0.000 claims description 29
- 238000001816 cooling Methods 0.000 claims description 6
- 239000012535 impurity Substances 0.000 claims description 6
- 230000002349 favourable effect Effects 0.000 abstract description 5
- 238000010438 heat treatment Methods 0.000 abstract description 4
- 239000000203 mixture Substances 0.000 description 11
- 239000003973 paint Substances 0.000 description 10
- 238000012360 testing method Methods 0.000 description 8
- 239000000243 solution Substances 0.000 description 5
- 239000007921 spray Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 239000000853 adhesive Substances 0.000 description 4
- 230000001070 adhesive effect Effects 0.000 description 4
- 238000005098 hot rolling Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000005452 bending Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 238000005336 cracking Methods 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- XNPKNHHFCKSMRV-UHFFFAOYSA-N 4-(cyclohexylamino)butane-1-sulfonic acid Chemical compound OS(=O)(=O)CCCCNC1CCCCC1 XNPKNHHFCKSMRV-UHFFFAOYSA-N 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 238000004279 X-ray Guinier Methods 0.000 description 1
- 238000010923 batch production Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 238000011437 continuous method Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000009957 hemming Methods 0.000 description 1
- 230000036651 mood Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000010186 staining Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
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
- C22C21/02—Alloys based on aluminium with silicon 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
-
- 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
- C22F1/05—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 of the Al-Si-Mg type, i.e. containing silicon and magnesium in approximately equal proportions
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Shaping Metal By Deep-Drawing, Or The Like (AREA)
- Air Bags (AREA)
Abstract
Aluminum sheet products having high strengths and favorable crashworthiness are disclosed. The aluminum alloys include Si, Mg and Mn in controlled amounts which provide high yield strengths while retaining formability and crash resistant properties.
The sheet products undergo heat treatment and slow quenching. The sheet products are particularly suitable for use as auto body sheet products.
The sheet products undergo heat treatment and slow quenching. The sheet products are particularly suitable for use as auto body sheet products.
Description
CI~SH I~ESISTA1~T ALUNIIhdUlVI ALL~~' SHEET
Plt~DU~TAhID 1~~I~,TFIC~D F' l~~IAI~ISAME
Field of the Invention The present invention relates to aluminum alloys, and morcd particularly relates to j aluminum sheet products in which alloy compositions and processing methods are controlled in order to produce improved crash resistance properties;.
Background of the Invention The use of aluminum sheet in automotive applications has generally been limited to Aluminum Association ~xxx alloys (Al-Mg-;~i) for outer panels and 5xxx alloys (Al~
1 C~ Mg) for inner panels and structural members. In order to maximize the weight savings potential of aluminum, it is desirable to replace relatively low strength 5xxx alloys in the structure with higher strength ~xxx alloys. However, a shox-tcoming of existing 6xxx auto body sheet CABS) alloys is their ability to absorb energy during crash situations. This is generally termed crashworthiness.
1 ~ Autobody sheet requires a combination of good forming properties along with good strength after paint baking operations. The forming properties require good stretch forming and good bending. This traditionally has been achieved with rapid water quenching from solution heat treat temperatures. However, rapid 'eater quenching often results in distortion, surface irregularities and water staining that are unacceptable for 20 outer auto body applications. Air quenching offers many ad~~antages over water quenching with respect to elin~i~~ating quench distortion problems, but air quenching can lead to poor bending perfornlance.
The present invention has been developed in view of the foregoing and to address other deficiencies of the prior art.
~S Summary of the Invention The present invention controls alloy compositions and quench rates to produce aluminum alloy sheet products exhibiting good as-processed formability and shape, and good crashworthiness and strength in the artificially aged conditior:.
An aspect of the invention is to provide a 6xxx alloy with a desired combination of strength and crashworthiness.
Another aspect of the present invention is to provide a heap; treated and slow quenched aluminum alloy sheet comprising frozen about O.S to about 0.7 wt.%
Si, from about O.S to about 0.7 wt.% leg, from about 0.1 to about 0.3 wt.% Mn, and the balance Al S and incidental impurities.
A further aspect of the present invention is to provide a method of treating an aluminum alloy sheet, the method comprising providing a heat treated aluminum alloy sheet comprising Si, l~Tg, Ivln, and the balance aluminum arid incia.entai impurities, and slow quenching the heat treated aluminum sheet at a rate of less than about 200°F/second.
these and other aspects of the present invention will be more apparent from the following description.
Brief Description of the L~rawin.~s Fig. 1 is a schematic diagram illustrating an alumim~m sheet heat treating and slow quenching process in accordance with an embodiment of the present invention.
1 S Fig. 2 is a graph of temperature versus time for a paint bake treatment.
Fig. 3 is a graph of yield strength versus line speed of~ a continuous heat treat furnace, illustrating strength properties for two different 6x;~x alloys without a slow quench and with a slow quench in accordance with embodiments of the present invention.
Figs. 4~a and 4b are graphs of tensile properties versus paint: bake time at 18S°C for 2f~ two different alloys.
Figs. Sa-Sc are computer generated illustrations taken from different views of a sample crash box made of alloy 6060 sheet without a slow quench.
Figs. 6a-6c are computer generated illustrations taken h°om different views of a sample crash box made of alloy 6xxA sheet with a slow quench.
2S Figs. 7a-7c are computer generated illustrations taken from different views of a sample crash box made of alloy 6060 sheet with a slow quench.
Plt~DU~TAhID 1~~I~,TFIC~D F' l~~IAI~ISAME
Field of the Invention The present invention relates to aluminum alloys, and morcd particularly relates to j aluminum sheet products in which alloy compositions and processing methods are controlled in order to produce improved crash resistance properties;.
Background of the Invention The use of aluminum sheet in automotive applications has generally been limited to Aluminum Association ~xxx alloys (Al-Mg-;~i) for outer panels and 5xxx alloys (Al~
1 C~ Mg) for inner panels and structural members. In order to maximize the weight savings potential of aluminum, it is desirable to replace relatively low strength 5xxx alloys in the structure with higher strength ~xxx alloys. However, a shox-tcoming of existing 6xxx auto body sheet CABS) alloys is their ability to absorb energy during crash situations. This is generally termed crashworthiness.
1 ~ Autobody sheet requires a combination of good forming properties along with good strength after paint baking operations. The forming properties require good stretch forming and good bending. This traditionally has been achieved with rapid water quenching from solution heat treat temperatures. However, rapid 'eater quenching often results in distortion, surface irregularities and water staining that are unacceptable for 20 outer auto body applications. Air quenching offers many ad~~antages over water quenching with respect to elin~i~~ating quench distortion problems, but air quenching can lead to poor bending perfornlance.
The present invention has been developed in view of the foregoing and to address other deficiencies of the prior art.
~S Summary of the Invention The present invention controls alloy compositions and quench rates to produce aluminum alloy sheet products exhibiting good as-processed formability and shape, and good crashworthiness and strength in the artificially aged conditior:.
An aspect of the invention is to provide a 6xxx alloy with a desired combination of strength and crashworthiness.
Another aspect of the present invention is to provide a heap; treated and slow quenched aluminum alloy sheet comprising frozen about O.S to about 0.7 wt.%
Si, from about O.S to about 0.7 wt.% leg, from about 0.1 to about 0.3 wt.% Mn, and the balance Al S and incidental impurities.
A further aspect of the present invention is to provide a method of treating an aluminum alloy sheet, the method comprising providing a heat treated aluminum alloy sheet comprising Si, l~Tg, Ivln, and the balance aluminum arid incia.entai impurities, and slow quenching the heat treated aluminum sheet at a rate of less than about 200°F/second.
these and other aspects of the present invention will be more apparent from the following description.
Brief Description of the L~rawin.~s Fig. 1 is a schematic diagram illustrating an alumim~m sheet heat treating and slow quenching process in accordance with an embodiment of the present invention.
1 S Fig. 2 is a graph of temperature versus time for a paint bake treatment.
Fig. 3 is a graph of yield strength versus line speed of~ a continuous heat treat furnace, illustrating strength properties for two different 6x;~x alloys without a slow quench and with a slow quench in accordance with embodiments of the present invention.
Figs. 4~a and 4b are graphs of tensile properties versus paint: bake time at 18S°C for 2f~ two different alloys.
Figs. Sa-Sc are computer generated illustrations taken from different views of a sample crash box made of alloy 6060 sheet without a slow quench.
Figs. 6a-6c are computer generated illustrations taken h°om different views of a sample crash box made of alloy 6xxA sheet with a slow quench.
2S Figs. 7a-7c are computer generated illustrations taken from different views of a sample crash box made of alloy 6060 sheet with a slow quench.
Figs. 8a-8c are computer generated illustrations takc;n frorr~ different views of a sample crash box made of alloy 6xxA sheet without a slow wench.
Detailed Description of Preferred Embodiments The present invention provides aluminum alloy sheet products having favorable crash resistant properties. As u;~ed herein, the term "sheet" refers to aluminum alloy products having thicknesses fiom 0.2 to 6.3 mm. For auto body sheet products, thicknesses oi° frorn 0.7 to 3.5 mm are preferred. The alumi~~_urn alloy sheet products exhibit favorable crash resistance or crashworthiness properties. For the purpose of this invention, crashworthiness is defined as the abi~aity of a material to absorb energy by plastic deformation without appreciable cracking. The crashworthiness of the sheet products can be quantified by critical fracture strain (CFS).
A preferred process path includes the following steps: casting of an aluminum alloy ingot by conventional or continuous methods; hot rolling; intermediate amlealing;
cold rolling; solution heat treating; and slow quenching, e.g.; air' quench or minimum distortion water quench. The steps of solution heat treating and slow quenching preferably occur on a continuoa.~s heat treater or temper line,. After slow quenching, the sheet may optionally be repeated and coil cooled. The optional cooling step may be performed as an off Iine batch process. The steps of solution heat treating and slow quenching, in addition to an optional repeating step, are schematically illustrated in Fig. 1.
In the solution heat treatment step, the aluminum alloy she~;t may be run through a continuous heat treater to substantially dissolve soluble phases formed during upstream processing. This process typically involves furnace temperatures of 800 to 1,100°F at speeds from 20 to 150 feet per minute. The temperature and dwell time in the furnace may be adjusted based upon allay composition and gauge.
In the slow quenching step, upon exit from the furnace zonf: of the continuous heat treater, the sheet is quenched at a controlled rate to retain the solute in solid solution.
flzis can be accomplished, for example, with air or minimurrt distooion water.
An aspect of this invention is the use of relatively slow quench rates that minimize sheet distortion while still developing favorable physical properties. As used herei~~, the term "slow quench" means quenching at a rate of Iess than about 200°F/second, preferably Iess than about 100°F/second. Quench rates for air type processes preferably range frorr~ about 20 to about I00°F/second, more preferably from about 40 to about 70°F/second. Mater quench rates preferably range f~oyn 50 to 1,000°F/sec, more preferably from 100 to 200°Flsecond.
In the optional rehearing step, a heating unit may follow the quench unit and any coil handling equipment, preferably just ahead of the coiling equipment on the exit end of the line. The heating unit raises the temperature of the sheet such that an elevated coiling temperature can be achieved. A preferred range of coiling temperatures is from about 130 to about 190°F. In the coil cooling step, the warm coil as allo~;ved to cool slowly, typically as a 5,000 to 50,000 1b. mass of metal. 'This typically results in cooling rates of from about 0.1 to about 5°F/hovr.
In accordance with an embodiment of the present invention, the composition of the aluminum alloy sheet is controlled in order to provide favorable crash resistance properties. The Si and li~g levels are controlled in order to providf; high strengths. The i 5 lvIn level is sufficient to control the grain size of the sheet, particularly during heat treating. Suitable alloys include 6xxx alloys such as 6009, 5060, 6063 and 6005.
Typical, preferred and more preferred alloy composition ranges are listed in Table 1.
Table 1 Alloy Compositions (Wt.°/~~
~Si ~ iVig ~ li~In ~ Fe Cu Al Typical ~ 0.5-0.7 0.5-0.7 ~ 0.1-0.3 0.35 rna~,0.20 ' balance max , Preferred 0.56-0.68 0.54-0.66 O.e2-0.18 O.IS-0.300.10 balance max ~
Mare Preferred ~ 0.58-O.G6 0.56-0.64 T 0.1.2-0.180.10 balance O.IS-0.25 max --A particularly preferred ~~l-liiIg-Si-~n alloy is listed in Table 2. Table 2 lists the preferred 6xxA alloy compositions and a 6060 alloy composition in wt.percentages, with the balance comprising aluminum and incidenta:~ impurities.
Table 2 Aluminum Alloy Sheet Compositions ~LL~Dy ~ ' s~9.I~~~ U~O Ci~ 1~I1 ~~U .1~~
v % I I ~~fi t ~ i I
____ _ target O.t~2 T 0.20 ~ -~ _ U.15 ~
0.60 6xxA min. 0.58 0.15 - 0.12 0.56 max. 0.66 0.25 0.10 0.1 ~; 0.6~r I ~
target '~ 0.56 I 0.20 ~ 0.075-- 0.55 6060 ' min. ' i 0.15 0.05 --- i 0.52 0.53 ~~ 0.5& 0.25 I 0.10 0.10 0.57 An advantage of the present invention is the improvement in the erashworthiness of the aluminum alloy sheet product, which may be measured by critical fracture strain S (CFS) and axial crush tests. f3sing the typical engineering stress-strain output from a standard r&n tension test, a critical fracture strain can be determined:
CFS = -ln( I et,eng) in which et~enb represents the total engineering thinning strain. The total engineering thinning stxain is a function of em, ~m and fir:
yt,eng = f(em~ ~m~ ~f) where em is the engineering strain at the maximum load; ~m is the engineering stress at the maximum load; and ~f is the engineering stress at the fracture load.
The following engineering assumptions are made in the development of the CFS:
strains in the thickness and width directions are the same before the maximum load 1 ~ (P~,aX); the true stress after P~ax 3,S a constant; and tile Wldth Strar&~2 IS COTIStant after ~"sax.
The total thinning strain at fracture may therefore be determi.tled. l:n accordance with the present invention, a minimum CFS erashworthiness value of about 15 is preferred, with a value of at least 18 being more preferred.
~ typical property comparison for alloys is shown in Table 3.
Table 3 Alloy ~'aeld Strength ' Crush Results CFS
-L_ 5083 145 MPa Mood with some cracking on tight folds 18 _»
6060 216 MPa Good with some cr acking at geometric constraints 21 6xxA 244 MPa Crood with some c-acking at tight folds 18 Twelve lots of materials 2.0 rrzm thick were fabricated. Details of the fabrication are given in Table 4. Prior to hot rolling, each of the cast samples was scalped and preheated at 590°C for 8 hours followed by 560°C for 9 hours.
The main variables were alloy composition, use of a slow spray quench at an approximate cooling rate of 150°F/second following hot rolling, and the line speed of the continuous heat treat furnace (CHT). The compositions of the two 6xxA and 6060 alloys studied are shown above in 'Table 2.
Table 4 C~ill Coil2 Coil3 Coil4 STEP 6xxA 6xxA 6060 6060 Hot Rolling 1080 x 1080 x 1080 x 1080 x 10 ~nm 8 nun 10 mm 8 mm Hot Rolling exit>450C >450C >450C >450C
t. C
Slozv Quench ~,.rS N~ . ~,ES ' NQ
~.fter ~
hot rolling ~ ' i i SHT Cont. Furnace550-570-570550-570-570550-570-570 550-.570-570 C C C
spray bar spray bar spray bar spray bar Speed 1 7 mt/min 5 mt/min 7 mt/min 5 mt/min Speed 2 I 1 miJmin8 mt/min 11 mt/min 8 mt/min Speed 3 15 m~/min - I2 mt/min15 mt/min 12 mt/min The sheet was evaluated in the as received T4 temper and also after a simulative paint bake treatment at 180°C ( S65°l~'~. p'ig. 2 is a temperature-time plot of a therrnocoupled sheet sample during the paint bake treatment:.
'fable 5 T ensile properties for Sheet Pr~d~acts in T4 T~umper ;. ~_ AST~~ ~ ~ -! ! Test A Unif'orxn' n ~ Rm IZp0.2 ~
-. A r ~1~~v !
I
I Alloy Quench ~
Speed Test Coil (mlmin) dlirection (ll~Pa)(lVIPa) (!) (%) _ ;
6060 No 12 L 164 95 ' 29 24 0.43 0.225 f X 155 94 22 21 0.518 0.221 T 152 88 30 25 0.749 0.215 8 ~ L 184 108 28 23 0.634 ~
~ 0.23 X 182 106 23 22 0.634 0.222 -T ~ ~178 104 25 19 0.749 0.227 ~
5 L 192 1I6 26 21 0.749 0.223 I
' X 189 115 27 19 0.518 0.216 __ _ i , T 192 116 26 21 0.685 0.22 6060 Yes 1, 15 L 183 113 28 25 0.595 0.216 X 187 110 25 21 0.518 0.24 T 185 108 25 20 0.749 0.232 ~ 1 L 180 111 _ 30 24 0.411 0.219 _ -X 183 109 27 22 0.277 0.216 ~
r ~ T 183 112 27 22 0.214 0.216 ~
__~ ~ 115 27 21 0.427 0.223 X 186 113 26 2I 0.346 0.223 T 188 112 26 20 0.267 0.224 6xxA 163 94 28 24 0.629 0.231 No L
X 167 90 23 21 0.634 0.243 T 159 91 25 20 0.629 0.222 8 L 196 109 28 22 0.629 0.246 !
X 192 109 25 21 0.518 0.24 ! i 189 105 25 21 ~ 0.629~
, ~ 0.247 T I
!
~ ~ 209 116 27 22 0.634 [
0.246 , L
X 204 119 24 20 0.518 0.238 T 200 113 25 18 0.629 0.233 6xxA 196 118 28 20 0.518 0.228 Yes 194 118 28 21 0.343 0.224 188 114 25 21 0.429 0.215 L 210 128 28 22 0.477 0.2291 X 209 129 ~ 22 0.477 0.225 T 203 I zz5 j 18 0.524 0.218 II 208 I 125 23 2I 0.682 0.232 L _ 26 i ~ r-.-, ~X
i i T
f I
L
f I 209 124 ~ ~ 2i j 0.6870.234 X _ 26 _ 207 ~ 124 20 I 0.525~
T 24 0.233 ~ I
The tensile properties of the sheet in the T 4 temper are presented in Table 5.
There was a slight tendency for the T4 yield strength to decrease with increasing CHT
line speed, which is probably indicative of incomplete dissolution of MgzSi at the faster line speed. Minor variations in other T~ properties were found.
Guided bend tests using T4 sheet pre-strained 10% show that the slow quench is beneficial to bending of both alloys. both alloys fabricated using the slow quench withstood the maximum sharp bend. Downflange and hemming tests illustrate that both alloys are tlat hem capable.
The sheet r&n tensile properties after the paint bake were measured using 2 inch gage length specimens. Table ~ lists the ran tc;nsile data.
Table 6 Tensile Properties far Sheet Products after Faint Bake ec~tron after PB ) I
r~zn test data (I. - dir _ 'I I LlneSpeed Uniform Total Slow meterslmi ~ YS 1JTS
Tong. Elong.
~
Alloy ~uencla I n Mpa) (MPa) r (avg) YS/LTS (/_) (%) n ~
s 237 247 I0.3 15.2 1.00640.0850 ~
239 f 249 0.96 10.4 16.1 0.96140.0845 6060 ! No 5 avg I .
i 238 j 248 10.4 15.7 0.98390.0848 ' 230 238 ' 10.1 15.5 0.94030.0906 I
6060 ~ No 8 avg I 230 239 0.97 11.0 15.4 0.99820.0910 230 i 238 10.6 15.5 0.96930.0908 197 206 9.3 15.3 0.92670.0958 6060 No 12 avg I92 ~ 201 0.95 9.7 15.0 0.96570.0976 194 204 9.5 15.2 0.94620.0967 236 ~ 243 10.2 17.1 0.72340.0897 6xxA Yes 7 avg 235 l 243 0.97 10.9 16.2 0.73010.0912 ! 235 243 10.6 16.7 0.72680.0905 237 245 10.3 17.0 0.76260.0919 i 6xxA ~ Yes 11 avg 237 244 0,97 10.7 18.0 0.74480.0913 ~
237 244 10.5 17.5 0.75370.0916 228 ~ 235 10.1 15.6 0,80570.0917 6xxA Yes 15 avg ~ 228 ~ 234 0.97 10.5 16.4 0.84910.0923 228 234 10.3 16.0 0.82740.0920 237 245 10.0 16.4 0.70260.0831 ! 6060 Yes 7 avg ~ 237 246 0.96 9.9 14.7 0.X20 0.0830 ~
! 237 i 246 10.0 15.6 0.70730.0831 ! ! I 239 247 10.4 15.6 ~ 0.65900.0822 ~
! 6060 I Yes ~ i 1 avg ~ ~ 0.97 10.3 16.9 0.66090.0839 236 245 f t I 238 ~ 246 30.4 16.3 0.66000.0831 I i 236 245 ? 0.0 15.2 0.69530.0804 6060 Yes 15 avg ~ 237 245 0.97 =0.1 16.5 0.65940.0815 ! 237 245 ___0. 15.9 0.67740.0810 i_ 249 257 9.8 14.8 1.00460.0832 GxxA No 5 avg 248 256 0.97 9.9 16.4 0.99650.0831 249 ~ 9.9 i5.6 1.00060.0832 ;?32 241 I0.3 16.3 1.08560.0904 ~
231 239 0.97 10.3 16.0 1.09170.0896 6xxA No 8 avg 232 240 10.3 16.2 1.08870.0900 I 165 176 10.1 16.4 1.00240.1137 i 6xxA ! No ~ 12 av ' 72 18 0.94 10.3 16.1 0.94790.1060 g ~ 169 2179 10.2 16.3 0.97520.1099 a Fig. 3 plots yield strength of the alloys as a function of the processing variables.
The yield strength has the tendency to decrease at the fastest ~I~'T line speeds due to incomplete dissolution of l~g2Si, Guinier x-ray data showed the presence of l~g2Si in the materials processed at the faster line speeds. Tie influence of line speed on yield strength zs most pronounced in the sheet rw-hich was processed without using the slow quench.
Fig. 4a is a graph of Rtn, Rp0.2 and A values versus paint bake time at 1~5°C for the 6060 sample listed in Table 6 which was subjected to ~;l~e slow quench and a CHT
speed of 11 meters/minute. i~ig. 4b is a similar graph for the ~fixxA sample which was likewise subjected to the slow quench and CH'T speed of 11 meters/minute.
Crash boxes were assembled having a rectangular cross section measuring 63 mm by I33 mm. Welds or rivets may be used at approximately I inch on center with the first and last weld approximately %2 inch from the end, The number of spot welds or rivets specified were 20 per flange. An adhesive sold under the designation l3etamate 1494 by Gurit Essex is a one-component toughened epoxy that is applied warm along the side seams of the crash boxes, followed by riveting. A pneumatic heated cartridge gun is used to dispense the adhesive at approximately 40 to 50°C (104 to I22°F). The metal components to be joined were also heated to approximately the same temperature to assist in application of the adhesive and improve flow and wettability. ~Che adhesive was applied to warm metal on the flanges just prior to spot welding or riveting.
Rivets were installed at the same locations specified for welding. End caps are then welded in place.
After assembly, the boxes were paint baked. The paint baked boxes were tested in axial crush. 'The crush loads and energy absorbed at displacements of 100, 150, and 200 mm is given in. Table 7.
Tabls 7 Axial Crush Test results of faint Baked Samples ~~ Crash (after P~) ---j lVlax . ' i '; ' i I CIiT load Mean road ~ Absorbed line fineri~
J
t Sample Slow Speed 100 150 200 ~
I No. Alloy wench meters/minkN .l/mm) mm mm rnm I
144.7 55.7 5941 8472 11039 144.4 56.5 6011 8470 11184 1 6060 No ~ 8 avg 144.9 52.8 5935 8746 10470 144.7 55.0 5962 8563 10898 156.3 54.9 6380 8364 10877 ~ 152.8 58.6 6323 8955 11602 2 6xxA Yes I1 avg i ~ ~ 157.0 53.4 ~ 8496 10571 I ~ 155.4 ~ 55.6 ~ 8605 11017 ' 162.2 [ 58.4 , 9146 5932 i ~ 162.2 ~ 51.1 5505 8000 10119 6xxA ~ Yes 11 avg 156.9 57.3 6690 9149 11361 i 160,4 55.6 6042 8765 11014 _ 154.6 50.4 6076 7924 9983 141.4 53.8 6205 8449 10670 3 6060 Yes ~ 11 avg 140.6 51.9 5554 8028 10278 145.5 52.0 5945 8134 10310 149.1 56.4 5771 8977 11170 [
148.1 ~ 6081 8644 11045 55.7 I 6060 Yes 11 avg f ,I [ 153.1 ~ 52.3 6437 8175 10364 i ~ ' 54.8 6096 8599 10860 150.1 _ j .
I 140.0 51.3 5752 8257 10156 j 147'8 5.6 5724 8469 11020 4 6xxA No ~ 8 avg 143.8 X 5992 8461 10455 X2.8 143.9 53.2 5823 8396 10544 Computer generated illustrations of the crushed appearance of the boxes are shown in Figs. 5-8. Figs. Sa-c are computer generated illustrations from different view of Sam_pie No. 1 listed in Table '~. figs. 6a-c are computer generated illustrations of Sample No. 2. Figs. %a-c are computer generated illustrations of Sample I\To. 3.
Figs. 8a-c are computer generated illustrations of Sample No. 4. There were no significant differences among the quantifiable crush parameters for the samples tested.
The performance of the materials rnet the goals of a sheet alloy product for use in crash critical applications. The paint baked sheet had yield strengths of about 235 MPa, total elongation of 1S% and good static crush performance. :i'hc T~ properties indicate acceptable formability.
Whereas particular embodiments of this invention have been described above for purposes of illustration, it will be evident to those skilled in the ant that numerous variations of the details of the present invention may be made without departing from the invention as defined in the appended clazrr~s.
t2
Detailed Description of Preferred Embodiments The present invention provides aluminum alloy sheet products having favorable crash resistant properties. As u;~ed herein, the term "sheet" refers to aluminum alloy products having thicknesses fiom 0.2 to 6.3 mm. For auto body sheet products, thicknesses oi° frorn 0.7 to 3.5 mm are preferred. The alumi~~_urn alloy sheet products exhibit favorable crash resistance or crashworthiness properties. For the purpose of this invention, crashworthiness is defined as the abi~aity of a material to absorb energy by plastic deformation without appreciable cracking. The crashworthiness of the sheet products can be quantified by critical fracture strain (CFS).
A preferred process path includes the following steps: casting of an aluminum alloy ingot by conventional or continuous methods; hot rolling; intermediate amlealing;
cold rolling; solution heat treating; and slow quenching, e.g.; air' quench or minimum distortion water quench. The steps of solution heat treating and slow quenching preferably occur on a continuoa.~s heat treater or temper line,. After slow quenching, the sheet may optionally be repeated and coil cooled. The optional cooling step may be performed as an off Iine batch process. The steps of solution heat treating and slow quenching, in addition to an optional repeating step, are schematically illustrated in Fig. 1.
In the solution heat treatment step, the aluminum alloy she~;t may be run through a continuous heat treater to substantially dissolve soluble phases formed during upstream processing. This process typically involves furnace temperatures of 800 to 1,100°F at speeds from 20 to 150 feet per minute. The temperature and dwell time in the furnace may be adjusted based upon allay composition and gauge.
In the slow quenching step, upon exit from the furnace zonf: of the continuous heat treater, the sheet is quenched at a controlled rate to retain the solute in solid solution.
flzis can be accomplished, for example, with air or minimurrt distooion water.
An aspect of this invention is the use of relatively slow quench rates that minimize sheet distortion while still developing favorable physical properties. As used herei~~, the term "slow quench" means quenching at a rate of Iess than about 200°F/second, preferably Iess than about 100°F/second. Quench rates for air type processes preferably range frorr~ about 20 to about I00°F/second, more preferably from about 40 to about 70°F/second. Mater quench rates preferably range f~oyn 50 to 1,000°F/sec, more preferably from 100 to 200°Flsecond.
In the optional rehearing step, a heating unit may follow the quench unit and any coil handling equipment, preferably just ahead of the coiling equipment on the exit end of the line. The heating unit raises the temperature of the sheet such that an elevated coiling temperature can be achieved. A preferred range of coiling temperatures is from about 130 to about 190°F. In the coil cooling step, the warm coil as allo~;ved to cool slowly, typically as a 5,000 to 50,000 1b. mass of metal. 'This typically results in cooling rates of from about 0.1 to about 5°F/hovr.
In accordance with an embodiment of the present invention, the composition of the aluminum alloy sheet is controlled in order to provide favorable crash resistance properties. The Si and li~g levels are controlled in order to providf; high strengths. The i 5 lvIn level is sufficient to control the grain size of the sheet, particularly during heat treating. Suitable alloys include 6xxx alloys such as 6009, 5060, 6063 and 6005.
Typical, preferred and more preferred alloy composition ranges are listed in Table 1.
Table 1 Alloy Compositions (Wt.°/~~
~Si ~ iVig ~ li~In ~ Fe Cu Al Typical ~ 0.5-0.7 0.5-0.7 ~ 0.1-0.3 0.35 rna~,0.20 ' balance max , Preferred 0.56-0.68 0.54-0.66 O.e2-0.18 O.IS-0.300.10 balance max ~
Mare Preferred ~ 0.58-O.G6 0.56-0.64 T 0.1.2-0.180.10 balance O.IS-0.25 max --A particularly preferred ~~l-liiIg-Si-~n alloy is listed in Table 2. Table 2 lists the preferred 6xxA alloy compositions and a 6060 alloy composition in wt.percentages, with the balance comprising aluminum and incidenta:~ impurities.
Table 2 Aluminum Alloy Sheet Compositions ~LL~Dy ~ ' s~9.I~~~ U~O Ci~ 1~I1 ~~U .1~~
v % I I ~~fi t ~ i I
____ _ target O.t~2 T 0.20 ~ -~ _ U.15 ~
0.60 6xxA min. 0.58 0.15 - 0.12 0.56 max. 0.66 0.25 0.10 0.1 ~; 0.6~r I ~
target '~ 0.56 I 0.20 ~ 0.075-- 0.55 6060 ' min. ' i 0.15 0.05 --- i 0.52 0.53 ~~ 0.5& 0.25 I 0.10 0.10 0.57 An advantage of the present invention is the improvement in the erashworthiness of the aluminum alloy sheet product, which may be measured by critical fracture strain S (CFS) and axial crush tests. f3sing the typical engineering stress-strain output from a standard r&n tension test, a critical fracture strain can be determined:
CFS = -ln( I et,eng) in which et~enb represents the total engineering thinning strain. The total engineering thinning stxain is a function of em, ~m and fir:
yt,eng = f(em~ ~m~ ~f) where em is the engineering strain at the maximum load; ~m is the engineering stress at the maximum load; and ~f is the engineering stress at the fracture load.
The following engineering assumptions are made in the development of the CFS:
strains in the thickness and width directions are the same before the maximum load 1 ~ (P~,aX); the true stress after P~ax 3,S a constant; and tile Wldth Strar&~2 IS COTIStant after ~"sax.
The total thinning strain at fracture may therefore be determi.tled. l:n accordance with the present invention, a minimum CFS erashworthiness value of about 15 is preferred, with a value of at least 18 being more preferred.
~ typical property comparison for alloys is shown in Table 3.
Table 3 Alloy ~'aeld Strength ' Crush Results CFS
-L_ 5083 145 MPa Mood with some cracking on tight folds 18 _»
6060 216 MPa Good with some cr acking at geometric constraints 21 6xxA 244 MPa Crood with some c-acking at tight folds 18 Twelve lots of materials 2.0 rrzm thick were fabricated. Details of the fabrication are given in Table 4. Prior to hot rolling, each of the cast samples was scalped and preheated at 590°C for 8 hours followed by 560°C for 9 hours.
The main variables were alloy composition, use of a slow spray quench at an approximate cooling rate of 150°F/second following hot rolling, and the line speed of the continuous heat treat furnace (CHT). The compositions of the two 6xxA and 6060 alloys studied are shown above in 'Table 2.
Table 4 C~ill Coil2 Coil3 Coil4 STEP 6xxA 6xxA 6060 6060 Hot Rolling 1080 x 1080 x 1080 x 1080 x 10 ~nm 8 nun 10 mm 8 mm Hot Rolling exit>450C >450C >450C >450C
t. C
Slozv Quench ~,.rS N~ . ~,ES ' NQ
~.fter ~
hot rolling ~ ' i i SHT Cont. Furnace550-570-570550-570-570550-570-570 550-.570-570 C C C
spray bar spray bar spray bar spray bar Speed 1 7 mt/min 5 mt/min 7 mt/min 5 mt/min Speed 2 I 1 miJmin8 mt/min 11 mt/min 8 mt/min Speed 3 15 m~/min - I2 mt/min15 mt/min 12 mt/min The sheet was evaluated in the as received T4 temper and also after a simulative paint bake treatment at 180°C ( S65°l~'~. p'ig. 2 is a temperature-time plot of a therrnocoupled sheet sample during the paint bake treatment:.
'fable 5 T ensile properties for Sheet Pr~d~acts in T4 T~umper ;. ~_ AST~~ ~ ~ -! ! Test A Unif'orxn' n ~ Rm IZp0.2 ~
-. A r ~1~~v !
I
I Alloy Quench ~
Speed Test Coil (mlmin) dlirection (ll~Pa)(lVIPa) (!) (%) _ ;
6060 No 12 L 164 95 ' 29 24 0.43 0.225 f X 155 94 22 21 0.518 0.221 T 152 88 30 25 0.749 0.215 8 ~ L 184 108 28 23 0.634 ~
~ 0.23 X 182 106 23 22 0.634 0.222 -T ~ ~178 104 25 19 0.749 0.227 ~
5 L 192 1I6 26 21 0.749 0.223 I
' X 189 115 27 19 0.518 0.216 __ _ i , T 192 116 26 21 0.685 0.22 6060 Yes 1, 15 L 183 113 28 25 0.595 0.216 X 187 110 25 21 0.518 0.24 T 185 108 25 20 0.749 0.232 ~ 1 L 180 111 _ 30 24 0.411 0.219 _ -X 183 109 27 22 0.277 0.216 ~
r ~ T 183 112 27 22 0.214 0.216 ~
__~ ~ 115 27 21 0.427 0.223 X 186 113 26 2I 0.346 0.223 T 188 112 26 20 0.267 0.224 6xxA 163 94 28 24 0.629 0.231 No L
X 167 90 23 21 0.634 0.243 T 159 91 25 20 0.629 0.222 8 L 196 109 28 22 0.629 0.246 !
X 192 109 25 21 0.518 0.24 ! i 189 105 25 21 ~ 0.629~
, ~ 0.247 T I
!
~ ~ 209 116 27 22 0.634 [
0.246 , L
X 204 119 24 20 0.518 0.238 T 200 113 25 18 0.629 0.233 6xxA 196 118 28 20 0.518 0.228 Yes 194 118 28 21 0.343 0.224 188 114 25 21 0.429 0.215 L 210 128 28 22 0.477 0.2291 X 209 129 ~ 22 0.477 0.225 T 203 I zz5 j 18 0.524 0.218 II 208 I 125 23 2I 0.682 0.232 L _ 26 i ~ r-.-, ~X
i i T
f I
L
f I 209 124 ~ ~ 2i j 0.6870.234 X _ 26 _ 207 ~ 124 20 I 0.525~
T 24 0.233 ~ I
The tensile properties of the sheet in the T 4 temper are presented in Table 5.
There was a slight tendency for the T4 yield strength to decrease with increasing CHT
line speed, which is probably indicative of incomplete dissolution of MgzSi at the faster line speed. Minor variations in other T~ properties were found.
Guided bend tests using T4 sheet pre-strained 10% show that the slow quench is beneficial to bending of both alloys. both alloys fabricated using the slow quench withstood the maximum sharp bend. Downflange and hemming tests illustrate that both alloys are tlat hem capable.
The sheet r&n tensile properties after the paint bake were measured using 2 inch gage length specimens. Table ~ lists the ran tc;nsile data.
Table 6 Tensile Properties far Sheet Products after Faint Bake ec~tron after PB ) I
r~zn test data (I. - dir _ 'I I LlneSpeed Uniform Total Slow meterslmi ~ YS 1JTS
Tong. Elong.
~
Alloy ~uencla I n Mpa) (MPa) r (avg) YS/LTS (/_) (%) n ~
s 237 247 I0.3 15.2 1.00640.0850 ~
239 f 249 0.96 10.4 16.1 0.96140.0845 6060 ! No 5 avg I .
i 238 j 248 10.4 15.7 0.98390.0848 ' 230 238 ' 10.1 15.5 0.94030.0906 I
6060 ~ No 8 avg I 230 239 0.97 11.0 15.4 0.99820.0910 230 i 238 10.6 15.5 0.96930.0908 197 206 9.3 15.3 0.92670.0958 6060 No 12 avg I92 ~ 201 0.95 9.7 15.0 0.96570.0976 194 204 9.5 15.2 0.94620.0967 236 ~ 243 10.2 17.1 0.72340.0897 6xxA Yes 7 avg 235 l 243 0.97 10.9 16.2 0.73010.0912 ! 235 243 10.6 16.7 0.72680.0905 237 245 10.3 17.0 0.76260.0919 i 6xxA ~ Yes 11 avg 237 244 0,97 10.7 18.0 0.74480.0913 ~
237 244 10.5 17.5 0.75370.0916 228 ~ 235 10.1 15.6 0,80570.0917 6xxA Yes 15 avg ~ 228 ~ 234 0.97 10.5 16.4 0.84910.0923 228 234 10.3 16.0 0.82740.0920 237 245 10.0 16.4 0.70260.0831 ! 6060 Yes 7 avg ~ 237 246 0.96 9.9 14.7 0.X20 0.0830 ~
! 237 i 246 10.0 15.6 0.70730.0831 ! ! I 239 247 10.4 15.6 ~ 0.65900.0822 ~
! 6060 I Yes ~ i 1 avg ~ ~ 0.97 10.3 16.9 0.66090.0839 236 245 f t I 238 ~ 246 30.4 16.3 0.66000.0831 I i 236 245 ? 0.0 15.2 0.69530.0804 6060 Yes 15 avg ~ 237 245 0.97 =0.1 16.5 0.65940.0815 ! 237 245 ___0. 15.9 0.67740.0810 i_ 249 257 9.8 14.8 1.00460.0832 GxxA No 5 avg 248 256 0.97 9.9 16.4 0.99650.0831 249 ~ 9.9 i5.6 1.00060.0832 ;?32 241 I0.3 16.3 1.08560.0904 ~
231 239 0.97 10.3 16.0 1.09170.0896 6xxA No 8 avg 232 240 10.3 16.2 1.08870.0900 I 165 176 10.1 16.4 1.00240.1137 i 6xxA ! No ~ 12 av ' 72 18 0.94 10.3 16.1 0.94790.1060 g ~ 169 2179 10.2 16.3 0.97520.1099 a Fig. 3 plots yield strength of the alloys as a function of the processing variables.
The yield strength has the tendency to decrease at the fastest ~I~'T line speeds due to incomplete dissolution of l~g2Si, Guinier x-ray data showed the presence of l~g2Si in the materials processed at the faster line speeds. Tie influence of line speed on yield strength zs most pronounced in the sheet rw-hich was processed without using the slow quench.
Fig. 4a is a graph of Rtn, Rp0.2 and A values versus paint bake time at 1~5°C for the 6060 sample listed in Table 6 which was subjected to ~;l~e slow quench and a CHT
speed of 11 meters/minute. i~ig. 4b is a similar graph for the ~fixxA sample which was likewise subjected to the slow quench and CH'T speed of 11 meters/minute.
Crash boxes were assembled having a rectangular cross section measuring 63 mm by I33 mm. Welds or rivets may be used at approximately I inch on center with the first and last weld approximately %2 inch from the end, The number of spot welds or rivets specified were 20 per flange. An adhesive sold under the designation l3etamate 1494 by Gurit Essex is a one-component toughened epoxy that is applied warm along the side seams of the crash boxes, followed by riveting. A pneumatic heated cartridge gun is used to dispense the adhesive at approximately 40 to 50°C (104 to I22°F). The metal components to be joined were also heated to approximately the same temperature to assist in application of the adhesive and improve flow and wettability. ~Che adhesive was applied to warm metal on the flanges just prior to spot welding or riveting.
Rivets were installed at the same locations specified for welding. End caps are then welded in place.
After assembly, the boxes were paint baked. The paint baked boxes were tested in axial crush. 'The crush loads and energy absorbed at displacements of 100, 150, and 200 mm is given in. Table 7.
Tabls 7 Axial Crush Test results of faint Baked Samples ~~ Crash (after P~) ---j lVlax . ' i '; ' i I CIiT load Mean road ~ Absorbed line fineri~
J
t Sample Slow Speed 100 150 200 ~
I No. Alloy wench meters/minkN .l/mm) mm mm rnm I
144.7 55.7 5941 8472 11039 144.4 56.5 6011 8470 11184 1 6060 No ~ 8 avg 144.9 52.8 5935 8746 10470 144.7 55.0 5962 8563 10898 156.3 54.9 6380 8364 10877 ~ 152.8 58.6 6323 8955 11602 2 6xxA Yes I1 avg i ~ ~ 157.0 53.4 ~ 8496 10571 I ~ 155.4 ~ 55.6 ~ 8605 11017 ' 162.2 [ 58.4 , 9146 5932 i ~ 162.2 ~ 51.1 5505 8000 10119 6xxA ~ Yes 11 avg 156.9 57.3 6690 9149 11361 i 160,4 55.6 6042 8765 11014 _ 154.6 50.4 6076 7924 9983 141.4 53.8 6205 8449 10670 3 6060 Yes ~ 11 avg 140.6 51.9 5554 8028 10278 145.5 52.0 5945 8134 10310 149.1 56.4 5771 8977 11170 [
148.1 ~ 6081 8644 11045 55.7 I 6060 Yes 11 avg f ,I [ 153.1 ~ 52.3 6437 8175 10364 i ~ ' 54.8 6096 8599 10860 150.1 _ j .
I 140.0 51.3 5752 8257 10156 j 147'8 5.6 5724 8469 11020 4 6xxA No ~ 8 avg 143.8 X 5992 8461 10455 X2.8 143.9 53.2 5823 8396 10544 Computer generated illustrations of the crushed appearance of the boxes are shown in Figs. 5-8. Figs. Sa-c are computer generated illustrations from different view of Sam_pie No. 1 listed in Table '~. figs. 6a-c are computer generated illustrations of Sample No. 2. Figs. %a-c are computer generated illustrations of Sample I\To. 3.
Figs. 8a-c are computer generated illustrations of Sample No. 4. There were no significant differences among the quantifiable crush parameters for the samples tested.
The performance of the materials rnet the goals of a sheet alloy product for use in crash critical applications. The paint baked sheet had yield strengths of about 235 MPa, total elongation of 1S% and good static crush performance. :i'hc T~ properties indicate acceptable formability.
Whereas particular embodiments of this invention have been described above for purposes of illustration, it will be evident to those skilled in the ant that numerous variations of the details of the present invention may be made without departing from the invention as defined in the appended clazrr~s.
t2
Claims (60)
1. A heat treated and slow quenched aluminum alloy sheet comprising from about 0.5 to about 0.7 wt.% Si, from about 0.5 to about 0.7 wt.% Mg, from about 0.1 to about 0.3 wt.% Mn, and the balance Al and incidental impurities.
2. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the Si comprises from about 0.58 to about 0.68 wt.%.
3. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the Si comprises from about 0.60 to about 0.66 wt.%.
4. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the Mg comprises from about 0.56 to about 0.66 wt.%.
5. The heat treated and slow quenched aluminum alloy sheet of claim I wherein the Mg comprises from about 0. 58 to about 0.64 wt.%.
6. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the Mn comprises from about 0.12 to about 0.18 wt.%.
7. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the ahaminum alloy comprises a maximum of 0.35 wt.% Fe.
8. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the aluminum alloy comprises from about 0.15 to about 0.30 wt.% Fe.
9. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the aluminum alloy comprises from about 0.15 to about 0.25 wt.% fe.
10. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the aluminum alloy comprises a maximum of 0.20 wt.% Cu.
11. The heat treated and slow quenched aluminum alloy sheet of claim I wherein the aluminum alloy comprises a maximum of 0.:10 wt.% Cu.
12. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the Si comprises from about 0.58 to about 0.68 wt.%, the Mg comprises from about 0.56 to about 0.66 wt.%, and the Mn comprises from about 0.12 to about 0.18 wt.%.
13. The heat treated and slow quenched aluminum alloy sheet of claim 12 wherein the aluminum alloy comprises from about 0.15 to about 0.30 wt.% Fe, and a maximum of 0.10 wt.% Cu.
14. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the Si comprises from about 0.60 to about 0.66 wt.%, the Mg comprises from about 0.58 to about 0.64 wt.%, and the Mn comprises from about 0.12 to about 0.18 wt.%.
15. The heat treated and slow quenched aluminum alloy sheet of claim 14 wherein the aluminum alloy comprises from about 0.15 to about 0.25 mt.% Fe, and a maximum of 0.10 wt.% Cu.
16. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the Si comprises about 0.62 wt.%, the Nig comprises 0.60 wt.%, and the Mn comprises about 0.15 wt.%.
17. The heat treated and slow quenched aluminum alloy sheet of claim 16 wherein the aluminum alloy comprises about 0.20 wt.% Fe.
18. The heat treated and show quenched aluminum alloy sheet of claim 1 wherein the sheet has a critical fracture strain of at least 15.
19. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the sheet has a critical fracture strain of at least 18.
20. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the sheet has a yield strength of at least 220 MPa.
21. The heat treated and slow quenched aluminum alloy sheet of claim 2 wherein the sheet has a yield strength of at least 230 MPa.
22. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the sheet has a yield strength of at least 240 MPa.
23. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the sheet has a critical fracture strain of at least 15, and a yield strength of at least 220 MPa.
24. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the sheet has a critical fracture strain of at least 15, and a yield strength of at least 230 MPa.
25. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the sheet has a critical fracture strain of at least 15, and a yield strength of at least 240 MPa.
26. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the sheet has a critical fracture strain of at least 18, and a yield strength of at least 220 MPa.
27. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the sheet has a critical fracture strain of at least 18, and a yield strength of at least 230 MPa.
28. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the sheet has a critical fracture strain of at least 18, and a yield strength of at least 240 MPa.
29. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the sheet has a thickness of from about 0.7 to about 3.5 mm.
30. The heat treated and slow quenched aluminum alloy sheet of claim 29 wherein the sheet comprises an auto body sheet.
31. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the sheet has been slow quenched at a rate of less than 200°F/second.
32. The heat treated and s.ow quenched aluminum alloy sheet of claim 1 wherein the sheet has been slow quenched at a rate of from about 20 to about 100°F/second.
33. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the sheet has been slow quenched at a rate of from about 40 to about 70°F/second.
34. The heat treated and slow quenched aluminum alloy sheet of claim 1 wherein the sheet has been slow quenched at a rate of about 150°F/second.
35. The heat treated and slow quenched aluminum alloy sheen of claim 1 wherein the sheet has been air quenched.
36. The heat treated and slow quenched aluminum allay sheet of claim 1 wherein the sheet has further been coil cooled.
37. The heat treated and slow quenched aluminum alloy sheet of claim 36 wherein the sheet has been coil cooled at a cooling rate of from about 0.1 to about 5°F/hour.
38. The heat treated and slow quenched aluminum alloy sheet of claim 36 wherein the sheet has been coil cooled from an initial coiling temperature of from about 130 to about 190°F.
39. A method of treating an aluminum alloy sheet, the method comprising:
providing a heat treated aluminum alloy sheet comprising Si, Mg, Mn, and the balance aluminum and incidental impurities; and slow quenching the heat treated aluminum sheet.
providing a heat treated aluminum alloy sheet comprising Si, Mg, Mn, and the balance aluminum and incidental impurities; and slow quenching the heat treated aluminum sheet.
40. The method of claim 39 wherein the sheet is slow quenched at a rate of less than 200°F/second.
41. The method of claim 39 wherein the sheet is slow quenched at a rate of from about 20 to about 100°F/second.
42. The method of claim 39 wherein the sheet is slow quenched at a rate of from about 40 to about 70°F/second.
43. The method of claim 39 wherein the sheet is air quenched.
44. The method of claim 39 wherein the sheet is coil cooled.
45. The method of claim 44 wherein the sheet is coil cooled at a cooling rate of from about 0.1 to about 5°F/hour.
46. The method of claim 44 wherein the sheet is coil cooled from an initial coiling temperature of from about 130 to about 190°F.
47. The method of claim 39 wherein the aluminum alloy comprises from about 0.5 to about 0.7 wt.% si, from about 0.5 to about 0.7 wt.% mg, from about 0.1 to about 0.3 wt.%
mn, and the balance al and incidental impurities.
mn, and the balance al and incidental impurities.
48. The method of claim 47 wherein the Si comprises from about 0.58 to about 0.68 wt.%, the Mg comprises from about 0.56 to about 0.66 wt.%, and the Mn comprises from about 0.12 to about 0.18 wt.%.
49. The method of claim 48 wherein the aluminum alloy comprises from about 0.15 to about 0.30 wt.% Fe, and a maximum of 0.10 wt.% Cu.
50. The method of claim 47 wherein the Si comprises from about 0.60 to about 0.66 wt.%, the Mg comprises from about 0.58 to about 0.64 wt.%, and the Mn comprises from about 0.12 to about 0.18 wt.%.
51. The method of claim 50 wherein the aluminum alloy comprises from about 0.15 to about 0.25 wt.% Fe, and a maximum of 0.10 wt.% Cu.
52. The method of claim 47 wherein the Si comprises about 0.62 wt.%, the Mg comprises 0.60 wt.%, and the Mn comprises about 0.15 wt.%.
53. The method of claim 39 wherein the sheet has a critical fracture strain of at least 15, and a yield strength of at least 220 MPa.
54. The method of claim 39 wherein the sheet has a critical fracture strain of at least 15, and a yield strength of at least 230 MPa.
55. The method of claim 39 wherein the sheet has a critical fracture strain of at least 15, and a yield strength of at least 240 MPa.
56. The method of claim 39 wherein the sheet has a critical fracture strain of at least 18, and a yield strength of at least 220 MPa.
57. The method of claim 39 wherein the sheet has a critical fracture strain of at least 18, and a yield strength of at least 230 MPa.
58. The method of claim 39 wherein the sheet has a critical fracture strain of at least 18, and a yield strength of at least 240 MFa.
59. The method of claim 39 wherein the sheet has a thickness of from about 0.7 to about 3.5 mm.
60. The method of claim 59 wherein the sheet comprises an auto body sheet.
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| US43612302P | 2002-12-23 | 2002-12-23 | |
| US60/436,123 | 2002-12-23 |
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| US8083871B2 (en) * | 2005-10-28 | 2011-12-27 | Automotive Casting Technology, Inc. | High crashworthiness Al-Si-Mg alloy and methods for producing automotive casting |
| US9890443B2 (en) * | 2012-07-16 | 2018-02-13 | Arconic Inc. | 6XXX aluminum alloys, and methods for producing the same |
| EP2712942B1 (en) * | 2012-09-27 | 2017-11-01 | Hydro Aluminium Rolled Products GmbH | Method and apparatus for thermally treating an aluminium workpiece and aluminium workpiece |
| US8636197B1 (en) * | 2012-10-04 | 2014-01-28 | Ford Global Technologies, Llc | Bonding of roof panels |
| FR3008427B1 (en) * | 2013-07-11 | 2015-08-21 | Constellium France | ALUMINUM ALLOY SHEET FOR AUTOMOBILE BODY STRUCTURE |
| JP6752146B2 (en) * | 2014-01-21 | 2020-09-09 | アーコニック テクノロジーズ エルエルシーＡｒｃｏｎｉｃ Ｔｅｃｈｎｏｌｏｇｉｅｓ Ｌｌｃ | 6000 series aluminum alloy |
| JP6785772B2 (en) | 2015-01-12 | 2020-11-18 | ノベリス・インコーポレイテッドＮｏｖｅｌｉｓ Ｉｎｃ． | Highly moldable aluminum sheet for automobiles with reduced or no surface roping and its manufacturing method |
| US20210025046A1 (en) * | 2017-08-02 | 2021-01-28 | Aleris Aluminum Duffel Bvba | Automotive outer panel made from a 6xxx-series aluminium alloy sheet product |
| CN114657406A (en) * | 2022-02-10 | 2022-06-24 | 山东南山铝业股份有限公司 | Production method of green circulating grade-keeping 6-series high-edge-covered automobile plate |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2273077A1 (en) * | 1974-05-31 | 1975-12-26 | Cegedur | Shock-resistant, deformable aluminium alloy extrusions - contg. silicon and magnesium and suitable for crash barriers and car bumpers |
| DE69633002T2 (en) * | 1996-05-03 | 2005-07-21 | Aluminum Company Of America | Vehicle frame components with improved energy absorption capability, method for their manufacture and an alloy |
| EP0808911A1 (en) * | 1996-05-22 | 1997-11-26 | Alusuisse Technology & Management AG | Component |
| CH690916A5 (en) * | 1996-06-04 | 2001-02-28 | Alusuisse Tech & Man Ag | Thermaformed and weldable aluminum alloy of the AlMgSi type. |
| CH693673A5 (en) * | 1999-03-03 | 2003-12-15 | Alcan Tech & Man Ag | Use of an aluminum alloy of the AlMgSi type for the production of structural components. |
| US6780259B2 (en) * | 2001-05-03 | 2004-08-24 | Alcan International Limited | Process for making aluminum alloy sheet having excellent bendability |
-
2003
- 2003-12-22 US US10/743,549 patent/US20050000609A1/en not_active Abandoned
- 2003-12-23 CA CA002454210A patent/CA2454210A1/en not_active Abandoned
- 2003-12-23 EP EP03029804A patent/EP1433866A3/en not_active Withdrawn
- 2003-12-24 JP JP2003427659A patent/JP2004204352A/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| US20050000609A1 (en) | 2005-01-06 |
| EP1433866A2 (en) | 2004-06-30 |
| EP1433866A3 (en) | 2004-07-07 |
| JP2004204352A (en) | 2004-07-22 |
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| Date | Code | Title | Description |
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| FZDE | Discontinued |