DE2510087A1 - ALUMINUM COLD FORMING ALLOY - Google Patents

Description

MITSUBISHI CHEMICAL IHD., LTD., Tokyo, Japan

Wrought aluminum alloy

The invention relates to a cold wrought aluminum alloy.

In general, Al-Mg type corrosion-resistant aluminum alloys have excellent mechanical properties and properties excellent corrosion resistance. They were therefore used for large structures such. B. for buildings, ships or bridges or the like. Used. However, these alloys have the disadvantage that they are particularly susceptible to stress corrosion cracking, since the intermetallic compound MgpAl ~ is readily available the grain boundaries is deposited so that corrosion occurs at the grain boundaries. Therefore one has with conventional Cold wrought alloys of high strength of the Al-Mg type lowered the magnesium content in order to overcome the disadvantages mentioned. This is e.g. B. the case with the aluminum alloy according to JIS H 4000 and 5083. These conventional alloys however, have insufficient mechanical strength for large structures. They have the disadvantage of low elongation (according to table 1). Ternary alloys of the Al-Zn-Mg type are age-hardenable by storage and have high strength, in particular excellent mechanical strength. They are weldable. However, these alloys have the disadvantage of low corrosion resistance and low stress corrosion cracking resistance.

It is the object of the present invention to provide a cold-wrought aluminum alloy to create, which has an excellent corrosion resistance

509838/0685

strength and stress corrosion cracking resistance as well as excellent has mechanical properties.

According to the invention, this object is achieved by means of an aluminum cold-wrought alloy with 4-7 wt .- ^ Mg (preferably more than 4 and up to 7 wt .- # Mg), 0.5-2 wt .- ^ Zn and at least one of the components Cr (0.05-0.5% by weight), Mn (0.1-0.6% by weight) and with less than 0.5 wt% impurities, which are preferably consist mainly of Fe and Si, the remainder being aluminum, dissolved. The said amount of contamination can in addition to Fe and Si also consist of small amounts of other impurities, which are preferably less than 0.1 wt .- ^ in relation to the total alloy.

In this alloy, Cr and / or Mn can be replaced by 0.05-0.25% by weight Ti and / or 0.05-0.25% by weight Zr. the Alloys of the present invention have excellent corrosion resistance and stress corrosion cracking resistance and good mechanical strength. The alloy containing Mn can be 0.05-0.25 wt. Ti and / or 0.05-0.25 wt. # Zr. Such an alloy has good mechanical strength.

The aluminum alloy according to the invention is cold deformable. The aluminum alloy can be produced without artificial aging being required and without causing a precipitation effect comes. If the magnesium content is increased, the mechanical strength is improved, but the processability and corrosion resistance, however, are deteriorated. Accordingly, the magnesium content should be 4-7 wt .- ^ and preferably 4.5-6.5 weight percent based on the total alloy be. The mechanical strength of the alloy is not affected by the zinc content. The zinc will added to improve processability and around to prevent corrosion at the grain boundaries due to the precipitation of MgpAl at the grain boundaries. If more than 2 wt .- ^ Zinc, a deterioration in the corrosion resistance is observed

509838 / DS35

• - 3 -

strength and hardenability. 2 wt - - Accordingly, the zinc content should be 0.5. $> 0.5 and preferably - be 1.5 wt .- ^ "By the addition of chromium and manganese, the mechanical properties, especially the strength and elongation, as well as the. The alloy can contain 0.05-0.5% by weight and preferably 0.1-0.3% by weight Cr or 0.1-0.6% by weight and preferably 0, 2-0.4 wt Properties and cold workability as well as corrosion resistance are impaired. By adding titanium and / or zirconium instead of or in addition to chromium and / or manganese, the mechanical strength, the corrosion resistance and the stress corrosion cracking resistance can be improved significantly. The content of titanium and zirconium is each 0.05 - 0.25 wt .- # and preferably 0.07-0.15 wt .- ^. By adding Mn on the one hand and Ti or Zr on the other hand, alloys with excellent elongation, good corrosion resistance and excellent stress corrosion cracking resistance can be obtained. The values achieved here correspond to an addition of Mn. On the other hand, however, the mechanical strength can be significantly improved so that it is higher than the mechanical strength of an alloy with Mn However, the corrosion resistance and mechanical properties of the alloy are adversely affected by an excessively large content of impurities. Thus, it is preferred to reduce the content of impurities to less than 0.5% by weight and especially less than 0.4 The content of other impurities, apart from iron and silicon, is less than 0.01% by weight for each individual impurity and less than 0.1% by weight for all impurities together.

5G3S38 / 0685

-A-

The aluminum alloys according to the invention thus contain. except for Al, Mg, Zn, Cr, Mn, Ti, Zr, Fe and Si essentially no other components.

In the following the invention is based on exemplary embodiments explained in more detail.

example

In each case, prepared according to Table 1 at a casting temperature of 750 ⁰ C, an aluminum leg by casting a molten aluminum alloy of the composition. A permanent mold with the internal dimensions 150 mm ι 110 m 30 mm is used. The blocks are freed from the casting skin and then homogenized for 24 h at 430 ⁰ C and then hot rolled at the same temperature. Thereafter, after the surface has been washed (the surface is treated with water), the product is cold-rolled to obtain a rolled product with a thickness of 1.5-2 mm. This rolled product is then cured ^{at about 370 ° C. for 5 hours.} The hardened product is used as a soft alloy for various tests. The cured product is then treated by cold rolling to give it a hardness of 1/4 H. The cold-hardened alloy thus obtained is used for various tests. The following test procedures are used:

(a) Breaking Strength. 0.2 Jq yield strength and elongation: JIS Z 2201

(b) Corrosion resistance:
JIS D 0201

(Partial immersion naten _o in artificial seawater for 6 M)

After the corrosion treatment, the test samples are examined for signs of corrosion on the surface and tested for their mechanical strength.

509838/0685

_ 5 -
(c) Stress corrosion cracking test:

Corrosive solution: aqueous solution of 5 Ί ° HaCl +

0.3 * H ₂ Og

Load: 70 # weight for 0.2 # stretch

border

Duration: time to break (h).

Palis does not break; 4000 - 5000 h.

The results are compiled in the tables below. In these tables means

0: the soft alloy and

H: the cold-hardened alloy (corresponding to 1/4 H).

Samples No. 13-15 are comparative samples.

Sample Kr. 15 is alloy 5083.

509338/0685

Table 1 Zn Mn Cr Type ir - 0.2% Strec
,border
kg / mm ^ strain at
game
No. Composition ($) 1.1 - 0.26 O mechanical properties 15.1 29.9 1 Mg ' 1.0 0.44 - · H Fracture-
firm
kg / mm * 21.3 25.1 2 5.0 1.4 0.19 0.16 O 30.6 14.3 31.0 3 5.0 1.1 - 0.45 H 31.7 24.4 18.9, ! 4 5.4 1.0 0.44 - O 30.7 15.3 33.6 J5 6.3 0.72 0.20 0.15 H 33.4 25.3 20.5 , 6 6.2 1.3 0.20 0.14 O 31.7 16.5 29.5 7th 6.5 1.6 0.22 0.15 H 34.6 26.2 20.0 8th 6.4 1.1 0.34 - O 32.5 16.0 30.0 ί
; ⁹ 6.6 1.0 0.34 - H 36.2 26.6 21.0 10 5.5 1.0 - - O 33.9 15.9 32.1 11
i 5.6 1.0 - - H 36.9 25.1 23.4 I.
12th 5.1 1.0 - - O 33.1 15.2 31.5 13th 5.0 1.0 - - H 36.4 26.0 22.8 14th 5.0 - 0.54 0.17 O 33.0 15.9 29.8 15th 6.2 H 37.1 28.6 18.9 4.5 O 34.7 19.5 25.0 H 38.6 27.9 16.8 O 34.5 24.2 19.8 H 35.9 34.1 15.3 O 39.5 15.4 32.3 H 42.8 24.9 20.3 O 30.5 18.7 23.0 H 33.6 27.9 15.8! O 33.3 12.3 30.1, H 36.1 28.0 12.3 O 26.8 13.3 32.8 H 33.2 30.8 14.6 O 29.3 15.7 22.5 '.H 36.1 33.0 9.0
. 1 29.4 36.5

50983S / Q585

- - - 7 -
Table 2 Composition (#) Zn Mn Cr Type 2 510087 Mg 1.1 - 0.26 O Figure of merit d
Corrosion
strength at
game
Mr. 5.0 1.0 0.44 - H 9 Duration up to
• Stress crack
corrosion
(H) 1
¹ 5.0 1.4 0.19 0.16 O 9 > 4000 2 5.4 1.1 - 0.45 H 9 > 4000 3 6.3 1.0 0.44 . - O 9 > 4000 .4 6.2 0.72 0.20 0.15 ' H 9 > 4000 5 6.5 1.3 0.20 0.14 O 9 > 50CiO 6th 6.4 1.6 0.22 0.15 H 9 > 5000; 7th 6.6 1.1 0.34 - O 9 > 4000 8th 5.5 1.0 0.34 - H 8th > 4000 9 5.6 1.0 - - O 7th > 4000 10 5.1 1.0 - - H 9 > 4000 11 5.0 1.0 - - O 9 > 5000 12th 5.0 1.0 - - H 9 > 5000 13th 6.2 - 0.54 0.17 O 9 > 5000 14th 4.5 H 8th > 5000 15th O 8th > 5000 H 9 > 5000 O 9 > 4000 i ¹ H 8th > 4000 i O 8th > 4000 H 9 > 4000 O 9 - H 8th - O 8th - H 8th O 8th 2000 H 7th 1000 O 7th 1000 H 8th 800 7th 2000 1000

509838/0685

As falselle 1 shows, the Ch2 ^ ~ Deimgr @ ns'3 is the soft one. Alloy, which or oä & x In © der fesiä © contains ₀ essentially SdJft! 2 © r as siepisaige H & s Ts ^ rfl ^ iQlislegleirtiiJige-äo until elongation "« Her cold-hardened alloy mag mrd etosh Sngalbe iron Or ader Mn © ste? Ιϊ3ί € β2ΐ ^ esentlieh? Ιϊ3ί € β2ΐ ^ esentlieh T © r "betterp may. sif & s & w £ more than twice OCE herkömmliehen Ssgiermaf AET _o 5083 _a The breaking strength of an alloy old ainem S-ehalt won about β $> Mg is particularly Jäoeli »31® erfindungsgemäSen Aluminiiam-Isgierangesi have aemerkenswert gu'fe © asaliaaisehe Eigensehaften Le are Tsrfleick sn äerkoumlisliea tension-proof

for

? * Si

£: 3BSi, © a Al'csiiia

® f © aigiii

Ife © i, © s Os

Bi © Κ

Ice? 73is © atli

Sr ₀ ? 083o Sarsli Snsata tg; i; 3r maa / or Hs. Are the

much Tereessert * ™ 3 © §ΐ3ϊΐΐϊΐκδ "ΐ ®it a G ehalt at more ds 2 Zn fi! aabes 3ine sehlsck ser-3 Ysrar" beit "bility and show sine lower SO2? accuracy rosio2i8fes _^!, The Tsrasoeifbarkeit and corrosion resistance -siSiu Liisät aissser si, Is © ei roig Ur ₁₉ pO84 _f seiest wena S5ai ^ aer Or Isei ^ egeoea, '<? Sarliser kinaus asooaclitet naa. 3 @ i Lisgies ^ HSigea ait siziem 0-ehalt.Tone more than £ fs In üei ssr iLiisIageniag Aiisscaeidiiiigen. Therefore, see these alloys aieMt for construction purposes. Ife-il: S'agat? © T * 3a 0, -. € '■ 5 - 0 _f 25' p ^: J? i tuid / gäer Ir instead of

r ~ η r

The aluminum alloys according to the invention are excellent as extrudable alloys, and essentially "Better than the match alloys. This can be shown by measuring the resistance to plastic deformation. The results are in Pig. 1 shown. The resistance to plastic deformation (kg / mm) is plotted on the ordinate and the abscissa is the reduction in cross-sectional area (%). The above diagram concerns samples made by casting and the graph below relates to samples made by hot working (50 ^). The samples have the following composition:

ο Mg: 5.4? 6, Zn: 1.1 #, Mn: 0.18 #, Cr: 0.14 $, Q Mg: 6.3 #, Zn: 1.1 #, Mn: 0.19% , Cr: 0.15 # x 5056 alloy

Alloy No. 5056 contains 5.4% Mg. The following test methods were used to perform the tests. The alloys were each cast in a cylindrical permanent mold, which has an inner diameter of 60 mm and a height of 200 mm. A cylindrical sample with a diameter of 15 mm and a height of 18 mm was cut from the center of the cast product. The results are shown in the graph above. On the other hand, the molded product was thermoformed to 5.0 io, and then a cylindrical sample each having a diameter of 15 mm and a height of 18 mm was cut out from the center of the product. The results are shown in the graph below. The compression tests were performed for each sample group at 430 ⁰ C. It can be seen that the aluminum alloys according to the invention have a significantly better processability than alloy No. 5056. The one for the extrusion of an alloy with 6.1 $ Mg, 1.0 fo Zn, 0.13 1 ° Cr and 0.13 # Mn required pressure is lower than that required for alloy no. 5083.

809838/0835

Moreover, the increase is smaller than with the alloy 5083. In the case of two-stage heating (4 - 5 h at 430 ⁰ C and then at 530 ⁰ C) of Strangpreßtests shows when conducted at 530 ⁰ C, a extrusion speed in the erf indungs contemporary Alloy which is more than twice the extrusion speed for alloy 5083. The aluminum alloy according to the invention is therefore outstandingly suitable as an extrusion alloy. In addition, the alloy according to the invention has excellent weldability. The joint effectiveness in the sweat test is 85%. The comparison alloys have the following composition:

Alloy ITr. 5056 alloy Ur. 5083

Mg 5.4 wt .- # Mg 4.5 wt .- ^

Mn 0.09 wt. # Mn 0.54 wt. #

Cr 0.1 wt% # Cr 0.17 wt%

509838/0685

Claims (9)

PiU1IIfIIiSprtCHE 1. Alxuainium cold forging alloy with 4-7 §ew ₉ -0 0.5 - 2.0 wt .- $ 2n _s 0.05 - O _S 5 Sew. - ^ or Tind / oses? 0.1-0.6 wt .- $ Mn and / or Q, 05-0..25 & ew _ä «^ ti • and / or 0.05-0.25 wt .- $ 2r iaad ^ eaiger than Ö _s g ter-impurities, remainder Al. 2. Aluminum- ^ itknetlegierajag Bach claim 1 _, with 4 ■ wt .- $ Mg, O ₉ 5 - 2 _s 0 8ew. ^ Zn and / or 0,1 - Oj6 G-ew, - $ Mn ind wesiiger ale Q ₉ 5 i-Tenmreinigungs (mainly Is isi SI J ₅ Eo 1 or 2 with 4-7 ß-ew.-ffe Mg ₉ 0.5 - 2 _g Q 0.1 - 0, 3 Crew _s - $ Gr and 0,2 .-- 9 _S 4 Gew _e - $ Ife C0 _s 3 · => O ₅ SI ' §' Cr * Mn) and less ale O ₅ "5 Sew .- ^ ¥ © naE ^ @ isigpinge & (is. Mainly Fe iiad Si), remainder Al. 4. Aluminum cold kneading aasä AsiSpsmeüi 1! old 4-7 wt .- # Mg, 0.5 - 2 ₉ 0 £ ew _o - $ Sa, O ₉ I - 0 _p g § @ tf _s -f -and 0.05 - 0.25 wt .- ^ Ti and / or 0 ₃ 05 - O ₅ 25 & ew .- $ Zr and less than 0.5 wt .- ^ S Teron purifications (mainly Fe and Si), remainder Al. 5. Aluminum clay kneading alloy saeli Anspameli-4 with 4-7 wt .- # Mg _? 0 _s 5 - 2 _? ö @ ew - ^ ^ n ₅ O ₅ I - G _S 6 © ew.-f ^ Mn and 0.07 - 0.15 Gw .- $ S fi -aaa / -3eLer C ₃ ö7 - 0 _s 15 § ew _o - ^ % τ ■ and less than 0.4 & ew _c - $ Tsnmreiaiigiiagen (ia äer main thing Ie and Si), remainder Al ». 6, Aluminum-Ealtknetlsglermig aae ^ ilsspraeSa 1 with 43 - S, 5 Sew _e <- $ Mg ₉ 0 _s 5 - 13 ^ © ^ _e -§5 Ia -md O ₉ I - 0.3 §i ^ s? "ana less than 0.4 Sew ο - ^ Tesimrsiaignsgea (is iss Sfe F ^ eiie Fe and Si) ₅ remainder Al ₄ 7. aluminum cold wrought alloy according to claim 1 with 4.5 - 6.5 wt. # Mg, 0.5 - 1.5 wt. # Zn, 0.2 - 0.4 wt. # Mn, and less than 0.4 wt. - $> impurities (mainly Pe and Si), remainder Al. 8. Aluminum cold wrought alloy according to claim 1 characterized by 4.5 - 6.5 wt .- # Mg, 0.5 - 1.5 wt .- # Zn, 0.1-0.3 wt% Cr and 0.2-0.4 wt% Mn (0.3-0.5 wt% Cr + Mn) and less than 0.5 wt .- ^ impurities (in the Mainly Pe and Si), remainder Al. 9. aluminum cold wrought alloy according to claim 1 with 4.5 - 6.5 wt. # Mg, 0.5 - 1.5 wt. # Zn, 0.2 - 0.4 wt. # Mn and 0.07-0.17 wt. # Ti and / or 0.07-0.15 wt. # Zr and less than 0.4 wt .- ^ impurities (mainly Pe and Si), remainder Al. 509838/0685