JP2012201923A - Aluminum extruded shape and extrusion molding method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extruded shape which has high strength, high ductility, and extrudability corresponding to JIS 6061-T6 and in which the fiber structure percentage at an extrusion ratio of 40 is 60% or more.SOLUTION: When Mn and/or Zr is added to and contained in an Al-Mg-Si alloy, an excessive Si state where Si is contained more than a balance composition of MgSi including 0.4 to 0.9% Mg and 0.7 to 1.2% Si is brought about and a relation between Mg and Si and a relation between Mn and Zr are regulated, thereby obtaining both good extrusion molding characteristics and high-strength mechanical properties. Further, the excessive Si accelerates the precipitation of a Mn or Zr compound, and at the same time, it precipitates as the element Si, thereby suppressing the transfer of a grain boundary during the extrusion molding, exhibiting the pinning effect of a crystal grain, suppressing the coarsening phenomenon of the crystal grain, and accelerating the formation of a fibrous structure of the crystal grain.

Description

  The present invention relates to an aluminum extruded shape and an extrusion molding method thereof.

  In order to make an aluminum extruded profile into a fibrous structure, an Al-Mg-Si alloy containing Mn, Cr and Zr is known. Patent Document 1 listed below describes Si: 0.6-1 0.1% by mass, Mg: 0.6 to 1.1% by mass, Cu: 0.1 to 0.5% by mass, Fe: 0.1 to 0.3% by mass, Ti: 0.001 to 0.20 Including one mass or more of Mn: 0.2-1.0% by mass, Cr: 0.1-0.3% by mass, Zr: 0.1-0.3% by mass, The billet is held at 480 to 580 ° C. for 1 to 8 hours using an aluminum alloy billet containing Mn + Cr + Zr so that the total of Mn + Cr + Zr is 0.2 to 1.0% by mass, and the balance is substantially Al. After cooling to room temperature at a cooling rate of ℃ / h or more, it is heated to 430 to 540 ℃ to perform hot extrusion, and then Cooling to 200 ° C. or less at an average cooling rate of 00 ° C./min or higher, or solution treatment at 500 to 560 ° C., and then holding at 160 to 220 ° C. for 1 to 20 hours, the fiber structure ratio is 70% or more It is supposed to be an aluminum extruded shape.

JP 2003-155535 A

  In this case, when the fiber structure ratio is 70% or more, good results are shown as strength, elongation, and Charpy impact value. However, when Mn, Cr, Zr is added to the Al—Mg—Si alloy, it is used for extrusion molding. In addition to increasing the deformation resistance of the billet and lowering the extrusion processability, there is a problem that the quenching sensitivity becomes sharp in press quenching, and in the case where a sufficient cooling rate cannot be obtained, the strength tends to be insufficient. .

  Further, even if a fiber structure ratio of 70% or more can be obtained, the extrusion ratio, that is, the ratio of the cross-sectional area of the container to the cross-sectional area of the extruded shape is not shown. When the extrusion ratio is small, the fiber structure ratio is relatively large. For example, when the extrusion ratio is relatively high such that the extrusion ratio exceeds 40, the fiber structure ratio generally tends to be low. Even in this case, it is not always possible to obtain a fiber structure ratio of 70% or more.

  The present invention has been made in view of such circumstances, and the problem to be solved is that while adding Mn and / or Zr to an Al-Mg-Si based alloy, the extrusion ratio is not impaired. Provided an aluminum extruded shape having high strength, high ductility, and extrudability by providing a fiber structure ratio of 60% or more even in the case of a high workability of 40 or more, and its extrusion molding Is in providing a way.

As a result of earnest research along the above-mentioned problems, it was found that when Mn and / or Zr was added to an Al-Mg-Si alloy, Si was excessively contained with respect to the balance composition of Mg ₂ Si. While ensuring the formability, it is possible to obtain mechanical properties with high strength equivalent to, for example, JIS 6061-T6 aluminum extrusions. Further, when Si is homo-treated, Mg ₂ Si is finely dispersed and precipitated. By promoting the precipitation of Mn-based or Zr-based compounds having these as precipitation sites, the crystal grain pinning effect (pinning effect) is exhibited, and by suppressing the grain coarsening phenomenon, Promotes fibrous organization and improves precipitation hardening characteristics. For example, even in an extruded shape having a high workability such as an extrusion ratio of 40 or more, the fiber structure ratio is 60% or more. The fact that may be a thing, this time, the alloy composition of the formula obtained based on analysis of experimental data of each extrusion, i.e., the Mg0.4~0.9%, Si0.7~1.2% of _Mg 2 Si In an excess Si state above the balance composition, the relationship between Mg and Si is set to -0.15Mg + 0.84 ≦ Si ≦ −0.5Mg + 1.45, ensuring extrudability and mechanical properties due to increased Mg, and Mn0.2 % Or less, Zr 0.2% or less, the relationship between Mn and Zr is Mn + Zr ≦ 0.2 and 0.67Mn + Zr ≧ 0.039, and the relationship between the excess Si, Mn and / or Zr is excess Si ≧ ( 0.6-1.56Mn + 0.22Zr + 3.93Mn and / or Zr) / (9.17Mn + 16.1Zr), while maintaining the above extrudability and high strength mechanical properties. And we have found the fact achievable effectively and reliably fibrous organization in Degata material.

The present invention has been made on the basis of such knowledge. That is, the invention according to claim 1 is obtained by adding Mn and / or Zr to an Al—Mg—Si based alloy to provide high strength, high ductility, and extrusion processing. Extrusion shaped material having both the properties of Mg and Si in an excess Si state more than the balance composition of Mg ₂ Si of 0.4 to 0.9% and Si 0.7 to 1.2%, and the relationship between Mg and Si −0.15Mg + 0.84 ≦ Si ≦ −0.5Mg + 1.45, Mn 0.2% or less, Zr0.2% or less, and the relationship between Mn and Zr is Mn + Zr ≦ 0.2 and 0.67Mn + Zr ≧ 0. 039, and the relationship of excess Si, Mn and / or Zr with the excess Si ≧ (0.6−1.56Mn + 0.22Zr + 3.93Mn and / or Zr) / (9.17Mn + 16.1Zr) More than 40 Fibrous tissue ratio of 60% or more, a tensile strength of 265MPa or more, 0.2% proof stress 245MPa or more, is obtained by an aluminum extruded profile which is characterized by comprising as least 8% elongation.

  In addition to the above, the invention described in claim 2 further adds Cr and Cu to obtain an aluminum extruded material equivalent to JIS 6061, and to prevent recrystallization after extrusion, and to refine the cast structure. By adding a small amount of Ti in order to achieve the above, the above-mentioned high strength, high ductility, and extrudability are combined as the aluminum extrudate corresponding to JIS 6061. Or, in addition to Zr, Cr ≦ 0.1%, Cu ≦ 0.25%, Fe0.1-0.3%, Ti0.003-0.1% is added and contained. 1. The aluminum extruded profile according to 1.

In the invention according to claim 3, when the aluminum extruded shape is extruded, the homogenization treatment of the billet having the alloy composition is performed at a heating rate of 100 to 300 ° C./Hr, a holding temperature of 510 to 590 ° C., and a holding time. 1 to 10 Hr, by eliminating the segregation of the billet as effectively as possible, and performing extrusion molding, even if the extrusion ratio is 40 to 90, a high degree of fibrous organization is achieved. As a result, it becomes possible to obtain an extruded shape having high strength, high ductility, and extrudability, and this is added to Mn and / or Zr in an Al-Mg-Si alloy. Te high strength, high ductility, a molding method of extrusion processability comorbid comprising the extruded profile, Mg0.4～0.9%, or more balance composition Si0.7～1.2% of _Mg 2 Si Relationship between Mg and Si in excess Si state −0.15Mg + 0.84 ≦ Si ≦ −0.5Mg + 1.45, Mn 0.2% or less, Zr0.2% or less, and the relationship between Mn and Zr is Mn + Zr ≦ 0.2 and 0.67Mn + Zr ≧ 0. 039, and the relationship of the excess Si, Mn and / or Zr is an aluminum alloy composition in which excess Si ≧ (0.6−1.56Mn + 0.22Zr + 3.93Mn and / or Zr) / (9.17Mn + 16.1Zr) After the billet homogenization treatment is performed at a heating rate of 100 to 300 ° C./Hr, a holding temperature of 510 to 590 ° C., and a holding time of 1 to 10 Hr, the aluminum extruded profile is extruded at an extrusion ratio of 40 to 90. This is a method for extrusion molding of an aluminum extruded section characterized by the following.

  The present invention uses these as the gist of the invention and is a means for solving the above problems.

Since the present invention is configured as described above, the invention according to claim 1 is based on the addition of Mn and / or Zr to the Al—Mg—Si alloy, and Si is added to the balance composition of Mg ₂ Si. By containing excessively, it is possible to ensure good extrudability and obtain high strength mechanical characteristics equivalent to, for example, JIS 6061-T6 aluminum extruded material. In this case, Mg ₂ Si is finely dispersed and precipitated to promote precipitation of Mn-based or Zr-based compounds having these as precipitation sites, thereby exhibiting a pinning effect (pinning effect) of crystal grains, and coarsening of crystal grains By suppressing the phenomenon, the fibrous organization of the crystal grains is promoted, and in addition, the precipitation hardening characteristics are improved. For example, even in an extruded shape having a high workability such as an extrusion ratio of 40 or more, The fibrous tissue ratios as be of a 60%, at this time, the alloy composition, Mg0.4~0.9%, Si0.7~1.2% of _Mg 2 Si balanced composition more excess Si state of Then, the relationship between Mg and Si is set to −0.15Mg + 0.84 ≦ Si ≦ −0.5Mg + 1.45 to ensure extrudability and mechanical properties due to increase in Mg, Mn 0.2% or less, Zr 0.2% In the following, the relationship between Mn and Zr is Mn + Zr ≦ 0.2 and 0.67Mn + Zr ≧ 0.039, and the relationship between the excess Si, Mn and / or Zr is excess Si ≧ (0.6−1.56Mn + 0 .22Zr + 3.93Mn and / or Zr) / (9.17Mn + 16.1Zr) allows the fibrous structure in the extruded shape to be maintained while maintaining the above extrudability and high strength mechanical properties. In addition, in order to ensure that the fiber can be achieved, it is possible to add the Mn and / or Zr to the Al—Mg—Si based alloy, while maintaining the extrudability without impairing the extrudability. It is possible to provide an aluminum extruded shape member having a structure ratio of 60% or more and having high strength, high ductility, and extrudability.

  In addition to the above, the invention described in claim 2 further comprises adding Cr and Cu to obtain an aluminum extruded material equivalent to JIS 6061, and for preventing recrystallization after extrusion, using Fe as an ingot crystal. By adding a small amount of Ti in order to refine the grains, the aluminum extrudate corresponding to JIS 6061 can have the above-mentioned high strength, high ductility, and extrudability.

  In the invention according to claim 3, when the aluminum extruded shape is extruded, the homogenization treatment of the billet having the alloy composition is performed at a heating rate of 100 to 300 ° C./Hr, a holding temperature of 510 to 590 ° C., and a holding time. 1 to 10 Hr, by eliminating the segregation of the billet as effectively as possible, and performing extrusion molding, even if the extrusion ratio is 40 to 90, a high degree of fibrous organization is achieved. It is possible to provide an extrusion method for an aluminum extruded shape which can be ensured to obtain an extruded shape having high strength, high ductility and extrudability.

It is a model figure which shows the influence on fibrous organization by the precipitation form of excess Si, Mn, and / or a Zr type compound.

In the following, the present invention will be described in more detail. The aluminum extruded profile in the present invention is, for example, a bumper reinforcing material, an automobile member such as a door arm, an electronic component such as an HDD arm material, and a public structural material such as a protective fence. As used, it is assumed that JIS 6061-T6 equivalent high strength, high ductility, and extrudability coexist, and at this time, the aluminum extruded profile is made of Al-Mg-Si based alloy with Mn and / or Zr. be those containing added, Mg0.4～0.9%, in the above balance composition Si0.7～1.2% of _Mg 2 Si excess Si state, the relationship between the Mg and Si -0. 15Mg + 0.84 ≦ Si ≦ −0.5Mg + 1.45, Mn 0.2% or less, Zr0.2% or less, and the relationship between Mn and Zr is Mn + Zr ≦ 0.2 and 0.67Mn + Zr ≧ 0.039, Above By setting the relationship of Si, Mn and / or Zr to excess Si ≧ (0.6−1.56Mn + 0.22Zr + 3.93Mn and / or Zr) / (9.17Mn + 16.1Zr), the extrusion ratio is 40 or more, fiber The composition ratio is 60% or more, the tensile strength is 265 MPa or more, the 0.2% proof stress is 245 MPa or more, and the elongation is 8% or more. In this example, the extruded aluminum material is added to the above Mn and / or Zr. Cr ≦ 0.1%, Cu ≦ 0.25%, Fe0.1 to 0.3%, and Ti0.003 to 0.1%.

In the alloy composition of an aluminum extruded profile, Mg improves the alloy strength (extrusion profile strength) by forming Mg ₂ Si together with Si, which will be described later, but it is possible to increase the deformation resistance of extrusion molding. However, if Mg is less than 0.4%, sufficient strength cannot be obtained, and if it is less than 0.55%, the strength tends to decrease. If it exceeds 0.9%, the extrudability deteriorates, and if it exceeds 0.75%, a tendency to decrease the extrudability occurs. Therefore, the Mg is 0.4 to 0.9%, preferably 0.55 to 0.55%. It should be 0.75.

Si forms Mg ₂ Si together with Mg to improve the alloy strength. The addition of Si does not impair the extrudability, and excess Si exceeding the balance of Mg ₂ Si is Mn and / or Or, even if the amount of Zr is small, it is easy to form the fibrous structure. However, if the content of Si is less than 0.7%, the effect of forming the fibrous structure is low, and if it is less than 0.8%, the tendency is reduced. If the content exceeds 1.2%, the ductility may decrease and intergranular corrosion may occur. On the other hand, if the content exceeds 1.0%, the tendency occurs. .2%, preferably 0.8 to 1.0%.

At this time, the Mg and Si have an alloy composition in the range of −0.15Mg + 0.84 ≦ Si ≦ −0.5Mg + 1.45, while ensuring good extrudability and the above JIS. It is possible to ensure mechanical strength equivalent to 6061-T6. The left side, that is, −0.15Mg + 0.84 ≦ Si, shows the boundary between Mg and Si concentration at which the surface pressure is 30 or less from the data of the surface pressure at the time of extrusion molding without cracking or peeling. By satisfying, the alloy strength of the aluminum extruded profile can be ensured, and when it is on the left side and Mg is small in quantity, for example, when Mg is 0.4% of the lower limit, Si is Is 0.78%, the mechanical strength, that is, the alloy strength can be secured. Also, the right side, that is, Si ≦ −0.5Mg + 1.45, shows the boundary between Mg and Si concentrations at which this is 245 MPa or more from the yield strength data obtained by the tensile test of the extruded profile, The range for avoiding extrusion molding defects such as cracking and peeling is shown. When Si is relatively large in the range of 0.7 to 1.2%, there is a problem with the strength and deformation resistance of the aluminum extruded shape. Although it does not occur, Al—Si—Mg ₂ Si ternary eutectic melting is likely to occur, and at the same time, if Mg is also at the upper limit side, deformation resistance increases, so that the generation of processing heat increases, and the above-mentioned eutectic melting occurs. Ductility and toughness due to crystal melting are reduced, and cracks are easily generated in the extruded aluminum shape. Therefore, when Mg exceeds 0.6%, it is necessary to regulate Si to less than 1.2%.

  Mn and / or Zr precipitates as a Mn-based and / or Zr-based compound during the homogenization treatment of the billet forming the aluminum extruded profile, and suppresses recrystallization during molding by the pinning effect. If it exceeds 20%, the extrudability and hardenability may be reduced, and if it exceeds 0.15%, this tendency occurs. Therefore, the Mn and / or Zr is 0.20%, preferably 0. .15% or less is recommended.

  When one of Mn and Zr is used or both of them are used, the relationship between Mn and / or Zr is Mn (%) + Zr (%) ≦ 0.2, 0.67 Mn (%) + Zr (%) ≧ 0.039, and the relationship with excess Si is as follows: excess Si ≧ (0.6−1.56Mn + 0.22Zr + 3.93Mn and / or Zr) / (9.17Mn + 16.1Zr) There is something to do.

  Regarding Mn and Zr, the above range of Mn (%) + Zr (%) ≦ 0.2 satisfies a surface pressure of 30 or less and a proof stress of 245 MPa so as to ensure extrudability and high strength mechanical properties. The above-mentioned 0.67 Mn (%) + Zr (%) ≧ 0.039 is the ratio of the fiber structure of the extruded shape, that is, the area of the fiber structure / the cross-sectional area of the extruded shape From the ratio data, the boundary of Mn and / or Zr concentration necessary for the fiber structure ratio to be 60% or more is shown, and the excess Si ≧ (0.6−1.56Mn + 0.22Zr + 3.93Mn and / or Zr ) / (9.17Mn + 16.1Zr) is the Mn and / or Zr and excess Si concentration required for the fiber structure ratio to be 60% or more for the interaction of Mn and / or Zr and excess Si with respect to the fiber structure ratio. boundary Show.

  Therefore, Mn and / or Zr can satisfy the above conditions by suppressing the concentration thereof as much as possible without impairing the extrusion moldability and without increasing the Mg that increases the deformation resistance. The excess Si can be effectively utilized to suppress recrystallization due to the excess Si and to form a fibrous structure of the aluminum extruded shape. In addition, in the above 0.67 Mn (%) + Zr (%) ≧ 0.039 Mn derived from the fiber structure ratio, the content was given a coefficient of less than 1 because the recrystallization suppressing effect of Mn compared to Zr. This is because the relative amount with Zr matches.

  On the other hand, Cr lowers the hardenability and extrudability compared to Mn and / or Zr. Therefore, it is preferable to avoid the addition of this, but when making an aluminum extruded shape corresponding to JIS 6061, Cr is an essential component, and since this Cr has an effect of suppressing recrystallization by itself, it may be added and contained, but even in this case, from the standpoint of ensuring hardenability and extrudability. In addition, it is necessary that the added content be 0.1% or less at the maximum.

  Fe has an effect of suppressing recrystallization and unnecessarily raises the purity of the base metal, so 0.1% or more of this is added and contained. The Fe content is preferably 0.1% to 0.3% because it causes a poor appearance such as a pickup during extrusion molding.

  Cu, as a component of JIS 6061 alloy, improves the strength of the extruded aluminum material, but has little effect on the fibrous organization. Therefore, Cu is added to an alloy equivalent to JIS 6061. Although it does not prevent inclusion, if it exceeds 0.25%, the extrudability deteriorates and the intergranular corrosion property is deteriorated. Therefore, the Cu is supposed to be 0.25% or less. .

  Ti is effective in preventing cast cracking by suppressing the crystal grains of the ingot at the time of billet casting of the aluminum extruded material and suppressing recrystallization during extrusion molding and thereby forming a fibrous structure. It is preferable to contain it, but if it is less than 0.003%, it is difficult to obtain the effect of miniaturization. On the other hand, if it exceeds 0.1%, a coarse intermetallic compound is produced and the extrusion moldability is lowered. Therefore, the Ti content is 0.003% to 0.1%.

As described above, an aluminum extruded shape having Mn and / or Zr added to the Al-Mg-Si alloy and having high strength, high ductility, and extrudability is used for the extrusion method. the composition in profile, i.e., Mg0.4～0.9%, and the excess Si at or above balance composition Si0.7～1.2% of _Mg 2 Si, -0.15Mg + 0 the relationship of Mg and Si .84 ≦ Si ≦ −0.5Mg + 1.45, Mn 0.2% or less, Zr 0.2% or less, and the relationship between Mn and Zr is Mn + Zr ≦ 0.2 and 0.67Mn + Zr ≧ 0.039, Using a billet of an aluminum alloy composition in which the relationship of excess Si, Mn and / or Zr is excess Si ≧ (0.6−1.56Mn + 0.22Zr + 3.93Mn · Zr) / (9.17Mn + 16.1Zr) Average The process, heating rate 100 to 300 ° C. / Hr, holding temperature 510-590 ° C., after the holding time 1～10Hr, there as extruding the shaped aluminum extrusion as extrusion ratio from 40 to 90.

Billet casting is carried out by melting aluminum of the above alloy composition by a conventional method and performing semi-continuous casting. The homogenization treatment is performed by placing the cast billet into a soaking furnace and subjecting it to a heat treatment by a conventional method. Is to do by. At this time, the homogenization treatment is performed in order to finely precipitate Mn and / or Zr-based compounds at 100 to 300 ° C./Hr so as not to lower the productivity while slightly slowing the temperature rising rate. Mg ₂ Si which becomes a uniform nucleation site is finely precipitated. That is, when the rate of temperature rise is less than 100 ° C./Hr, it is not preferable from the viewpoint of productivity, and when it exceeds 300 ° C./Hr, Mg ₂ Si decreases, so that Mn and / or the precipitation sites thereof. The Zr-based compound is coarsely precipitated, the recrystallization inhibiting effect is reduced, and when the temperature exceeds 250 ° C./Hr, the tendency is generated. Therefore, the rate of temperature rise is 100 to 300 ° C./Hr, preferably 100 to 250 ° C. / Hr is preferable.

  The holding temperature and holding time of the homogenization treatment are set at 510 to 590 ° C., which is slightly higher, for 1 to 10 hours, and the precipitation of Mn and / or Zr-based compounds is carried out during the extrusion molding. The transformation is performed so that the transformation of β → α of the AlFeSi-based compound causing the defect is sufficiently caused. At this time, if the holding temperature is lower than 510 ° C., the precipitation of Mn and / or Zr-based compounds is insufficient, and if it is lower than 540 ° C., the tendency is caused. When the temperature exceeds 570 ° C., Mn and / or Zr-based compounds tend to be coarsened, and it is necessary to avoid long-time holding. Is from 510 to 590 ° C, preferably from 540 to 570 ° C, and the holding time is from 1 to 10 hours, preferably from 3 to 5 hours.

  It should be noted that the billet cooling rate has a small influence on the structure, but may lead to a decrease in the strength of the extruded profile, and is preferably 100 ° C./Hr or higher. In this case, the upper limit is the capacity of the cooling facility. It may be determined from the relationship of the diameter of the billet.

  On the other hand, the extrusion molding of the extruded shape may be performed by the direct extrusion method according to a conventional method. However, the structure of the extruded shape and the high-strength mechanical properties are affected by the extrusion molding conditions. Among the complex factors that determine this, the greater the extrusion ratio, the easier the recrystallization during extrusion molding. For example, in the case of JIS 6061 aluminum alloy, the fiber is relatively easy at an extrusion ratio of 20 or less. However, when the extrusion ratio exceeds 40, it tends to cause recrystallization. Therefore, in the case of the JIS 6061 aluminum alloy, the extrusion shape should be a fibrous structure with an extrusion ratio of 40 or more. However, when the alloy composition described above is used, the extrusion ratio is 40 to 90. Even if the extrusion ratio is 40 to 90, the fibrous structure is formed by recrystallization. It can be above.

  The higher the molding temperature of the extrusion molding, that is, the solution temperature, the more easily recrystallization occurs during extrusion molding. Generally, when the temperature exceeds 580 ° C., recrystallization tends to occur. However, in the case of an extruded shape having a high degree of processing, for example, if it exceeds 560 ° C., it tends to cause recrystallization. At this time, the temperature is set to 560 ° C. or less. Is preferred.

  In the extrusion molding, the cooling rate, that is, the quenching rate, increases the tendency to cause recrystallization. However, in order to secure the mechanical properties described later, the cooling temperature is a rapid cooling of 5 ° C./second or more. It is preferable to apply the rapid cooling at 5 ° C./second or more, and the influence on the tissue can be avoided. However, if the cooling delay time leading to rapid cooling is increased, the possibility of recrystallization increases. Therefore, it is preferable that the extruded profile be rapidly cooled within 10 seconds after exiting the die outlet.

  In the case of the above alloy composition, the degree of processing, particularly the extrusion ratio, the shape temperature, and the cooling rate or the cooling delay are the extrusion ratio 40 to 90, the shape temperature 530 to 580 ° C., the cooling delay 3 to 10 seconds, and the cooling rate 20 By setting it to -50 ° C./second, it becomes possible to easily achieve a fiber structure ratio of 60%.

  The mechanical properties of the extruded shape depend on the shape temperature and the cooling rate. The shape temperature should be 490 ° C. or higher in order to sufficiently dissolve Mg and Si that contribute to precipitation hardening. desirable. However, as described above, if it is too high, recrystallization occurs, the elongation deteriorates rapidly, and there is a tendency to cause appearance defects such as hot cracking and peeling. Therefore, the upper limit of the shape temperature is 580 ° C. It is preferable that

  As the cooling rate increases, it is desirable to perform rapid cooling of 5 ° C./second or more in order to force the solid solution Mg and / or Si to be supersaturated and improve the strength of the extruded profile. In general, the strength and ductility are negatively correlated, but if the cooling rate is 15 ° C./second or more, the elongation tends to increase, which is more desirable. The upper limit of the cooling rate may be determined based on the capacity of the cooling facility, the shape unit weight, and the surface area. However, since the cooling delay time affects the mechanical characteristics, it is desirable to rapidly cool within 10 seconds.

  The preferable extrusion conditions from the viewpoint of both the shape structure, that is, the fibrous structure and the mechanical properties of the strength are: when the extrusion ratio is 40 to 90, the shape temperature is 490 to 580 ° C., and the cooling is performed. It is preferable that the delay is within 10 seconds and the cooling rate is 15 ° C./second or more. Note that the lower limit of the cooling delay and the upper limit of the cooling rate are not values determined from the material characteristics, and therefore, these may be followed in accordance with ordinary methods.

  The aging treatment may be performed by artificial aging according to a conventional method so as to impart mechanical properties equivalent to JIS 6061-T6 to the extruded shape. The temperature is set to 205 ° C. for 60 to 200 minutes, and the temperature is set to a low temperature for a long time, for example, 170 to 185 ° C. for 200 to 400 minutes.

  An Al—Mg—Si-based aluminum alloy billet having a component composition shown in Table 1 was cast by hot top casting, and homogenized under the conditions shown in Table 2. Thereafter, extrusion processing is performed at the profile temperature and extrusion ratio shown in Table 2 (the profile shape is a round pipe), and immediately after extrusion molding, press quenching is performed online by water cooling, and each of the hollow pipes of the round pipe is extruded. A profile was obtained. A homogenization treatment (aging treatment) described in Table 2 was performed on these extruded shapes, and as shown in Table 1, a total of 14 specimens of Sample 1 to Sample 8 (7 samples for Sample 2) were prepared. .

  The unreachable formula (1) is the above-mentioned “−0.15Mg + 0.84 ≦ Si ≦ −0.5Mg + 1.45”, (2) is the above “Mn + Zr ≦ 0.2”, and (3) is the above “0”. .67Mn + Zr ≧ 0.039 ”, (4) shows the above“ excess Si ≧ (0.6−1.56Mn + 0.22Zr + 3.93Mn and / or Zr) / (9.17Mn + 16.1Zr) ”, respectively. It shows that the alloy composition is not satisfactory.

  Mechanical properties, fiber structure ratios, and extrusion moldability were measured for each of Samples 1 to 8 (7 samples 2). For mechanical properties, JIS 13B specimens were collected from each sample and subjected to a tensile test. The fiber structure ratio was measured by observing the macro structure of the cross section perpendicular to the extrusion direction, and the area ratio was measured using image analysis software. The extrudability was evaluated by the surface pressure indicated on the pressure gauge attached to the press during extrusion molding. The results are shown in Table 2.

According to Table 2, Sample 1 (Mg 0.55%, Si 1.00%, Fe 0.18%, Ti 0.01%, Zr 0.10%), Sample 2 (Mg 0.55%, Si 1.00%, Fe 0.18) %, Ti 0.01%, Mn 0.05%, Zr 0.05%), Sample 3 (Mg 0.55%, Si 1.00%, Fe 0.18%, Ti 0.01%, Mn 0.04%, Cr 0.04%) , Zr0.04%) The extruded shape of the alloy composition was subjected to a homogenization treatment with an extrusion ratio of 45, a heating rate of 200 ° C./Hr, a holding temperature of 550 ° C., and a holding time of 4 Hr. extrusion by performing, sample 1 at a tensile strength 312MPa, yield strength 290 MPa, elongation 12%, fibrous tissue ratio 77%, the surface pressure 25 kgf / mm ^2, sample 2, tensile strength 295MPa, yield strength 275 MPa, elongation 1 %, Fibrous tissue ratios of 80%, a surface pressure 22 kgf / mm ^2, Sample 3, tensile strength was 286 MPa, yield strength 265 MPa, elongation 12%, fibrous tissue ratios of 85%, and the surface pressure 27 kgf / mm ^2, both hot cracking There was nothing. Sample 2-1 was subjected to a homogenization treatment with an extrusion ratio of 45, a temperature increase rate of 100 ° C./Hr, a holding temperature of 550 ° C., a holding time of 4 Hr, and an extrusion profile temperature of 510 ° C., whereby a tensile strength of 284 MPa, The yield strength is 260 MPa, the elongation is 14%, the fiber structure ratio is 98%, the surface pressure is 25 kgf / mm ² , and there is no hot cracking. Further, with respect to Sample 2-2, the extrusion ratio is 80 and the heating rate is 300 ° C./Hr. By applying a homogenization treatment at a holding temperature of 580 ° C., a holding time of 10 hours, and an extrusion profile temperature of 570 ° C., a tensile strength of 320 MPa, a yield strength of 296 MPa, an elongation of 12%, a fiber structure ratio of 65%, a surface pressure of 23 kgf / mm ² There were no cracks.

When the tensile strength is 265 MPa or more, the proof stress is 245 MPa or more, the elongation is 8% or more, the fiber structure ratio is 60% or more, the surface pressure is 30 kgf / mm ² or less, and there is no hot cracking, the above results indicate that the mechanical strength, The fiber structure ratio and the extrusion moldability were satisfactory.

On the other hand, Sample 4 (Mg 0.55%, Si 0.70%, Fe 0.18%, Ti 0.01%, Mn 0.05%, Zr 0.05%), Sample 5 (alloy composition changed from Samples 1 to 3 above) Mg 0.55%, Si 1.00%, Fe 0.18%, Ti 0.01%, Mn 0.03%, Zr 0.01%), Sample 6 (Mg 0.80%, Si 1.20%, Fe 0.18%, Ti0 0.01%, Mn 0.05%, Zr 0.05%), sample 7 (Mg 0.55%, Si 1.00%, Fe 0.18%, Ti 0.01%, Mn 0.15%, Zr 0.15%), sample 8 (Mg 0.55%, Si 1.00%, Fe 0.18%, Ti 0.01%, Cr 0.13%) has an extrusion ratio of 45, a heating rate of 200 ° C./Hr, and a holding temperature of 550. ℃ 、 Holding time 4Hr homogenization treatment, press Doing extruded at profile temperatures 540 ° C., in Sample 4, 10% elongation, a surface pressure 25 kgf / mm ^2, hot cracking is not, but the tensile strength 245 MPa, yield strength 220 MPa, in fibrous tissue ratio 40% Yes, sample 5 has a tensile strength of 304 MPa, a proof stress of 288 MPa, a surface pressure of 21 kgf / mm ² , and no hot cracking, but has an elongation of 7% and a fiber structure ratio of 25%. Sample 6 has a tensile strength of 334 MPa and a proof stress Although it is 303 MPa, elongation is 8%, and fiber structure ratio is 62%, the surface pressure is 36 kgf / mm ² and hot cracking occurs. Sample 7 has an elongation of 13%, fiber structure ratio of 91%, hot cracking without tensile strength 252MPa, yield strength 230 MPa, a surface pressure 32 kgf / mm ^2, sample 8, tensile strength 277MPa, yield strength 252MPa, elongation 11%, fibrous tissue ratio 84%, hot cracking is not, but a surface pressure 32 kgf / mm ^2. Further, as shown in Table 2 as Samples 2-3 to 2-6, Sample 2 was further homogenized with an extrusion ratio of 120, a heating rate of 200 ° C./Hr, a holding temperature of 550 ° C., and a holding time of 4 Hr. When processed and extruded at an extrusion profile temperature of 540 ° C., the tensile strength is 305 MPa, the yield strength is 282 MPa, the elongation is 12%, the surface pressure is 29 kgf / mm ² , and there is no hot cracking, but the fiber structure ratio is 10%. When the extrusion ratio is 45, a homogenization treatment is performed at a heating rate of 200 ° C./Hr, a holding temperature of 550 ° C., a holding time of 4 Hr, and extrusion is performed at an extrusion profile temperature of 590 ° C. Homogeneity of surface pressure 20kgf / mm ² , no hot cracking, elongation 7%, fiber structure ratio 7%, extrusion ratio 45, heating rate 400 ° C / Hr, holding temperature 550 ° C, holding time 4Hr When the extrusion processing is performed at an extrusion profile temperature of 540 ° C., the tensile strength is 299 MPa, the yield strength is 276 MPa, the elongation is 13%, the surface pressure is 22 kgf / mm ² , and there is no hot cracking, but the fiber structure ratio is 45%. Yes, when the extrusion ratio is 45, a homogenization treatment is performed at a heating rate of 200 ° C./Hr, a holding temperature of 590 ° C. and a holding time of 12 hours, and extrusion is performed at an extrusion profile temperature of 540 ° C., a tensile strength of 290 MPa The yield strength was 270 MPa, the elongation was 9%, the surface pressure was 21 kgf / mm ² , and there was no hot cracking, but the fiber structure ratio was 39%.

  That is, in Samples 1 to 3, by setting Si to 1.0%, excess Si secures a high strength mechanical property and a high fiber structure ratio due to its pinning effect, while Samples 4 to 8 show By not satisfying the formula of 1 Note, it has become impossible to satisfy any of the mechanical properties, the fiber structure ratio, and the extrudability, and even with the alloy composition of Sample 2, the conditions for the homogenization treatment Depending on the case, the elongation and the fiber structure ratio could not be satisfied, and the sample 2-3 had a high extrusion ratio of 120. In the sample 2-4, the shape material temperature at the time of extrusion was as high as 590 ° C. In the sample 2-5, the rate of temperature increase in the homogenization treatment is as fast as 400 ° C./Hr, so that Mn and / or Zr-based compounds are not finely dispersed and are sufficient. Pinning effect is obtained In the sample 2-6, the temperature of the homogenization treatment is high and the time is long, so that the Mn and / or Zr-based compound is coarsely precipitated, and the pinning effect is also sufficient. Is not obtained, and it is recognized that the fiber structure ratio has been lowered.

Claims (3)

An extruded profile that contains Mn and / or Zr added to an Al-Mg-Si alloy and has high strength, high ductility, and extrudability. Mg 0.4 to 0.9%, Si 0.7 -1.2% Mg ₂ Si in an excess Si state more than the balance composition, and the relationship between Mg and Si is -0.15Mg + 0.84 ≦ Si ≦ −0.5Mg + 1.45, Mn is 0.2% or less, Zr0 .2% or less, the relationship between Mn and Zr is Mn + Zr ≦ 0.2 and 0.67Mn + Zr ≧ 0.039, and the relationship between the excess Si, Mn and / or Zr is excess Si ≧ (0.6− By making 1.56Mn + 0.22Zr + 3.93Mn and / or Zr) / (9.17Mn + 16.1Zr), the fiber structure ratio is 60% or more, the tensile strength is 265 MPa or more, the 0.2% proof stress is 245 MPa or more, and the elongation is 8%. Aluminum extrusion profiles, characterized by comprising as an upper.   In addition to Mn and / or Zr, Cr ≦ 0.1%, Cu ≦ 0.25%, Fe0.1-0.3%, Ti0.003-0.1% are added and contained The aluminum extruded profile according to claim 1. An Al-Mg-Si-based alloy containing Mn and / or Zr, and having a high strength, high ductility, and extrudability, is a method for forming an extruded profile, Mg 0.4-0.9%, An excess Si state equal to or higher than the balance composition of Mg ₂ Si with 0.7 to 1.2% Si is set, and the relationship between Mg and Si is set to −0.15Mg + 0.84 ≦ Si ≦ −0.5Mg + 1.45, Mn 0.2% Hereinafter, Zr is 0.2% or less, the relationship between Mn and Zr is Mn + Zr ≦ 0.2 and 0.67Mn + Zr ≧ 0.039, and the relationship between the excess Si, Mn and / or Zr is excess Si ≧ (0 .6-1.56Mn + 0.22Zr + 3.93Mn and / or Zr) / (9.17Mn + 16.1Zr), the homogenization treatment of the billet of the aluminum alloy composition was performed at a heating rate of 100 to 300 ° C./Hr, a holding temperature of 510 to 59 ° C., after the holding time 1～10Hr, extrusion molding method of an aluminum extruded profile, which comprises extruding the shaped aluminum extrusion as extrusion ratio 40 to 110.