KR100209208B1 - Manufacturing method of aluminum alloy with panel - Google Patents

Abstract

Mg content is 4 to 10 wt%, Fe, Mn, Cr, Ti and Zr content is

0.4 wt% f f g 1.5 wt% ...... (I)

(Where f = [Fe] + 1.1 [Mn] + 1.1 [Cr] + 3 [Ti] + 3 [Zr], [Fe], [Mn], [Cr,], [Ti] and [Zr] Is a value f that satisfies the weight percent content of Fe, Mn, Cr, Ti, and Zr, respectively, and the remainder is cast by molten aluminum alloy composed of Al to obtain an ingot; After hot-rolling the ingot, the following equation Ⅱ

-log (f-0.2) + 8 R Cold rolling, which satisfies -60 log (f-0.2) + 50 .... (II), is cold rolled with R to obtain a rolled sheet; Rolling plate temperature rise rate 100 Temperature from 450 to 550 Raise the temperature to 300 seconds or less at the temperature for final annealing treatment; Cooling Rolled Plate 100 A method for producing an aluminum alloy sheet for a body panel material, comprising the step of cooling to at least a minute / minute to obtain an aluminum alloy sheet.

Description

Aluminum alloy plate for body panel and manufacturing method

1 is a graph showing the relationship between the Fe equivalent in the aluminum alloy and the cold rolling rate.

The present invention relates to an aluminum alloy plate for use in body panels made of automobiles. More specifically, the present invention relates to an aluminum alloy plate that is reproducible and excellent in formability such as deep drawing and bulging.

In recent years, lightweight structural materials are required for environmental protection and fuel consumption reduction. In particular, efforts have been actively made to develop lightweight automobile parts that are conventionally formed of mild steel sheets. As an attempt, aluminum alloy plates have begun to be used for structural materials such as automobile parts, automobile wheel parts, and building materials.

The aluminum alloy plate used as the structural material is required to be excellent in all properties such as strength, formability, corrosion resistance, etc. Therefore, Al-Mg alloys having excellent properties are generally used.

However, the conventional aluminum alloy sheet is poor in formability because of poor ductility as compared to the mild steel sheet, and this ductility defect is due to the presence of coarse intermetallic compound in the aluminum alloy sheet. Thus, attempts have been made to improve the ductility by increasing the purity of the alloy metal matrix or by reducing the content of coarse intermetallic compounds by annealing aluminum alloys with increased Mg content at high temperatures. Increasing manufacturing costs can lead to significant problems in practical applications.

The aluminum material is not only lightweight but also easily recycled. However, regeneration causes impurity contamination, that is, contamination with elements other than alloying elements, and coarse intermetallic compounds derived from impurities present in the alloy metal matrix degrade ductility and deteriorate formability. As the component particles increase due to regeneration, precipitation and recrystallization are promoted and the grain size decreases. If the grain size of the aluminum alloy plate is reduced, the ductility and formability deteriorate, and, furthermore, due to the decrease in grain size, Riders line often occurs to affect the appearance of the aluminum alloy plate.

In addition, in order to increase the grain size, in order to lower the driving force of recrystallization, a method of cold rolling the aluminum alloy at a relatively small cold rolling rate is used. On the other hand, when the grain size is too large, ductility and formability deteriorate. To form an orange peel on the aluminum alloy plate. Therefore, in order to realize a material excellent in appearance after sheet formation and excellent in ductility and formability, it is necessary to select an appropriate cold rolling rate.

The present invention has been completed based on the above situation, and an object of the present invention is to provide an aluminum alloy plate excellent in ductility and formability while maintaining a good appearance after sheet formation. The present inventors have found that the crystal grain size can be adjusted by selecting an appropriate cold rolling rate according to the increase amount of impurities, and the moldability can be improved by achieving sufficient ductility, and completed the present invention based on this finding.

More specifically, the present invention

Mg content is 4 ~ 10wt%, Fe, Mn, Cr, Ti and Zr content is

(Where f = [Fe] + 1.1 [Mn] + 1.1 [Cr] + 3 [Ti] + 3 [Zr], [Fe], [Mn], [Cr,], [Ti] and [Zr] Is a value f that satisfies the weight percent content of Fe, Mn, Cr, Ti, and Zr, respectively, and the remainder is cast by molten aluminum alloy composed of Al to obtain an ingot; After hot-rolling the ingot, the following equation Ⅱ

Cold rolling to satisfy the cold rolling process by R to obtain a rolled plate; Rolling plate temperature rise rate 100 Temperature from 450 to 550 Raise the temperature to 300 seconds or less at the temperature for final annealing treatment; Cooling Rolled Plate 100 It is to provide a method for producing an aluminum alloy plate for a vehicle body panel material, which comprises a step of cooling to at least / min to obtain an aluminum alloy plate.

In the above method, a process annealing process is appropriately performed during the process in order to adjust the cold rolling in the above range.

In addition, the present invention is Mg content of 4 to 10 wt%, Fe, Mn, Cr, Ti and Zr content is the following formula

[Equation 1]

0.4 wt% f 1.5 wt% .... (I)

(Where f = [Fe] + 1.1 [Mn] + 1.1 [Cr] + 3 [Ti] + 3 [Zr], [Fe], [Mn], [Cr,], [Ti] and [Zr] Is limited to a value f that satisfies the weight percent content of Fe, Mn, Cr, Ti, and Zr, respectively, and the balance of Al is 20 to 80. It is to provide an aluminum alloy plate used for the phosphor body panel material.

In the present invention, Cu may be added to the aluminum alloy at 0.5 wt% or less. Other objects and advantages of the invention are apparent from the following detailed description.

Hereinafter, the reason why the alloy component is limited as described above in the present invention will be described in the tube.

Mg is an important component not only to increase the strength and ductility of the aluminum alloy plate but also to improve moldability. The Mg content should be limited to 4-10 wt%, which is sufficiently improved when the Mg content is 4 wt% or less. On the other hand, when Mg is added in more than 10wt% does not show an improvement effect in proportion to the content increase, high Mg content inevitably increases the manufacturing cost. As a result, there is a difficulty in producing an aluminum plate industrially.

Cu is an element to increase the strength and ductility of the aluminum alloy plate in the same manner as Mg, Cu content should be less than 0.5wt%. When the Cu content exceeds 0.5wt%, not only corrosion resistance and castability, but also hot rolling formation of the aluminum alloy sheet deteriorates. As a result, it becomes very difficult to industrially produce the aluminum alloy plate.

Fe, Mn, Cr, Zr and Ti are effective to form microcrystalline particles during recrystallization, but if they are present in a large amount in aluminum alloy, the corrosion resistance, toughness and moldability deteriorate, so that Fe is 1.0wt% or less, and Mn is 1.0 It is preferable that wt% or less, Cr be 0.3 wt% or less, Ti 0.2 wt% or less, and Zr 0.3 wt% or less.

As a result of evaluating these five elements according to refining using Fe as a reference element, it is efficient that Mn and Cr are 1.1 times or more than Fe, and Ti and Zr are 3 times or more than Fe when refining. When the ability of Mn, Cr, Ti, and Zr to form micrograin crystals is expressed in Fe equivalents, the effect of each element can be expressed as 1.1 [Mn], 1.1 [Cr], 3 [Ti], 3 [Zr]. , [Mn], [Cr], [Ti] and [Zr] are the contents (wt%) of Mn, Cr, Ti and Zr, respectively.

Therefore, the effect provided by the mixture of all elements present in the impurities during refining is

f = [Fe] + 1.1 [Mn] + 1.1 [Cr] + 3 [Ti] + 3 [Zr] can be expressed as the total of the Fe equivalent of each element.

In the present invention, f is 0.4wt% f It should be defined to satisfy 1.5 wt%. If the f value is 0.4 wt% or less, the manufacturing cost is high, whereas if the f value is 0.4 wt% or less, the manufacturing cost is high, while if the f value is more than 1.5 wt%, corrosion resistance, toughness, and aluminum alloy plate The moldability of the deteriorates.

When the aluminum alloy is regenerated, the Si contamination level does not change as much as Fe, so no mention is made of Si here, but the Si content should be suppressed to 0.5 wt% or less in view of formability. In the Al-Mg alloy of the present invention, B, Be and mismetal are added to improve refining, castability, and the like.

As long as B, Be and micrometal are added at 0.1 wt% or less, 0.2 wt% or less, and 0.2 wt% or less, the effect of the present invention is not impeded.

Hereinafter, the manufacturing process will be described.

In the aluminum alloy sheet of the present invention, the crystal grain size is 20 ~ 80 As long as the impurity element amount is increased, the moldability does not deteriorate. Grain size 20 Below, the ductility and moldability of an aluminum alloy plate deteriorate and a Löder line generate | occur | produces. On the other hand, the grain size is 80 If exceeded, moldability also deteriorated and orange peel was formed in the aluminum alloy plate.

In order to obtain the aluminum alloy plate, the following process is required.

The cold rolling (%) during the cold rolling treatment performed after hot rolling the ingot satisfying the above formula I is given by the following formula II.

[Equation 2]

-l _og (f-0.2) + 8 R It must be within the range specified by -60 l _og (f-0.2) + 50 .... (II).

When cold rolling is less than the minimum value defined by Equation II, the recrystallization of aluminum alloy is slowed down to grow coarse grains, and the grain size is 80 Beyond.

On the other hand, when cold rolling exceeds R, the maximum value defined by Equation II, recrystallization of the aluminum alloy is promoted, and the grain size is 20 It is not preferable to reduce excessively below. Next, in order to adjust R within the above range for cold rolling, a process annealing process is performed during the process.

In the final annealing treatment, the aluminum alloy was heated up to 100 450 ~ 550 over / min Heated to and maintained at 300 seconds or less at that temperature. Annealing temperature is 450 If it is below, recrystallization is preferentially carried out in a specific orientation, and the resulting crystals have an undesirable anisotropy, while the annealing temperature is 550. If exceeded, the crude crystal grains grow undesirably.

In the final annealing treatment, the temperature increase rate is 100 / Min or more, the temperature increase rate is 100 If it is below, recrystallization advances preferentially to a specific orientation, and the resulting crystal | crystallization becomes undesirably high in anisotropy.

In the final annealing treatment, the aluminum alloy is kept at that temperature for less than 300 seconds at the time of quenching treatment, and when the annealing time exceeds 300 seconds, the granulator is easily generated.

In the final annealing treatment, the cooling rate is 100 It should be set at least per minute and the cooling rate is 100 Below, the Löder line is easily generated.

Hereinafter, the present invention will be described in detail.

Various types of aluminum alloys having the composition shown in Table 1 were cast by direct cold casting to form an ingot having a thickness of 100 mm, a width of 300 mm, and a height of 250 mm. The ingots are hot rolled on both sides of the entire surface to a depth of 10 mm to form a 5 mm thick hot rolled plate. Next, the final cold rolling is performed on the hot rolled plate at the cold rolling rate shown in Table 2. Thereafter, the cold rolled sheet was subjected to a final annealing under the conditions shown in the following Table 2 to form an aluminum alloy sheet having a thickness of 1 mm. On some hot rolled plates, 360 degrees during cold rolling process Press annealing is appropriately performed for 2 hours at. In Table 2, the ranges of cold rolling rates used for the final cold rolling treatment are shown. This range is calculated from the compositions shown in Table 1.

The grain size of the aluminum alloy plate is measured by the sectioning method. Next, a tensile test piece specified in Japanese Industrial Standard (JIS) NO. 5 is manufactured from an aluminum alloy plate, and the tensile test is performed at 10 mm / min. As a result, the maximum tensile strength, yield tensile strength and elongation are measured, and finally the ductility is evaluated.

In addition, stretch molding and draw molding were tested to evaluate moldability, and the results are shown in Table 3. 500mm stretch test This is done by measuring the height of the stretch forming using a punch with its head. It is desirable that the stretch forming height be 18 mm or more. Draw molding test is 50mm at draw speed 2.2 The draw molding height is measured using a punch with a round head. The draw molding depth is preferably 13 mm or more. The stretch forming and draw forming tests are carried out under lubricating conditions using a corrosion resistant oil having a viscosity of 5 cst. The gastric changes according to grain size were evaluated by observing the appearance after forming the aluminum alloy plate, and the results of the appearance change are shown in Table 3.

As is apparent from Table 3, in the examples of the present invention, the particle size is 20 to 80 Phosphorus aluminum alloy sheet showed satisfactory results in ductility, formability, and appearance after sheet formation (see FIG. 1). The other aluminum alloy plate is not satisfactory in ductility, formability and appearance after sheet formation.

As described above, according to the method for producing the aluminum alloy plate of the present invention, even if the impurities increase by regeneration, if the production within the scope of the present invention all properties such as ductility, moldability, and appearance after sheet molding Satisfactory aluminum alloy sheet can be obtained efficiently.

According to the present invention, even when impurities are increased by regeneration as long as the final cold rolling rate is appropriately selected, an aluminum alloy sheet for use of a vehicle body panel material having excellent appearance after sheet molding can be obtained. Therefore, the present invention provides an industrially superior effect.

Claims (6)

Mg content is 4-10 wt%, Fe 1.0 wt% or less, Mn 1.0 wt% or less, Cr 0.13 wt% or less, Ti 0.2% or less, Zr 0.3 wt% or less, Fe, Mn , Cr, Ti Zr content is represented by the following formula I Wherein f = [Fe] + 1.1 [Mn] + 1.1 [Cr] + 3 [Ti] + 3 [Zr], and [Fe], [Mn], [Cr], [Ti] and [Zr] are Each of which represents the weight percent content of Fe, Mn, Cr, Ti, and Zr). Aluminum alloy sheet for panel panels Mg content is 4 ~ 10wt%, Fe below 1.0wt%, Mn below 1.0wt%, Cr below 0.3wt%, Ti below 0.2wt%, Zt below 0.3%, Cu below 0.5wt% Fe, Mn, Cr, Ti, Zr content is represented by the following formula I 0.4wt f 1.5wt% .... (I) Wherein f = [Fe] + 1.1 [Mn] + 1.1 [Cr] + 3 [Ti] + 3 [Zr], and [Fe], [Mn], [Cr], [Ti] and [Zr] are Each of which represents the weight percent content of Fe, Mn, Cr, Ti, and Zr). Aluminum alloy plates for body panel materials. The mg content is 4-10 wt%, Fe 1.0 wt% or less, Mn 1.0 wt% or less, Cr 0.3 wt% or less, Ti 0.2 wt% or less, Zr 0.3% or less, Si 0.5 wt% or less Fe, Mn Cr, Ti, Zr content is represented by the following formula I 0.4wt f 1.5wt% .... (I) Wherein f = [Fe] + 1.1 [Mn] + 1.1 [Cr] + 3 [Ti] + 3 [Zr], and [Fe], [Mn], [Cr], [Ti] and [Zr] are Each of which represents the weight percent content of Fe, Mn, Cr, Ti, and Zr). Aluminum alloy plates for body panel materials. Mg content is 4 ~ 10wt%, Fe 1.0wt% or less, Mn 1.0wt% or less, Cr 0.3wt% or less, Ti 0.2% or less, Zr 0.3% or less, Fe, Mn, Cr , Ti, Zr content is 0.4wt f 1.5wt% .... (I) Wherein f = [Fe] + 1.1 [Mn] + 1.1 [Cr] + 3 [Ti] + 3 [Zr], and [Fe], [Mn], [Cr], [Ti] and [Zr] are Each represents a weight% content of Fe, Mn, Cr, Ti, and Zr), and the molten aluminum alloy whose balance is Al is cast to obtain an ingot; After hot rolled ingot, -log (f-0.2) + 8 R -60 log (f-0.2) + 50 .... (II) Cold rolling to cold rolling rate R satisfying to obtain a rolled sheet; Rolling plate temperature rise rate 100 Temperature over 450 ~ 550 The final annealing treatment was carried out at a temperature of less than 300 seconds; Cold rolling rate 100 A method for producing an aluminum alloy sheet for a body panel material, comprising the step of obtaining an aluminum alloy sheet by cooling for more than / min. Mg content is 4-10 wt%, Fe 1.0 wt% or less, Mn 1.0 wt% or less, Cr 0.3 wt% or less, Ti 0.2 or less, Zr 0.3 or less, Cu 0.5 wt% or less And Fe, Mn, Cr, Ti, Zr content is 0.4wt f 1.5wt% .... (I) Wherein f = [Fe] + 1.1 [Mn] + 1.1 [Cr] + 3 [Ti] + 3 [Zr], and [Fe], [Mn], [Cr], [Ti] and [Zr] are Each represents a weight% content of Fe, Mn, Cr, Ti, and Zr), and the molten aluminum alloy whose balance is Al is cast to obtain an ingot; After hot rolled ingot, -log (f-0.2) + 8 R -60 log (f-0.2) + 50 .... (II) Cold rolling to cold rolling rate R satisfying to obtain a rolled sheet; Rolling plate temperature rise rate 100 Temperature over 450 ~ 550 The final annealing treatment is carried out at the temperature of 300 seconds or less; Cold rolling rate 100 A method for producing an aluminum alloy sheet for a body panel material, comprising the step of obtaining an aluminum alloy sheet by cooling for more than / min. Mg content is 4-10 wt%, Fe 1.0 wt% or less, Mn 1.0 wt% or less, Cr 0.13 wt% or less, Ti 0.2% or less, Zr 0.3% or less, Si 0.5 wt% or less Fe, Mn, Cr, Ti Zr content is represented by the following formula I 0.4wt f 1.5 wt% ...... (I) Wherein f = [Fe] + 1.1 [Mn] + 1.1 [Cr] + 3 [Ti] + 3 [Zr], and [Fe], [Mn], [Cr], [Ti] and [Zr] are Each represents a weight% content of Fe, Mn, Cr, Ti, and Zr), and the molten aluminum alloy whose balance is Al is cast to obtain an ingot; After hot rolled ingot, -log (f-0.2) + 8 R -60 log (f-0.2) + 50 .... (II) Cold rolling to cold rolling rate R satisfying to obtain a rolled sheet; Rolling plate temperature rise rate 100 Temperature over 450 ~ 550 The final annealing treatment was carried out at a temperature of less than 300 seconds; Cold rolling rate 100 A method for producing an aluminum alloy sheet for a body panel material, comprising the step of obtaining an aluminum alloy sheet by cooling for more than / min.