JPH10263616A - Method for cold-rolling aluminum or aluminum alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a defect which is mainly a problem at the time of cold- rolling the sheet or the foil of aluminum or aluminum alloy and to improve the quality of the surface. SOLUTION: Using cold-rolling rolls which has the thickness of 2-20 μm of Cr plating on the surface and whose surface roughness Ra is 0.01-0.5 μm and, when the kinetic viscosity of rolling oil at 40 deg.C is expressed by η (Pa.s), the radius of the work roll by R (mm), the speed of the work roll by VR (mm/s), deformation resistance by (p) (Pa), the speed of the sheet on the outlet side by Vf (mm/s), rolling reduction by Δh (mm) and draft by (r), by adjusting the equivalent amount td of the oil film to be introduced to the cold-rolling roll which is shown by η×(VR+(1-r)×Vf )/(Δh/R)<1/2> ×P) to >=10<-7> mm, aluminum or aluminum alloy is cold-rolled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cold rolling aluminum or an aluminum alloy for improving the quality of a plate surface having excellent lubricity.

[0002]

2. Description of the Related Art When cold rolling aluminum or an aluminum alloy (hereinafter referred to as aluminum material), the aluminum material adheres from the surface of the rolled plate to the surface of the rolling roll to form a roll coating. It will be rolled while contacting the roll coating. Therefore, since the surface quality of a rolled sheet depends on the properties of roll coating, the properties of roll coating in cold rolling are very important. The roll coating properties are affected by the rolling conditions such as the material of the rolled sheet, the type of rolling oil, and the material of the work roll surface. Therefore, the choice of the treatment method for the work roll surface is indispensable for controlling the roll coating.

[0003] The cold rolling technology for aluminum materials requires improvement of the quality of the sheet surface, improvement of the rolling property under high pressure, and the like. In particular, demands for cold rolling technology, such as improvement in surface quality, have been increasing from the trend toward high quality of rolled aluminum products in recent years. However, conventional cold rolling of an aluminum material using a work roll for cold rolling does not sufficiently satisfy such requirements. That is, in the conventional cold rolling method of an aluminum material, the properties of the surface of the aluminum material plate are controlled by the roughness of the surface of the roll for cold rolling and the material of the roll body. In cold rolling, the ability to reduce oil pits is small, and the surface quality cannot be improved. That is, in cold rolling of an aluminum material using a conventional work roll, the aluminum oxide film formed on the roll surface during rolling becomes rough, and oil pits are likely to occur. For this reason, it is difficult to improve the quality of the plate surface.

[0004] In order to improve the quality of the sheet surface, there has been proposed a roll for cold rolling, the surface of which has been subjected to heat treatment and processing (Japanese Patent Application Laid-Open No. HEI 3-165906). According to this conventional technique, a roll for cold rolling having excellent wear resistance can be obtained. Further, a roll for cold rolling having a defined composition has been proposed (Japanese Patent Laid-Open No. 4-66649). According to this conventional technique, a roll for cold rolling having excellent wear resistance and glitter can be obtained. However, in these prior arts, although the current lubricity and the quality of the plate surface can be maintained for a long period of time, it is impossible to obtain an improved lubrication.

[0005] A work roll for hot rolling having a Cr plating layer on the surface has been proposed (Japanese Patent Laid-Open No. 2-211).
902). According to this conventional technique, the roll surface can be maintained in a good state in hot rolling, and the quality of the plate surface can be improved.

[0006]

However, between hot rolling and cold rolling, various conditions such as the roll roughness, the temperature of the rolled material and the rolling oil are greatly different, so that the occurrence of roll coating is completely different. . For this reason, even if the aluminum material is cold-rolled according to this conventional technique, it is possible to prevent the occurrence of oil stains due to residual oil generated due to excessive lubrication, to reduce the poor gloss of the plate surface due to the generation of oil pits on the plate surface, and to reduce the pinhole No improvement such as reduction is made. For this reason, it is difficult to cope with mass production and high quality orientation of rolled aluminum products.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to prevent defects which are mainly a problem when cold rolling a thin plate or foil of aluminum material and improve the quality of the surface of the plate. Another object is to provide a cold rolling roll and a cold rolling method for an aluminum alloy.

[0008]

According to the present invention, there is provided a method for cold rolling aluminum or an aluminum alloy, comprising the steps of: providing a Cr plating layer having a thickness of 2 to 20 μm on a surface;
a is 0.01 to 0.5 μm, and the kinematic viscosity of the rolling oil at 40 ° C. is determined as η (Pa ·
s), the work roll radius R (mm), the work roll speed _{V R (mm / s),} p (Pa) the entry side deformation resistance, leaving the side plates speed _{V f (mm / s),} Δh the reduction rate (Mm),
When the rolling reduction was _{r, η × (V R +} (1-r) × V f)
/ ((Δh / R) ^1/2 × p), wherein the oil film equivalent td introduced into the cold rolling roll is 10 ⁻⁷ mm or more.

The oil film equivalent td is preferably at least 10 ^-6 mm.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of intensive studies conducted by the present inventors to solve the above-mentioned problems, a Cr plating layer having an appropriate thickness is formed on the surface of a work roll for cold rolling, and the surface roughness R is reduced.
a is appropriate, and by using this work roll, an appropriate equivalent oil film is introduced into the work roll and the aluminum material is cold-rolled, whereby lubricity is improved and there are almost no defects such as oil pits. It has been found that a high quality plate surface can be obtained.

Hereinafter, the reasons for limiting the numerical values of the roll for cold rolling according to the present invention will be described.

When the thickness of the Cr plating layer is less than 2 μm, the thickness of the Cr plating layer is less than 2 μm. The surface of the material becomes rough. On the other hand, if the thickness of the Cr plating layer exceeds 20 μm, plating cracks increase, and the surface of the roll becomes rough due to the surface roughness of the roll, causing seizure on the surface of the aluminum material. Therefore, the thickness of the Cr plating layer is set to 2 to 20 μm.

Surface roughness Ra: 0.01 to 0.5 μm If the surface roughness Ra is less than 0.01 μm, poor engagement or slip occurs when the aluminum material is passed through a roll. When the surface roughness Ra exceeds 0.5 μm, poor gloss of the aluminum material surface occurs. Therefore, the surface roughness R
a is set to 0.01 to 0.5 μm.

The kinematic viscosity of the rolling oil at 40.degree.
(Pa), the work roll radius R (mm), the work roll speed V _R (mm / s), the entry side deformation resistance p (P
a), the output side plate speed is V _f (mm / s), and the reduction amount is Δh
(Mm), when the rolling reduction was r, the oil film equivalent td introduced into the cold rolling roll _{η × (V R + (1} -r) ×
V _f ) / ((Δh / R) ^1/2 × p). If the oil film equivalent td introduced into the roll for cold rolling is less than 10 ^-7 mm, seizure of the plate surface due to excessive rolling load may occur. Therefore, the oil film equivalent td introduced into the cold rolling roll is set to 10 ^-7 mm or more. If the oil film equivalent td is 10 ^-6 mm or more, it is easier to prevent image sticking. Therefore, the oil film equivalent td is preferably 10 ^-6 mm or more.

When a conventional work roll in which the surface of a special forged steel is polished to a desired roughness is used to cold-roll an aluminum material, the surface of the roll coating becomes rough, oil pits increase, and aluminum Poor gloss on the surface of the material occurs, and pinholes occur frequently in the rolling of extremely thin foils.

In the present invention, an appropriate thickness of C
The aluminum material is cold-rolled using a work roll having an r-plated layer and having a surface roughness regulated to an appropriate value. For this reason, since the plating layer is formed uniformly, the aluminum oxide is formed uniformly on the surface of the work roll, and the roughening of the plate surface due to uneven adhesion of the plating layer or peeling of the plating layer is prevented. Furthermore, seizure due to plating cracks of the roll and poor biting and slippage during passing of the aluminum material are prevented. Also, during cold rolling,
Since the rolling speed, rolling reduction, viscosity of rolling oil, rolling tension, and the like are adjusted to control the equivalent td of the oil film introduced between the work roll and the aluminum material to an appropriate value, appropriate lubricity is obtained. At the same time, the amount of oil pits generated on the surface of the aluminum material is reduced, and poor gloss on the surface and pinholes when rolling the foil are prevented. Further, the rolling load of the aluminum material is reduced, and seizure on the surface of the aluminum material is prevented.

[0017]

EXAMPLES Examples of the present invention will be described below in comparison with comparative examples that depart from the scope of the claims.

First Example First, using cold rolling oil for aluminum material having a kinematic viscosity at 40 ° C. of 4.1 × 10 ⁻³ Pa · s, the thickness of the inlet side plate was 0.5 mm, JIS with a board width of 1430mm
Single-stand 6-high rolling mill (work roll diameter: 580 mm, work roll barrel length: 2240 mm, intermediate roll diameter: 1300)
mm, intermediate roll barrel length: 2240 mm, backup roll diameter: 1300 mm, backup barrel length: 2
240 mm), the rolling reduction is 40%, and the rolling speed is 3, 5
Cold rolling was performed at various oil film equivalents at 0, 500 or 1500 mpm while measuring the rolling load and the exit side plate speed. At this time, a conventional work roll having a surface polished to a special forged steel and having a surface roughness Ra of 0.4 μm or a work roll having a 5 μm Cr plating layer formed on the surface of the conventional work roll was used. .

Next, a sample was sampled from the cold-rolled aluminum alloy coil, and SEM observation of the plate surface was performed to evaluate rolling lubricity and plate surface quality. The result is shown in FIG. FIG. 1 is a graph showing the relationship between the cold rolling of a JIS 3004 series aluminum alloy coil with the horizontal axis representing the oil film equivalent td determined from the exit side plate speed and the vertical axis representing the rolling load. In FIG. 1, a graph with hatching indicates a case where a work roll having a Cr plating layer is used, and a graph without hatching indicates a case where a conventional work roll is used.

As shown in FIG. 1, the rolling using a work roll having a Cr plating layer, in which the equivalent td of the introduced oil film is 10 ^-7 mm or more, is smaller than that using a conventional work roll. As a result, the rolling load is significantly reduced. On the other hand, when the oil film equivalent td is less than 10 ⁻⁷ mm,
In rolling using a work roll having a Cr plating layer, the rolling load was higher than that using a conventional work roll, and seizure occurred due to insufficient lubrication.

Second Embodiment The same cold rolling oil and rolling mill as those of the first embodiment are used, and the JIS having an incoming side plate thickness of 0.5 mm and a plate width of 1430 mm is used.
A 1050 series aluminum alloy coil with a rolling reduction of 40
%, And the rolling speed was 3, 50, 500 or 1500 mpm, and cold rolling was performed at various oil film equivalents while measuring the rolling load and the exit side plate speed. At this time, a normal work roll having a surface polished to a special forged steel and having a surface roughness Ra of 0.4 μm, or a work roll having a 5 μm thick Cr plating layer formed on the surface of the conventional work roll. It was used.

Next, a sample was sampled from the cold-rolled aluminum alloy coil, and SEM observation of the plate surface was performed to evaluate rolling lubricity and plate surface quality. The result is shown in FIG. FIG. 2 shows the oil film equivalent td on the horizontal axis.
FIG. 2 is a graph showing the relationship between JIS 1050 series aluminum alloy coils when they are cold-rolled, with the rolling load taken on the vertical axis. In FIG. 2, a hatched graph shows a case where a work roll having a Cr plating layer is used, and a non-hatched graph shows a case where a conventional work roll is used.

As shown in FIG. 2, similar to the first embodiment,
The equivalent td of the introduced oil film is 10 ^-7 mm or more, and C
In rolling using a work roll having an r plating layer,
The rolling load is significantly reduced as compared with the case where a conventional work roll is used. On the other hand, the oil film equivalent td is 10 ⁻⁷ m
If it is less than m, the rolling effect using a work roll having a Cr plating layer is lower in rolling load than that using a conventional work roll, but the effect is small. Also, as in the first embodiment, burn-in occurred due to insufficient lubrication.

Third Example Using a cold rolling oil for aluminum foil having a kinematic viscosity at 40 ° C. of 3.0 × 10 ⁻³ Pa · s, the thickness of the entry side plate was set to 0.1 mm.
JIS 1 which is 02 mm and the board width is 1430 mm
Single-stand four-high rolling mill (work roll diameter: 280 mm, work roll barrel length: 1900 mm, backup roll diameter: N30 series aluminum alloy foil coil)
(790 mm, backup barrel length: 1840 mm)
Then, the rolling was performed at a rolling reduction of 40%, a rolling speed of 3, 50, 500 or 1500 mpm and various oil film equivalents, while measuring the rolling load and the exit side plate speed. At this time, the special forged steel was polished to a surface roughness Ra of 0.4.
A normal work roll having a thickness of μm or a work roll having a 5 μm-thick Cr plating layer formed on the surface of the conventional work roll was used.

Next, a sample was sampled from the cold-rolled aluminum alloy coil, and SEM observation of the foil surface was performed to evaluate rolling lubricity and plate surface quality. The result is shown in FIG. FIG. 3 shows the oil film equivalent td on the horizontal axis.
FIG. 3 is a graph showing the relationship between JIS 1N30-based aluminum alloy foil coils when they are cold-rolled, taking the rolling load on the vertical axis. In FIG. 3, a graph with hatching shows a case where a work roll having a Cr plating layer is used, and a graph without hatching shows a case where a conventional work roll is used.

As shown in FIG. 3, similarly to the first and second embodiments, in rolling using a work roll having an introduced oil film having an equivalent weight td of 10 ⁻⁷ mm or more and a Cr plating layer, The rolling load is significantly reduced as compared with the case where a conventional work roll is used. On the other hand, when the oil film equivalent td is less than 10 ⁻⁷ mm, although the rolling load using the work roll having the Cr plating layer is lower than that using the conventional work roll,
The effect is small. Further, as in the first and second embodiments, seizure occurred due to insufficient lubrication.

[0027]

As described above, in the present invention, a work roll having a Cr plating layer formed on its surface is used, an appropriate equivalent oil film is introduced, and cold rolling is performed, thereby reducing the rolling load. It is possible to reduce the amount of oil pits, reduce the amount of oil pits generated, and perform rolling under high pressure, and improve the quality of the surface of the aluminum material. Therefore, it is possible to easily control the roll coating as compared with the conventional rolling method using a work roll, and it is caused by poor gloss of the aluminum material surface due to excessive oil pits and oil pits which have conventionally occurred. Defects on the surface of the aluminum material such as pinholes can be reduced, and an aluminum material having a surface of excellent quality can be stably obtained. Thus, the productivity of the aluminum material can be improved.

[0028]

[Brief description of the drawings]

[0029]

FIG. 1 is a graph showing the relationship between the oil film equivalent td on the horizontal axis and the rolling load on the vertical axis when cold rolling a JIS 3004 series aluminum alloy coil.

[0030]

FIG. 2 is a graph showing the relationship between the oil film equivalent td on the horizontal axis and the rolling load on the vertical axis when cold rolling a JIS 1050-based aluminum alloy coil.

[0031]

FIG. 3 is a graph showing the relationship between the oil film equivalent td on the horizontal axis and the rolling load on the vertical axis when the JIS 1N30-based aluminum alloy foil coil is cold-rolled.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Ando 15 Kinugaoka, Moka-shi, Tochigi Pref. Kobe Steel Moka Works

Claims (2)

[Claims] 1. A chromium film having a thickness of 2 to 20 μm on its surface.
Has a plating layer and surface roughness Ra of 0.01 to 0.5 μm
The kinematic viscosity of the rolling oil at 40 ° C. is η (Pa · s), and the work roll radius is R.
(Mm), the work roll speed V _R (mm / s), the entry side deformation resistance p (Pa), leaving the side plates speed V _f (mm /
s), when the reduction amount is Δh (mm) and the reduction ratio is r,
_{η × (V R + (1} -r) × V f) / ((Δh / R) 1/2 ×
A cold rolling method for aluminum or an aluminum alloy, wherein an oil film equivalent td introduced into the cold rolling roll represented by p) is 10 ^-7 mm or more. 2. The cold rolling method for aluminum or aluminum alloy according to claim 1, wherein the oil film equivalent td is 10 ^-6 mm or more.