JP6598007B2 - Method for producing Fe-Ni alloy thin sheet - Google Patents

Description

  The present invention relates to a method for manufacturing an Fe—Ni alloy thin plate used for, for example, a lead frame, a metal mask, and the like.

The Fe—Ni-based alloy thin plate used for a lead frame, a metal mask, or the like is used in combination with other members by performing processing such as etching or pressing, for example. This Fe—Ni-based alloy sheet is usually finished so as to satisfy desired required characteristics by performing strain relief annealing and softening annealing before and after finish rolling.
On the other hand, the applicant of the present application is a lead frame material made of an Fe—Ni-based alloy containing Ni: 30 to 60% by mass% as disclosed in, for example, Japanese Patent Laid-Open No. 6-172828 (Patent Document 1), Proposal of an invention of a lead frame material having excellent etching properties having a fibrous rolling structure by a spectroscope in a cross section perpendicular to the width direction and having a {100} orientation integration degree of the rolled surface of 50% or more. Yes. Further, as JP-A-6-279946 (Patent Document 2), in a shadow mask material made of Fe-Ni-based amber alloy containing Ni: 30 to 40% in mass% and the balance Fe and inevitable impurities, Proposed an invention of a shadow mask material excellent in etching property having a rolled rolling structure with a microscopic examination in a cross section perpendicular to the plate width direction and having a {100} orientation integration degree of the rolled surface of 85% or more. ing.

Japanese Patent Laid-Open No. 06-172928 Japanese Patent Laid-Open No. 06-279946

The inventions of Patent Document 1 and Patent Document 2 described above were annealed in a temperature range of 650 to 1000 ° C. for the purpose of reducing the residual strain inside the material as a desired plate thickness in the cold rolling process. Is.
However, in recent years, Fe—Ni-based alloy thin plates have been widely used from the viewpoint of productivity, and processing methods such as etching processing, press processing, and laser processing have been diversified. There is a request. Further, the above-described residual strain is not a problem, and there is a use application that requires excellent steepness.
In response to such a request, the Fe-Ni alloy thin plates of Patent Document 1 and Patent Document 2 described above have the following problems. First, since the heat treatment is performed, the manufacturing cost is high. Further, by annealing in the temperature range of 650 to 1000 ° C. after rolling, the dislocations remaining in an unstable state inside the material become stable, thereby reducing distortion. On the other hand, a shape change occurs with the release of the residual strain, and there is a possibility that the final finished rolled shape or the final shape after shape correction may change, which is not preferable in terms of steepness.
An object of the present invention is to provide a Fe-Ni alloy that not only enhances productivity but also realizes a wide and excellent steepness in a thin Fe-Ni alloy sheet having a thickness of 0.25 mm or less. It is to provide a method for manufacturing a thin plate.

The present invention has been made in view of the above-described problems.
That is, in the present invention, Ni + Co: 35.0 to 43.0% (Co: 0 to 6.0%), Si: 0.5% or less, Mn: 1.0% or less, and the balance is Fe in mass%. And a step of preparing a cold rolling material comprising impurities, and a cold rolling step in which cold rolling and continuous annealing are repeated at least once on the cold rolling material, and the final in the cold rolling step The cold finish rolling is performed under the conditions of a rolling load of 150 kg / mm or less per unit width, a rolling speed of 1.7 m / s or more and a forward tension of 250 to 400 MPa, a thickness of 0.25 mm or less, and the final cold rolling. This is a method for producing a Fe—Ni-based alloy thin sheet that is not heat-treated after intermediate finish rolling.
Preferably, the final cold finish rolling is a rolling load of 130 kg / mm or less per unit width and a rolling speed of 3.3 m / s or more, and Fe- which does not perform a shape correction process after the final cold finish rolling process. This is a method for producing a Ni-based alloy.
More preferably, the work roll used in the cold rolling step is a method for producing an Fe—Ni alloy thin plate which is an alloy tool steel roll.
According to the manufacturing method of the present invention described above, the steepness of the Fe—Ni alloy thin plate having a thickness of 0.25 mm or less is expressed by the floating height when the Fe—Ni alloy thin plate is placed on a horizontal surface plate. When evaluated, the maximum content may be 0.75% or less.

  According to the present invention, an appropriate rolling condition is set in a thin Fe—Ni alloy sheet having a thickness of 0.25 mm or less, and the conventional Fe—Ni alloy sheet is performed at the end. By omitting the heat treatment, excellent steepness can be achieved, and further, manufacturing cost reduction, productivity improvement, and energy saving effect can be expected.

The present invention is described in detail below.
<Material composition>
First, the chemical composition defined in the present invention will be described. The Fe—Ni-based alloy having the composition defined in the present invention has a composition necessary for obtaining a desired thermal expansion. In addition, a composition is the mass%.
[Ni + Co: 35.0 to 43.0% (Co is 0 to 6.0%)]
As described above, Ni and Co are elements necessary for obtaining a desired coefficient of thermal expansion. If the Ni + Co content is less than 35.0%, the austenite structure tends to be unstable. On the other hand, if it exceeds 43.0%, the coefficient of thermal expansion increases and the low thermal expansion characteristics are not satisfied. Therefore, the Ni + Co content is 35.0%. -43.0%. Note that Co is not necessarily added, but a part of Ni can be replaced by Co in a range of up to 6.0%.
[Si: 0.5% or less, Mn: 1.0% or less]
Si and Mn are usually contained in Fe-Ni alloys in trace amounts for the purpose of deoxidation, but if added excessively, segregation is likely to occur, so Si is 0.5% or less, and Mn is 1.0. % Or less. In addition, although the minimum of Si and Mn is not specifically limited, Since it adds as a deoxidation element as mentioned above, 0.05% of Si and 0.05% of Mn remain not a little.
[The balance is Fe and impurities]
The elements other than the above elements may be substantially Fe, but impurities inevitably contained in production are included. Impurity elements that need to be particularly restricted include C. For example, when used for an etching application, the upper limit is preferably set to 0.05%.
In order to improve press punchability, a free-cutting element such as S may be contained at 0.020% or less. Elements such as B that improve the hot workability may be contained at 0.0050% or less.

<Cold rolling material>
In the present invention, a material for cold rolling is prepared through hot rolling. Since an oxide layer is formed on the hot-rolled material, the oxide layer is removed, for example, mechanically or chemically to obtain a material for cold rolling. In addition, the edge is prepared so as to be a cold rolling material so as not to cause defects such as cracks from the edge of the cold rolled material during cold rolling. The thickness of the cold rolling material is preferably about 2.0 to 5.0 mm.
Then, cold rolling and continuous annealing are repeated once or more on the cold rolling material described above to obtain a desired plate thickness, and the final cold finish rolling is performed. The rolling rate before final rolling may be 50 to 85%, and continuous annealing may be performed in a heating furnace at 850 to 1000 ° C. in 10 to 60 seconds. And it is preferable to perform the final cold finish rolling by setting the hardness to 120 to 150 HV at the stage before the final cold rolling.
As described above, in the present invention, excellent steepness can be imparted to a wide Fe—Ni alloy thin plate. The “wide” as used in the present invention refers to a width of 500 to 1500 mm, for example.

Next, the final cold finish rolling conditions will be described in detail.
In the present invention, the thickness of the Fe—Ni alloy thin sheet is set to 0.25 mm or less in the final cold finish rolling. The reason why the thickness is 0.25 mm or less is, for example, that the thickness is required for a lead frame or a metal mask. A preferable plate thickness is 0.15 mm or less.
<Rolling load>
In the present invention, the rolling load per unit width in the final cold finish rolling is set to 150 kg / mm or less. In the rolling process, a load is applied to the entire rolling roll by applying a load to both ends of the roll. For this reason, when the rolling load is high, the rolling load particularly at the material edge portion becomes high, and the elongation of the edge portion becomes high. Moreover, the load distribution difference in the width direction applied to the rolling roll is also increased, and it is difficult to obtain a flat shape. Therefore, the final cold finish rolling is set to 150 kg / mm or less with a relatively light load.
In addition, in the case of a Fe-Ni alloy thin sheet of 0.25 mm or less, by reducing the rolling load itself to 150 kg / mm or less, not only the load applied to the material edge portion is reduced, but also the load distribution difference in the width direction is In addition, it is possible to obtain an effect of facilitating shape control by roll bending control and leveling control.
The lower limit of the rolling load is not particularly defined, but if the rolling load becomes too low, the plate thickness is not reduced, and rolling itself to obtain a desired plate thickness becomes difficult, so the lower limit is set to 35 kg / mm. Is.

<Rolling speed>
In the present invention, the rolling speed in the final cold finish rolling is set to 1.7 m / s or more. When the rolling speed is excessively low, the amount of mill oil biting is reduced, the contact area between the rolling roll and the material is increased, the frictional resistance is increased, and the rolling load is increased. Further, the cost increases due to the decrease in productivity. Therefore, the rolling speed is set to 1.7 m / s or more. In addition, although the upper limit of rolling speed is not specifically defined, it is realistic to set it to 8.3 m / s or less from the structure of a rolling mill.
<Rolling tension>
Along with the rolling speed described above, the rolling tension also affects the rolling load. Especially when looking at the forward tension, if the tension is high, the elongation at the center of the plate after rolling may increase and the shape may deteriorate, and if the rolling tension is excessively high, the material being rolled may break. There is. On the other hand, if the tension is too low, the rolling load is increased to obtain a desired plate thickness. Therefore, the forward tension of rolling in the final cold finish rolling is 250 to 400 MPa.
As described above, the number of passes of the cold finish rolling performed in the final cold finish rolling of the present invention described above is sufficient. By combining the above conditions, it is possible to obtain an Fe—Ni alloy thin plate having excellent steepness.

<Omission of heat treatment>
Another feature of the present invention is that no heat treatment such as softening annealing or strain relief annealing is performed after the final cold finish rolling described above.
In general, when softening annealing to recrystallize the structure or strain relief annealing in which heat treatment is performed at a temperature lower than the recrystallization temperature, the transition remaining in an unstable state inside the material becomes stable. Although the strain is reduced, a shape change occurs as the residual strain is released. Therefore, the shape adjusted by the final cold finish rolling may deteriorate. For this reason, the heat treatment is omitted for the purpose of maintaining the excellent steepness formed by processing.
The omission of the heat treatment suppresses the manufacturing cost, and it can be expected to improve productivity and save energy as well as manufacture inexpensive materials. In addition, depending on the intended use, an effect of improving etching processability (etching rate) can be expected due to residual strain remaining.

<Omission of shape correction>
Generally, after the final cold finish rolling, shape correction using a tension leveler or the like is performed for the purpose of obtaining a higher steepness. Of course, also in the present invention, in order to obtain an excellent steepness, shape correction can be performed after the final cold finish rolling. However, in the present invention, in the final cold finish rolling described above, the above-mentioned shape correction step is also performed by setting the rolling load per unit width to 130 kg / mm or less and the rolling speed to 3.3 m / s or more. It can be omitted.
The rolling mill uses a roll bending control and a leveling control mechanism for the purpose of making the load distribution in the sheet width direction applied to the rolling roll uniform. However, when the rolling load is high, the load distribution difference becomes large, and the roll bending control and leveling control amount for making the load distribution uniform also increase, so that the shape control becomes difficult. Therefore, shape control by roll bending control and leveling control can be achieved by setting the rolling load per unit width to 130 kg / mm or less and the rolling speed to 3.3 m / s or more in the final cold finish rolling. By making the combination easier, even if the shape correction process is omitted, the steepness when making the product width after cold rolling is the floating height when the thin plate is placed on a horizontal surface plate It can be evaluated to be 0.75% or less (preferably 0.50% or less).

<Work roll>
The work roll used in the cold rolling step of the present invention is preferably an alloy tool steel roll having a composition defined in JIS-G4404. More preferably, high-speed tool steel or cold mold steel is used.
In addition to the alloy tool steel roll described above, the work roll includes a carbide roll. Since the carbide roll has a high Young's modulus and rigidity, it may be difficult to adjust the shape even if a roll bending mechanism of a rolling mill is used, and is not particularly suitable for wide materials. Therefore, when there is a shape change in the sheet width direction of the wide material, it is preferable to use a work roll of alloy tool steel that can make the shape change in the width direction more uniform and easily obtain excellent steepness. good.
In particular, the diameter of the work roll used for the final cold finish rolling is preferably 60 to 200 mm. If the diameter of the work roll is excessively large, the number of passes during the final cold finish rolling may increase, and the productivity may be deteriorated. In addition, when the diameter of the work roll is excessively small, it may be difficult to adjust the shape of the Fe—Ni alloy during the final cold finish rolling. Therefore, the diameter of the work roll is preferably 60 to 200 mm.

Next, the Fe—Ni alloy thin plate obtained by the above-described method for producing the Fe—Ni alloy thin plate of the present invention will be described.
<Steepness>
In the present invention, after the final cold finish rolling of the Fe—Ni alloy thin plate, the steepness when the product width is obtained is evaluated by the floating height when the thin plate is placed on a horizontal surface plate. .75% or less (preferably 0.50% or less).
In recent years, Fe-Ni alloy thin plates have been widely used from the viewpoint of productivity, and the diversification of processing methods such as etching processing, press processing, and laser processing has progressed, and the above-described residual strain does not become a problem and is more excellent. There are uses that require steepness. When the steepness is excessively high (bad), for example, when a desired processing is performed using a widened Fe-Ni alloy thin plate, a conveyance defect occurs in the line. Cannot be obtained, and problems such as difficulty in assembly with other members occur. Therefore, the steepness is set to 0.75% or less (preferably 0.50% or less). The lower limit of the steepness is not particularly limited, but it is best to have a completely flat shape (steepness of 0.00%). However, since it is extremely difficult to manufacture a completely flat shape, the practical lower limit of the steepness is about 0.01%.
The steepness is measured by cutting a thin plate into a certain length, placing it on a horizontal surface plate, and measuring the rising height of the thin plate using a laser displacement meter or the like. At this time, the steepness may be calculated from data in which the floating heights are recorded in a matrix at every fixed length in the plate width and plate length directions.

Vacuum-melting, soaking treatment, hot pressing and hot rolling were performed to prepare a hot rolled material having a thickness of 3.0 mm. It was 170-190HV when the hardness of the hot-rolled material was measured. Table 1 shows the chemical composition of the hot-rolled material.
After that, the oxide layer on the surface of the hot rolled material is removed by chemical polishing and mechanical polishing, rough rolling is performed, cracks at the time of hot rolling at both ends in the material width direction are removed by trim processing, and cold rolling is performed. Prepared materials for use.
Next, after repeating cold rolling and continuous annealing on the above-mentioned cold pressure raw material, as the final cold finish rolling, the present invention examples (No. 1 to 6) and comparative examples (No. 21, 22) and the results of manufacturing in the conventional examples (Nos. 31 to 33) are shown in Table 2. In addition, the work roll used for the final cold finish rolling uses high-speed tool steel, uses a diameter of 120 mm, the final cold finish rolling pass is one in the present invention and the comparative example, and the conventional example is The final thickness was set to 0.1 mm by performing a plurality of times. The hardness before the final cold finish rolling is 135 HV, and the width is 800 mm.
In addition, the steepness measurement shown in Table 2 was performed using a three-dimensional shape measuring instrument on a Fe—Ni alloy thin plate test piece on a horizontal surface plate cut to a length of 700 mm, and a measurement area width of 800 mm × length of 700 mm. Was measured using a laser displacement meter or the like. The steepness was calculated from data in which the floating height was recorded in a matrix for each fixed length (width direction: 14 mm, length direction: 8 mm).

From the results shown in Table 2, No. 1 of the present invention. It can be seen that in Nos. 1 to 6, an excellent steepness was obtained while improving the productivity by omitting the heat treatment (strain relief annealing) after the final cold finish rolling. In addition, the present invention No. It can be seen that No. 3 is only finish rolling, and an excellent steepness is obtained and shape correction can be omitted.
From the above results, by applying the manufacturing method of the present invention, a thin Fe—Ni alloy thin plate having a thickness of 0.25 mm or less can have excellent steepness even when the width is increased. And the manufacturing cost reduction, productivity improvement, and an energy-saving effect can be expected by omitting the last heat processing performed when manufacturing the conventional Fe-Ni type alloy thin plate.

Claims (3)

Ni + Co by mass%: 35.0-43.0% (where Co is 0-6.0%), Si: 0.05% -0.5 % , Mn: 0.05% -1.0% , The balance includes a step of preparing a cold rolling material composed of Fe and impurities, and a cold rolling step in which cold rolling and continuous annealing are repeated at least once on the cold rolling material, and the cold rolling step The final cold finish rolling is performed under the conditions of a rolling load per unit width of 35 to 150 kg / mm 2 , a rolling speed of 1.7 to 8.3 m / s and a forward tension of 250 to 400 MPa, and a thickness of 0.25 mm or less. Fe-, characterized in that, after the final cold finish rolling, no heat treatment is performed , and the steepness evaluated by the floating height when placed on a horizontal surface plate is 0.75% or less at maximum. Manufacturing method of Ni-based alloy thin plate. The final cold finish rolling has a rolling load of 130 kg / mm or less per unit width and a rolling speed of 3.3 m / s or more, and the shape correction process is not performed after the final cold finish rolling process. The manufacturing method of the Fe-Ni type alloy of Claim 1. The work roll used in the cold rolling step is an alloy tool steel roll, and the method for producing a Fe-Ni alloy thin plate according to claim 1 or 2.