Method for producing Fe-Ni alloy sheet, and Fe-Ni alloy sheet

Abstract

Provided are: an Fe-Ni alloy sheet which is capable of reducing the amount of width warping while maintaining the amount of heat shrinkage at the level of a conventional material; and a method for producing the Fe-Ni alloy sheet. A method for manufacturing an Fe-Ni alloy thin plate, the method comprising: a finish cold rolling step for performing finish cold rolling of a cold rolling raw material at a reduction rate of 5-50% to obtain a thin plate material; a shape correction step for correcting the shape of the thin plate material after the finish cold rolling; and a step in which the shape-corrected sheet material is subjected to stress relief annealing, in which an annealing furnace used in the stress relief annealing step has at least a temperature raising part and a holding part, and when the temperature in the holding part is T DEG C, the temperature raising part is set within a temperature range of 0.7 T (DEG C) or more and less than T (DEG C), and the holding part is set within a temperature range of 0.7 T (DEG C) or more and less than T (DEG C). The heating temperature is set to gradually increase from the inlet side to the outlet side of the thin plate when the thin plate passes through the temperature raising part, and TS / (TS + TH) is 0.3-0.8 when the in-furnace residence time of the thin plate in the temperature raising part is set as TS and the in-furnace residence time of the thin plate in the holding part is set as TH.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a Fe-Ni alloy thin plate and the Fe-Ni alloy thin plate. Background Art

[0002] Fe-Ni alloy sheets are used for various purposes such as metal mask materials, lead frame materials, and substrates of electronic components due to their low thermal expansion characteristics. Various solutions have been proposed in the past to improve the heat shrinkage of such Fe-Ni alloy sheets or to suppress the shape defects of the materials.

[0003] For example, in Patent Document 1, a method for manufacturing a lead frame material is described for the purpose of providing a lead frame material with less heat shrinkage or residual stress and less burrs during stamping (excellent stamping properties). The method is characterized in that a rolled material of a metal material containing Fe-36 wt% to 52 wt% Ni is finish-rolled, then slit-processed, and then the slit-processed material is subjected to sufficient stress relief annealing in the range of 630°C to 700°C, and then straightened by a leveler.

[0004] In addition, in Patent Document 2, the applicant proposed a method for manufacturing Fe-Ni alloy thin plate in order to solve the problem of heating shrinkage, for example, to achieve excellent flatness even with a width of more than 60 mm, characterized in that straightening based on a straightener is performed after the final cold rolling, and stress relief annealing based on a continuous annealing furnace is performed after the straightening based on the straightener, and then longitudinal cutting is performed.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Laid-Open No. 6-145811

[0008] Patent Document 2: Japanese Patent Application Publication No. 2006-97073 Summary of the invention

[0009] Problems to be solved by the invention

[0010] As also described in Patent Documents 1 and 2, various methods have been proposed in the past to solve the problem of heat shrinkage. However, the residual stress imparted to the thin plate during shape correction using a straightener is released in the subsequent processing steps, which may lead to poor width warping. In order to eliminate the poor width warping, the strain released in the processing step can be reduced by lowering the stress relief annealing temperature, but the low stress relief annealing temperature has a tendency that the residual stress is not released and the heat shrinkage amount increases. Achieving both the reduction in heat shrinkage amount and the reduction in width warping is not recognized as a topic in Patent Documents 1 and 2, and there is room for further research.

[0011] Therefore, an object of the present invention is to provide an Fe-Ni alloy thin plate and a method for producing the same which can reduce the amount of width warpage while maintaining the amount of heat shrinkage at the level of existing materials.

[0012] Technical means of solving problems

[0013] The present inventors have repeatedly studied stress relief annealing conditions, and have found that shape defects when cutting a thin plate after stress relief annealing can be suppressed by controlling the heating pattern, thereby completing the present invention.

[0014] That is, one embodiment of the present invention is a method for manufacturing an Fe-Ni alloy thin plate, comprising: a finishing cold rolling process, in which a raw material for cold rolling is subjected to finishing cold rolling with a reduction rate of 5% to 50% to form a thin plate having a thickness of less than 0.2 mm, wherein the raw material for cold rolling contains, by mass%, C: ≤0.02%, Si: ≤0.5%, Mn: ≤1.0%, Ni+Co: 28% to 52% (wherein Co is 0% to 20%), and the remainder contains Fe and unavoidable impurities; a shape correction process, in which the shape of the thin plate after finishing cold rolling is corrected; and a stress relief annealing process, in which the shape-corrected thin plate is subjected to stress relief annealing. A thin plate is subjected to stress relief annealing to obtain an Fe-Ni alloy thin plate, wherein the annealing furnace used in the stress relief annealing process comprises at least a heating section and a holding section, and when the temperature in the holding section is set to T°C, the heating section is set within a temperature range of 0.7T(°C) or more and less than T(°C), and is set such that the heating temperature gradually increases from the entry side toward the exit side of the thin plate when the thin plate passes through the heating section, and when the furnace residence time of the thin plate in the heating section is set to TS and the furnace residence time of the thin plate in the holding section is set to TH, TS / (TS+TH) is 0.3 to 0.8.

[0015] In addition, another embodiment of the present invention is a Fe-Ni alloy thin plate, which contains, by mass%, C: ≤0.02%, Si: ≤0.5%, Mn: ≤1.0%, Ni+Co: 28%~52% (wherein Co is 0%~20%), and the remainder contains Fe and unavoidable impurities. The thickness of the Fe-Ni alloy thin plate is less than 0.2 mm, and the heating shrinkage of the Fe-Ni alloy thin plate when heated at 500℃×3min is less than 10μm, and the width warping is less than 55μm.

[0016] Effects of the Invention

[0017] The present invention can provide a material that can maintain the amount of heat shrinkage at the same level as existing materials. DETAILED DESCRIPTION

[0018] The present invention is described in detail below. However, the present invention is not limited to the embodiments listed here, and can be appropriately combined or modified within the scope of the technical concept of the present invention. In the present invention, a hot-rolled material having a composition containing C: ≤ 0.02%, Si: ≤ 0.5%, Mn: ≤ 1.0%, Ni + Co: 28% to 52%, and the remainder containing Fe and unavoidable impurities is prepared. The hot-rolled material of the Fe-Ni alloy sheet having the composition specified in the present invention has the composition required to obtain the desired thermal expansion coefficient. The reasons for specifying the composition range are as follows.

[0019] [C: ≤ 0.02 mass %]

[0020] C is an element that affects etching properties. If too much C is contained, etching properties are inhibited, so the upper limit of C is set to 0.02%. The lower limit can be 0%, but it is not particularly limited because it is contained in a large amount in the manufacturing process.

[0021] [Si: ≤ 0.5 mass %, Mn: ≤ 1.0 mass %]

[0022] Si and Mn are usually used for deoxidation purposes and are contained in trace amounts in Fe-Ni alloys. Excessive inclusions can easily cause segregation, so Si is set to 0.5% or less and Mn is set to 1.0% or less. The preferred Si and Mn amounts are Si: 0.3% or less and Mn: 0.8% or less. The lower limits of Si and Mn are not particularly limited, and can be set, for example, to 0.01% for Si and 0.01% for Mn.

[0023] [Ni+Co: 28% to 52% by mass (wherein Co is 0% to 20%)]

[0024] Ni is an element that has the function of adjusting the thermal expansion coefficient and has a significant impact on the low thermal expansion characteristics. If the content is less than 28% or exceeds 52%, the effect of reducing the thermal expansion coefficient disappears, so the range of Ni is set to 28% to 52%. The preferred lower limit of the Ni amount is 30%, the more preferred lower limit of the Ni amount is 32%, and the further preferred lower limit of the Ni amount is 35%. The further more preferred lower limit is 39%. In addition, the preferred upper limit of the Ni amount is 50%, the more preferred upper limit of the Ni amount is 45%, and the further preferred upper limit of the Ni amount is 42%. The components other than the above are Fe and unavoidable impurities.

[0025] In addition, in this embodiment, in order to adjust the thermal expansion characteristics or maintain high strength, a part of Ni can be replaced by Co. In order to easily give the above effect to the material, the upper limit of Co is preferably set to 20%. The upper limit of Co is more preferably 18%, the upper limit of Co is further preferably 6%, and the upper limit of Co is most preferably 1%.

[0026] The plate thickness of the hot-rolled material is not particularly limited, but if it is too thick, the number of passes in the subsequent cold rolling step may increase or shape adjustment during rolling may become difficult, so the upper limit of the thickness is realistically set to 5 mm.

[0027] <Raw materials for cold rolling>

[0028] In this embodiment, the hot rolled material is used as a raw material for cold rolling. Since an oxide layer is formed on the hot rolled material, the oxide layer can be removed mechanically or chemically, for example. In addition, the edge can be adjusted by trimming, etc., so as to avoid undesirable conditions such as cracks from the edge of the cold rolled material during cold rolling. In addition, as required, a homogenization heat treatment can also be performed at the stage before cold rolling. Such processing can be performed to produce a raw material for cold rolling.

[0029] <Intermediate cold rolling, intermediate annealing>

[0030] In the present invention, before the finish cold rolling described later, in order to adjust the plate thickness, intermediate cold rolling can be performed more than once to make a raw material for cold rolling. In the present embodiment, the case where the intermediate cold rolling is introduced is described, but in the case where the plate thickness is adjusted to the desired plate thickness at the time point after hot rolling, the intermediate cold rolling can also be omitted. In addition, in order to soften the material after work hardening and remove the work strain, the plate after the intermediate cold rolling can also be subjected to intermediate annealing (such as recrystallization annealing) to make a raw material for cold rolling. The temperature of the intermediate annealing can be set to a temperature above 800°C. When the temperature during annealing is less than 800°C, the material cannot be fully softened and the desired properties may not be obtained. The upper limit of the annealing temperature is not particularly limited, and the possibility of not being able to obtain the desired properties when the temperature is raised too high is also high, so it can be set to about 1100°C. At this time, the heating holding time can be appropriately adjusted according to the composition of the material or the plate thickness. In addition, the intermediate annealing can be carried out by continuously passing the thin plate after the intermediate cold rolling through a heating furnace set to the desired temperature. For example, the intermediate cold-rolled sheet can be pulled out from a coiled state, passed through a heating furnace, and then coiled into a coil. Here, if the sheet thickness is adjusted from 0.1 mm to 0.5 mm, it is easy to obtain the desired sheet thickness, so it is preferred.

[0031] <Fine cold rolling>

[0032] In the manufacturing method of the present embodiment, it is characterized in that the cold rolling raw material is subjected to finish cold rolling with a reduction ratio of 5% or more and 50% or less. By confining the range of the reduction ratio, the elongation difference between the center and the end of the thin plate (hereinafter, also simply recorded as cold-rolled material) after the finish cold rolling is reduced, thereby suppressing the generation of an excessively large corrugated shape, and it is easy to adjust to a flat shape after the shape correction process described later. When the reduction ratio is less than 5%, a center buckle is generated, and the flatness of the center of the thin plate (hereinafter, also recorded as shape-corrected material) after shape correction tends to decrease. When the reduction ratio exceeds 50%, the end wave becomes stronger, and the flatness of the shape-corrected material tends to decrease. The preferred lower limit of the reduction ratio is 7%, the preferred upper limit of the reduction ratio is 40%, and the further preferred upper limit of the reduction ratio is 30%.

[0033] In addition, the thin plate (cold-rolled material) after fine cold rolling can also be set to a strip with a width of 1000 mm or less. The lower limit of the width of the preferred strip is 300 mm, and the lower limit of the width of the more preferred strip is 500 mm. In addition, when used for lead frames or metal masks, the suitable plate thickness is 1 mm or less, preferably 0.8 mm or less, more preferably 0.5 mm or less, and further preferably 0.2 mm or less, and further more preferably 0.1 mm or less. In addition, the lower limit of the plate thickness is not particularly limited. If it is too thin, it is not suitable for half etching, so it can be set to 0.01 mm, for example. Preferably 0.05 mm, more preferably 0.08 mm.

[0034] <Shape Correction Process>

[0035] In the manufacturing method of the present embodiment, the cold-rolled material after the fine cold rolling is corrected in shape. Thus, the excessive edge wave or middle wrinkle remaining in the cold-rolled material is corrected, and the flatness can be greatly improved. The device used in the shape correction can use a shape correction device previously used such as a roller straightener or a stretching straightener (a stretching straightener is used in the present embodiment). Here, in the shape correction, the elongation is set to 0.05% to 0.3%. When the elongation exceeds 0.3%, excessive tension is applied to the cold-rolled material, so the risk of the cold-rolled material breaking increases. In addition, when the elongation is less than 0.05%, the shape correction effect is insufficient and the target flatness may not be reached. In addition, regarding the upper limit of the number of shape corrections in the present embodiment, if the number is too many, the desired shape may not be obtained, so it can be set to less than two times. There is a tendency that a sufficient shape correction effect can be obtained as long as it is about two times.

[0036] <Stress relief annealing process>

[0037] In this embodiment, a thin plate material that has been shape-corrected (hereinafter referred to as a shape-corrected material) is subjected to stress relief annealing to obtain an Fe-Ni alloy thin plate. In the present invention, a heat treatment furnace having at least a temperature rise section and a holding section is used in the stress relief annealing step. In the temperature rise section, when the shape-corrected material passes through the temperature rise section, the set heating temperature on the exit side of the shape-corrected material is set higher than the set heating temperature on the entry side of the shape-corrected material. That is, the stress relief annealing step of the present invention is characterized in that, when the predetermined stress relief annealing temperature is set to T (°C), first, the temperature rise section is within a temperature range of 0.7T (°C) or more and less than T (°C), and when the shape-corrected material passes through, the set heating temperature on the exit side of the shape-corrected material is set higher than the set heating temperature on the entry side of the shape-corrected material, and the set heating temperature gradually increases from the entry side to the exit side of the shape-corrected material. Furthermore, it is characterized in that there is a holding section set to the stress relief annealing temperature T (°C). By performing stress relief annealing heating under the above conditions, it is possible to suppress shape defects caused by rapid heating without reducing the passing speed of the shape-corrected material, and obtain a thin plate with a good shape. Here, the "gradual increase" means that the set temperature in the furnace increases from the entrance side to the exit side of the annealing furnace, and includes, for example, continuous increase, step increase, exponential increase, logarithmic increase, etc.

[0038] When the set heating temperature of the heating section is less than 0.7T(℃), the shape correction material cannot rise to the desired temperature, and the characteristics may be reduced. The lower limit of the set heating temperature of the preferred heating section is 0.8T(℃). When the set heating temperature of the heating section is above T(℃), the possibility of poor shape (warping) increases due to the rapid heating of the thin plate.

[0039] In addition, it is ideal that the heat treatment furnace as a whole is preferably composed of a heating part and a holding part, but within the scope that does not hinder the effect of the present invention, a cooling part with a set heating temperature lower than that of the holding part can also be set on the outlet side of the heat treatment furnace. The stress relief annealing is also similar to the intermediate annealing, and the thin plate material after the shape correction process can be continuously passed through a heating furnace set to a desired temperature. The furnace used in the heat treatment process can also use existing furnaces such as vertical furnaces and horizontal furnaces (horizontal furnaces), but in order to prevent breakage in the through plate or further increase the steepness of the thin plate, it is preferably used. A vertical furnace that does not require tension in the conveying direction and is difficult to produce deflection caused by its own weight.

[0040] In the present embodiment, when the residence time of the shape correcting material in the temperature rising section in the furnace is set to TS and the residence time of the shape correcting material in the holding section in the furnace is set to TH, TS / (TS+TH) is set to 0.3 to 0.8. In this way, the area of ​​the temperature rising section can be fully ensured, and the rapid heating of the shape correcting material can be suppressed, so that the occurrence of shape defects can be further suppressed. In the case where the residence time of the shape correcting material in the temperature rising section in the furnace is too long than the residence time of the shape correcting material in the holding section in the furnace, the strain of the shape correcting material may not be fully removed, and the desired characteristics may not be obtained, or it may take time to reach the desired annealing temperature, thereby reducing productivity. In the case where the residence time of the shape correcting material in the temperature rising section in the furnace is shorter than the residence time of the shape correcting material in the holding section, the holding section becomes too long, which may cause shape defects due to overheating of the shape correcting material. The preferred lower limit of TS / (TS+TH) is 0.35, and a more preferred lower limit is 0.40. The preferred upper limit of TS / (TS+TH) is 0.70, and a more preferred upper limit is 0.60.

[0041] The set heating temperature in the holding portion in the present embodiment is preferably 450°C to 700°C. When it is less than 450°C, stress cannot be fully relieved. On the other hand, when it exceeds 700°C, shape defects occur, and processing defects such as poor stamping will occur in subsequent processing steps. In the present embodiment, the set heating temperature can be adjusted according to the plate thickness within the range of the set heating temperature. For example, it is preferred that the temperature is set closer to the lower limit as the plate thickness is thinner. The lower limit of the temperature of the holding portion is more preferably 550°C, and the upper limit of the temperature of the holding portion is more preferably 680°C. In addition, the type of non-oxidizing gas introduced into the furnace can be selected from nitrogen, argon, hydrogen mixed gas, etc. In addition, the total time for the shape correction material to pass through the heat treatment furnace is preferably adjusted to 20 seconds to 60 seconds. By adjusting to the above numerical value, the shape suppression effect of the present invention can be reliably obtained.

[0042] The Fe-Ni alloy sheet obtained by the method of the present invention has the excellent characteristics of reducing both the amount of heat shrinkage and the amount of width warpage. That is, the amount of heat shrinkage of the Fe-Ni alloy sheet of the present invention is less than 10 μm under the condition of 500°C×3min. The preferred amount of heat shrinkage is less than 8 μm, and more preferably less than 7 μm. In addition, the amount of width warpage of the Fe-Ni alloy sheet of the present invention is less than 55 μm. It is preferably less than 50 μm, more preferably less than 45 μm, and further preferably less than 40 μm. In addition, the method for measuring the amount of heat shrinkage is, for example, marking two points of the sample and measuring the distance between the two points. Then, a heat treatment is performed by inserting the sample into a heating furnace for heating and then air cooling, and the distance between the two marked points is measured again, which can be measured by measuring the distance difference before the heat treatment. In addition, the method for measuring the amount of width warpage can be measured by placing a Fe-Ni alloy sheet processed into the product width on a platform and measuring the floating amount from the platform. The suitable plate thickness is 1 mm or less, preferably 0.8 mm or less, more preferably 0.5 mm or less, further preferably 0.2 mm or less, further more preferably 0.1 mm or less. In addition, the lower limit of the plate thickness is not particularly limited, and if it is too thin, it is not suitable for half etching, so, for example, it can be set to 0.01 mm. Preferably, it is 0.05 mm, and more preferably 0.08 mm.

[0043] Example

[0044] The Fe-Ni alloy having the composition shown in Table 1 was hot pressed and hot rolled to prepare a hot rolled material with a thickness of 3.0 mm. The oxide layer on the surface of the hot rolled material was removed by chemical grinding and mechanical grinding, and the cracks during hot rolling at both ends in the width direction of the rolled material were removed by trimming. The hot rolled material was divided into the present invention example and the comparative example, and intermediate cold rolling and intermediate annealing were performed respectively to produce intermediate cold rolled materials (raw materials for cold rolling) with a width of 700 mm and a thickness of 0.125 mm. Then, the present invention example and the comparative example were subjected to one pass of finish cold rolling at a reduction rate of 20% to produce a thin plate shape (cold rolled material) with a thickness of 0.10 mm. Then, a shape correction with an elongation of 0.05% to 0.3% was performed using a stretching straightening machine, and then stress relief annealing as shown in Table 2 was performed to produce samples of the Fe-Ni alloy thin plates of the present invention example and the comparative example. The vertical annealing furnace used in the stress relief annealing process has a heating section and a holding section in a non-oxidizing gas environment, and is set to gradually increase the heating temperature from the entrance side to the exit side of the shape correction material when the shape correction material passes through the heating section. The setting temperature of the entrance side of the heating section, the setting temperature of the exit side of the heating section, and the setting temperature of the holding section are shown in Table 2. Here, the heat treatment time of the stress relief annealing is 26 seconds.

[0045] Various test pieces were collected from the samples of the examples of the present invention and the comparative examples, and the respective heat shrinkage and width warping were measured. The heat shrinkage was obtained by marking the sample at two points, measuring the distance between the two points, inserting the sample into a heating furnace, heating it at 500°C × 3min, and then air cooling it for heat treatment, measuring the distance between the two marked points again, and measuring the difference in distance from before the heat treatment. In addition, the width warping was obtained by placing an Fe-Ni alloy sheet processed to the product width on a platform and measuring the floating amount from the platform. The measurement results are shown in Table 2.

[0046] [Table 1]

[0047] (mass %)

[0048] C Si Mn Ni The remainder 0.005 0.06 0.55 40.75 Fe and inevitable impurities

[0049] [Table 2]

[0050]

[0051] ※TS: The residence time of the thin plate in the heating section in the furnace

[0052] TH: The residence time of the thin plate in the holding section in the furnace

[0053] As shown in Table 2, the heat shrinkage of the Fe-Ni alloy sheet obtained by the manufacturing method of the present invention is less than 5 μm. In addition, the warpage is also excellent at less than 40 μm. On the other hand, there is a concern that the comparative example is a material that is easily deformed during product processing because of excessive heat shrinkage or warpage.

Claims

1. A method for manufacturing a Fe-Ni alloy thin plate, comprising: A finishing cold rolling process, wherein a raw material for cold rolling is subjected to finishing cold rolling at a reduction rate of 5% to 50% to produce a thin plate having a thickness of less than 0.2 mm, wherein the raw material for cold rolling contains, by mass%, C: ≤ 0.02%, Si: ≤ 0.5%, Mn: ≤ 1.0%, Ni+Co: 28% to 52% (wherein Co is 0% to 20%), and the remainder contains Fe and unavoidable impurities; a shape correction step of correcting the shape of the thin plate after the finish cold rolling; and A stress relief annealing step is performed on the shape-corrected thin plate to obtain a Fe-Ni alloy thin plate. The annealing furnace used in the stress relief annealing step at least comprises a temperature rising part and a holding part. When the temperature in the holding portion is set to T°C, the temperature rising portion is set within a temperature range of 0.7T(°C) or more and less than T(°C), and the heating temperature is set to gradually increase from the entry side toward the exit side of the thin plate when the thin plate passes through the temperature rising portion. When the residence time of the thin plate material in the temperature rising section in the furnace is TS and the residence time of the thin plate material in the holding section in the furnace is TH, TS / (TS+TH) is 0.3 to 0.

8.

2. An Fe-Ni alloy sheet, comprising, by mass%, C: ≤ 0.02%, Si: ≤ 0.5%, Mn: ≤ 1.0%, Ni+Co: 28% to 52% (wherein, Co is 0% to 20%), and the rest includes Fe and unavoidable impurities. The Fe-Ni alloy sheet has a thickness of 0.2 mm or less, a heat shrinkage of 10 μm or less when heated at 500° C. for 3 min, and a width warpage of 55 μm or less.

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