JPH08269636A - Stainless steel for press plate and its production - Google Patents

Abstract

PURPOSE: To produce a stainless steel for a press plate free from the generation of distortion (warpage) even if being used for a long time and having high hardness and to provide a method for advantageously producing the same. CONSTITUTION: This is a stainless steel for a press plate contg., by weight, 0.01 to 0.20% C, 0.1 to 3.0% Si, 10 to 20% Mn, 15 to 25% Cr, 2 to 10% Ni, 0.03 to 1.0% Cu, 0.05 to 0.8% V, 0.001 to 0.1% Al and 0.20 to 0.50% N. Furthermore, the method for producing the same in which the hot rolled sheet is subjected to cold working at >=20% draft at the time of final cold rolling and is thereafter subjected to aging treatment at 400 to 600 deg.C according to necessity is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stainless steel for a press plate used in manufacturing a multilayer printed wiring board, and more particularly, to obtain flatness of the printed wiring board.
This is a proposal regarding the press plate material (plate-shaped or strip-shaped) that is used when sandwiching both sides and the manufacturing method.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for multifunctional electronic devices and cost reduction, and as a method for fulfilling these demands, multilayering of printed wiring boards is progressing. This is because the multilayer printed wiring board enables high-density wiring that cannot be realized with a single-layer board, and greatly contributes to multifunctionalization of electronic devices and cost reduction. The standard manufacturing process for such a multilayer printed wiring board is to stack a copper clad laminated board (inner layer circuit board) and an adhesive layer (insulating layer) or prepreg for multi-layering, and heat-press molding with a hot press machine. This is a method of forming a multi-layer printed wiring board by forming a conductor and then forming a plated conductor following the formation of holes such as through holes.

As described above, the press plate is used for manufacturing a multilayer printed wiring board, and a copper clad laminate serving as a substrate and one to a plurality of prepregs or insulating adhesive layers and copper foils are superposed on each other. It is used when sandwiching the upper and lower sides with the press plate, and further disposing a hot plate on the outer side of the press plate and sandwiching the plate under heating to perform molding.

As a press plate material for such a printed wiring board, stainless steel plates such as SUS-304, SUS-301, SUS-630 have been conventionally used because they are required to have high hardness and good flatness. It was However, recently, since the copper foil attached to the substrate has become thin, there has been a problem that the copper foil is ruptured or wrinkled in the process of hot pressing the resin. It is considered that this is because there is a difference in the coefficient of thermal expansion between the press plate material such as SUS-304, SUS-301, and SUS-630 and the copper foil.

On the other hand, in Japanese Patent Publication No. 5-8265,
By proposing a high manganese austenitic stainless steel whose thermal expansion coefficient is close to that of copper, we are trying to eliminate the breakage and wrinkling that occur in the copper foil. Certainly, high manganese austenitic stainless steel has excellent properties as a press plate material, but has a drawback that it cannot be used due to warpage during use. Regarding conventional high-manganese austenitic stainless steels, the required hardness is secured by cold working, but the hardness obtained by this method is determined by the cold working rate, which is a manufacturing constraint. Therefore, it was not always possible to obtain the desired hardness.

[0006]

As described above, even the method described in Japanese Patent Publication No. 5-8265 can prevent the occurrence of breakage and wrinkles to some extent. However, this conventional high-manganese austenitic stainless steel has a drawback that it is not usable due to warpage during use. In addition, there is a limit in achieving the required hardness only by the cold working rate. In view of the above-mentioned problems, an object of the present invention is to propose a stainless steel for press plate which is free from distortion (warpage) even when used for a long time and has high hardness, and an advantageous manufacturing method thereof. .

[0007]

The inventors of the present invention have investigated the warpage that occurs during use of the press plate, and find that between the change in high temperature hardness and the magnitude of this warpage, the hardness at high temperature is high. It has been found that there is a correlation that when the value decreases, warpage occurs. Therefore, the effects on high temperature hardness of high manganese austenitic stainless steels, especially the effects of constituent elements, were investigated. As a result, it has been found that the addition of V is effective in suppressing the decrease in hardness at high temperatures, and this effectively eliminates the occurrence of warpage during use. Further, in order to obtain high hardness, it is preferable to increase the cold working rate, but as described above, the hardness obtained by this method is limited. Therefore, as a result of investigating the effects of various elements on the hardness after cold working in high manganese austenitic stainless steel, addition of Cu, V and Al is effective. It was found that a high hardness can be realized by their synergistic effect.
Moreover, it has been found that the steel of the present invention can be increased in hardness more easily than before because the hardness can be increased by subjecting it to an aging treatment after cold working.

That is, the gist of the present invention developed on the basis of the above findings is the following constitution. (1) C: 0.01 to 0.20 wt%, Si: 0.1 to 3.0 wt%, Mn: 1
0-20wt%, Cr: 15-25wt%, Ni: 2-10wt%,
Cu: 0.03 to 1.0 wt%, V: 0.05 to 0.8 wt%, Al:
0.001 to 0.10 wt% and N: 0.20 to 0.50 wt%,
Stainless steel for press plates consisting of balance Fe and unavoidable impurities. (2) C: 0.01 to 0.20 wt%, Si: 0.1 to 3.0 wt%, Mn: 1
0-20wt%, Cr: 15-25wt%, Ni: 2-10wt%,
Cu: 0.03 to 1.0 wt%, V: 0.05 to 0.8 wt%, Al:
0.001 to 0.10 wt% and N: 0.20 to 0.50 wt%,
When manufacturing a cold-rolled sheet by cold rolling one or more times with annealing based on the hot-rolled sheet of stainless steel consisting of the balance Fe and unavoidable impurities, at the time of final cold rolling, 20%
A method for manufacturing a stainless steel for a press plate, which is characterized in that cold working is performed at the above working rates. (3) C: 0.01 to 0.20 wt%, Si: 0.1 to 3.0 wt%, Mn: 1
0-20wt%, Cr: 15-25wt%, Ni: 2-10wt%,
Cu: 0.03 to 1.0 wt%, V: 0.05 to 0.8 wt%, Al:
0.001 to 0.10 wt% and N: 0.20 to 0.50 wt%,
When manufacturing a cold-rolled sheet by cold rolling one or more times with annealing based on the hot-rolled sheet of stainless steel consisting of the balance Fe and unavoidable impurities, at the time of final cold rolling, 20%
A method for producing a stainless steel for a press plate, which comprises cold working at the above working rates and then performing an aging treatment at a temperature of 400 to 600 ° C.

In the concrete method of the present invention, the hot-rolled sheet is subjected to a plurality of treatments (annealing-pickling-cold rolling), followed by annealing-pickling-20% or more final cold rolling-correction- A press plate material is manufactured through each step of polishing.

[0010]

The reason for limiting the composition of the stainless steel according to the present invention as described above will be described below. C: 0.01 to 0.20 wt% C is an austenite forming element, which is a component that stabilizes the austenite structure, prevents the formation of work-induced martensite, and at the same time imparts strength by solid solution strengthening. To obtain these effects, at least
0.01wt% is necessary. However, its content is 0.20wt%
Therefore, the upper limit was made 0.20 wt%. Especially, the range of 0.03 to 0.12 wt% is more preferable.

Si: 0.1 to 3.0 wt% Si is an element effective as a deoxidizing component at the time of steel making and for increasing the steel strength. Addition of 0.1 wt% or less has a small effect. On the other hand, the addition of more than 3.0 wt% impairs the hot workability and promotes the tendency of σ phase formation, so the upper limit was made 3.0 wt%. Especially, the range of 0.5 to 1.5 wt% is more preferable.

Mn: 10 to 20 wt% Mn is an element effective for stabilizing the austenite structure, and it is necessary to add at least 10 wt%. However, if added excessively, ordinary melting and hot working become difficult, so the upper limit was made 20 wt%. Above all, 13 ~ 16wt%
Is more preferable.

Ni: 2-10 wt% Ni is an element that stabilizes the austenite structure,
It is a component that has the effect of improving corrosion resistance or hot workability, and for that purpose at least 2 wt% must be added. However, excessive addition causes an increase in cost, so the upper limit was made 10 wt%. Above all, the range of 3 to 6 wt% is more preferable.

Cr: 15 to 25 wt% Cr is a basic component as stainless steel, and at least 15 wt% is necessary to maintain corrosion resistance. However, if the addition amount exceeds 25 wt%, ferrite will be generated and the hot workability will be deteriorated, so the upper limit was made 25 wt%. Especially, the range of 16 to 20 wt% is more preferable.

Cu: 0.03 to 1.0 wt% Cu has the effect of increasing the hardness after cold working in cooperation with V and Al in the component system of the present invention, and for this purpose, at least 0.03 wt%. The above is necessary. However, if its content exceeds 1.0 wt%, solidification segregation will increase, leading to deterioration of hot workability, so the upper limit was made 1.0 wt%. Especially, the range of 0.4 to 0.8 wt% is more preferable.

V: 0.05 to 0.8 wt% V suppresses the decrease in hardness at high temperatures, minimizes the warpage that occurs during use of the press plate, and reduces the hardness after cold working.
It has a large effect in cooperation with Cu and Al.
For this, at least 0.05 wt% is required. However, excessive addition deteriorates the hot workability and raises the cost, so the upper limit is made 0.8 wt%. Above all,
The range of 0.2 to 0.6 wt% is more preferable.

Al: 0.001 to 0.10 wt% Al is an element added for deoxidation, and as described above, the combined addition of Cu and V improves the hardness of steel by its synergistic effect. If the addition amount is 0.001 wt% or less, the effect is small, and on the contrary, a large amount of inclusions are generated to deteriorate the polishing property.
On the other hand, if added in excess of 0.10 wt%, surface defects are likely to occur, so the upper limit was made 0.10 wt%. Above all, 0.03-
The range of 0.08 wt% is more preferable.

N: 0.20 to 0.50 wt% N, like C, is an austenite forming element, which stabilizes the austenite structure, prevents the formation of work-induced martensite, and at the same time imparts strength by solid solution strengthening. Works effectively. At least 0.20 wt for this
% Addition is required. However, its content is 0.50wt%
If it exceeds the range, blowholes may be generated during the ingot making, which is not preferable. Therefore, the upper limit is set to 0.50 wt%. Especially, the range of 0.20 to 0.40 wt% is more preferable.

Next, the manufacturing method of the present invention is characterized by a series of steps in which a steel slab having the above-mentioned composition is subjected to hot rolling including necessary heat treatment and cold rolling into a product sheet. The description will be focused on the configuration. Cold rolling The hot rolled sheet of stainless steel having the above composition is subjected to a cold rolling treatment including a necessary heat treatment. During this cold rolling, in the present invention, a working ratio of 20% or more at the time of final cold rolling is used. Cold rolling. The reason why the cold rolling rate is set to 20% or more is to secure the hardness necessary for the press plate material, and even if the aging treatment is performed later, in order to obtain sufficient hardness, it is necessary to perform the cold rolling during the cold rolling. A moderate processing rate is essential. Preferably, the processing rate is 40 to 60%.

Straightening and Polishing The stainless steel cold-rolled sheet thus obtained is then subjected to mechanical straightening using a sheet leveler or the like in order to impart required flatness, if necessary. This correction is difficult because the press plate material has a very high hardness. However,
When manufacturing a press plate material based on the method of the present invention,
Because the amount of age hardening is very large, cold rolling is finished at a lower working rate than before, straightening is then performed, and then this can be aged to obtain almost the same hardness as before. It is convenient. Further, it is desirable to carry out polishing thereafter. In this sense, the manufacturing method of the present invention reduces mechanical restrictions and expands the degree of freedom in production.

Aging Treatment Condition In the present invention, in order to obtain the hardness required as a press plate material, the cold rolling sheet is further subjected to an aging treatment after the cold rolling. This aging treatment is performed in the temperature range of 400 to 600 ° C. The reason for this is that the increase in hardness due to aging is small at a temperature of less than 400 ° C, while the aging treatment at a temperature of more than 600 ° C rather softens, so the temperature was set to 400 to 600 ° C. Above all, it is more preferable to carry out the treatment within the range of 450 to 550 ° C.
The holding time in this aging treatment is not particularly limited, but it is desirable to perform the holding time in the range of 1 minute or more. Preferably 1
Minutes or more and 4 hours or less.

[0022]

[Examples] In Table 1, invention examples (No. 1 to 6) and comparative examples (No. 7)
~ 10) shows the composition of components. All of the test materials were smelted in the usual smelting process of stainless steel (smelting by electric furnace, vacuum or argon / oxygen deoxidation treatment) and then made into a continuous casting slab, which was hot-rolled to a plate thickness of 5 mm. Hot rolled plate,
Furthermore, after cold rolling and heat treatment at any cold rolling rate are repeated to obtain a cold rolled sheet with a final sheet thickness of 1.0 mm, it is straightened and then 500
It was cut into a size of mm × 500 mm, and a press plate material was obtained through a polishing process.

Table 2 shows the cold rolling rate, the hardness after cold rolling, the polishing property evaluation result, and the actual printed wiring board manufacturing result for each steel material (No. 1 to 10). The hardness after cold rolling was evaluated by measuring the Vickers hardness of the manufactured steel material. The evaluation of the abradability was evaluated as × when the flaws remained on the plate surface when abraded, and as ○ when the flaws did not remain. The size of the warp that occurs during use depends on the size of the warp after manufacturing the printed wiring board for 200 times, using a 500 mm × 500 mm plate as the press plate, and performing the above-mentioned hot pressurization process once. Compared. As shown in Table 2, in the steel of the present invention, V was added to Cu and Al.
It can be seen that the occurrence of warpage during use is small because of the combined addition of and. Further, because of the above-mentioned composite addition, the hardness after cold working is large.

Next, the cold-worked material was subjected to an aging treatment under the conditions shown in Table 3 and its hardness was measured. As shown in Table 3, the hardness can be increased by performing the aging treatment under the proper conditions according to the present invention. On the other hand, N
o.1-a (out of cold rolling), No.2-a, 3-a (no aging treatment)
, No.2-b, c (out of temperature), No.4-a (out of processing rate), No.5
In case of -a (out of temperature), age hardening is low.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3]

[0028]

As described above, the stainless steel for a press plate according to the present invention hardly causes warpage during use and has a high hardness, so that a press plate material having a long life can be obtained, which is advantageous in cost. Is. Also, the present invention
The degree of freedom in production is dramatically increased.

Claims (3)

[Claims] 1. C: 0.01 to 0.20 wt%, Si: 0.1 to 3.0 wt
%, Mn: 10 to 20 wt%, Cr: 15 to 25 wt%, Ni: 2 to 10
wt%, Cu: 0.03 to 1.0 wt%, V: 0.05 to 0.8 wt%,
Stainless steel for press plates containing Al: 0.001 to 0.10 wt% and N: 0.20 to 0.50 wt% and the balance Fe and inevitable impurities. 2. C: 0.01 to 0.20 wt%, Si: 0.1 to 3.0 wt%
%, Mn: 10 to 20 wt%, Cr: 15 to 25 wt%, Ni: 2 to 10
wt%, Cu: 0.03 to 1.0 wt%, V: 0.05 to 0.8 wt%,
Al: 0.001 to 0.10 wt% and N: 0.20 to 0.50 wt% are added, and cold-rolling is performed by one or more cold rolling processes based on a hot-rolled stainless steel sheet containing the balance Fe and unavoidable impurities. A method for producing a stainless steel for a press plate, which comprises cold working at a working rate of 20% or more during final cold rolling in manufacturing a rolled sheet. 3. C: 0.01 to 0.20 wt%, Si: 0.1 to 3.0 wt
%, Mn: 10 to 20 wt%, Cr: 15 to 25 wt%, Ni: 2 to 10
wt%, Cu: 0.03 to 1.0 wt%, V: 0.05 to 0.8 wt%,
Al: 0.001 to 0.10 wt% and N: 0.20 to 0.50 wt% are added, and cold-rolling is performed by one or more cold rolling processes based on a hot-rolled stainless steel sheet containing the balance Fe and unavoidable impurities. At the time of final cold rolling, cold working is performed at a working rate of 20% or more, and then 400 to 600
A method for producing a stainless steel for a press plate, which comprises performing an aging treatment at a temperature of ° C.