JPH1030155A - Iron-nickel alloy stock excellent in press formability, and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an Fe-Ni alloy stock for electron gun parts, for use in deep drawing and excellent in press formability, and its production. SOLUTION: The crystalline grain size of an alloy stock, having a composition consisting of, by weight, 30-55% Ni, <=0.5% Si, <=1.5% Mn, <=0.2% Al, and the balance Fe with inevitable impurities, is regulated to astatine grain size No.7 to 12 by final annealing, and the surface roughness of the stock is controlled by mechanical surface grinding or rolling so that center line average height (Ra) and maximum height (Rmax) are regulated to 0.05-0.25μm and <=3.5μm, respectively. It is preferable to control the intensity I(100) of the (100) crystal orientation existing parallel to sheet thickness so that I(100) /I0 <=7 is satisfied, where I0 means the (100) crystal orientation intensity of nonoriented specimen (powder specimen).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Fe--Ni alloy material having good pressability and a method for producing the same, and particularly to a nonmagnetic stainless steel used for an electron gun component, for example, an electron gun electrode material. The present invention relates to an Fe—Ni alloy material having improved press workability for drawing and a method for producing the same.

[0002]

2. Description of the Related Art Generally, electron gun parts used for picture tubes and the like are made of a non-magnetic stainless steel Fe-Cr-Ni-based alloy material having a thickness of about 0.05 to 0.5 mm by pressing into a predetermined shape. It is made by drawing.

However, recently, electrodes for accelerating thermionic electrons emitted from the cathode of an electron gun have been placed on low thermal expansion characteristics rather than the fact that magnetic permeability, which is a nonmagnetic index, is close to 1. Has become. That is, with the recent increase in definition and performance of picture tubes such as computer displays, subtle dimensional changes due to thermal expansion of electrode parts have affected the performance (color purity) of screens on panels. It is. Therefore, Fe-Ni alloys having low expansion characteristics, particularly Fe-42% Ni alloys (42 alloys), have begun to be used as electron gun electrode materials.

[0004] Although many techniques relating to the punching property have been proposed for Fe-Ni alloy materials, there has been little application for deep drawing, so that the technique for improving the drawing process has hardly been studied. .

[0005]

The Fe-Ni alloy is originally not good in drawability, and in recent years, the improvement of the press working speed has been pursued, and the oil used at the time of pressing has a low viscosity and is easily degreased. Tend to be used, F
The e-Ni alloy has become a severe condition in which drawing cracks are likely to occur. Therefore, there is a strong demand for Fe-Ni alloy materials with improved press workability for deep drawing applications. An object of the present invention is to develop a Fe—Ni alloy material for electron gun parts having good pressability and a method for producing the same.

[0006]

As a result of repeated studies to solve such problems, the grain size of the Fe-Ni alloy material is set to 7.0 to 12.0 in austenite grain size.
The roughness of the metal surface is set to a center line average roughness (Ra) of 0.05 to
It has been found that the drawability can be further improved by setting the maximum height (Rmax) to not more than 3.5 μm and 0.25 μm. Heretofore, there is no finding that improvement can be obtained by quantifying the surface roughness in relation to the drawability and further by quantifying the two indices Ra and Rmax. Furthermore, (10
0) It has been found that the pressability can be further improved by controlling the crystal orientation quantitatively.

Based on these findings, the present invention provides (1) 30% to 55% Ni, 0.5% or less Si,
n: 1.5% or less, Al: 0.2% or less, the balance being Fe and inevitable impurities, and the crystal grain size is represented by austenite crystal grain size. 7 to 12 and a center line average roughness (Ra) of 0.05 to 0.25 μ
Fe-Ni alloy material for electron gun parts having good pressability, characterized by having a surface roughness of 3.5 m or less and a maximum height (Rmax) of 3.5 μm or less, and (2) a (100) crystal orientation. The alloy according to (1), wherein the strength I ₍₁₀₀₎ is 7 or less as expressed by I ₍₁₀₀₎ / I _O (I _O : (100) crystal orientation strength of a non-directional sample (powder sample)). Provide the material. The present invention also provides (3) Ni: 30 to 5% by weight.
5%, Si: 0.5% or less, Mn: 1.5% or less, A
l: 0.2% or less, the alloy material consisting of the balance Fe and inevitable impurities has a grain size expressed by austenite grain size in the final annealing. 7 to 12 and control the surface roughness of the material so that the center line average roughness (Ra) is 0.05 to 0.25 μm and the maximum height (Rmax) is 3.5 μm or less. An object of the present invention is to provide a method for producing a Fe—Ni alloy material for electron gun parts having excellent pressability. The surface roughness can be controlled by mechanical surface polishing or rolling. It is recommended that mechanical surface polishing be performed immediately before pressing.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Fe-Ni for electron gun parts according to the present invention
The reasons for limiting the alloy components of the alloy material and the reasons for limiting the crystal grain size and the surface roughness will be described below. (Ni): Ni is an important element that determines the thermal expansion characteristics of the Fe—Ni alloy. If it is less than 30% or more than 55%, the thermal expansion coefficient becomes too large, which is not preferable. Therefore, the range of the Ni component is set to 30 to 55%.

(Si): Si is mainly used as a deoxidizing agent, and is present in a small amount as an A-based, B-based, or C-based inclusion in an Fe—Ni alloy. Also, the solid solution Si is made of Fe
It is preferable to contain a small amount of -Ni alloy because it hardens and improves the punchability. However, if the content of Si exceeds 0.5%, the Fe—Ni alloy becomes too hard, and the mold life is undesirably reduced. Therefore, the component range of Si is set to 0.5% or less. For the above reason, a preferable Si component range is 0.005 to 0.5.
%.

(Mn): Mn is usually added for the purpose of deoxidizing and improving hot workability. As a result, MnO-based inclusions, MnS-based inclusions, or further react with Si to form Mn-Si-O-based inclusions. Mn is also Si
Similarly, since the Fe—Ni alloy is hardened, it is effective in improving the punching property. However, if it exceeds 1.5%, the alloy becomes too hard, and the mold life is undesirably shortened. Therefore,
The component range of Mn is 1.5% or less. From the viewpoint of improving the punchability, the content is preferably set to 0.1 to 1.5%.

(Al): Al is usually added for the purpose of deoxidation. As a result, Al ₂ O ₃ -based inclusions are formed. A
l is also effective for improving the punching property because it hardens the Fe—Ni alloy, but if it exceeds 0.2%, the alloy becomes too hard and the life of the mold is shortened. Therefore,
The component range of Al is set to 0.2% or less. A preferred range of the Al component is 0.005 to 0.2%.

The Fe-Ni alloy material for an electron gun component according to the present invention has a grain size expressed by austenite grain size, and is expressed by N
o. Adjusted to 7-12. No. The reason for setting it to 7 to 12 is that if it is smaller than 7, roughening occurs on the surface of the pressed product at the time of pressing, and if it is larger than 12, the drawability is reduced and cracks are easily generated.

The Fe—Ni alloy material for electron gun parts according to the present invention has a center line average roughness (Ra) of 0.05 to 0.25 μm.
In addition, the surface has a maximum height (Rmax) of 3.5 μm or less. The roughness was measured by a surface roughness measuring device. Center line average roughness (Ra) 0.05 to
The reason why the thickness is set to 0.25 μm is that if the thickness is smaller than 0.05 μm, no improvement in the pressability is recognized, and if it exceeds 0.25 μm, the improvement in the pressability is saturated, and conversely, the surface becomes rough. The reason why the maximum height (Rmax) is set to 3.5 μm or less is that if the maximum height (Rmax) exceeds 3.5 μm, cracks are liable to occur, and improvement in pressability cannot be seen. It is considered that the pressability is improved because oil enters the unevenness of the material surface during the press working, and the oil retention is improved.

The intensity of the (100) crystal orientation existing parallel to the plate surface is defined as I ₍₁₀₀₎ and a non-directional sample (powder sample)
When the (100) crystal orientation strength of I is defined as I _O , (100)
It is preferable to set I ₍₁₀₀₎ / I _O as an index of the degree of integration of crystal planes to 7 or less. The reason is that when the priority is increased to a level exceeding 7, the limit drawing ratio is reduced, and the ear of the drawn product is also increased, so that the pressability is significantly reduced.

The Fe—Ni alloy material for electron gun parts of the present invention is manufactured, for example, as follows. First, an alloy component satisfying the composition ratio of each of the above-mentioned components is melted and cast, and then hot forging or rolling is performed, and then cold rolling and annealing are repeated to finish to a predetermined thickness. At this time, the austenite grain size is controlled to be 7 to 12 in the final annealing. The degree of integration of the (100) crystal orientation is controlled by changing the annealing conditions and the degree of cold rolling. Center line average roughness (Ra) and maximum height (R
max) controls buff the final thickness of material,
It can be carried out by mechanically polishing the surface with a grindstone, a cutter or the like. It is recommended that mechanical surface polishing be performed immediately before pressing. Further, the surface roughness can be controlled by using a dull roll at the time of final rolling.

[0016]

【Example】

(Examples and Comparative Examples) Each of the alloy components having the compositions shown in Table 1 was melted and cast into an ingot, then subjected to hot rolling, and then repeatedly subjected to cold rolling and annealing to obtain an annealed material having a sheet thickness of 0.4 mm. Was manufactured. This annealed material was mechanically polished with an abrasive having various roughnesses and a feather impregnated with SiC. In addition, separately from this, at the time of final rolling, rolling using a rolling roll (dull roll) having various roughness,
Materials having different surface roughness were manufactured, and those subjected to final annealing were also manufactured. Materials having different degrees of integration of (100) crystal orientations were manufactured by variously changing the annealing conditions and the degree of cold rolling. In the measurement of the crystal orientation, an (100) crystal orientation existing parallel to the plate surface was measured using an X-ray diffractometer.
Then, in order to examine the pressability (drawability) of these materials, the critical draw ratio was determined.

The limit drawing ratio is obtained from the intersection of the cup wall strength and the flange deformation force obtained by a deep load drawing test. Note that a water-soluble wax was used as a lubricant at the time of pressing. Apart from this, the aperture ratio is 1.33
Then, all the test materials were squeezed using a flat-bottom punch to evaluate whether or not the processed product had rough skin. The results are shown in Table 1.

[0018]

[Table 1]

As is clear from Table 1, the alloy N of the present invention
o. 1 to 4 are comparative alloy Nos. Nos. 5 to 8 and Nos. 10)
Each of them has a large limit drawing ratio and shows excellent drawability. In addition, the comparative alloy No. When the crystal grain size is too large (the crystal grain size No. is as small as 6), as is apparent from comparison with No. 6, the occurrence of surface roughness is recognized, which is unsuitable as a pressed product.

[0020]

As described above, the Fe—Ni alloy material of the present invention is a material that significantly improves the pressability and is unlikely to cause drawing cracks even under severe pressing conditions.
Therefore, it is possible to meet future severe requirements for processing electron gun parts.

Claims (6)

[Claims] 1. Ni: 30 to 55% by weight, Si:
An alloy material comprising 0.5% or less, Mn: 1.5% or less, Al: 0.2% or less, the balance being Fe and unavoidable impurities.
o. 7 to 12 and a center line average roughness (Ra) of 0.05 to 0.25 μm and a maximum height (Rmax) of 3.
An Fe-Ni alloy material for electron gun parts having good pressability, having a surface roughness of 5 μm or less. 2. The intensity I ₍₁₀₀₎ of the (100) crystal orientation existing parallel to the plate surface is I ₍₁₀₀₎ / I _O (I _O : the (100) crystal orientation intensity of the non-directional sample (powder sample). 7)
The alloy material according to claim 1, wherein: 3. Ni: 30 to 55% by weight, Si:
An alloy material comprising 0.5% or less, Mn: 1.5% or less, Al: 0.2% or less, and the balance Fe and unavoidable impurities is subjected to a final annealing so that the grain size is expressed as austenite grain size.
o. 7 to 12 and a center line average roughness (Ra) of 0.05 to 0.25 μm and a maximum height (Rma).
A method for producing an Fe—Ni alloy material for electron gun parts having good pressability, characterized by controlling the material surface roughness so that x) is 3.5 μm or less. 4. The method according to claim 3, wherein the control of the surface roughness is performed by mechanical surface polishing. 5. The method according to claim 4, wherein a mechanical surface polishing is performed immediately before the pressing. 6. The method according to claim 3, wherein the control of the surface roughness is performed by rolling.