JPH0813101A - Iron-nickel alloy for electronic parts, excellent in hot workability - Google Patents

Abstract

PURPOSE:To produce an Fe-Ni alloy for electronic parts, excellent in hot workability. CONSTITUTION:This alloy is an Fe-Ni alloy for electronic parts, excellent in hot workability, in which 30-52% Ni is contained and the amounts of S, O, and Sn as inevitable impurities are limited to <=0.007%, <=0.006%, and <=0.1%, respectively, and to which 0.0001-0.006% Ca is added in the range satisfying Ca/(S+O+0.1XSn)=0.1 to 6, or, this alloy is an Fe-Ni-Co alloy for electronic parts, excellent in hot workability, in which 26-38% Ni and 1-20% Co are contained and the amounts of S, O, and Sn as inevitable impurities are limited to <=0.007%, <=0.006%, and <=0.1%, respectively, and to which 0.0001-0.006% Ca is added in the range satisfying Ca/(S+O+0.1X Sn)=0.1 to 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a shadow mask for a color picture tube excellent in hot workability, an IC lead frame, a P
The present invention relates to Fe-Ni alloys for electronic parts such as B-grade and PD-grade permalloy.

[0002]

2. Description of the Related Art Fe-Ni-based alloys and Fe-Ni-Co-based alloys containing 26 to 52 wt% of Ni have room temperature to 300%.
It has a low coefficient of thermal expansion in the temperature range over ℃ or has excellent soft magnetic characteristics, and is widely used as a material for electronic parts such as shadow masks for color picture tubes, IC lead frames, PB grade and PD grade permalloys. There is.

However, these Fe-Ni-based alloys and Fe-Ni-Co-based alloys are inherently poor in hot rolling performance, and when a continuous casting slab is cast by a curved continuous casting machine, the This alloy is prone to surface cracks and corner cracks during bending back. If this surface flaw is left as it is, it will become a serious defect in the final product, so it is necessary to remove the flaw. Therefore, the yield is remarkably reduced, the time required for manufacturing is long, and the cost is inevitably increased accordingly.

Generally, surface defects during hot working are as follows.
It is thought to be formed by. That is, curved continuous casting machine
When casting a continuous cast slab with, the slab has a strain rate of 2 ×
10 ^-3S^-1Slow deformation with some bending and bending back. this
At the edge of the slab and near the surface layer, the temperature drops compared to the center.
The temperature becomes 700 ° C. or lower. like this
If the ductility is poor under high temperature deformation conditions, surface defects will occur.

As a conventional high Fe-Ni alloy and its manufacturing method, there is one disclosed in JP-A-62-40343. This manufacturing method uses Ni: 30.0 to 52.0 wt.
%, Si: 0.40 wt% or less, Mn: 0.10 to 0.
80 wt%, C: 0.05 wt% or less, Al: 0.00
6 to 0.02 wt%, P: 0.010 wt% or less, S:
In producing an Fe-Ni alloy containing 0.002 wt% or less, O: 0.005 wt% or less, and satisfying the condition of S + P / 10 ≦ 0.0020 wt% and the balance Fe, slab rolling and hot rolling Heating temperature in rolling is 10
The temperature is 60 to 1250 ° C, and the finishing temperature is 800 ° C or higher.

[0006]

However, even when the above-mentioned conventional alloy is used, it is not possible to suppress the slab surface cracking at the time of bending and under bending at low strain rate deformation during continuous casting as described above. There is a problem that you cannot do it.

The present invention has very few defects in the manufacturing process deformation step, that is, continuous casting, can significantly shorten the slab defect removal process, improve the slab yield, and contribute to the manufacturing cost reduction Ni: 26 to 52 wt% The present invention aims to provide an electronic / electromagnetic material, such as a 36Ni alloy that is an Invar material, a 42Ni alloy for a lead frame, an Fe-Ni-based alloy such as permalloy, and an Fe-Ni-Co-based alloy.

[0008]

The Fe-Ni-based alloy for electronic parts having excellent hot workability according to the present invention has a Ni content of 30%.
.About.52 wt%, and S as an unavoidable impurity,
O and Sn are each S: 0.007 wt% or less, O:
It is regulated to 0.006 wt% or less and Sn: 0.1 wt% or less, and Ca is in the range of 0.0001 to 0.006 wt% and Ca / (S + O + 0.1 × Sn) = 0.1 to 6 So, it was added.

Further, Ni is 26 to 38 wt%, Co: 1.
~ 20wt%, and S as an unavoidable impurity,
O and Sn are each S: 0.007 wt% or less, O:
It is regulated to 0.006 wt% or less and Sn: 0.1 wt% or less, and Ca is in the range of 0.0001 to 0.006 wt% and Ca / (S + O + 0.1 × Sn) = 0.1 to 6 It was added as described above.

[0010]

As described in the prior art, it is understood that the ductility of 700 ° C. or higher is extremely important for the occurrence of flaws during continuous casting of Fe-Ni alloys. A method of accurately examining hot rolling performance is to use the drawing value of a test piece in a high temperature tensile test, but it is generally well known that the drawing value and the tendency of flaw occurrence are well known, and Slab defects during continuous casting tend to occur frequently when the drawing value is less than 50%.

We have found that many Fe--Ni systems and F
A high temperature tensile test was performed on the e-Ni-Co alloy,
The defect occurrence tendency was examined. In the case where the grain boundary strength is lowered and the grain boundary fracture is dominant, it is clear that the reduction value is less than 50% and the ductility is low, leading to the occurrence of defects.

The decrease in hot ductility of Fe-Ni alloys under low strain rate deformation is caused by segregation of S, O, or Sn existing as unavoidable impurities in the alloy into grain boundaries or sulfides,
It is governed by the precipitation of oxide or tin compounds at the grain boundaries. Here, S has the most adverse effect, and O and Sn have the effect of promoting the adverse effect of S. The hot ductility of Fe-Ni alloys under low strain rate deformation is
It is considered that the influence of the impurities is particularly remarkable because the Fe-Ni alloy targeted by the present invention has a significant segregation tendency of the impurity elements and the dynamic precipitation occurs at the low strain rate deformation.

In order to suppress the decrease in hot ductility as described above, it is essential to reduce the amounts of Sn, O and S to below a specific value and to add an appropriate amount of Ca according to the total amount of these impurity elements. Become.

Sn is an impurity element that is inevitably mixed from scrap as an iron source during the melting of the present alloy. It forms a compound with a low melting point at the austenite grain boundaries and lowers the grain boundary strength. It is an extremely harmful element for ductility. If the Sn content exceeds 0.1 wt%, the ductility of 700 ° C. or higher intended in the present invention cannot be improved even if the O and S contents are reduced and Ca is added in a trace amount described later. Therefore, the upper limit of the Sn amount is set to 0.1 wt%.
The lower limit is not specified, but it is 0.000 from the economical aspect of melting.
It is 1 wt% or more.

O exists as an impurity element in the present alloy, but if the content thereof exceeds 0.006 wt%, the amount of oxides in the present alloy increases, and in particular, in the case of Ca, which is a feature of the present invention, When a small amount is added, a large amount of low melting point oxide is formed, which deteriorates hot ductility. When the O content is 0.006 wt% or less, excellent hot ductility intended in the present invention can be obtained under the control of Sn and S content and the addition of an appropriate amount of Ca. From the above, the O amount was determined to be 0.006 wt% or less. The lower limit is not particularly specified, but is 0.0002 wt% or more from the economical aspect of melting.

S is a harmful element that reduces the hot ductility of the present alloy at 700 ° C. or higher. In particular, when the present alloy is deformed at a low strain rate at 700 ° C., it is strongly involved in the grain boundary breakage that remarkably occurs. When the amount of S exceeds 0.007 wt%, surface cracks of the slab frequently occur due to the above-mentioned grain boundary fracture, so the amount of S was set to 0.007 wt% or less. The lower limit is not specified, but it is 0.0001 from the economical aspect of melting.
wt% or more.

The excellent hot ductility intended in the present invention cannot be achieved only by controlling the Sn, O, and S amounts described above.

FIG. 1 is a graph showing the relationship between the temperature and the aperture value of the Fe-Ni alloy. The graph shown by the solid line in FIG. 1 corresponds to the material No. 2 in the invention example of Table 1 of the examples described later among the alloys of the present invention, and Sn: 0.0
03 wt%, O: 0.0011 wt%, S: 0.000
6 wt%, Ca: 0.0002 wt%, Ca / (S + O
+ 0.1 × Sn) = 0.1. Also, the graph indicated by the dotted line is a comparative alloy, Sn: 0.028 wt%,
O: 0.0032 wt%, S: 0.0024 wt% and C
a is additive-free (material No. 1 in Table 1 of the example)
3). In this case, as the temperature is processed (cooled), the aperture value drops sharply from around 1100 ° C.
It is a low value of less than 40% near 0 ° C. Although it recovers once by the temperature decrease thereafter, it starts to deteriorate again at around 800 ° C and reaches about 30% at around 700 ° C. On the other hand, the component alloy of the present invention always exhibits high ductility at 700 ° C. or higher, and a dramatic improvement in hot ductility under low strain rate deformation was observed. In addition, 7 of the comparative alloy described above
The fracture surface at a tension of 00 ° C. exhibited a grain boundary fracture surface, and the above-mentioned Sn, S, and O were concentrated in this grain boundary fracture surface. This is presumed to indicate that the grain boundary was embrittled by these impurity elements and the grain boundary was destroyed.

From the above, it was judged that it is necessary to satisfy the component range of the present invention in order to reduce the occurrence of surface defects during continuous casting. The temperature range for bending and unbending during continuous casting is 700 ° C. or higher and 1300
By setting the temperature to be equal to or lower than 0 ° C, it becomes possible to suppress the occurrence of surface flaws in the above-mentioned continuous cast slab. In particular, the material of the present invention has high ductility at around 1000 ° C. in addition to ductility at around 700 ° C., and therefore has high hot ductility at around 1000 ° C. where continuous casting slab is bent during continuous casting, Generation of surface flaws on the slab during bending during casting or during ingot-bulk rolling is suppressed.

Next, a hot tensile test was conducted using Fe--Ni based alloys in which the respective amounts of Sn, S, and O were independently within the range of the present invention, and the Ca amount was changed, to 700 to 1300 ° C. As a result of investigating the minimum value of the aperture value in the above, and examining the relationship between Sn, S, O and the Ca addition amount, the aperture value is Ca / (S + O +
We found that it can be arranged with the parameter of 0.1 × Sn). The results are shown in the graph of FIG. It is clear from this figure that the Ca / (S + O + 0.1 × Sn) has a high ductility of 50% or more in the range of 0.1 to 6, and the aperture value shows a low value before and after this range. It was Also, C
As the amount of a, 0.0001 wt% or more alone, 0.0
It was also found that the above high ductility can be obtained by setting the content within the range of 06 wt% or less.

Thus, the Fe--N, which is the object of the present invention,
The high hot rolling performance of the i-based alloy is that Sn, S, and O contents are 0.1 wt% or less and 0.007 wt% or less, respectively.
Is less than 0.006 wt% and the amount of Ca is 0.000
1 to 0.006 wt% or less and Ca / (S + O + 0.
It was found that when 1 × Sn) was added to Ca so as to fall within the range of 0.1 to 6, it was obtained.

The above is Sn, S, O, Ca, Ca / (S +
This is the reason why each amount of O + 0.1 × Sn) is defined within the range of the present invention.

Fe—Ni alloy, F, which is the subject of the present invention
The e-Ni-Co-based alloy is an alloy such as Invar alloy, 42 alloy for lead frame, PD permalloy, and the like which is required to have physical properties such as thermal expansion characteristics and magnetic characteristics.

Ni is a basic component of the present alloy and is an element that changes the coefficient of thermal expansion. For a color picture tube shadow mask (hereinafter simply referred to as a shadow mask), Ni is used to prevent color misregistration. 30 to 1 required for
The upper limit of the average thermal expansion coefficient in the temperature range of 00 ° C is 30 ×
It is 10 ^-6 ° C. N satisfying the condition of this average thermal expansion coefficient
The i amount is in the range of 30 to 38 wt% in the Fe-Ni alloy. Therefore, for a shadow mask for a color picture tube, the amount of Ni should be limited to the range of 30 to 38 wt%. Even within such a range of Ni content, the preferable Ni content that can reduce the average thermal expansion coefficient is 35 to 3
It is 7 wt%, and further preferable amount of Ni that can further lower the average thermal expansion coefficient is 35.5 to 36.5 w.
t%.

Even when Co is contained within the range of less than 1.0 wt%, the amount of Ni satisfying the upper limit of the average thermal expansion coefficient is 30 to 38 wt%. Even in such a case, the preferable amount of Ni that lowers the average coefficient of thermal expansion is 3
It is 5 to 37 wt%. Further, in the case of a Fe-Ni-Co based alloy containing 1 to 8 wt% of Co, the Ni content range satisfying the above-mentioned average thermal expansion coefficient is 26 to 38 wt%.
In addition, the amount of Ni is 30 to 33 wt% and the amount of Co is 3
By setting the content to ˜8 wt%, the average coefficient of thermal expansion becomes even lower and excellent.

For IC lead frames, the Ni content is more than 38 wt% and 52 wt% to maintain the thermal expansion matching with semiconductor elements, glass, ceramics and the like.
It is necessary to be less than or equal to%. In addition, such Ni
Even within the range of the amount, the amount of Ni is appropriately selected according to the thermal expansion coefficient of the semiconductor element, glass, ceramics, etc. used with the lead frame.

Even when Co is contained within the range of less than 1.0 wt%, the Ni content for maintaining the consistency of thermal expansion for the IC lead frame exceeds 38 wt%, 52
It is less than wt%. Although Fe-Ni-Co based alloys are also the subject of the present invention as a material for IC lead frames, in this case, Co: 5-20 wt%, Ni: 26-
Within the range of 33 wt%, it is possible to maintain the consistency of thermal expansion for the IC lead frame.

[0028]

EXAMPLES Invar alloys (Fe-36Ni alloys) and 42 alloys (Fe-42w) which are typical of Fe-Ni alloys
t% Ni alloy), permalloy (Fe-45wt% Ni alloy), Kovar (Fe-30wt% Ni-17wt% C)
Inventive material and comparative material in each alloy such as o alloy) are melted in an electric furnace, and the materials shown in Table 1 are prepared by external refining,
High temperature tensile testing of these materials was performed.

[0029]

[Table 1]

The test was conducted at a strain rate of 1 × 10 ^-3 S ^-1 in the temperature range of 700 to 1300 ° C., and the drawing value was examined to evaluate the hot rolling performance. In addition, these materials are cast by a curved continuous casting machine and bent and unbent at 700 ° C. or higher, 1
The continuous cast slab obtained was examined in the temperature range of 300 ° C. or lower for defects. The judgment of the defect generation tendency was conducted by examining the edge section of the slab. For the quantification, the total length on the surface of the crack reaching a depth of 2 mm or more was adopted in the unit area of the slab cross section.

Material Nos. 1 to N of each Fe-Ni alloy
o. 9 is the material of the present invention, the sole amount of Sn, S, O and Ca and Ca / (S + O + 0.1 × Sn) are within the scope of the present invention, and the aperture value at 700 to 1300 ° C. is 50%. The above is higher than that of the comparative example described later, and the occurrence of surface defects is significantly less than that of the comparative example.

On the other hand, materials No. 10 to No. 15
Are those in which the sole amount of Sn exceeds the upper limit of the present invention, the sole amount of S exceeds the upper limit of the present invention, the sole amount of O exceeds the upper limit of the present invention, the sole amount of Ca and Ca / ( S + O + 0.1 × Sn) is less than the lower limit specified in the present invention, and the amount of Ca alone exceeds the upper limit specified in the present invention, C
a / (S + O + 0.1 × Sn) exceeds the upper limit specified in the present invention, and the aperture value at 700 to 1300 ° C. is 5 in each case.
It is less than 0%, which is lower than that of the examples of the present invention, and the occurrence of surface flaws is significantly increased as compared with the examples of the present invention.

Thus, in the alloy of the present invention, Sn,
It is essential to control each amount of S, O, Ca, and Ca / (S + O + 0.1 × Sn) in order to improve hot ductility at 700 to 1300 ° C., and by doing so,
It is understood that it becomes possible to suppress the occurrence of surface flaws on the CC slab.

Further, in such an alloy of the present invention, 100
It was confirmed that since the hot ductility near 0 ° C. is also high, the occurrence of surface defects during the ingot-bulk rolling is extremely small and the manufacturability is excellent.

[0035]

According to the present invention, when an Fe-Ni-based alloy or an Fe-Ni-Co-based alloy is produced by a continuous casting method or an ingot-bulk rolling method, the occurrence of surface flaws is extremely low, and the flaw removal step is performed. Can be significantly shortened, the yield of slabs can be improved, the manufacturing cost can be greatly reduced, and its industrial value in terms of economic efficiency and productivity is extremely large.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the temperature and the aperture value of a Fe—Ni alloy.

FIG. 2 is a graph showing the relationship between the value of Ca / (S + O + 0.1 × Sn) and the aperture value.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Wakasa 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd.

Claims (2)

[Claims] 1. Ni-containing 30 to 52% by weight,
In addition, S, O, and Sn as unavoidable impurities are S: 0.007% or less, O: 0.006% or less, and Sn:
It is regulated to 0.1% or less, and Ca is 0.0001 to 0.
006% and Ca / (S + O + 0.1 × Sn) = 0.
An Fe-Ni-based alloy for electronic parts having excellent hot workability, which is added so as to fall within the range of 1 to 6. 2. Ni-26-38%, Co:
1 to 20% and S as an unavoidable impurity,
O and Sn are respectively S: 0.007% or less, O: 0.0
06% or less, Sn: 0.1% or less, Ca is 0.0001 to 0.006%, and Ca / (S + O +
F for electronic parts having excellent hot workability, characterized by being added so as to be within a range of 0.1 × Sn) = 0.1-6
e-Ni-Co alloy.