JPH11279707A - Free machining low thermal expansion alloy and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an alloy having free machining property by containing a specified ratio in each of C, Si, Mn, Ni, Co and W, satisfying a specified relation between Ni and Co and making the balance essentially Fe. SOLUTION: A metal content, by weight, is <=0.2% C, <=1% Si, <=1% Mn, 26-43.5% Ni, <=20% Co, 0.507% W, satisfying 34.5% <=Ni+0.8Co<=43.5%, and Ni+0.8Co is a Ni equivalent, further the alloy contains one or two kinds among S, Se in a range of 0.04%<=S+0.4Se<=0.12%, further preferably Mn in a range of 1>=Mn>=2.3(S+0.4Se) or Ca in a range of Ca>=3.8(S+0.4Se). W has an effect to improve machainability in particular a tool life and its content is suitably 1.5-5 wt.%. The thermal expansion coefficient of the alloy can further be lowered by rapidly cooling from 700-900 deg.C. It is suitable for use in a precision machine part, etc., and machining expense is not so high.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a free-cutting low-thermal-expansion alloy suitable for use in precision machine parts and the like, and a method for producing the same. The free-cutting low-thermal-expansion alloy of the present invention is suitable for (1) semiconductor-related equipment, (2) measuring equipment, (3) machine tools, (4) optical equipment, (5) dies, and the like. as,
Plates and arms such as polishing machines and steppers, roll frames for slicing machines, rotors for dry vacuum pumps, recognition unit arms for mounting equipment, racks for bonding machines, blocks and frames for drawing equipment,
Examples include a base and a column of a silicon wafer grinder, a tray of an inspection device, a base and a frame of an exposure device, and (2), for example, a gauge of a squareness measuring device, a C frame of a non-contact plate thickness measuring device. , Thin film thickness measuring device spindle, bridge measuring device measuring beam, ultra-precision aspherical measuring device frame, optical gyro bobbin, component analyzer mirror stand and light source stand, etc. For example, base column of precision grinding machine, spindle and inspection machine of centerless grinding machine, tool post of cutting machine, spindle head of machining center, magnet chuck of cylindrical grinding machine, table of aspherical processing machine, printed circuit board drilling machine Motor case, lower arm of wire electric discharge machine, connecting rod of precision press machine, column of jig borer, etc. Far lens barrel of the base of the laser oscillator, based or frame of a laser processing machine, a lens supporting base astronomical telescope, housing or the like of the recognition device and the like,
Examples of (5) include a mold for a CFRP mold or a GFRP mold, a positioning jig for a press mold, and a hot runner for a plastic injection mold.

[0002]

2. Description of the Related Art Invar (36% Ni-Fe alloy) and Super Invar (32% Ni-5% Co-Fe alloy) have been known as practical low thermal expansion alloys. Alloy from room temperature to 100
Since the coefficient of thermal expansion between ° C and 0 ° C to 1 × 10 ⁻⁶ / ° C is extremely low, it is used for applications requiring dimensional accuracy such as precision machine parts. In addition, 42 in consideration of use at higher temperatures
% Ni-Fe alloy or Kovar (29% Ni-17Co-
Fe alloy), for example, in Kovar from room temperature to 450
It has a characteristic that the coefficient of thermal expansion between ° C and that of Invar and Super Invar is smaller than that of Invar and Super Invar, and is used for applications that require low thermal deformation at high temperatures.

However, these low thermal expansion alloys
Since the machinability is low and the cutting work usually performed to finish the material into a desired shape requires a great deal of cost, the range of use thereof is limited.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a free-cutting low-thermal-expansion alloy which does not require a large amount of cost for cutting, and a method for producing the same. With the goal.

[0005]

The inventor of the present invention has made intensive studies to solve the above-mentioned problems, and as a result, the above-described invar,
The basic composition of various conventionally used low thermal expansion alloys such as Super Invar, 42% Ni-Fe alloy and Kovar is used as a basic composition, and a specific amount of W is added thereto.
It has been found that free cutting properties can be imparted. Also,
In addition, by adding S and / or Se, Mn, and Ca in a certain range, the machinability is further improved, and the thermal expansion coefficient is increased by cooling such an alloy with water from 700 to 900 ° C. Was further reduced.

[0006] The present invention has been made based on such findings, and in terms of% by weight, C: 0.2% or less;
i: 1% or less, Mn: 1% or less, Ni: 26 to 43.5
%, Co: 20% or less, W: 0.5 to 7%, and 34.5% ≦ Ni + 0.8Co ≦ 43.5%
And the balance is substantially composed of Fe.

[0007] The present invention also relates to a C: 0.2% by weight.
%, Si: 1% or less, Ni: 26-43.5%, C
o: 20% or less, W: contained in the range of 0.5 to 7%, and one or two of S and Se in 0.04%
≦ S + 0.4Se ≦ 0.12%, Mn is contained in the range of 1 ≧ Mn ≧ 2.3 (S + 0.4Se) +0.2, and 34.5% ≦ Ni + 0.8Co ≦ 43. .
An object of the present invention is to provide a free-cutting, low-thermal-expansion alloy, which satisfies 5% and the balance substantially consists of Fe.

[0008] Further, the present invention relates to the present invention, wherein C: 0.
2% or less, Si: 1% or less, Mn: 1% or less, Ni: 2
6-43.5%, Co: 20% or less, W: 0.5-7%
In addition, one or two of S and Se are contained in a range of 0.04% ≦ S + 0.4Se ≦ 0.12%, and Ca is Ca ≧ 3.8 (S + 0.4Se). And 34.5% ≦ Ni + 0.8Co ≦
It is intended to provide a free-cutting, low-thermal-expansion alloy, which satisfies 43.5% and the balance substantially consists of Fe.

Further, the present invention provides a method for producing a free-cutting low thermal expansion alloy, which comprises rapidly cooling a material having any one of the above-mentioned compositions from a temperature of 700 ° C. to 900 ° C. It is.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described specifically. The basic composition of the alloy according to the invention is, in% by weight, C:
0.2% or less, Si: 1% or less, Mn: 1% or less, N
i: 26-43.5%, Co: 20% or less, W: 0.5
７7%, 34.5% ≦ Ni + 0.8Co ≦ 43.5%, and the balance is substantially Fe.

C: 0.2% or less C is an element that has an adverse effect on the low thermal expansion property, so it is preferable that C is small. Conventionally, graphite has been deposited in this type of alloy to obtain free-cutting properties. However, in the present invention, it is not necessary to deposit graphite in order to secure free-cutting properties with W. Therefore, when the C content is 0.2
% Or less. However, in the case of a cast alloy, it is preferable to contain 0.1% or more to improve castability.

Si: 1% or less Si is an element added as a deoxidizing agent, but if it exceeds 1%, the effect of an increase in the coefficient of thermal expansion is large. Therefore,
The amount of Si is set to 1% or less. However, in the case of a cast alloy, the content is preferably 0.5% or more in order to improve the fluidity of the molten metal.

Mn: 1% or less Mn is an element effective for deoxidation and for fixing S to improve workability. However, if it exceeds 1%, the coefficient of thermal expansion increases. Therefore, the Mn content is set to 1% or less.

Ni: 26 to 43.5% Ni is an element necessary for reducing the thermal expansion together with the following Co. If the Ni content is less than 26%, the desired low thermal expansion property cannot be obtained even if the Co content is adjusted, and if the Ni content is more than 43.5%, the low thermal expansion property cannot be obtained.
The range is 5%.

Co: 20% or less Co is an element added for realizing a decrease in the coefficient of thermal expansion in combination with the above-mentioned Ni, but if it exceeds 20%, the coefficient of thermal expansion becomes high. And

34.5% ≦ Ni + 0.8Co ≦ 43.5
% Ni + 0.8Co is Ni equivalent, and even if Ni and Co satisfy the above range, when Ni equivalent is less than 34.5% or more than 43.5%, a low coefficient of thermal expansion cannot be obtained. Therefore, the Ni equivalent is in the range of 34.5 to 43.5%.

The preferred ranges of Ni, Co and Ni equivalent vary depending on the temperature range in which low thermal expansion is required. That is, in order to make the coefficient of thermal expansion in the range of 20 to 150 ° C. 4 × 10 ⁻⁶ / ° C. or less, Ni: 30 to 3
7.5%, Co: 8% or less, Ni equivalent: 34.5-3
7.5% is preferred. Further, in order to set the coefficient of thermal expansion in the range of 20 to 300 ° C. to 6 × 10 ⁻⁶ / ° C. or less, N
i: 28 to 40.5%, Co: 14% or less, Ni equivalent:
37.5-40.5% is preferred. Furthermore, 20 to 45
In order to set the coefficient of thermal expansion in the range of 0 ° C. to 8 × 10 ⁻⁶ / ° C. or less, Ni: 26 to 43.5%, Co: 20% or less, Ni equivalent: 40.5 to 43.5% Is preferred.

W: 0.5 to 7% W is the most important element for the present invention,
In particular, it has the effect of improving the tool life. However, if the amount is less than 0.5%, the effect of improving machinability is not sufficiently exhibited, and if it exceeds 7%, the coefficient of thermal expansion increases. Therefore, the W amount is in the range of 0.5 to 7%. Note that W
Is preferably 1.5 to 5%.

From the viewpoint of further improving machinability, the above composition further contains one or two of S and Se in a range of 0.04% ≦ S + 0.4Se ≦ 0.12%, Mn is 1 ≧ Mn ≧ 2.3 (S + 0.4Se) +0.
It is preferable to contain in the range of 2. Alternatively, one or two of S and Se may be added to the above composition at 0.1.
Contained in the range of 04% ≦ S + 0.4Se ≦ 0.12%,
It is preferable to add Ca in a range of Ca ≧ 3.8 (S + 0.4 Se). S and Se form sulfides and selenides, which further extend the tool life and reduce the cutting force, thereby contributing to the improvement of machinability, but with a significant decrease in ductility. If the amount is less than the above range, the effect of improving machinability is not obtained, and if the amount exceeds the above range, ductility does not recover even when Mn or Ca described below is used in combination. Since Mn or Ca is combined with S and Se to improve the morphology of sulfide and selenide and suppress the decrease in ductility, S and Se necessary for improving machinability can be contained. In order to achieve the effect, M
n needs to be 2.3 (S + 0.4 Se) +0.2 or more, and Ca needs to be 3.8 (S + 0.4 Se) or more.

The alloy of the present invention may be either an alloy used by subjecting an ingot or slab to plastic working such as rolling or forging, or a cast alloy produced by casting into a mold. Also,
The manufacturing conditions are not particularly limited.

However, in the present invention, it is preferable to rapidly cool a raw material manufactured in a predetermined shape from a temperature in the range of 700 to 900 ° C. Thereby, micro segregation of Ni or Co is alleviated, and the thermal expansion coefficient can be further reduced. The rapid cooling method is preferably water cooling, but may be air cooling or oil cooling.

[0022]

Embodiments of the present invention will be described below. With a high frequency induction melting furnace, alloys having the chemical compositions shown in Tables 1 and 2 were melted and cast, and a φ35 mm × L220 mm round bar,
And a round bar of φ100 mm × L400 mm was obtained. In Table 1, No. Nos. 1-33 are materials of the present invention. 1 to
No. 11 is for low temperature. Nos. 12 to 22 are for medium temperature. 23
33 are for high temperature. Also, in Table 2, 34-4
No. 1 is a comparative material of a low temperature alloy. Nos. 44 to 51 are comparative materials for middle temperature alloys. 54 to 61 are comparative materials for high temperature alloys,
No. Reference numerals 64 to 68 are comparative materials in which any one of Ni, Co, and Ni equivalent deviates. Further, in Table 2, No. Nos. 42 and 43 are conventional materials for low temperature alloys. Nos. 52 and 53 are conventional materials of alloy for medium temperature. 62 and 63 are conventional materials of a high temperature alloy.

[0023]

[Table 1]

[0024]

[Table 2]

The thermal expansion coefficient was measured using the above-mentioned 35 mm × L220 mm round bar. The coefficient of thermal expansion is 20 to 150 ° C for low temperature alloys, 20 to 300 ° C for medium temperature alloys,
For high temperature alloys, measurements were made in the range of 20-450 ° C. The machinability was evaluated using φ100 mm × L400 mm. The machinability is no. 42, N for medium temperature
o. No. 52 for high temperature applications. The tool life ratio was evaluated by using a tool life ratio in which the tool life of No. 62 was set to 1 and a cutting resistance. Tables 3 and 4 show these results. In these machinability tests, a cemented carbide tool was used as a cutting tool, and a cutting speed of 100 was used.
m / min, depth of cut 2.0mm, feed 0.2mm / re
v. Under the conditions described above.

[0026]

[Table 3]

[0027]

[Table 4]

As shown in Table 3, it was confirmed that in the examples of the present invention, machinability better than that of the conventional material was obtained while maintaining the desired low thermal expansion property.

On the other hand, as shown in Table 4, Ni,
No. of the comparative example in which the Co amount or the Ni equivalent is out of the range of the present invention. Nos. 64 to 68 had a large thermal expansion coefficient at any temperature and were unsuitable as a low thermal expansion material. In addition, in the case of No. Nos. 34, 44 and 54 had poor machinability.
No. 2 with a large amount of W 35, 45, and 55 showed values with large thermal expansion coefficients. Further, in the case of No. 3 in which the amounts of C, Si and Mn are larger than the range of the present invention. 39-41, 49-51, 59-6
1 has a large thermal expansion coefficient. In addition, S or Se comes off, or Mn or Ca is less than S + 0.4Se in N.
o. 36-38, 46-48, 56-58 had low elongation.

Next, the above No. 1,2,12,13,2
Using a 35 mm × L220 mm round bar sample having a composition of 3,24, the thermal expansion coefficient of the as-cast and water-cooled state at 850 ° C. was measured. No. for low temperature 1, 2 is 2
No. 0 to 150 ° C., medium temperature 12 and 13 are 20-30
No. 0 ° C and high temperature 23 and 14 were measured at 20 to 450 ° C. Table 5 shows the results.

[0031]

[Table 5]

As shown in Table 5, by water cooling,
It was confirmed that the coefficient of thermal expansion was further reduced as compared to as-cast.

[0033]

As described above, according to the present invention,
A low thermal expansion alloy having free cutting properties can be obtained. Therefore, a great deal of cost is not required for cutting.

Claims (5)

[Claims] C .: 0.2% by weight or less, Si:
1% or less, Mn: 1% or less, Ni: 26 to 43.5%,
Co: 20% or less, W: 0.5 to 7%,
A free-cutting, low-thermal-expansion alloy satisfying 34.5% ≦ Ni + 0.8Co ≦ 43.5% and substantially consisting of Fe. 2. In% by weight, C: 0.2% or less, Si:
1% or less, Ni: 26 to 43.5%, Co: 20% or less, W: 0.5 to 7%, and one or two of S and Se are 0.04%. ≤S + 0.4
Se ≦ 0.12%, Mn is 1 ≧ Mn ≧
2.3 (S + 0.4Se) +0.2 contained within a range satisfying 34.5% ≦ Ni + 0.8Co ≦ 43.5%
A free-cutting low-thermal-expansion alloy characterized by satisfying the above, and substantially consisting of Fe. 3. C .: 0.2% or less by weight, Si:
1% or less, Mn: 1% or less, Ni: 26 to 43.5%,
Co: 20% or less, W: 0.5 to 7%,
Further, one or two of S and Se are set to 0.04
% ≦ S + 0.4Se ≦ 0.12%
Is added within the range of Ca ≧ 3.8 (S + 0.4Se) and satisfies 34.5% ≦ Ni + 0.8Co ≦ 43.5%, with the balance substantially consisting of Fe. Low thermal expansion alloy. 4. The free-cutting low thermal expansion alloy according to claim 1, wherein W is 1.5 to 5% by weight. 5. A free-cutting low-thermal-expansion alloy, characterized by rapidly cooling a material having the composition according to claim 1 from a temperature of 700 ° C. or more and 900 ° C. or less. Production method.