JPH04210450A - Wire for wire saw and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a wire having small wire diameter, small in a cutting margin and having cutting speed same as that of the conventional product by specifying the content of C, Mn and Cr in a steel having a specified compsn. and the plating thickness of a wire. CONSTITUTION:A steel contg., by weight, 0.90 to 1.10% C, <=0.4% Si, <=0.4% Mn, 0.10 to 0.30$ Cr, <=0.003% Al as inevitable impurities and the balance Fe is subjected to hot rolling into a hot rolled wire having 4.5 to 6.0mm wire diameter. This wire rod is subjected to wire drawing into a wire having 0.7 to 0.9mum wire diameter and is thereafter subjected to final patenting treatment constituted of gammanizing treatment at 900 to 1100 deg.C and isothermal transformation treatment at 550 to 600 deg.C into a wire having a pearlite structure having 145 to 160kgf/mm<2> tensile strength. This wire is subjected to wire drawing into a wire having 0.20 to 0.30mm wire diameter, is thereafter plated with copper or brass having 8 to 12mu thickness and is then subjected to final wire drawing to obtain an objective wire having 0.080 to 0.125mum wire diameter, 4.3 to 4.7mu plating thickness and 4.0 to 4.4kgf breaking load.

Description

[Detailed description of the invention]

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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength ultrafine wire, and more particularly to a wire for a wire saw used to cut silicon wafers. These wires are wires for cutting by free abrasive processing using diamond particles. [0002]

[Prior Art] Japanese Patent Application Laid-open No. 60-204865 states that
~ By regulating the 1n content range to less than 0.3% to suppress the formation of a suitable cooling structure after lead pachinko jig, and by regulating the amount of elements such as C, Si, and Nin, wire breakage during stranding is reduced and high strength is achieved. and high-toughness and ductility ultra-fine wires and high carbon steel wire rods for steel cords, and also,
Publication No. 24046 discloses a high-toughness, high-ductility wire material for ultra-fine wire in which the tensile strength of the lead patenting material is increased and the wire drawing processing rate is reduced by setting the Si content to 1.00% or more. ing. [0003] JP-A No. 60-204865 discloses that steel having a carbon content of 0.90% or less is drawn to a diameter of 0.5 mm or less, and has a tensile strength of 250 kg. This is a high carbon steel wire rod for producing ultra-fine wires with a diameter of 1.0% or more. Tensile strength used: 300kgf
The present invention relates to a high carbon steel wire rod for producing ultrafine wires with a wire diameter of 0.5 mm or less. [0004] Steels with a stiff composition have been used for wires for wire saws, but in all cases, when the breaking load is 4.0 kgf or more, only wires for wire saws with a wire diameter of 0, iso μm or more have been obtained. [0005]

[Problems to be Solved by the Invention] In the case of cutting using a wire saw, it is used to cut Si wafers, etc., and the cutting time is longer than when considering cutting out more Si wafers from one Si single crystal. Less wire saw wire is required. Furthermore, when cutting with a wire for a conventional wire saw and reducing the wire diameter to reduce cutting marks, the cutting speed had to be significantly lowered because the wire did not have sufficient strength. Therefore, there are expectations for the development of a wire for wire saws that has the same cutting speed as conventional products and has fewer cutting edges. [00061 An object of the present invention is to provide such a wire for a wire saw and a method for manufacturing the same. [00071

[Means for Solving the Problems] The present invention has the following configuration in order to achieve the above object. That is, the wire for a wire saw of the present invention has a weight ratio of C: 0.9.
0-1. ．． 10%, Si: 0.4% or less, Mn: 0.4
% or less, Cr: 0.10 to 0.30% as the main component,
A steel consisting of iron and other inevitable impurities with the inevitable impurity At being 0.003% or less,
And wire diameter: 0.08~0.125m, Cu or brass plating thickness: 4.3~4.7μm, breaking load 4.0~4.4
kgf, and its manufacturing method includes hot rolling the above-mentioned steel into a hot rolled wire rod with a wire diameter of 4.5 to 6.0 mm, and then rolling the hot rolled wire rod as needed. L of times or more
By combining P treatment and wire drawing IT'-, the wire diameter can be reduced to 0.
After making the wire 7~0°9mm, apply 900mm to the wire.
γ raw treatment in the temperature range of ~1100°C and 5JO ~600
A final patenting process consisting of constant temperature transformation treatment in the temperature range of ℃ is applied to achieve a tensile strength of 145 to 160 kgf/mm.
- The wire is made into a wire with a barley l- structure having a □, and the wire is coated with a wire having a wire diameter of 0.20 to 0.30 mm (after wire drawing, the thickness is 8 to 2 μm), and copper plating or brass plating is applied to the wire. After application, the wire diameter o, oso~0.
It is characterized by the final wire drawing process of 12,571 m of wire. [00081 The present invention will be described in detail below. [Function] In the ultra-fine wire of the present invention, the amount of C is increased to increase the strength after the patenting treatment, thereby preventing the appearance of pro-eutectoid cementite 1 and deterioration of the shape of lamellae in barley 1. This was suppressed by adding Cr, and the strength was increased by making the pearlite finer. In addition, by making the barley h finer, the ductility of the cementite layer became comparable to that of conventional steel. Furthermore, by keeping the amounts of Cr, Si, and Mn added low, the ductility of the Ferrite 1 phase was maintained at the same level as conventional steel, and the ductility of the material was increased. By designing the composition to increase the strength after patenting treatment only by refining the structure, we succeeded in increasing the strength and ductility after patenting to a level higher than that of conventional steels. Therefore, even though the strength after patenting is increased, the deterioration in ductility of the ultra-fine wire manufactured by increasing the drawing rate remains at the level of conventional steel, making it possible to achieve high strength and high ductility. [00101 By using this high strength and high ductility material,
When the wire diameter is made smaller than before, it is now possible to secure the optimal breaking load while maintaining the optimal plating thickness. The reasons for limiting the ingredients will be described below. In normal patenting treatment, pro-eutectoid ferrite 1 precipitates along the prior austenite grain boundaries even when the eutectoid component is around 0.8%, and this pro-eutectoid ferrite is the cause of the decrease in ductility after wire drawing. The present inventors have found that. C is an economical and effective reinforcing element, but it is also an effective element in reducing the amount of precipitated cementite. Therefore, in order to make the final wire into an ultra-fine wire with a breaking strength of 4.0 kgf or more and increase ductility, it is necessary to set the breaking strength to 0.90% or more, but if it is too high, the ductility will decrease and the drawability will deteriorate. The upper limit is 1.10%. [0011] Si is an element necessary for deoxidizing steel, and therefore, when its content is too low, the deoxidizing effect becomes insufficient. In addition, Si dissolves in solid solution in the ferrite 1 phase in the pearlite formed after heat treatment and increases the strength after patenting, but on the other hand, it reduces the ductility of the ferrite and the ductility of the ultra-fine wire after wire drawing. It should be 0.4% or less. ~1n is a small amount of Mn to ensure hardenability of the steel
It is desirable to add However, the addition of a large amount of Mn causes segregation, and during patenting, Baini 1
-, a suitable cooling structure such as marten size 1 occurs, which impairs subsequent wire drawability, so the content should be 0.5% or less. [0012] In the case of a hypereutectoid steel like the one of the present invention, a cementite network is generated in the structure after patenting, and thick cementite tends to precipitate. In order to achieve high strength and high ductility in this steel,
It is necessary to make the pearlite fine and eliminate the cementite network and thick cementite as described above. Cr suppresses the appearance of such abnormal parts of cementite and has the effect of making pearlite finer. However, addition of a large amount increases the dislocation density in the ferrite after heat treatment, which significantly impairs the ductility of the ultra-fine wire after drawing. Therefore, the amount of Cr to be added should be 0.10% or more so that the effect can be expected, and 0.30% or less so as not to increase the dislocation density in the ferrite and impair the ductility. [0013] As with conventional ultra-fine steel wires, the S content is set to 0.020% or less to ensure ductility, and P also impairs the ductility of the wire, so the content is set to 0.020% or less. It is desirable to do so. Al2O3 such as Al2O3 and MgOAl2O3 are the cause of decreasing the ductility of ultra-fine wires.
There are non-ductile inclusions mainly composed of Therefore, in the present invention, the Al content is set to 0.003% or less in order to avoid a decrease in ductility due to non-ductile inclusions. [0014] Moreover, the reason for limiting the structural requirements of the wire is as follows. The reason why the diameter of the wire is set to 0.125 mm or less is that in the case of a wire for a wire saw, a wire having a small wire diameter reduces the number of cuts during cutting and improves the yield. However, when the diameter of the wire is less than 0.080 mm, the breaking load is reduced to 4.0 mm while maintaining sufficient ductility.
It is not possible to secure more than 0 kgf. For this reason, the wire diameter is o,
It is set to oso~0.125 num. [0015] Furthermore, unless the final plating thickness is 4.3 μm or more, the attraction of diamond particles will be poor.
If it exceeds 4.7μm, the strength of the plated part will be low, so the breaking load of the wire should be reduced to 4.7μm. It becomes difficult to make it more than Okgf. The reason why the breaking load is 4.0 kgf or more is that the breaking load is 4.0 kgf or more. If the load is less than 4.4 kgf, sufficient tension cannot be applied during cutting, and the cutting efficiency will drop significantly.Also, the reason why the load should be less than 4.4 kgf is that if the load exceeds this value, the wire will become brittle. This is because it becomes unusable. [00161 The reason for the limitation of the manufacturing method of the wire is as follows. The reason why the wire diameter for final patenting is set to 0.7 mmφ or more is that if the wire diameter is smaller than this, the area reduction rate becomes small and the required load cannot be obtained. Also, 0
．． The reason why the wire diameter is set to be 9 mmφ or less is that when a wire of 0.125 μm or less is drawn, the strength becomes too high and the wire becomes brittle. [0017-1 In the final patenting treatment, unless the γ ratio treatment temperature is set at 900°C or higher, it will not be sufficient to promote the re-solid solution of carbides, and if the temperature is set at 1100°C or higher, the γ grain size will become too large, resulting in transformation. It becomes difficult to obtain a healthy pearlite structure later. In addition, the isothermal transformation temperature is set to 55
When the temperature is below 0℃, the tensile strength is 160kgf/III
In addition to being III2 or higher, a large amount of bainite structure appears in the structure after the final patenting process, which deteriorates the wire properties after wire drawing. Also, when isothermal transformation is performed at a temperature exceeding 600°C. Strength after final patenting treatment: 145kgf/m
It becomes difficult to make it more than m2. [0018] After drawing the wire to a diameter of 0.20 to 0.30 mm, copper plating or brass plating with a plating thickness of 8 IJ, m or more is done to increase the plating thickness at the final wire diameter without reducing productivity. This is to ensure a thickness of 4.3 μm or more. [0019]

EXAMPLE A wire for a wire saw was manufactured using a wire rod of 5.5 Mφ made by wire rod rolling. Table 1 shows the chemical composition, manufacturing conditions, wire specifications, and cutting conditions of the sample in the second case. Regarding the cutting condition, when the cutting speed at which stable cutting is possible for 8-inch silicon is obtained is 0.9 mm/min or more, it is rated O, and when it is lower than this, it is rated x. In addition, the cutting allowance is ○ if the cutting allowance is less than 25011m.
Cases of 250μ■ or more were marked as ×. [0020) Sample numbers 1 to 11 are wires for wire saws manufactured based on the present invention. All wires satisfy the cutting speed and cutting margin, and exhibit characteristics that are better than conventional products. Sample numbers 12 to 15 are wires manufactured for comparison. Sample No. 12 had a carbon content different from that of the present invention in steel composition, and had a wire diameter larger than that of the present invention, and was prepared for comparison of cutting allowance. [00211 Sample No. 13 has a different carbon content and steel composition than the present invention, and a smaller breaking load than the present invention, and was prepared for comparison of cutting speeds. Sample No. 14 has the same steel composition as the steel of the present invention, has a smaller plating thickness during manufacturing conditions than the present invention, and was prepared in order to make the plating thickness of the final wire smaller than that of the present invention and to compare the cutting speed. . [0022] Sample No. 15 has the same steel composition as the steel of the present invention, is manufactured at a higher isothermal transformation temperature in the manufacturing conditions than the steel of the present invention, and the breaking load in the final wire is reduced.
Prepared for comparison of cutting speeds. [0023]

[Table 1] [00241 As shown in Table 1, the present invention shows good cutting conditions under all conditions, while the comparative material shows poor cutting speed and cutting conditions. Either one is defective. [0025]

As described above, the wire for a wire saw according to the present invention is particularly effective in cutting silicon wafers, etc., because it can cut at the same cutting speed as the conventional wire and with a reduced cutting margin.

Claims (4)

[Claims] Claim 1: The main components are C0.90-1.10%, Si0.4% or less, Mn0.4% or less, Cr0.10-0.30% in weight proportion, and the inevitable impurity Al is 0.003%.
% or less of iron and other unavoidable impurities, and has a wire diameter of 0.08 to 0.125 mm, a Cu plating thickness of 4.3 to 4.7 μm, and a breaking load of 4.0 to 4.4 kgf. Wire for wire saw. [Claim 2] The main components are C0.90-1.10% Si0.4% or less Mn0.4% or less Cr0.10-0.30% by weight, and the inevitable impurity Al is 0.003%
% or less of iron and other unavoidable impurities, and has a wire diameter of 0.08 to 0.125 mm, a brass plating thickness of 4.3 to 4.7 μm, and a breaking load of 4.0 to 4.4 kgf. Wire for wire saw. 3. The main components are C0.90-1.10%, Si0.4% or less, Mn0.4% or less, Cr0.10-0.30% in weight proportion, and the inevitable impurity Al is 0.003%.
% or less of iron and other unavoidable impurities is hot rolled into a hot rolled wire rod with a wire diameter of 4.5 to 6.0 mm, and then the hot rolled wire rod is made into a hot rolled wire rod with a wire diameter of 0.7 to 6.0 mm. After drawing into a 0.9 mm wire, the wire was
A final patenting treatment consisting of a gamma treatment in a temperature range of 0°C and a constant temperature transformation treatment in a temperature range of 550 to 600°C is performed to obtain a pearlite structure wire having a tensile strength of 145 to 160 kgf/mm^2, Furthermore, after drawing the wire into a wire with a wire diameter of 0.20 to 0.30 mm, copper plating or brass plating is applied to a thickness of 8 to 12 μm, and then a wire with a wire diameter of 0.080 to 0.125 μm is formed. A method of manufacturing a wire for a wire saw, characterized by carrying out a final wire drawing process. 4. The manufacturing method according to claim 3, wherein a wire having a wire diameter of 0.7 to 0.9 mm is formed by combining the hot rolled wire rod with one or more LP treatments and wire drawing.