Ultra-pure diamond wire base material for drawing and preparation method of ultra-pure diamond wire base material

Abstract

The invention discloses an ultra-pure diamond wire base material for drawing and a preparation method thereof. The diamond wire base material comprises the following chemical components in percentage by mass: 1.05-1.15% of C, 0.15-0.25% of Si, 0.3-0.5% of Mn, 0.15-0.25% of Cr, 0.005-0.015% of Nb, 0.005-0.01% of V, less than or equal to 0.008% of P, less than or equal to 0.002% of S, less than or equal to 0.001% of Al, less than or equal to 0.001% of Ti, less than or equal to 0.0025% of O + N + H and the balance of Fe and inevitable impurities. The preparation method comprises the steps of vacuum smelting and casting, electroslag remelting and forging. In the vacuum smelting and casting stage, 0.007-0.009% of Fe2O3 is added after pure iron is completely melted down. The diamond wire base material provided by the invention has the characteristics of high purity, small segregation degree, suitability for large-scale production and the like.

Description

Technical Field

[0001] The invention belongs to the field of steel materials, and in particular relates to an ultra-pure diamond wire mother material for drawing and a preparation method thereof. Background Art

[0002] Influenced by the demand for "carbon emissions", the world's energy structure has gradually changed, green development has become a global consensus, the pace of green energy transformation has further accelerated, and the advanced photovoltaic industry has become an important support for advancing the energy revolution.

[0003] Diamond wire is an important part of the upstream of the industry, and it is the key to ensuring the quality and thinning of silicon wafers. Electroplated diamond wire is mainly composed of a busbar, a metal nickel layer, diamond particles, etc., in which the busbar is a carrier, and the metal nickel layer, diamond particles, etc. are attached to the busbar through various processes. This type of material has extremely strict requirements on the control of inclusions in the parent material, especially alumina inclusions. Alumina inclusions have poor plasticity during the drawing process. When preparing ultrafine diamond wire (less than 40 microns), alumina inclusions are required to be less than 1 / 5 of the diameter. At present, most of the relevant patents in my country involve drawing wires and how to prepare diamond wire cutting wires from parent materials, and there are few reports on the process technology for controlling the parent material and its inclusions.

[0004] The patent application with publication number CN108866433A provides a high-carbon, low-aluminum, low-oxygen steel for cutting wire and a vacuum induction melting method thereof. The invention obtains a low-oxygen, low-aluminum parent material with Al≤0.003% and O≤0.002% by controlling the timing and sequence of carbon addition, refining time, and chamber pressure at different stages. Although it obtains a parent material with lower aluminum and oxygen, this type of parent material still has large-particle, difficult-to-deform aluminum oxide inclusions in the ingot; in addition, the smelting method described is not representative, and only involves smelting without introducing the subsequent processes, so it is of little reference value.

[0005] The patent application with publication number CN110230008A provides an ultrafine ultra-high strength steel wire, a wire rod for ultrafine ultra-high strength steel wire and a production method thereof, wherein a slag system containing a relatively high Al2O3 is selected during electroslag remelting. Although alumina has the effect of reducing slag resistance and reducing power consumption, since the alloy matrix contains a certain amount of metallic silicon and the slag pool temperature is relatively high, the following reaction Si+Al2O3--SiO2+Al is very likely to occur, thereby increasing the aluminum content in the steel and the number of alumina inclusions, affecting the subsequent drawing process.

[0006] The patent with announcement number CN112899566B provides a 5000MPa grade diamond wire wire rod and its production method, but the patent adopts high-specification pure iron smelting, which is costly and has poor applicability. At the same time, the vacuum ingot is directly used as a vacuum consumable electrode, which has strict requirements on electrode quality. In addition, the vacuum induction ingot is prone to produce large internal stress and form more shrinkage holes during solidification. When it is directly used as an electrode for consumable remelting, it is easy to cause the electrode to fall off due to shrinkage cracking, and form white spot defects after falling into the molten pool, which has a great impact on the mechanical properties of the alloy. In general, this method is costly, the process is unclear, and the applicability is limited, so it is not very meaningful for large-scale production.

[0007] Based on the above analysis, it is necessary to develop a method for preparing diamond wire matrix that is low-cost, widely applicable, and easy to mass-produce. Summary of the invention

[0008] The present invention aims to provide an ultra-pure diamond wire mother material for drawing and a preparation method thereof. The diamond wire mother material has the characteristics of high purity, small segregation, and is suitable for large-scale production.

[0009] To achieve the above purpose, the technical solution of the present invention is as follows:

[0010] The present invention comprises the following steps:

[0011] The invention discloses an ultra-pure diamond wire mother material for drawing, wherein the chemical composition thereof is as follows by mass percentage: C: 1.05-1.15%, Si: 0.15-0.25%, Mn: 0.3-0.5%, Cr: 0.15-0.25%, Nb: 0.005-0.015%, V: 0.005-0.01%, P≤0.008%, S≤0.002%, Al≤0.001%, Ti≤0.001%, O+N+H≤0.0025%, and the balance is Fe and unavoidable impurities.

[0012] The method for preparing the ultra-pure diamond wire mother material for drawing of the present invention comprises a vacuum smelting and casting stage, an electroslag remelting stage, and a forging stage.

[0013] Preferably, in the vacuum smelting and casting stage of the present invention: the ingredients are calculated according to the target composition, and the required alloy material is baked at 150°C for more than 2 hours; then the industrial pure iron is loaded into the induction furnace, and after it is melted, 0.007-0.009% Fe2O3 is added through a secondary feeding device, and refined for 15-20 minutes, and some inclusions are removed by floating using electromagnetic stirring, followed by alloying, and after the alloying is completed, detection and analysis are performed, and after the composition is qualified, the temperature is raised and the steel is tapped, and finally cast into a round ingot with a diameter of 100±5mm.

[0014] Preferably, in the electroslag remelting stage of the present invention: the obtained vacuum ingot is cut off and welded to a dummy electrode, and the slag is prepared according to the following ingredients: CaO: 25-30%, CaF2: 60-65%, SiO2: 10-12%; the slag and arc starting agent (consistent with the composition of the base material) are baked at 500°C for more than 12 hours, and electroslag remelting is performed after baking.

[0015] Preferably, in the forging stage of the present invention, the electroslag ingot is heated to 1200°C and kept warm for 1.5 to 2.5 hours, then taken out of the furnace and forged, the initial forging temperature is controlled at 1150 to 1170°C, the final forging temperature is greater than 900°C, the first deformation amount is ≥30% and it is not returned to the furnace, the ingot is forged once, and finally forged into a square ingot of 50*50*L or 60*60*L.

[0016] Furthermore, in the method for preparing the ultra-pure diamond wire base material for drawing of the present invention, the proportion of alumina inclusions smaller than 2 μm after electroslag remelting accounts for no less than 85% of the total alumina inclusions, and the maximum inclusion size does not exceed 4 μm.

[0017] Furthermore, the diamond wire base material prepared by the method of the present invention has a grain size of ≥7 and a central carbon segregation index of <1.05.

[0018] The beneficial effects of the present invention are:

[0019] 1) By adding a certain amount of iron oxide, the aluminum and titanium elements in the steel can be controlled below 0.001%, and some large-sized inclusions can be floated and removed through refining + electromagnetic stirring.

[0020] 2) By adding a certain proportion of SiO2 to the electroslag system, the burning of silicon in the base material can be avoided, thereby ensuring the uniformity and consistency of the composition and obtaining an alloy ingot with dense structure and few inclusions after electroslag remelting.

[0021] 3) During the forging process, the first pressing amount is ensured to be greater than 30%, and the final forging temperature is greater than 900°C. This method can ensure that the forged ingot has uniform structure, refined grains, and excellent properties.

[0022] 4) This method can be used to obtain ultra-pure, uniformly structured forging ingots. DETAILED DESCRIPTION

[0023] Example 1

[0024] An ultra-pure diamond wire mother material for drawing, the preparation method of which includes vacuum smelting and casting, electroslag remelting, and forging; the details are as follows:

[0025] 1) Vacuum smelting and casting

[0026] According to the target composition, 0.352 kg of carbon powder, 0.064 kg of metal silicon, 0.128 kg of electrolytic manganese, 0.064 kg of metal chromium, 0.0035 kg of ferroniobium, 0.0046 kg of ferrovanadium and 31.38 kg of pure iron were calculated and weighed; the alloy material was baked at 150 ° C for 2.5 hours; then the industrial pure iron was loaded into the induction furnace, and after it was melted, 0.0224 kg of iron oxide was added, and refined for 15 minutes, and some inclusions were removed by electromagnetic stirring; after the refining was completed, argon was filled and alloying began gradually. After the alloying was completed, samples were taken for testing. The results are shown in Table 1. The composition was qualified, and then the temperature was increased and cast into a round ingot with a diameter of 95 mm.

[0027] Table 1 Measured values ​​of steel composition in Example 1 (%)

[0028] element C Si Mn Cr Nb V P S Al Ti Measured value 1.12 0.205 0.399 0.199 0.0065 0.0073 0.003 0.002 0.001 0.0009

[0029] 2) Electroslag remelting

[0030] The round ingot with a diameter of 95 mm was cut off and welded to the dummy electrode, and the slag was prepared. The composition and content of the slag are shown in Table 2.

[0031] Table 2 Composition and content of slag in Example 1 (%)

[0032] Element <![CDATA[CaF2]]> CaO <![CDATA[SiO2]]> content 65 25 10

[0033] The above slag and arc starting agent (same as the ingot composition) were baked at 500℃ for 13h, and then electroslag remelting was performed. In the arc starting stage, the secondary voltage was 18V and the secondary current was 1.8kA. In the smelting stage, the power was gradually increased to a secondary voltage of 31.5V and a secondary current of 2.5kA. In the shrinkage feeding stage, the smelting power was gradually reduced to a secondary voltage of 27V and a secondary current of 1.5kA. After electroslag remelting, Ingot.

[0034] 3) Forging

[0035] The electroslag ingot obtained in step 2) is heated to 1200°C and kept warm for 2 hours; then it is taken out of the furnace and placed on a forging table for forging. The initial forging temperature is 1170°C, the final forging temperature is 950°C, the first pressing amount is 45mm, and after 6 rapid forgings, a rectangular forged ingot with a cross-sectional size of 60mm×60mm is obtained.

[0036] Example 2

[0037] An ultra-pure diamond wire mother material for drawing, the preparation method of which includes vacuum smelting and casting, electroslag remelting, and forging; the details are as follows:

[0038] 1) Vacuum smelting and casting

[0039] According to the relevant target composition, 0.336Kg of carbon powder, 0.048Kg of metal silicon, 0.096Kg of electrolytic manganese, 0.048Kg of metal chromium, 0.0059Kg of ferroniobium, 0.0055Kg of ferrovanadium, and 31.46Kg of pure iron were calculated and weighed. The alloy material was baked at 150°C for 3h. Then the pure iron was loaded into the induction furnace, and after it was melted, 0.0256Kg of iron oxide was added, and it was refined for 20min, and some inclusions were removed by electromagnetic stirring. After it was melted, the protective atmosphere of argon was filled and alloying began step by step. After the alloying was completed, samples were taken for testing. The results are shown in Table 3. The composition was qualified, and then the temperature was raised and cast into a round ingot with a diameter of 100mm.

[0040] Table 3 Measured values ​​of steel composition in Example 2 (%)

[0041] element C Si Mn Cr Nb V P S Al Ti Measured value 1.05 0.15 0.3 0.15 0.005 0.005 0.003 0.002 0.0008 0.0009

[0042] 2) Electroslag remelting

[0043] The round ingot with a diameter of 100 mm was cut off and welded to the dummy electrode, and the slag was prepared; the composition and content of the slag are shown in Table 4.

[0044] Table 4 Slag composition content of Example 2 (%)

[0045] Element <![CDATA[CaF2]]> CaO <![CDATA[SiO2]]> content 60 28 12

[0046] The above slag and arc starting agent (same as the ingot composition) are baked at 500℃ for 14h, and then electroslag remelting is performed. In the arc starting stage, the secondary voltage is 19V and the secondary current is 1.9kA. In the smelting stage, the power is gradually increased to 30V and 2.5kA. In the shrinkage feeding stage, the smelting power is gradually reduced to 25V and 1.3kA. After electroslag remelting, Ingot.

[0047] 3) Forging

[0048] The electroslag ingot was heated to 1200°C and kept warm for 2.5 hours, then taken out of the furnace and placed on a forging table for forging. The initial forging temperature was 1150°C, the final forging temperature was 970°C, the first pressing amount was 48mm, and after 5 rapid forgings, a rectangular forging ingot with a cross-sectional size of 50mm×50mm was obtained.

[0049] Example 3

[0050] An ultra-pure diamond wire mother material for drawing, the preparation method of which includes vacuum smelting and casting, electroslag remelting, and forging; the details are as follows:

[0051] 1) Vacuum smelting and casting

[0052] According to the relevant target composition, the carbon powder is calculated and weighed, 0.368Kg, metal silicon is 0.08Kg, electrolytic manganese is 0.16Kg, metal chromium is 0.08Kg, ferroniobium is 0.005Kg, ferrovanadium is 0.0092Kg, and pure iron is 31.3Kg. The alloy material is baked at 150℃ for 5h. Then the pure iron is loaded into the induction furnace, and after it is melted, 0.0288Kg of iron oxide is added, and it is refined for 18min, and some inclusions are removed by electromagnetic stirring. After it is melted, the protective atmosphere argon is filled and alloying is started step by step. After the alloying is completed, the samples are taken for testing. The results are shown in Table 5. The composition is qualified, and then the temperature is raised and cast into a round ingot with a diameter of 105mm.

[0053] Table 5 Measured values ​​of steel composition in Example 3 (%)

[0054] element C Si Mn Cr Nb V P S Al Ti Measured value 1.15 0.25 0.5 0.25 0.015 0.01 0.0015 0.001 0.0009 0.0008

[0055] 2) Electroslag remelting

[0056] The round ingot with a diameter of 105 mm was cut off and welded to the dummy electrode, and the slag was prepared. The slag composition is shown in Table 6.

[0057] Table 6 Slag composition content of Example 3 (%)

[0058] Element <![CDATA[CaF2]]> CaO <![CDATA[SiO2]]> content 62 27 11

[0059] The above slag and arc starting agent (same as ingot composition) were baked at 500℃ for 15h, and then electroslag remelting was performed. In the arc starting stage, the secondary voltage was 17V and the secondary current was 1.7kA. In the smelting stage, the power was gradually increased to a secondary voltage of 28V and a secondary current of 2.5kA. In the shrinkage feeding stage, the smelting power was gradually reduced to a secondary voltage of 26V and a secondary current of 1.3kA. After electroslag remelting, Ingot.

[0060] 3) Forging

[0061] The electroslag ingot obtained in step 2 was heated to 1200°C and kept warm for 1.5 hours. It was then taken out of the furnace and placed on a forging table for forging. The initial forging temperature was 1160°C, the final forging temperature was 940°C, the first pressing amount was 46mm, and after 5 rapid forgings, a rectangular forged ingot with a cross-sectional size of 50mm×50mm was obtained.

[0062] Statistics were taken on the inclusions and grain size of the alloy ingot after electroslag remelting in the example, and the results are shown in Tables 7 and 8.

[0063] Table 7 Alumina inclusion size and gas statistics in alloy ingots after electroslag remelting in various examples

[0064]

[0065] Table 8 Grain size rating and segregation statistics of various embodiments

[0066] Grain size rating Central carbon segregation Example 1 Level 7 1.03 Example 2 7.5 1.02 Example 3 Level 7 0.98

[0067] It is not difficult to know from the above results that the diamond wire mother material prepared by the present invention has the advantages of high purity and uniform structure.

Claims

1. An ultra-pure diamond wire base material for drawing, characterized in that: The chemical composition of the diamond wire base material is C: 1.05-1.15%, Si: 0.15-0.25%, Mn: 0.3-0.5%, Cr: 0.15-0.25%, Nb: 0.005-0.015%, V: 0.005-0.01%, P≤0.008%, S≤0.002%, Al≤0.001%, Ti≤0.001%, O+N+H≤0.0025%, and the balance is Fe and unavoidable impurities.

2. A method for preparing the ultra-pure diamond wire matrix for drawing as claimed in claim 1, characterized in that: The method comprises a vacuum smelting and casting stage, an electroslag remelting stage and a forging stage; in the vacuum smelting and casting stage, after the pure iron is completely melted, 0.007-0.009% Fe2O3 is added, and the mixture is refined for 15-20 minutes, and electromagnetic stirring is used to float the mixture to remove some inclusions, followed by alloying. After the alloying is completed, the composition is tested and analyzed to be qualified, and the temperature is raised to tap the steel, and the steel is finally cast into an ingot.

3. The method for preparing an ultra-pure diamond wire matrix for drawing according to claim 2, characterized in that: During the electroslag remelting stage, 10-12% SiO2 is added to the slag system.

4. The method for preparing an ultra-pure diamond wire matrix for drawing according to claim 2, characterized in that: In the electroslag remelting stage, the chemical composition of the slag system and its mass percentage are CaO: 25-30%, CaF2: 60-65%, and SiO2: 10-12%.

5. The method for preparing an ultra-pure diamond wire matrix for drawing according to claim 2, characterized in that: In the forging stage, the initial forging temperature is controlled between 1150 and 1170° C., the final forging temperature is greater than 900° C., the first deformation amount is ≥30% and the steel is not returned to the furnace, and the steel is forged in one step.

6. The method for preparing an ultra-pure diamond wire matrix for drawing according to claim 2, characterized in that: After the electroslag remelting, the proportion of alumina inclusions smaller than 2 μm in the total alumina inclusions is not less than 85%, and the maximum inclusion size does not exceed 4 μm.

7. The method for preparing an ultra-pure diamond wire matrix for drawing according to claim 2, characterized in that: The diamond wire base material prepared by the method has a grain size of ≥7 and a central carbon segregation index of <1.05.

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