Solder for brazing diamond tool and preparation method thereof

Abstract

The invention discloses a solder for brazing a diamond tool and a preparation method of the solder, and belongs to the technical field of brazing. The solder for the diamond brazing tool, provided by the invention, consists of the following components in percentage by mass: 10-25% of Ni; 5-10% of Cr; 2-4% of B; 3-6% of Si; 1%-3% of Mn; and the balance Fe and impurities. According to the solder provided by the invention, the wettability, the brazing strength and the heat stability of metal and diamond can be effectively improved, and the brazing temperature is reduced, so that the heat loss of the diamond in the brazing process can be reduced. The invention further provides a preparation method of the solder.

Description

Technical Field

[0001] The present invention relates to the technical field of brazing, and in particular to a solder for brazing diamond tools and a preparation method thereof. Background Art

[0002] Diamond tools, such as grinding wheels, saw blades, abrasive discs, etc., usually braze diamonds on a metal substrate; in traditional technologies, solders used for brazing diamond tools include nickel-based solders, copper-based solders, silver-based solders, etc. Copper-based and silver-based solders have relatively low melting points, but insufficient high-temperature strength and cannot meet the requirements of high-load tools; although nickel-based solders have good wettability and high strength, the solder layer of nickel-based solders has a high hardness, which is not conducive to the toughness of diamonds, and nickel-based solders are prone to cause diamond graphitization at high temperatures, resulting in a diamond utilization rate of less than 1 / 3 in diamond tools.

[0003] Therefore, there is an urgent need to find a new solder for brazing diamond tools to reduce the thermal loss of diamonds, improve the brazing strength, and the wettability of brazing for fine steel stones and metal substrates. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. For this purpose, the present invention provides a solder for brazing diamond tools, which can effectively improve the wettability, brazing strength, and thermal stability of metals and diamonds, and reduce the brazing temperature, thereby reducing the thermal loss of diamonds during the brazing process.

[0005] The present invention also provides a preparation method for the above solder.

[0006] According to an embodiment of the first aspect of the present invention, a solder for brazing diamond tools is provided. By mass percentage, the solder is composed of the following components:

[0007]

[0008] The balance is Fe and impurities.

[0009] The solder according to the embodiment of the present invention has at least the following beneficial effects:

[0010] The solder provided by the present invention adds B, Si, and Mn on the basis of the Fe-Ni-Cr series solder and accurately controls their contents. Among them, B and Si are very important elements, which play roles in reducing the melting point, improving the wettability and fluidity, etc.; Mn can increase the strength of the solder; overall, the solder provided by the present invention has good brazing performance, small thermal damage to diamonds and small thermal stress, and at the same time has a narrow solid-liquid phase range (the solid phase of this solder is 850-900 °C), and the brazing temperature does not exceed 930 °C.

[0011] In addition, the solder provided by the present invention has good wettability to both diamond and metal matrix materials, a low wetting angle, good climbing degree of diamond, good holding force, and good high-temperature resistance through reasonable composition design.

[0012] Due to the reasonable composition design, the solder provided by the present invention has better performance and lower cost compared with high-temperature nickel-based brazing solders.

[0013] According to some embodiments of the present invention, in the solder, the mass percentage content of Ni is 15-20%. For example, it can be specifically about 16%, 17%, 18% or about 19%.

[0014] According to some embodiments of the present invention, in the solder, the mass percentage content of Cr is 7-9%. For example, it can be specifically about 7.5%, 8% or about 8.5%.

[0015] According to some embodiments of the present invention, in the solder, the mass percentage content of B is 3-3.5%. For example, it can be specifically about 3.1%, 3.2%, 3.3% or about 3.4%.

[0016] According to some embodiments of the present invention, in the solder, the mass percentage content of Si is 5-6%. For example, it can be specifically about 5.2%, 5.5% or about 5.8%.

[0017] Moreover, the total content of boron and silicon in the solder of the present invention > 6 wt%. For example, it can be specifically about 7%, 8%, 9% or about 10%. Thus, the obtained solder has the advantages of low melting point, good fluidity, good wettability, and high strength.

[0018] According to some embodiments of the present invention, in the solder, the mass percentage content of Mn is 1-2%. For example, it can be specifically about 1.5%.

[0019] According to some embodiments of the present invention, the impurities include oxygen. Among them, in the solder, the content of the impurities ≤ 0.02%. For example, it can be specifically about 0.018%, 0.015%, 0.013% or about 0.01%.

[0020] According to some embodiments of the present invention, the solidus temperature of the solder is 850-900 °C. Specifically, it can be 890-900 °C; for example, it can be specifically about 892 °C, 894 °C, 896 °C or about 898 °C.

[0021] According to some embodiments of the present invention, the liquidus temperature of the solder is 950-970 °C. For example, it can be specifically about 955, 960 or about 965 °C.

[0022] According to some embodiments of the present invention, the particle size of the solder is ≤ 110 μm. For example, it can specifically be about 106 μm or about 100 μm.

[0023] According to an embodiment of the second aspect of the present invention, there is provided a method for preparing the solder provided in the embodiment of the first aspect of the present invention, and the preparation method includes the following steps:

[0024] S1. Co-refine Fe, NiFe alloy, FeCr alloy, BFe alloy and the first part of Si;

[0025] S2. Add Mn and the second part of Si to the melt obtained in step S1, and perform deoxidation and slag formation;

[0026] S3. Add the remaining Si to the melt obtained in step S2, and atomize and granulate.

[0027] Since the preparation method adopts all the technical solutions of the solder for brazing diamond tools in the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments. Further,

[0028] In the solder provided by the present invention, the melting point of the corresponding simple substance of the component (if the preparation raw material uses the corresponding simple substance) is usually about 1000 - 1200 °C. In order to improve the component uniformity of each element and ensure the control of the oxygen content during the soldering process, the present invention optimizes the feeding sequence and controls the melting parameters, realizing the effective control of the final component of the obtained solder. For example: The present invention adds a part of silicon in step S1 and step S2 respectively. During this process, silicon mainly promotes the melting of the melt and removes oxygen in the impurities. In step S3, adding the remaining silicon can effectively control the silicon content in the solder. Another example is that in the preparation method provided by the present invention, intermediate alloys such as ferrochromium, nickel iron, and ferroboron are used as preparation raw materials, with a lower melting temperature and a short complete melting time, thereby prolonging the service life of the crucible, reducing production accidents such as furnace leakage, and ensuring the stability and reliability of large-scale production.

[0029] In summary, by using the preparation method provided by the present invention, the chemical composition and uniformity of the obtained solder are effectively controlled, providing a material guarantee for preparing high-quality welds. This solder can be widely used in fields such as aviation, metallurgy, machinery, and electric power, with significant social and economic benefits. At the same time, the cost of the preparation process is reduced, and the safety and stability of the preparation process are improved.

[0030] According to some embodiments of the present invention, in step S1, when adding the preparation raw materials, the position sequence in the furnace is, from bottom to top, the first part of Si, Fe, NiFe alloy, FeCr alloy, BFe alloy and. Thus, better deoxidation, impurity removal, and increased melting (refining) efficiency can be achieved.

[0031] According to some embodiments of the present invention, in step S1, the mass percentage of the first part of Si in the total amount of Si is 15-17%; for example, specifically it can be 16.5-17%; more specifically it can be about 1 / 6.

[0032] According to some embodiments of the present invention, in the NiFe alloy, the mass percentage of Fe is 15-25%; for example, specifically it can be about 20% (at this time the alloy is abbreviated as NiFe20 alloy).

[0033] According to some embodiments of the present invention, in the FeCr alloy, the mass percentage of Cr is 25-35%. For example, specifically it can be about 30% (at this time the alloy is abbreviated as FeCr30 alloy).

[0034] According to some embodiments of the present invention, in the BFe alloy, the mass percentage of B is 15-25%; for example, specifically it can be about 20% (at this time the alloy is abbreviated as B20Fe alloy).

[0035] According to some embodiments of the present invention, in step S1, the refining temperature is 600-800 °C. For example, specifically it can be about 650 °C, 700 °C or about 750 °C.

[0036] According to some embodiments of the present invention, in step S1, the refining duration is 30-40 min. For example, specifically it can be about 35 min.

[0037] According to some embodiments of the present invention, in step S2, the mass percentage of the second part of Si in the total amount of Si is 60-70%. For example, specifically it can be 65-68%. More specifically it can be about 2 / 3.

[0038] According to some embodiments of the present invention, in step S2, when adding the preparation raw materials, the temperature of the melt obtained in step S1 is 600-800 °C. For example, specifically it can be about 650 °C, 700 °C or about 750 °C.

[0039] According to some embodiments of the present invention, in step S2, the deoxidation and slag making duration is 10-20 min. For example, specifically it can be about 12 min, 15 min or about 18 min.

[0040] According to some embodiments of the present invention, in step S3, the mass percentage of the remaining Si in the total amount of Si is 15-17%; for example, specifically it can be 16.5-17%; more specifically it can be about 1 / 6.

[0041] According to some embodiments of the present invention, in step S3, when adding the remaining Si, the temperature of the melt obtained in step S2 is 1100 - 1200 °C. For example, it can specifically be about 1110 °C, 1120 °C, 1130 °C, 1140 °C, 1150 °C or about 1180 °C.

[0042] According to some embodiments of the present invention, in step S3, after adding the remaining Si, the obtained mixture is continuously melted for 1 - 3 min. For example, it can specifically be about 1.5 min, 2 min or about 2.5 min.

[0043] According to some embodiments of the present invention, in step S3, the medium for atomization granulation is at least one of nitrogen and argon.

[0044] According to some embodiments of the present invention, in step S3, the pressure for atomization granulation is 2 - 6 MPa. For example, it can specifically be about 3 MPa, 4 MPa or about 5 MPa.

[0045] According to some embodiments of the present invention, in step S3, in the atomization granulation, the flow rate of the melt obtained in step S3 is 3.0 - 5.0 kg / min. For example, it can specifically be about 3.5 kg / min, 4 kg / min or about 4.5 kg / min.

[0046] According to some embodiments of the present invention, in step S3, it further includes performing particle size classification on the obtained solder after the atomization granulation. The method used for particle size classification includes screening.

[0047] Unless otherwise specified, the actual meaning of "about" in the present invention is that the allowable error is within the range of ±2%, for example, about 100 is actually 100 ± 2% × 100.

[0048] Unless otherwise specified, "between... and..." in the present invention includes the endpoints, for example, "between 2 and 3" includes the endpoint values 2 and 3.

[0049] Other features and advantages of the present invention will be described in the following specification, and, in part, will become apparent from the specification, or will be understood by implementing the present invention. Detailed Embodiments

[0050] The following will clearly and completely describe the concept of the present invention and the technical effects generated in combination with the embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts shall fall within the scope of protection of the present invention.

[0051] In the description of the present invention, the descriptions with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0052] Example 1

[0053] In this example, a solder for brazing diamond tools was prepared. By mass percentage, its designed components are as follows:

[0054]

[0055] The balance is Fe and impurities.

[0056] And elemental Fe, elemental Mn, NiFe20 alloy, FeCr30 alloy, B20Fe alloy, and elemental Si were weighed according to the above designed components.

[0057] The specific preparation method of the solder in this example includes the following steps:

[0058] S1. In the crucible of the melting furnace, the first part of Si (1 / 6 of the total amount of Si) - elemental Fe - NiFe20 alloy - FeCr30 alloy - B20Fe alloy were loaded in sequence from bottom to top;

[0059] The above substances were melted at a temperature of 700 °C for 35 minutes;

[0060] S2. Maintaining the temperature of 700 °C, the second part of Si (2 / 3 of the total amount of Si), and the designed amount of elemental Mn were added to the melt obtained in step S1; sufficient deoxidation and slag formation were carried out for 15 minutes.

[0061] S3. When controlling the temperature of the melt obtained in step S2 to be 1150 °C, the remaining amount of elemental Si (1 / 6 of the total amount of Si) was added, and after continuing to melt for 2 minutes, atomization to obtain alloy powder was started. The atomization medium was nitrogen, the atomization pressure was 6 MPa, and the flow rate of the melt obtained in step S3 was 3.5 kg / min.

[0062] S4. The prepared powder was sieved, and the particle size specification was less than 106 μm.

[0063] Using the technical solution provided in this example, the experiment was repeated four times.

[0064] Comparative Example 1

[0065] In this example, a solder for brazing diamond tools was prepared, which differed from Example 1 in that:

[0066] The preparation method adopted specifically included the following steps:

[0067] D1. Prepare the raw material elements Ni, Cr, Si, Fe, Mn and FeB alloy (B content 19.90 wt%) according to the designed composition;

[0068] D2. Use an induction melting and atomization integrated furnace to prepare the solder: load the elements Ni - Cr - Si - Fe - Mn - FeB alloy into the crucible from bottom to top in sequence, heat to melt the raw materials, then conduct high-temperature refining. The high-temperature refining temperature is 1550 °C. After about 1 h, atomize to obtain alloy powder. The atomization medium is nitrogen, the atomization pressure is 6 MPa, and the alloy liquid flow rate is 3.5 kg / min; the prepared powder is screened, and the particle size specification is less than 106 μm.

[0069] The technical solution provided in this example was repeated for four tests.

[0070] Test Example 1

[0071] In this example, the true compositions of multiple batches of solders prepared in Example 1 and Comparative Example 1 were tested. The test method was energy dispersive spectroscopy (EDS) analysis; the test results are shown in Table 1.

[0072] Table 1 Actual compositions of solders obtained in the example and the comparative example

[0073]

[0074] The results in Table 1 show that the solder prepared in the comparative example had poor compositional uniformity and a high oxygen content. More specifically, for the solder obtained in the example, except for elements Ni and O, the deviation of the content of other minor elements from the designed content was within ±0.25%, and more specifically, usually within the range of ±0.2%. However, the deviation between the designed value and the actual value in Comparative Example 1 generally exceeded the range of ±0.2% and could reach up to 0.3%. That is, in the preparation method adopted in Comparative Example 1, even if the temperature and other parameters were strictly controlled, it was difficult to control the actual composition of the obtained solder.

[0075] In this example, the yield rates of the solders obtained in the example and the comparative example were also tested. The yield rate refers to that the atomized powder screened to be <106 μm in one furnace is the finished product, otherwise it is the defective product. The test methods were sieving method and laser particle size analysis; the results showed that the yield rate of the solder obtained in Example 1 was 92.2%, and the yield rate of the solder obtained in Comparative Example 1 was 65.8%.

[0076] In this example, the leakage rate during the preparation of the solder in the examples and comparative examples was also counted. The results showed that the average leakage rate of Example 1 was 2%, and the average leakage rate of Comparative Example 1 was 14%.

[0077] From the above comparison, it can be seen that although the design components are the same, by using the preparation method provided by the present invention, the yield of the obtained solder can be significantly improved, the leakage rate can be reduced, the impurity content and the melting time required can be reduced, that is, the cost is significantly reduced.

[0078] Test Example 2

[0079] In this example, the solid-liquid phase temperatures of the solders obtained in the examples and comparative examples were tested. The specific test method was to detect with a differential scanning calorimeter (DSC). The test results are shown in Table 2.

[0080] Table 2 Solid-liquid phase temperatures of the solders obtained in the examples and comparative examples

[0081]

[0082]

[0083] The results in Table 2 showed that the solidus temperature of the solder prepared in the comparative example was 5-10 °C higher than that of the example.

[0084] In this example, the specific life of the diamond tool after welding the solders obtained in the examples and comparative examples was also tested. Among them, the diamond tool was a diamond saw blade, and the metal matrix was mainly 45# steel. The main welding condition affecting the diamond tool was the brazing temperature. The lower the brazing temperature, the smaller the damage to the diamond. In actual production, the brazing temperature of the liquidus temperature + 20 °C was generally selected for brazing. In this example, for comparison, the brazing diamond temperature of all examples / comparative examples was set at 1000 °C; the test results are shown in Table 3.

[0085] Table 3 Lifespan of diamond tools welded with the solders obtained in the examples and comparative examples.

[0086]

[0087] The results in Table 2 showed that the lifespan of the solder prepared in the comparative example decreased by about 18.4% compared with that of the example.

[0088] From the above results, it can be seen that within the range of the ratio and preparation conditions provided by the present invention, the obtained solder has low impurity content, high component uniformity, low leakage rate, high yield, and low solid-liquid phase temperature. Most importantly, the diamond tool obtained by welding has a long service life.

[0089] The above has made a detailed description of the embodiments of the present invention. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention within the scope of knowledge possessed by those of ordinary skill in the art. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A solder for brazing diamond tools, characterized in that, By mass percentage, the solder consists of the following components: Ni 10 - 25%; Cr 5～10％； B 2～4％； Si 3 - 6%; Mn 1 - 3%; The balance is Fe and impurities.

2. The solder according to claim 1, characterized in that, In the solder, the mass percentage content of Ni is 15 - 20%.

3. The solder according to claim 1, wherein In the solder, the mass percentage content of Cr is 7 - 9%.

4. The solder according to claim 1, wherein In the solder, the mass percentage content of B is 3 - 3.5%.

5. The solder according to claim 1, wherein In the solder, the mass percentage content of Si is 5 - 6%.

6. The solder according to claim 1, characterized in that, In the solder, the mass percentage content of Mn is 1 - 2%.

7. The solder according to any one of claims 1 to 6, characterized in that, The solid phase temperature of the solder is 850 - 900 °C; and / or, the particle size of the solder is ≤110 μm.

8. A method for preparing a solder according to any one of claims 1 to 7, characterized in that, The preparation method includes the following steps: S1. Co-refine Fe, NiFe alloy, FeCr alloy, BFe alloy and the first part of Si; S2. Add Mn and the second part of Si to the melt obtained in step S1, and carry out deoxidation and slag formation; S3. Add the remaining Si to the melt obtained in step S2, and atomize and granulate.

9. The preparation method according to claim 8, wherein In step S1, the temperature of the refining is 600 - 800 °C.

10. The preparation method according to claim 8, wherein, In step S3, when adding the remaining Si, the temperature of the melt obtained in step S2 is 1100 - 1200 °C.

Images