CN113319464B - Annular nickel-based self-brazing solder and preparation method and application thereof - Google Patents

Abstract

The invention relates to the technical field of brazing materials, in particular to a ring-shaped nickel-based self-brazing filler metal and its preparation method and application. A ring-shaped nickel-based self-brazing solder of the present invention is mainly prepared from the following raw materials in parts by weight: 79.5-91.7 parts of nickel-based solder, 0.5-3 parts of B powder, 1.2-11.1 parts of Si powder, thickening 0.3-0.5 parts of agent and 3-8 parts of water. Through the cooperation of various components, the self-brazing performance of the solder can be realized; made into a ring shape, the quantitative and automatic addition of the solder can be realized, without material waste, suitable for automatic brazing, and the welding material can obtain excellent welding performance. . The annular nickel-based self-brazing filler metal of the present invention does not contain flux components, does not produce flux residues to corrode joints, has better self-brazing performance, and meets environmental protection requirements; the preparation method of the present invention has simple operation and high production efficiency High, low cost, overcome the difficult problem of making rings from nickel-based solder.

Description

A kind of annular nickel-based self-brazing filler metal and its preparation method and application

technical field

The invention relates to the technical field of brazing materials, in particular to a ring-shaped nickel-based self-brazing filler metal and its preparation method and application.

Background technique

Due to its superior high temperature performance and good corrosion resistance, stainless steel is widely used in the manufacture of heat exchanger piping. In recent years, stainless steel heat exchangers have become heat exchange devices commonly used in metallurgy, chemical industry, energy, transportation, light industry, food and other industrial sectors. Brazing is a key link in the manufacture of stainless steel heat exchanger piping, which determines the service life of the heat exchanger. With the improvement of people's quality of life, the requirements for the welding quality of stainless steel heat exchangers are getting higher and higher. The welding quality of stainless steel heat exchangers is largely dependent on the brazing material used.

Nickel-based brazing filler metal has good compatibility with most iron-based alloys, and is a common brazing material for brazing stainless steel. Nickel-based brazing filler metal is a kind of high-temperature brazing filler metal that is based on nickel and added with elements that can lower the melting point and increase the thermal strength. Nickel-based solder is hard, brittle, and has poor processability, so it is difficult to process it into ring-shaped or filamentary solder. The existing method is to prepare nickel-based solder metal powder into paste solder, which is coated on the surface of the pipeline to be brazed for brazing. However, during the brazing process, the paste solder cannot realize the Accurate quantitative addition, easy to turbulent flow, bubbling or collapse after brushing, not only easy to block pipelines, waste materials and poor weld formation. In addition, most of the traditional nickel-based solders do not have self-brazing properties. During the brazing process, it is often necessary to continuously brush and add flux. Most of the fluxes contain fluoride, which is volatile during the brazing process, pollutes the environment, and endangers human health; residual Flux residues are highly corrosive and can easily cause corrosion and leakage of stainless steel pipelines. In addition, continuous brushing of flux also leads to low brazing efficiency and high brazing cost.

In view of this, the present invention is proposed.

Contents of the invention

An object of the present invention is to provide a ring-shaped nickel-based self-brazing solder without flux, which can realize self-brazing, quantitative, and automatic addition of solder without wasting materials, is suitable for automatic brazing, and makes the welding material obtain Excellent welding performance.

Another object of the present invention is to provide a method for preparing ring-shaped nickel-based self-brazing filler metal, which is simple in operation, high in production efficiency, and low in cost, and overcomes the difficulty of making rings from nickel-base filler metal.

Another object of the present invention is to provide an application of ring-shaped nickel-based self-brazing filler metal in induction brazing of stainless steel pipe fittings and/or brazing of low carbon steel. Compared with the existing brazing filler metal, the same effect is achieved, and the present application does not need to add flux and gas shielded welding, and can save more than half of the brazing filler metal and half of the brazing time.

In order to realize the above-mentioned purpose of the present invention, special adopt following technical scheme:

A ring-shaped nickel-based self-brazing filler metal, mainly made of the following raw materials in parts by weight:

79.5-91.7 parts of nickel-based solder, 0.5-3 parts of B powder, 1.2-11.1 parts of Si powder, 0.3-0.5 parts of thickener and 3-8 parts of water.

Preferably, the mass ratio of the Si powder to the B powder is 2.4-3.7.

Preferably, the particle size of the Si powder is 250-325 mesh;

Preferably, the particle size of the Si powder is 270-300 mesh.

Preferably, the particle size of the B powder is 300-500 mesh;

Preferably, the particle size of the B powder is 325-400 mesh.

Preferably, the nickel-based solder includes at least one of BNi74CrSiB, BNi82CrSiB, BNi92SiB and BNi95SiB;

Preferably, the particle size of the nickel-based solder is 250-325 mesh;

More preferably, the particle size of the nickel-based solder is 270-300 mesh;

Preferably, the thickener includes hydroxypropyl starch.

Preferably, the ratio of the inner diameter to the outer diameter of the annular nickel-based self-brazing filler metal is (5-8): (10-12).

The preparation method of ring-shaped nickel-based self-brazing filler metal as mentioned above may further comprise the steps:

The mixture of nickel-based solder, Si powder, B powder, thickener and water is put into a mold provided with an annular groove to form a ring-shaped blank, and the ring-shaped blank is dried.

Preferably, the drying temperature is 80-120° C., and the drying time is 1.5-3 hours.

Preferably, the drying temperature is 90-100° C., and the drying time is 1.8-2.5 hours.

Application of the ring-shaped nickel-based self-brazing filler metal as described above in induction brazing of stainless steel pipe fittings and/or brazing of low carbon steel.

Compared with prior art, the beneficial effect of the present invention is:

(1) A ring-shaped nickel-based self-brazing filler metal of the present invention does not contain flux components, and through the cooperation of Si and B components, the nickel-based filler metal has excellent self-brazing performance.

(2) The preparation method of a ring-shaped nickel-based self-brazing filler metal of the present invention has the advantages of simple operation, high production efficiency and low cost, and overcomes the difficult problem that the nickel-based filler metal is difficult to make into a ring.

(3) a kind of ring-shaped nickel-based self-brazing filler metal of the present invention can realize the flux-free brazing of stainless steel pipe fittings under atmospheric environment, compared with the brazing paste of prior art, reach the same effect, the application can save More than half the brazing filler metal, half the time. It also has excellent brazing effect when applied to brazing of ordinary low carbon steel.

Description of drawings

In order to more clearly illustrate the specific implementation of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings that need to be used in the specific implementation or description of the prior art. Obviously, the accompanying drawings in the following description The drawings show some implementations of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative work.

Fig. 1 is the picture of annular nickel-based self-brazing filler metal of the present invention;

Fig. 2 is the mold structural representation that the present invention prepares annular nickel-based self-brazing filler metal;

Fig. 3 is the brazing seam topography figure of the 316L stainless steel pipe that adopts ring-shaped nickel-base self-brazing filler metal in the embodiment of the present invention 5 induction brazing to obtain;

Fig. 4 is the brazing seam topography figure of the 316L stainless steel pipe that adopts existing nickel-based paste solder to obtain;

Fig. 5 is the surface topography figure that adopts annular nickel-base self-brazing filler metal among the present invention to carry out common low carbon steel brazing;

Fig. 6 is a surface topography diagram of ordinary low-carbon steel brazing by using existing nickel-based paste solder.

Reference signs:

1-annular groove, 2-mold base.

Detailed ways

Embodiments of the present invention will be described in detail below in conjunction with examples, but those skilled in the art will understand that the following examples are only for illustrating the present invention, and should not be considered as limiting the scope of the present invention. Those who do not indicate the specific conditions in the examples are carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used were not indicated by the manufacturer, and they were all commercially available conventional products.

According to one aspect of the present invention, the present invention relates to a kind of annular nickel-based self-brazing filler metal, mainly made by the raw material of following parts by weight:

79.5-91.7 parts of nickel-based solder, 0.5-3 parts of B powder, 1.2-11.1 parts of Si powder, 0.3-0.5 parts of thickener and 3-8 parts of water.

The annular nickel-based self-brazing filler metal of the present invention can realize the self-brazing of the brazing filler metal, the quantitative and automatic addition of the brazing filler metal through the cooperation of each component, does not waste materials, is suitable for automatic brazing, and makes the welding material obtain Excellent welding performance.

The elements acting as self-brazing in the present invention are Si and B. Si and B can not only reduce the melting temperature of nickel-based solder alloy, but also are strong reducing agents. At brazing temperatures, the oxides they produce are more stable than those produced by elements such as nickel, cobalt, and iron. Therefore, Si and B elements have a strong deoxidation and reduction effect on the oxides of nickel, cobalt, iron and other elements. Si, B react with oxygen to produce B ₂ O ₃ and SiO ₂ respectively. The melting point _{of B2O3} is 580°C and that of _SiO2 is 1713°C. B ₂ O ₃ is boron anhydride, which is the main component of brazing flux. It can form fusible borate with oxides of copper, zinc, nickel and iron. In theory, it can achieve film removal and protection. However, B ₂ Although the melting point of O ₃ is low, its viscosity is high and its fluidity is not good. The formed oxide slag is difficult to float out of the surface, thus deteriorating the self-brazing performance of the solder. The research found that when B ₂ O ₃ and SiO ₂ exist at the same time, they can form borosilicate with low melting point with oxides of copper, zinc, nickel and iron. This borosilicate has low viscosity and low density. The fluidity is good, and the oxidized slag produced is easier to float out of the alloy surface, so that the brazing surface is protected, so that the brazing filler metal can flow and fill the joints, thereby completing flux-free brazing.

In one embodiment, the nickel-based solder is 79.5 to 91.7 parts, and 80 parts, 80.5 parts, 81 parts, 81.5 parts, 82 parts, 82.5 parts, 83 parts, 83.5 parts, 84 parts, 84.5 parts can also be selected. parts, 85 parts, 85.5 parts, 86 parts, 86.5 parts, 87 parts, 87.5 parts, 88 parts, 88.5 parts, 89 parts, 89.5 parts, 90 parts, 90.5 parts, 91 parts or 91.5 parts.

In one embodiment, the B powder is 0.5-3 parts, and 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts or 3 copies.

In one embodiment, the Si powder is 1.2 to 11.1 parts, 1.2 parts, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8, 9, 10, 11 or 11.1 servings.

In one embodiment, the thickener is 0.3-0.5 parts, and 0.32 parts, 0.34 parts, 0.35 parts, 0.36 parts, 0.37 parts, 0.38 parts, 0.4 parts, 0.42 parts, 0.45 parts, 0.46 parts can also be selected. parts, 0.47 parts, 0.48 parts or 0.49 parts.

In one embodiment, the amount of water is 3-8 parts, and 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts or 8 parts can also be selected.

The mass ratio of the Si powder to the B powder is 2.4-3.7.

In a preferred embodiment, the mass ratio of the Si powder to the B powder is 2.4 to 3.7, and 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4 can also be selected. , 3.5, 3.6 or 3.7.

From the binary phase diagram of B ₂ O ₃ and SiO ₂ , it can be seen that when the content of SiO ₂ is 60% to 70%, that is, when the mass ratio of Si powder to B powder is kept between 2.4 and 3.7, the two formed The melting temperature of borosilicate is around 800-1000°C. At this time, matching the brazing temperature of nickel-based solder at 980-1050°C can make nickel-based solder have the best self-brazing performance.

Preferably, the particle size of the Si powder is 250-325 mesh.

More preferably, the particle size of the Si powder is 270-300 mesh.

Preferably, the nickel-based solder includes at least one of BNi74CrSiB, BNi82CrSiB, BNi92SiB and BNi95SiB.

BNi74CrSiB (BNi-1) is mainly used for brazing of high-temperature alloys, stainless steel, hard alloys, etc. It is corrosion-resistant, has high strength at high temperatures, and has good penetration. base, chromium base, iron base, etc.

During the brazing process, BNi82CrSiB (BNi-2) solder has low melting temperature and good wettability, and the formed brazed joint has good high temperature strength, excellent oxidation resistance and corrosion resistance. .

BNi92SiB (BNi-3) is an ultra-high temperature resistant brazing material, which is very suitable for high-demand connection brazing, and has excellent connection performance even for not very good narrow seams and brazing environments.

BNi95SiB (BNi-4) has high strength, high temperature performance and corrosion resistance.

Coordinating with the above-mentioned specific nickel-based solder of the present invention and other components can realize self-brazing of solder, quantitative solder, automatic addition, no waste of material, suitable for automatic brazing, and excellent welding performance of the soldering material. Improve brazing efficiency.

Preferably, the particle size of the nickel-based solder is 250-325 mesh.

More preferably, the particle size of the nickel-based solder is 270-300 mesh.

Preferably, the thickener includes hydroxypropyl starch.

Preferably, the particle size of the nickel-based solder is 150-200 mesh;

Preferably, the particle size of the nickel-based solder is 180-200 mesh.

The present invention limits the particle size of the nickel-based solder to be in an appropriate range, and the effect of coordinating with other components is better.

Preferably, the ratio of the inner diameter to the outer diameter of the annular nickel-based self-brazing filler metal is (5-8): (10-12).

The specific ratio of the inner ring diameter to the outer ring diameter of the present invention is more conducive to enhancing the brazing performance of the later-stage brazing material.

In one embodiment, the ratio of the inner diameter to the outer diameter of the annular nickel-based self-brazing filler metal is (5-8): (10-12), and 5:10, 5:12, 6: 10 or 7:10.

The preparation method of annular nickel-based self-brazing filler metal as above, it may further comprise the steps:

The mixture of nickel-based solder, Si powder, B powder, thickener and water is put into a mold provided with an annular groove to form a ring-shaped blank, and the ring-shaped blank is dried.

The preparation method of the annular nickel-based self-brazing filler metal of the invention has the advantages of simple operation, high production efficiency and low cost.

Preferably, the drying temperature is 80-120° C., and the drying time is 1.5-3 hours.

In one embodiment, the drying temperature is 80°C to 120°C, 85°C, 87°C, 90°C, 92°C, 95°C, 98°C, 100°C, 102°C, 105°C, 107°C can also be selected , 110°C, 113°C, 115°C, 117°C or 119°C.

Preferably, the drying temperature is 90-100° C., and the drying time is 1.8-2.5 hours.

In a preferred embodiment, the preparation method of the annular nickel-based self-brazing filler metal comprises the following steps;

(a) Weigh Si powder, B powder, distilled water, hydroxypropyl starch, and solder metal powder, first add solder powder and hydroxypropyl starch to distilled water and stir to make a paste, then add solder metal powder to stir and press Agglomerate materials, set aside;

(b) Get a mold whose surface is provided with an annular groove, and evenly brush one layer of release agent in the groove;

(c) Scraping the dough-shaped material prepared in step (a) into the annular groove in the mold of step (b) with a scraper, flattening, and scraping off excess dough-like material outside the groove;

(d) Buckle the mold upside down on a metal plate covered with a layer of release paper, vibrate gently, and take out ring-shaped solder blanks one by one;

(e) Place the metal plate covered with ring-shaped brazing filler metal in step (d) in an oven and dry to obtain ring-shaped nickel-based self-brazing filler metal; the drying temperature is 80-120° C., and the drying time is 1.5 ~3h.

The picture of annular nickel-based self-brazing filler metal of the present invention is as shown in Figure 1.

The schematic diagram of the mold structure for preparing annular nickel-based self-brazing filler metal according to the present invention is shown in FIG. 2 .

Application of the ring-shaped nickel-based self-brazing filler metal as described above in induction brazing of stainless steel pipe fittings and/or brazing of low carbon steel.

Compared with the brazing paste in the prior art, the same effect is achieved. The present application does not contain flux components, and can save more than half of the brazing filler metal and half of the time. The ring-shaped nickel-based self-brazing filler metal of the present invention also has excellent brazing effect when it is applied to the brazing of ordinary low-carbon steel.

The present invention will be further explained below in conjunction with specific examples.

Example 1

A ring-shaped nickel-based self-brazing filler metal, mainly made of the following raw materials in parts by weight:

91.7 parts of nickel-based solder, 0.5 parts of B powder, 1.2 parts of Si powder, 0.3 parts of thickener and 3 parts of water;

The mass ratio of the Si powder to the B powder is 2.4;

The nickel-based solder is BNi74CrSiB;

The thickener is hydroxypropyl starch;

The ring inner diameter of the nickel-based self-brazing filler metal is Φ8mm, the outer diameter of the ring is Φ16mm, and the wire diameter is Φ4mm.

The preparation method of described annular nickel-based self-brazing filler metal, comprises the following steps:

(a) Weigh Si powder, B powder, distilled water, hydroxypropyl starch, brazing metal powder, first add hydroxypropyl starch to distilled water and stir to make a paste, then add Si powder, B powder, brazing metal powder and stir , Pressed into a lump material, set aside;

(b) get the mold that a surface is provided with annular groove, as shown in Figure 2, the mold structure of shaped groove comprises annular groove 1 and mold matrix 2; Brush one deck release agent evenly in the groove;

(c) Scraping the dough-shaped material prepared in step (a) into the annular groove in the mold of step (b) with a scraper, flattening, and scraping off excess dough-like material outside the groove;

(d) Buckle the mold upside down on a metal plate covered with a layer of release paper, vibrate gently, and take out ring-shaped solder blanks one by one;

(e) Put the metal plate covered with annular brazing filler metal in step (d) in an oven, and dry to obtain annular nickel-based self-brazing filler metal; the drying temperature is 80° C., and the drying time is 3 hours.

Example 2

A ring-shaped nickel-based self-brazing filler metal, mainly made of the following raw materials in parts by weight:

89.6 parts of nickel-based solder, 1 part of B powder, 2.4 parts of Si powder, 0.4 parts of thickener and 4 parts of water;

Described Si powder and described B powder mass ratio are 2.4;

The nickel-based solder is BNi82CrSiB;

The thickener is hydroxypropyl starch;

The ring inner diameter of the nickel-based self-brazing filler metal is Φ6mm, the outer diameter of the ring is Φ14mm, and the wire diameter is Φ4mm.

The preparation method of described annular nickel-based self-brazing filler metal, comprises the following steps:

(a) Weigh Si powder, B powder, distilled water, hydroxypropyl starch, brazing metal powder, first add hydroxypropyl starch to distilled water and stir to make a paste, then add Si powder, B powder, brazing metal powder and stir , Pressed into a lump material, set aside;

(b) get the mold that a surface is provided with annular groove, as shown in Figure 2, the mold structure of shaped groove comprises annular groove 1 and mold matrix 2; Brush one deck release agent evenly in the groove;

(c) Scraping the dough-shaped material prepared in step (a) into the annular groove in the mold of step (b) with a scraper, flattening, and scraping off excess dough-like material outside the groove;

(d) Buckle the mold upside down on a metal plate covered with a layer of release paper, vibrate gently, and take out ring-shaped solder blanks one by one;

(e) Put the metal plate covered with ring-shaped brazing filler metal in step (d) in an oven, and dry to obtain ring-shaped nickel-based self-brazing filler metal; the drying temperature is 120° C., and the drying time is 1.5 h.

Example 3

A ring-shaped nickel-based self-brazing filler metal, mainly made of the following raw materials in parts by weight:

87.5 parts of nickel-based solder, 1.5 parts of B powder, 3.6 parts of Si powder, 0.5 parts of thickener and 5 parts of water;

Described Si powder and described B powder mass ratio are 2.4;

The nickel-based solder is BNi92SiB;

The thickener is hydroxypropyl starch;

The ring inner diameter of the nickel-based self-brazing filler metal is Φ5mm, the outer diameter of the ring is Φ15mm, and the wire diameter is Φ5mm.

The preparation method of the annular nickel-based self-brazing filler metal, except that the drying temperature is 90° C. and the drying time is 2 hours, other operating steps are the same as in Example 1.

Example 4

A ring-shaped nickel-based self-brazing filler metal, mainly made of the following raw materials in parts by weight:

85.7 parts of nickel-based solder, 2 parts of B powder, 6 parts of Si powder, 0.3 parts of thickener and 6 parts of water;

The mass ratio of the Si powder to the B powder is 3;

The nickel-based solder is BNi95SiB;

The thickener is hydroxypropyl starch;

The ring inner diameter of the nickel-based self-brazing filler metal is Φ6mm, the outer diameter of the ring is Φ14mm, and the wire diameter is Φ4mm.

The preparation method of the annular nickel-based self-brazing filler metal is the same as in Example 1.

Example 5

A ring-shaped nickel-based self-brazing filler metal, mainly made of the following raw materials in parts by weight:

82.6 parts of nickel-based solder, 2.5 parts of B powder, 8.75 parts of Si powder, 0.4 parts of thickener and 7 parts of water;

Described Si powder and B powder mass ratio are 3.5;

The nickel-based solder is BNi95SiB;

The thickener is hydroxypropyl starch;

The ring inner diameter of the nickel-based self-brazing filler metal is Φ7mm, the outer diameter of the ring is Φ13mm, and the wire diameter is Φ3mm.

The preparation method of the annular nickel-based self-brazing filler metal is the same as in Example 1.

Example 6

A ring-shaped nickel-based self-brazing filler metal, mainly made of the following raw materials in parts by weight:

79.5 parts of nickel-based solder, 3 parts of B powder, 11.1 parts of Si powder, 0.5 parts of thickener and 8 parts of water;

Described Si powder and B powder mass ratio are 3.7;

The nickel-based solder is BNi82CrSiB;

The thickener is hydroxypropyl starch;

The ring inner diameter of the nickel-based self-brazing filler metal is Φ6mm, the outer diameter of the ring is Φ14mm, and the wire diameter is Φ4mm.

The preparation method of the annular nickel-based self-brazing filler metal is the same as in Example 1.

Experimental example 1

At present, in order to weld complex components, it is sometimes necessary to make nickel-based solder paste from nickel-based solder. The conventional preparation method of existing nickel-based solder paste is as follows: take 5-15 parts by weight of ethyl cellulose , 15-60 parts of terpineol, 2-10 parts of hydrogenated castor oil, 2-15 parts of butyl carbitol, 2-8 parts of sorbitan monostearic acid, 2-6 parts of cellulose alkyd butyrate , fully stirred and left to stand to prepare a transparent organic binder for later use; then weigh 15-30 parts of organic binder, 60-80 parts of nickel-based solder powder, and 5-15 parts of CaF ₂ , pour them into a container, Stir evenly, then prepare nickel-based solder paste.

In order to investigate the brazing efficiency and the amount of brazing material between the brazing material of the present invention and the existing nickel-based brazing paste, two kinds of brazing filler metals were used to carry out induction brazing tests on 316L stainless steel pipe fittings. Under the premise of ensuring the same brazing effect of each pipe fitting as far as possible, 50 316L stainless steel pipe fittings of the same specification are brazed with two kinds of brazing materials, and the average amount of brazing material, flux and brazing time of each pipe fitting is calculated, as shown in Table 1 below. Show. It can be seen that compared with Example 5 of the present invention, in order to achieve the same welding effect, at least half of the existing nickel-based solder paste needs to be wasted, and the brazing time is doubled. The brazing materials obtained in Examples 1-4 and Example 6 of the present invention also have excellent welding effects, save brazing materials, and improve brazing efficiency.

The brazing seam topography figure of the 316L stainless steel pipe that adopts the ring-shaped nickel-based self-brazing filler metal to obtain in the embodiment of the present invention 5 is as shown in Figure 3; The seam topography is shown in Figure 4.

Table 1 Comparison of brazing efficiency, brazing filler metal dosage, and brazing flux dosage

Experimental example 2

In order to investigate the welding effect of the brazing material of the present invention and the existing nickel-based solder paste on common carbon steel plates, flame brazing tests of common low-carbon steel were carried out with two kinds of brazing materials respectively. The size specification of carbon steel plate is 50mm×50mm×2mm. In order to ensure that the test conditions are the same, the consumption of the nickel-based solder paste is exactly the same as that of the brazing material of the present invention, and two kinds of solder are used to carry out the flame brazing test on the low carbon steel plate of the same specification. After the flame brazing test, compare two kinds of brazing material brazing area size, brazing surface quality, as shown in table 2 below, Fig. 5 adopts ring-shaped nickel-based self-brazing filler metal in the present invention (taking embodiment 5 as example ), and Fig. 6 is a brazing surface topography diagram using an existing nickel-based solder paste (nickel-based solder paste in Experimental Example 1). It can be seen from Table 2, Fig. 5 and Fig. 6 that under the premise of the same amount of solder, the brazing area of the brazing material of the present invention is larger, and the brazing surface quality is better.

Table 2 Brazing effect of ordinary low carbon steel

group Amount of solder/g Brazing area/mm² Brazing Surface Quality Example 5 1.523 325 bright and clean Existing nickel-based solder paste 1.522 96.5 Much slag, not smooth

It should be noted that at last: above each embodiment is only in order to illustrate technical scheme of the present invention, and is not intended to limit; Although the present invention has been described in detail with reference to foregoing each embodiment, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. range.

Claims (14)

1. The annular nickel-based self-brazing solder is characterized by being mainly prepared from the following raw materials in parts by weight:

79.5 to 91.7 parts of nickel-based brazing filler metal, 2.5 to 3 parts of B powder, 8 to 11.1 parts of Si powder, 0.3 to 0.5 part of thickening agent and 3 to 8 parts of water;

the mass ratio of the Si powder to the B powder is 3.1-3.7.

2. The annular nickel-based self-brazing filler metal according to claim 1, wherein the Si powder has a particle size of 250 to 325 meshes.

3. The annular nickel-based self-brazing filler metal according to claim 2, wherein the Si powder has a particle size of 270 to 300 meshes.

4. The annular nickel-based self-brazing filler metal according to claim 1, wherein the particle size of the powder B is 300 to 500 meshes.

5. The annular nickel-based self-brazing filler metal according to claim 4, wherein the particle size of the powder B is 325 to 400 meshes.

6. The annular nickel-based self-brazing filler metal according to claim 1, wherein the nickel-based filler metal comprises at least one of BNi74CrSiB, BNi82CrSiB, BNi92SiB, and BNi95 SiB.

7. The annular nickel-based self-brazing filler metal according to claim 1, wherein the particle size of the nickel-based brazing filler metal is 250 to 325 mesh.

8. The annular nickel-based self-brazing filler metal according to claim 7, wherein the particle size of the nickel-based brazing filler metal is 270 to 300 meshes.

9. The annular nickel-based self-brazing filler metal according to claim 1, wherein the thickener comprises hydroxypropyl starch.

10. The annular nickel-based self-brazing filler metal according to claim 1, wherein a ratio of an inner diameter to an outer diameter of the annular nickel-based self-brazing filler metal is (5 to 8): (10 to 12).

11. The method for preparing the annular nickel-based self-brazing filler metal according to any one of claims 1 to 10, comprising the following steps:

and putting the mixture of the nickel-based brazing filler metal, the Si powder, the B powder, the thickening agent and the water into a die provided with an annular groove for forming to obtain an annular blank, and drying the annular blank.

12. The method for preparing the annular nickel-based self-brazing filler metal according to claim 11, wherein the drying temperature is 80 to 120 ℃, and the drying time is 1.5 to 3 hours.

13. The method for preparing the annular nickel-based self-brazing filler metal according to claim 12, wherein the drying temperature is 90 to 100 ℃ and the drying time is 1.8 to 2.5 hours.

14. Use of the annular nickel-based self-brazing filler metal according to any one of claims 1 to 10 in induction brazing of stainless steel pipes or brazing of low carbon steel.

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