阅读说明：本技术 一种硬质合金刀具的无钎剂钎焊方法 (Brazing flux-free brazing method for hard alloy cutter ) 是由 龙伟民 钟素娟 黄俊兰 裴夤崟 程亚芳 李永 周许升 聂孟杰 于 2021-08-12 设计创作，主要内容包括：本发明属于钎焊方法领域,具体涉及一种硬质合金刀具的无钎剂钎焊方法。该方法包括以下步骤：(1)装配钢基体、银基钎料和硬质合金,形成构件；(2)准备一可密封空间,可密封空间设置有与外部环境连通的开口,可密封空间内放置有吸氢钯粉,将步骤(1)的构件置于可密封空间内,加热使吸氢钯粉释放出氢气,由氢气将可密封空间内的空气由所述开口赶出,然后进行钎焊。本发明将吸氢钯粉和刀具工件同时置于可密封空间,利用吸氢钯粉释放氢气将空间内部替换为氢气氛围,然后进行钎焊作业,该方法相对整体气保护法,对操作和设备的要求低,非常适于实际生产。(The invention belongs to the field of brazing methods, and particularly relates to a brazing flux-free brazing method for a hard alloy cutter. The method comprises the following steps: (1) assembling a steel matrix, silver-based brazing filler metal and hard alloy to form a component; (2) preparing a sealable space, wherein the sealable space is provided with an opening communicated with the external environment, hydrogen-absorbing palladium powder is placed in the sealable space, the component obtained in the step (1) is placed in the sealable space, hydrogen is released from the hydrogen-absorbing palladium powder by heating, air in the sealable space is expelled from the opening by the hydrogen, and then brazing is carried out. The hydrogen-absorbing palladium powder and the cutter workpiece are simultaneously placed in the sealable space, hydrogen is released by the hydrogen-absorbing palladium powder to replace the interior of the space with a hydrogen atmosphere, and then brazing operation is performed.)

1. A brazing flux-free brazing method for hard alloy cutters is characterized by comprising the following steps:

(1) assembling a steel matrix, silver-based brazing filler metal and hard alloy to form a component;

(2) preparing a sealable space, wherein the sealable space is provided with an opening communicated with the external environment, hydrogen-absorbing palladium powder is placed in the sealable space, the component obtained in the step (1) is placed in the sealable space, hydrogen is released from the hydrogen-absorbing palladium powder by heating, air in the sealable space is expelled from the opening by the hydrogen, and then brazing is carried out.

2. The fluxless brazing method for cemented carbide tools according to claim 1, wherein the silver-based brazing filler metal contains Li and P.

3. The brazing method for brazing a cemented carbide tool according to claim 2, wherein the mass ratio of Ag, Li and P in the silver-based brazing filler metal is 50 to 60:0.3 to 0.5:0.03 to 0.05.

4. The fluxless brazing method for cemented carbide tools according to claim 3, wherein the silver-based brazing filler metal consists of the following components in parts by weight: 50.0 to 60.0 parts of Ags, 20.0 to 25.0 parts of Cus, 1.0 to 5.0 parts of Mns, 0.5 to 3.0 parts of Nis, 1.0 to 2.0 parts of Sns, 0.3 to 0.5 part of Lis, and 0.03 to 0.05 part of P.

5. The fluxless brazing method for cemented carbide tools according to claim 1, wherein the opening of the sealable space forms an open end, and the hydrogen-absorbing palladium powder is placed in the sealable space at an end remote from the open end, the member being disposed between the opening and the hydrogen-absorbing palladium powder.

6. The fluxless brazing method for cemented carbide tools according to claim 5, wherein the brazing site of the member is located above the hydrogen-absorbing palladium powder.

7. The fluxless brazing method for cemented carbide tools according to claim 1, wherein the brazing is a local induction brazing for a portion to be welded of the member.

8. The fluxless brazing method for cemented carbide tools according to claim 7, wherein the sealable space is defined by a base plate and a glass cover covering the base plate, and the local induction brazing is performed outside the glass cover.

9. The brazing method for brazing a cemented carbide tool according to claims 1 to 8, wherein the heating is performed at a temperature of 40 ℃ to 60 ℃ at which hydrogen is released from the hydrogen-absorbing palladium powder.

10. The fluxless brazing method for cemented carbide tools according to claims 1 to 8, wherein the brazing temperature is 850 ℃ to 900 ℃.

Technical Field

The invention belongs to the field of brazing methods, and particularly relates to a brazing flux-free brazing method for a hard alloy cutter.

Background

The hard alloy cutter has excellent use performance, so the hard alloy cutter is widely applied to machining of metal materials, nonmetal materials, such as turning, milling, cutting and the like, and can only be used in machining of materials, such as alloy steel, chilled cast iron and the like. The hard alloy tool bit is formed by pressing and sintering WC, TiC, Co and other powder, the tool base body is usually made of carbon steel and stainless steel with good comprehensive performance, and the tool bit and the steel base body are brazed through brazing.

Currently, the common brazing methods for cemented carbide tools are furnace brazing and induction brazing. The brazing in the furnace is integral heating, which easily causes the softening of a steel matrix of the cutter, and the heat treatment is carried out after the brazing, otherwise, the service performance is influenced. The induction brazing can be used for local heating, so that the heat damage of the steel matrix of the cutter is avoided, and the brazing efficiency is high. However, conventional induction brazing of cemented carbide tools requires the use of a brazing flux. This is because the flux is the "head soldier" in the brazing process and plays a role in film removal and flow aid. The main component of the brazing flux is mostly fluoride, gas and residue are easily generated in the brazing process, the environment is polluted, and defects such as a large number of air holes, incomplete penetration, inclusion and the like are easily formed in brazing seams, so that the strength and the reliability of the hard alloy cutter are influenced.

In order to solve the problems of the induction brazing of the hard alloy cutter, the whole gas protection induction brazing is adopted in the related prior art, but the whole brazing process needs to be kept in a protection gas state, so that the operation is inconvenient, and the brazing efficiency and the cost are influenced.

Disclosure of Invention

The invention aims to provide a brazing flux-free brazing method for a hard alloy cutter, which is convenient for realizing brazing flux-free brazing of the hard alloy cutter.

In order to achieve the purpose, the technical scheme of the brazing method without the brazing flux for the hard alloy cutter is as follows:

a brazing flux-free brazing method for hard alloy cutters comprises the following steps:

(1) assembling a steel matrix, silver-based brazing filler metal and hard alloy to form a component;

(2) preparing a sealable space, wherein the sealable space is provided with an opening communicated with the external environment, hydrogen-absorbing palladium powder is placed in the sealable space, the component obtained in the step (1) is placed in the sealable space, hydrogen is released from the hydrogen-absorbing palladium powder by heating, air in the sealable space is expelled from the opening by the hydrogen, and then brazing is carried out.

The method for brazing the hard alloy cutter without the brazing flux has the advantages that the hydrogen-absorbing palladium powder and the cutter workpiece are simultaneously placed in the sealable space, hydrogen is released by the hydrogen-absorbing palladium powder to replace the inside of the space with a hydrogen atmosphere, and then brazing operation is carried out.

Preferably, the silver-based solder contains Li and P. The silver-based brazing filler metal containing Li and P can be used for further deoxidizing in a local micro environment of brazing, so that the brazing quality without brazing flux is further optimized.

More preferably, in the silver-based brazing filler metal, the mass ratio of Ag to Li to P is 50-60: 0.3-0.5: 0.03-0.05. Further preferably, the silver-based solder comprises the following components in parts by weight: 50.0 to 60.0 parts of Ags, 20.0 to 25.0 parts of Cus, 1.0 to 5.0 parts of Mns, 0.5 to 3.0 parts of Nis, 1.0 to 2.0 parts of Sns, 0.3 to 0.5 part of Lis, and 0.03 to 0.05 part of P. The silver-based brazing filler metal is adopted for brazing without brazing flux, so that defects of pores, inclusions and the like in a brazing seam of the obtained cutter are few, and the strength of the brazing seam is high.

Preferably, the opening of the sealable space forms an open end, and the hydrogen-absorbing palladium powder is placed at an end of the sealable space remote from the open end, the member being disposed between the opening and the hydrogen-absorbing palladium powder. More preferably, the brazing site of the member is located above the hydrogen-absorbing palladium powder. The hydrogen density is small, the brazing part of the component is arranged above the hydrogen-absorbing palladium powder, and the component is arranged between the opening and the hydrogen-absorbing palladium powder, so that the deoxidation effect of the brazing part can be further optimized.

Preferably, the brazing is local induction brazing for the part to be welded of the component. More preferably, the sealable space is surrounded by a base plate and a glass cover covering the base plate, and the local induction brazing is performed outside the glass cover.

Preferably, the heating makes the temperature of hydrogen-absorbing palladium powder releasing hydrogen be 40-60 ℃. The time for heat preservation can be selected to be 20-30 s.

Preferably, the temperature of the brazing is 850-900 ℃. Through the two-step heating method, the deoxidation and the brazing are carried out in order, and the brazing process control can be better realized under simpler and more convenient conditions.

Drawings

FIG. 1 is a schematic view of a brazing apparatus for brazing hard metal cutting tools according to the present invention;

FIG. 2 is a braze joint topography using prior art fluxless brazing and the fluxless brazing of example 1, (a) fluxless brazing, (b) fluxless brazing;

in the figure, 1-a sealable space, 2-a lifting platform, 3-a steel substrate, 4-brazing filler metal, 5-a hard alloy tool bit, 6-an inductor and 7-hydrogen-absorbing palladium powder.

Detailed Description

Aiming at the defects of the existing induction brazing under the condition of brazing flux and the induction brazing under the protection of whole gas, the invention develops a brazing flux-free brazing method of a hard alloy cutter, which can overcome the defects of the conventional induction brazing method and enhance the strength and reliability of a brazed joint.

In the invention, a schematic diagram of a soldering flux-free soldering device is shown in fig. 1, a lifting platform 2 is arranged in a sealable space 1 enclosed by a glass cover and a bottom plate, a component consisting of a steel matrix 3, a solder 4 and a hard alloy tool bit 5 is placed on the lifting platform 2, an inductor 6 is sleeved outside the glass cover, and local induction soldering is carried out on a part to be soldered in the glass cover.

The glass cover is cylindrical (can cover the whole welding workpiece; under other implementation conditions, the glass cover can also be square or prismatic), and comprises a left side wall, a right side wall and a cylinder body connected between the left side wall and the right side wall, wherein the middle part of the left side wall is provided with an opening, and hydrogen absorption palladium powder 7 is arranged at a position close to the right side wall. The lifting platform comprises a main body section for placing the components and a lifting section connected to the tail end of the main body section, and the height of the lifting section is higher than that of the main body section. Hydrogen-absorbing palladium powder 7 is placed on the elevated section and below the part to be welded.

When the device works, a proper amount of hydrogen-absorbing palladium powder and a workpiece are placed in a sealed glass cover, and an induction welding machine sensor is sleeved outside the glass cover. Firstly heating to a preheating temperature, releasing hydrogen from the palladium powder, forming a hydrogen atmosphere in the glass cover, and then quickly heating to a brazing temperature, thereby realizing the local gas shield welding induction brazing of the cutter. In addition, the solder used for soldering is a silver-based solder containing Li and P which are better deoxidizing elements and can consume O at the soldering part in the closed space₂The method is favorable for realizing the fluxless brazing of the cutter.

Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.

Concrete embodiment of brazing method without brazing flux for hard alloy cutter

Example 1

In the brazing method of the hard alloy cutter without the brazing flux, the device is used, high-frequency brazing is selected, silver-based brazing filler metal is placed in a steel matrix groove, is assembled with the hard alloy cutter head, and is placed in a closed space. Meanwhile, a proper amount of palladium powder is placed in the closed space, a power supply is started, the palladium powder is heated to a preheating temperature and is kept warm, and hydrogen is released by the palladium powder; and then heating to the brazing temperature, melting, wetting and filling the brazing filler metal, and realizing the brazing without the brazing flux of the cutter.

The silver-based solder is prepared from the following raw materials in parts by mass: 50.0 parts of Ag, 20.0 parts of Cu, 1.0 part of Mn, 0.5 part of Ni, 1.0 part of Sn, 0.3 part of Li and 0.03 part of P.

The hydrogen-absorbing palladium powder is prepared by fully absorbing hydrogen in sponge palladium in a hydrogen absorption furnace at 800 ℃, cooling and taking out.

The method specifically comprises the following steps:

(1) putting sponge palladium into a hydrogen furnace to fully absorb hydrogen, cooling and grinding into powder for later use;

(2) carrying out sand blasting and ultrasonic cleaning on the surfaces to be welded of the steel matrix groove and the hard alloy cutter head matched with the steel matrix groove for later use;

(3) placing the brazing filler metal at the bottom of a steel substrate groove, filling a hard alloy head, and assembling and fixing;

(4) placing the assembled workpiece on a lifting workbench, and adjusting the position of the workbench to enable the part to be welded to be located at a proper heating position of an induction welding machine; placing a proper amount of hydrogen-absorbing palladium powder beside the workbench, and placing the workpiece and the palladium powder in a sealed glass cover;

(5) sleeving an inductor of an induction welding machine outside the glass cover, starting a power supply, heating to a preheating temperature, preserving heat, absorbing hydrogen palladium powder to release a large amount of hydrogen, and discharging air in the glass cover, wherein the cover is in a hydrogen atmosphere; the preheating temperature is 50 ℃, and the heat preservation time is 20S.

(6) And (4) rapidly heating to the brazing temperature, melting, wetting and filling the brazing filler metal, and finishing the tool brazing. The brazing temperature was 880 ℃.

Example 2

The brazing method of the cemented carbide tool of the present example is basically the same as that of example 1, except that: the silver-based solder is prepared from the following raw materials in parts by mass: ag52.0 parts, Cu21.0 parts, Mn2.0 parts, Ni0.8 parts, Sn1.2 parts, Li0.4 parts and P0.04 parts.

Example 3

The brazing method of the cemented carbide tool of the present example is basically the same as that of example 1, except that: the silver-based solder is prepared from the following raw materials in parts by mass: ag54.0 parts, Cu22.0 parts, Mn3.0 parts, Ni1.0 parts, Sn1.4 parts, Li0.5 parts and P0.05 parts.

Example 4

The brazing method of the cemented carbide tool of the present example is basically the same as that of example 1, except that: the silver-based solder is prepared from the following raw materials in parts by mass: ag56.0 parts, Cu23.0 parts, Mn4.0 parts, Ni1.5 parts, Sn1.6 parts, Li0.3 part and P0.03 part.

Example 5

The brazing method of the cemented carbide tool of the present example is basically the same as that of example 1, except that: the silver-based solder is prepared from the following raw materials in parts by mass: ag58.0 part, Cu24.0 part, Mn5.0 part, Ni2.0 part, Sn1.8 part, Li0.4 part and P0.04 part.

Example 6

The brazing method of the cemented carbide tool of the present example is basically the same as that of example 1, except that: the silver-based solder is prepared from the following raw materials in parts by mass: 60.0 parts of Ag60.0 parts of Cu25.0 parts of Mn1.0 parts of Ni3.0 parts of Sn2.0 parts of Li0.5 parts of P0.05 parts of Ni.

In other embodiments of the brazing method without the brazing flux, the appropriate amount of the hydrogen-absorbing palladium powder is selected according to the size of the part to be brazed, the hydrogen atmosphere is ensured to be obtained in the brazing process, the temperature for heating the hydrogen-absorbing palladium powder to release hydrogen can be 40 ℃ or 60 ℃, and the heat preservation time is determined according to the size of the sealed space and can be 8s, 10s and 20 s. The temperature of induction brazing can be generally selected to be about 850 ℃ and 900 ℃.

Second, Experimental example

Experimental example 1

At present, the common brazing method for the hard alloy cutter is brazing flux-containing induction brazing, and in order to examine the comparison effect between the brazing flux-free induction brazing and the brazing flux-containing induction brazing of the invention, the brazing filler metal in the embodiments 1 to 6 is used together with the corresponding brazing flux to perform flux-containing brazing of the hard alloy cutter, and then the brazing filler metal in the embodiments 1 to 6 is used to perform flux-free brazing of the hard alloy cutter according to the steps of the embodiment 1. Comparing the appearance of the brazing seam of the brazed joint of the two tools of brazing with flux and brazing without flux, as shown in figure 2.

As can be seen from the figure, the brazing seam obtained by the fluxless brazing has few defects, slag inclusion and air holes are hardly seen, and the brazing seam has more defects of inclusion and air holes when the flux brazing is carried out.

The 12 cemented carbide tool braze joints were processed into standard shear specimens (according to the regulations of GB/T11364-.

TABLE 2 shear strength of the braze joint

Number of tests	Average shear strength/MPa of soldering seam with soldering flux	Mean shear strength/MPa of brazing flux seam without brazing flux
			Example 1	179.4	228.6
Example 2	200.1	230.5
			Example 3	210.6	238
Example 4	216	245.2
			Example 5	221.6	248.7
Example 6	226.5	252

It can be seen that the strength of the tool seams obtained by brazing without the flux is higher than that obtained by brazing with the flux.

Experimental example 2

The comparison of the environmental protection effects of the brazing filler metal in the embodiment 1 of the invention in the processes of brazing the cutters without the brazing flux and brazing the cutters with the brazing flux is examined, and the brazing flux required by each cutter in the process of brazing the cutters with the brazing flux is 2.3g, the used brazing flux is silver brazing flux 308, and the main components of boric acid, borax, potassium fluoride and the like are serious in smoke generation, volatilize toxic gas and pollute the environment in the brazing process.

Therefore, the brazing without the brazing flux is more environment-friendly than the brazing with the brazing flux, and the requirement of green and environment-friendly manufacturing industry is better met.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.