CN110682030A

CN110682030A - Vacuum brazing solder for nickel-based diamond thin-wall drill bit and diamond tapper

Info

Publication number: CN110682030A
Application number: CN201911112343.6A
Authority: CN
Inventors: 童筱钧; 杨振楠
Original assignee: Changzhou Institute of Technology
Current assignee: Changzhou Institute of Technology
Priority date: 2019-11-14
Filing date: 2019-11-14
Publication date: 2020-01-14

Abstract

The invention discloses a vacuum brazing solder for a nickel-based diamond thin-wall drill bit and a diamond tapper, which comprises the following components in percentage by weight: ni 70-81%, Cr 10-14%, Fe 2-6%, Si 2-4%, B1.5-3.5%, and W0.5-2.5%. The brazing method is used for vacuum brazing of the diamond thin-wall drill bit and the diamond tapper, can obtain higher welding strength, has small welding internal stress, reduces the rate of cracks generated by the diamond, and prolongs the service life of the tool.

Description

Vacuum brazing solder for nickel-based diamond thin-wall drill bit and diamond tapper

Technical Field

The vacuum brazing solder is used for the vacuum brazing solder of diamond thin-wall drill bits and diamond tappers.

Background

The diamond thin-wall drill bit and the diamond hole digger are mainly used for punching on hard articles with higher surface hardness, such as jade, rock, ceramic tile, ceramic, glass and the like.

Because the hardness of diamond microparticles on the surfaces of the diamond thin-wall drill bit and the diamond hole opener is higher than that of ceramics and glass, the drilling operation can be completed on the articles with higher hardness.

When drilling, the diamond thin-wall drill bit and the diamond hole digger always spray water to the working medium to reduce the temperature in order to reduce the temperature. Otherwise, the holding force of the solder to the diamond microparticles is reduced due to the temperature rise, so that the diamond microparticles fall off greatly, and the service life of the hole opener and the drill bit is shortened. Besides the influence of the diamond soldering process, the diamond particles fall off early, and the first reason is that the working temperature of the silver-based solder and the copper-based solder is originally low, and the second reason is that the holding force of the silver-based solder and the copper-based solder is smaller than that of the nickel-based solder.

The diamond brazing solder is mainly divided into three types, namely copper-based solder, nickel-based solder and copper-based solder. The solder components are Cn-Sn-Ti, Ag-Cu-Ti, Ni-Cr, etc.

Cn-Sn-Ti, Ag-Cu-Ti element Ti (3-8%) is generated by adding strong carbide to generate Ti_xC_yThe compound bonds the diamond to the solder. However, the Ti has extremely high activity and is easy to oxidize in air to lose efficacy, the addition amount is too small and cannot play a corresponding role, and the excessive addition amount can cause excessive reaction to cause excessive welding internal stress to cause diamond cracks.

Chinese patent application No. 201210564857.7 discloses an AgCuTiSi silver-based vacuum brazing solder formulation, wherein the silver content is 60% to 71%, and the cost is high. Chinese patent application nos. 201610532403.X, 201510525911.0 disclose ag-based solder and solder paste, respectively, based on AgCuZn, which are unsuitable for soldering under vacuum because the components including Zn volatilize in a large amount under vacuum, thus affecting the use and soldering effect. Chinese patent with application number 201010174482.4 discloses a Ni-based vacuum brazing solder with the contents of Ni 83-90% of Cr 3-7% of B3%, which is mainly used for hot-pressing one-step forming of large diamond particles to form a multi-layer brazing diamond drill bit. Experiments show that when the brazing filler metal is applied to diamond micro-particle vacuum brazing of a non-hot pressing process, the wettability and the bonding strength between diamond micro-particles and a solder are insufficient, and the climbing of the solder is low.

Disclosure of Invention

In order to reduce the cost of the brazing solder, improve the brazing effect, increase the holding force of the solder on diamond particles at high temperature and control cracks of the diamond particles after vacuum welding, the invention properly adjusts the NiCr brazing filler metal and prepares the amorphous brazing filler metal. Aiming at the defects of the existing welding flux, the invention provides the nickel-based diamond brazing welding flux, which is used for welding diamond microparticles to the surface of a billet of a thin-wall drill or a hole opener in vacuum, so that the holding force of the diamond microparticles is improved, and the number of cracks of the diamond microparticles is reduced.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the vacuum brazing solder for the nickel-based diamond thin-wall drill bit and the diamond tapper comprises the following components in percentage by weight: ni 70-81%, Cr 10-14%, Fe 2-6%, Si 2-4%, B1.5-3.5%, and W0.5-2.5%.

Furthermore, the brazing solder comprises the following components in percentage by weight: ni 81%, Cr 10%, Fe 2%, Si 2%, B3% and W2%.

Furthermore, the brazing solder is mainly made of Ni-Cr alloy, and Fe, Si2, B and W are added.

Further, the diamond microparticles are welded on the surface of the billet of the thin-wall drill and the hole opener in vacuum through the brazing solder.

Further, the brazing filler metal powder is mixed with a binder and made into a paste form for use.

Furthermore, the crack of the diamond micro-particles is reduced by 30 to 40 percent by adopting the vacuum thin-wall drill welded by the welding flux.

The invention has the following outstanding advantages:

the brazing method is used for vacuum brazing of the diamond thin-wall drill bit and the diamond tapper, can obtain higher welding strength, has small welding internal stress, reduces the rate of cracks generated by the diamond, and prolongs the service life of the tool.

Detailed Description

The present invention will be further described with reference to the following examples.

The invention provides a nickel-based solder in a vacuum environment for solving various problems of brazing in air. The method hopes that the steel matrix is connected with the diamond in a brazing mode, and diamond microparticles are prevented from falling off and cracking in the drill hole.

The diamond has high interface energy with common metal and alloy thereof, so that the diamond cannot be infiltrated by common low-melting-point alloy, and the weldability is extremely poor. At present, the weldability between diamond and metal is mainly improved by adding strong carbide such as Ti and Cr into alloy solder to form carbon compound or by metallizing the surface of diamond.

The nickel has high melting point, excellent oxidation resistance and corrosion resistance, good plasticity and high strength.

When the chromium equivalent is 6 to 20 percent, the nickel-chromium alloy can form a Ni-Cr solid solution with nickel, and the heat strength, oxidation resistance and corrosion resistance of the nickel are improved. The wettability of the brazing filler metal can be improved along with the increase of the chromium content; when the content of chromium is more than 16%, the wettability is reduced as the content of chromium is increased. In addition, chromium can also change the precipitation and distribution of sulfide central impurities in the brazing seams.

Boron can greatly reduce the melting point of nickel, thereby improving the wettability of the brazing filler metal and improving the fluidity. Along with the increase of the boron content in the brazing filler metal, the corrosion of the brazing filler metal to the base metal is greatly increased. The boron has extremely low solubility in nickel, can diffuse into a crystal boundary during brazing, strengthens the crystal boundary, and can improve the remelting temperature of the brazing filler metal after being separated from a brazing filler metal system. However, the content of boron is too high, and the inkstone brittle phase can be formed in the brazing seam. Therefore, the content of the strain in the filler metal should be controlled within a proper range.

When the silicon content is 2 to 5 percent, the high-temperature strength of the brazing filler metal is not greatly influenced; when the content is too high, the high temperature strength of the solder is lowered, and the wettability of the solder is best when the silicon content is in the range of 3 to 5%. Therefore, the silicon content in the common needle material is controlled below 5 percent most.

Carbon can lower the melting point of nickel and increase the strength of the solder, but the effect is weaker. Carbon has little effect on the wettability of the solder. Diffusion of carbon into the base metal increases strength and hardness, causing a decrease in plasticity and corrosion resistance. Therefore, the carbon content of the brazing material is generally controlled to 0.5% or less, except for the brazing of heavy members.

The iron in the iron solder is usually brought in by harmless impurities, and can improve the mechanical property of a brazing seam, but when the content is too high, the high-temperature nitriding resistance of the solder is reduced, and the iron is generally controlled in a certain range.

Tungsten is a high melting point metal (3830oC) and belongs to a solid solution strengthening element. After tungsten enters NiCr solid solution, the recrystallization temperature of the brazing seam is increased, stable carbide can be precipitated, and the high-temperature strength of the brazing seam is improved. After tungsten enters Ni-Cr solid solution, the recrystallization temperature of the brazing seam is increased, stable carbide can be precipitated, and the high-temperature strength of the brazing seam is improved. The iron in the brazing filler metal is usually brought by harmless impurities, and can improve the mechanical property of a brazing seam, but when the content is too high, the high-temperature oxidation resistance of the brazing filler metal is reduced, and the high-temperature oxidation resistance is generally controlled in a certain range.

In conclusion, the nickel-based brazing filler metal containing Ni, Cr, Si, B, C, Fe and W has a complex multiphase structure and low vapor pressure, and is particularly suitable for brazing in a vacuum atmosphere. Through repeated adjustment, a diamond brazing solder is provided, and the brazing solder comprises the following components, by weight, Ni 70-81%, Cr 10-14%, Fe 2-6%, Si 2-4%, B1.5-3.5%, and W0.5-2.5%.

ー the preferable scheme is that the brazing solder comprises the components of Ni 81%, Cr 10%, Fe 2%, Si 2%, B3% and W2% by weight. The single crystal diamond brazing solder in the invention mainly comprises Ni-Cr (Ni 81%, Cr 10%) alloy, Fe 2%, Si 2%, B3% and W2%, and in addition, the melting point of the solder can be effectively reduced, so that the welding can be carried out at a lower temperature.

In production, the brazing solder powder is often mixed with a station-bonding agent and used in the form of a paste.

Example 1:

weighing 1000 g of Ni 81%, Cr 10%, Fe 2%, Si 2%, B3% and W2% respectively, wherein the total weight of Ni810 g, Cr100 g, Fe20 g, Si20 g, B30 g and W20 g, mixing together on a ball mill to form powder, and obtaining the brazing solder of the invention.

Example 2:

weighing 1000 g of Ni 77%, Cr 12%, Fe 3%, Si 4%, B3% and W1% respectively, wherein the Ni770 g, the Cr120 g, the Fe30 g, the Si40 g, the B30 g and the W10 g are mixed together and mixed on a ball mill to form powder, and the brazing solder can be prepared.

According to observation statistics of a vacuum thin-wall drill welded by adopting solders in example 1 and example 2 through a microscope, diamond microparticle cracks are reduced by 34.2% and 41.3% respectively; compared with the drill bit and the hole digger with the same specification sold in the market, the service life (hours) of the drill bit and the hole digger is respectively increased by 31.2 percent and 42.9 percent.

Example 3:

weighing 810 g of Ni, 100 g of Cr, 20 g of Fe, 20 g of Si, 30 g of B and 20 g of W respectively, mixing together, and mixing on a ball mill to form powder to obtain the brazing solder. The brazing solder of the invention can be prepared with the weight percentage contents of 71%, 20%, 1% and 8% respectively.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The vacuum brazing solder for the nickel-based diamond thin-wall drill bit and the diamond tapper is characterized in that: the brazing solder comprises the following components in percentage by weight: ni 70-81%, Cr 10-14%, Fe 2-6%, Si 2-4%, B1.5-3.5%, and W0.5-2.5%.

2. The vacuum brazing filler metal for nickel-based diamond thin-walled drill bits and diamond tappers of claim 1, wherein: the brazing solder comprises the following components in percentage by weight: ni 81%, Cr 10%, Fe 2%, Si 2%, B3% and W2%.

3. The vacuum brazing filler metal for nickel-based diamond thin-walled drill bits and diamond tappers of claim 1, wherein: the brazing solder is mainly Ni-Cr alloy, and Fe, Si2, B and W are added.

4. The vacuum brazing filler metal for nickel-based diamond thin-walled drill bits and diamond tappers of claim 1, wherein: and welding the diamond microparticles to the surface of the billet of the thin-wall drill and the hole opener in vacuum through the brazing solder.

5. The vacuum brazing filler metal for nickel-based diamond thin-walled drill bits and diamond tappers of claim 1, wherein: the brazing solder powder is mixed with a station-bonding agent and made into a paste form for use.

6. The vacuum brazing filler metal for nickel-based diamond thin-walled drill bits and diamond tappers of claim 1, wherein: the diamond micro-particle cracks of the vacuum thin-wall drill welded by the welding flux are reduced by 30 to 40 percent.