Process for preparing nano-scale tungsten carbide powder

Abstract

The invention discloses a process for preparing nano-scale tungsten carbide powder, belonging to the technical field of shield cutters. The process for preparing nano-scale tungsten carbide powder disclosed by the invention comprises the following steps: 1, mixing, namely mixing 55-60wt% of an aqueous solution of ammonium metatungstate and nanometer carbon black powder, uniformly stirring into fluid, adding the fluid into a mold, and performing compression molding to obtain a precursor; 2, carrying out deep freezing, namely rapidly transferring the precursor into a deep freezing space for performing rapid deep freezing, wherein the temperature is 150-160 DEG C below zero, and the time is 200-240 minutes; 3, freezing, namely rapidly transferring the rapidly frozen precursor into a vacuum freezing drying storehouse to be frozen; 4, carbonizing, namely closing a cold trap of the vacuum freezing drying storehouse, raising the temperature to 900-1200 DEG C, and carrying out carbonization reduction reaction to obtain a nano tungsten carbide block; and 5, grinding, namely grinding the nano tungsten carbide block into nano tungsten carbide powder by using a grinder. According to the process disclosed by the invention, the problem that the shield cutter is poor in wear resistance and impact resistance is solved.

Description

[0001] The application of the present invention is a divisional application, the application number of the parent application: 2017109271549; the name of the parent application: a manufacturing process of plasma arc surfacing welding of tungsten carbide cutter rings for shield cutters; the application date of the parent application: 2017-09-30. technical field

[0002] The invention relates to the technical field of shield cutting tools, in particular to a manufacturing process of nanoscale tungsten carbide powder. Background technique

[0003] At present, major cities in my country are constructing rail transit projects vigorously. Due to its incomparable advantages, the shield method has been widely used in the construction of rail transit tunnels. With the continuous construction and densification of the line, shield tunneling encounters underground obstacles such as pile foundations of existing buildings (structures) from time to time. Since the existing shield cutting t...

Examples

Embodiment 1

[0039] The manufacturing process of the plasma arc surfacing welding tungsten carbide cutter ring for the shield cutter of this embodiment, the steps applied to the shield cutter are as follows:

[0040] Step 1. Use the plasma arc as the heat source, and the temperature is above 3500°C. The powder feeder supplies the powder to the surfacing gun and blows it into the arc. The high temperature generated by the plasma arc is used to rapidly heat the tungsten carbide nanopowder and the outer edge surface of the knife ring. Together with melting, mixing, diffusion, with the relative movement of the surfacing gun and the knife ring body, the liquid alloy gradually solidifies after the plasma arc leaves, forming a wear-resistant surfacing layer with a thickness of 3mm;

[0041] Step 2. Flip the knife ring body, repeat step 1 to deposit a wear-resistant surfacing layer on the other side of the outer edge of the knife ring.

[0042]The manufacturing process of the plasma arc surfacing ...

Embodiment 2

[0044] The manufacturing process of the plasma arc surfacing welding tungsten carbide cutter ring for the shield cutting tool of this embodiment, the basic steps are the same as that of embodiment 1, the difference and improvement are: the surfacing gun is a 3D manipulator surfacing gun; the wear-resistant surfacing layer Thickness is 3~5mm, is 5mm in the present embodiment; The width of the outer edge of the knife ring is 1 / 6~1 / 5 of the diameter of the knife ring body, in the present embodiment, the diameter of the knife ring body is 432mm, and the outer edge of the knife ring The width of the edge is 72mm, and the thickness is 20mm; the manufacturing process of the nanoscale tungsten carbide powder is:

[0045] Step 1: Mixing: Mix 55%wt% ammonium metatungstate aqueous solution and nano-carbon black powder, the ratio is 1:0.05, stir evenly to form a fluid, add it to the mold and press to form a precursor, the purpose is to fix tungsten sources and carbon sources;

[0046] St...

Embodiment 3

[0058] The manufacturing process of the plasma arc surfacing welding tungsten carbide cutter ring for the shield cutting tool of this embodiment, the basic steps are the same as that of embodiment 2, the difference and improvement are: the thickness of the wear-resistant surfacing layer is 5mm; the cutter ring The width of the outer edge is 1 / 5 of the diameter of the knife ring body, and the diameter of the knife ring body is 432mm.

[0059] The production process of nanoscale tungsten carbide powder is:

[0060] Step 1: Mixing: mix 60%wt% ammonium metatungstate aqueous solution and nano-carbon black powder, the ratio is 1:0.1, stir evenly to form a fluid, add it to the mold and press it to form a precursor, the purpose is to fix tungsten sources and carbon sources;

[0061] Step 2: deep freezing: quickly transfer the precursor into the deep freezing space for rapid deep freezing; the temperature is -150~-160°C, and the time is 200~240min;

[0062] Step 3: Freeze-drying: qui...

[0001] The application of the present invention is a divisional application, the application number of the parent application: 2017109271549; the name of the parent application: a manufacturing process of plasma arc surfacing welding of tungsten carbide cutter rings for shield cutters; the application date of the parent application: 2017-09-30. technical field

[0002] The invention relates to the technical field of shield cutting tools, in particular to a manufacturing process of nanoscale tungsten carbide powder. Background technique

[0003] At present, major cities in my country are constructing rail transit projects vigorously. Due to its incomparable advantages, the shield method has been widely used in the construction of rail transit tunnels. With the continuous construction and densification of the line, shield tunneling encounters underground obstacles such as pile foundations of existing buildings (structures) from time to time. Since the existing shield cutting t...

Examples

Embodiment 1

[0039] The manufacturing process of the plasma arc surfacing welding tungsten carbide cutter ring for the shield cutter of this embodiment, the steps applied to the shield cutter are as follows:

[0040] Step 1. Use the plasma arc as the heat source, and the temperature is above 3500°C. The powder feeder supplies the powder to the surfacing gun and blows it into the arc. The high temperature generated by the plasma arc is used to rapidly heat the tungsten carbide nanopowder and the outer edge surface of the knife ring. Together with melting, mixing, diffusion, with the relative movement of the surfacing gun and the knife ring body, the liquid alloy gradually solidifies after the plasma arc leaves, forming a wear-resistant surfacing layer with a thickness of 3mm;

[0041] Step 2. Flip the knife ring body, repeat step 1 to deposit a wear-resistant surfacing layer on the other side of the outer edge of the knife ring.

[0042]The manufacturing process of the plasma arc surfacing ...

Embodiment 2

[0044] The manufacturing process of the plasma arc surfacing welding tungsten carbide cutter ring for the shield cutting tool of this embodiment, the basic steps are the same as that of embodiment 1, the difference and improvement are: the surfacing gun is a 3D manipulator surfacing gun; the wear-resistant surfacing layer Thickness is 3~5mm, is 5mm in the present embodiment; The width of the outer edge of the knife ring is 1 / 6~1 / 5 of the diameter of the knife ring body, in the present embodiment, the diameter of the knife ring body is 432mm, and the outer edge of the knife ring The width of the edge is 72mm, and the thickness is 20mm; the manufacturing process of the nanoscale tungsten carbide powder is:

[0045] Step 1: Mixing: Mix 55%wt% ammonium metatungstate aqueous solution and nano-carbon black powder, the ratio is 1:0.05, stir evenly to form a fluid, add it to the mold and press to form a precursor, the purpose is to fix tungsten sources and carbon sources;

[0046] St...

Embodiment 3

[0058] The manufacturing process of the plasma arc surfacing welding tungsten carbide cutter ring for the shield cutting tool of this embodiment, the basic steps are the same as that of embodiment 2, the difference and improvement are: the thickness of the wear-resistant surfacing layer is 5mm; the cutter ring The width of the outer edge is 1 / 5 of the diameter of the knife ring body, and the diameter of the knife ring body is 432mm.

[0059] The production process of nanoscale tungsten carbide powder is:

[0060] Step 1: Mixing: mix 60%wt% ammonium metatungstate aqueous solution and nano-carbon black powder, the ratio is 1:0.1, stir evenly to form a fluid, add it to the mold and press it to form a precursor, the purpose is to fix tungsten sources and carbon sources;

[0061] Step 2: deep freezing: quickly transfer the precursor into the deep freezing space for rapid deep freezing; the temperature is -150~-160°C, and the time is 200~240min;

[0062] Step 3: Freeze-drying: qui...