KR20020010848A - Material devolperment of Tungsten carbide at wear resistance tool - Google Patents

Abstract

PURPOSE: A method for developing a wear-resistant tool of a cemented carbide alloy is provided to lengthen the life span of a tool by increasing the hardness of a head part and the strength of a body part and to reduce the production unit cost by changing the material for the body part. CONSTITUTION: A method for developing a wear-resistant tool of a cemented carbide alloy comprises the steps of inputting such solvents as hexane, methyl and alcohol with WC, Co and other materials to a cylinder; uniformly mixing the materials by rotating the materials with cemented carbide balls; pressurizing the milled materials in a die after drying; and sintering the material in a vacuum furnace. The hardness, gravity and cut-resistance are determined by the composition of WC and Co and the particular size of WC.

Description

Material development in wear-resistant tools of cemented carbides {Material devolperment of Tungsten carbide at wear resistance tool}

The present invention relates to a tool used for drilling in mining, civil engineering, construction equipment Figure 1 is one of these tools and is a hammer bit used for drilling.

Hammer bit refers to the whole tool consisting of cemented carbide button bit (general standard 19 (D) X 30 (L) mm) and shank as shown in FIG.

Figure 2 is a drilling device equipped with a hammer bit described above is a machine used to drill rock layers during underground development, building foundation work. As shown in FIG. 3, the axis of the hammer bit rotates to drill the rock layer, which is subjected to extreme wear and impact shear stress. 6-2 is a tool used to thicken an aged asphalt layer with a tool called point attack, and FIG. 6-3 is a cross bitting tool used for mine development.

As such, the rock asphalt mineral is subjected to extreme abrasion impact when the tool is rotated, punched, etc., so the tool must have high hardness and high strength. Cemented carbide bit with such characteristics is widely used, and suitable grades are selected and used according to the type of geological working conditions.

Figure 4 shows the assembly process of the hammer bit and consists of cemented carbide bit and shank. Shank is a general tool steel that is heat-treated and has no direct contact with the skin (rock, asphalt, minerals, concrete), and holds the cemented carbide bit. Therefore, the cemented carbide bit and the shank are made separately and the cemented carbide bit is cold pressed into the shank as shown in FIG. 4.

An object of the present invention is to increase the hardness of the cemented carbide bit into the shank to extend the life of the tool and to reduce the manufacturing cost through structural improvement. For this purpose, the material of cemented carbide was dualized (貳元 化), which means that the material consists of two kinds in one bit. This is because the purpose of the head part and the body of the button bit in Figure 4-1 is different. The head part is practically required to stiffen the hard workpiece, so it is required to have high hardness and the body part is combined with the shank to absorb shocks. The materials for these two uses are clearly different and can only be achieved by man-made tool restructuring. Conventional tools consisted of only one material, which solves this problem.

Fig. 1-Appearance of Hammabit

Figure 2-Drilling equipment picture

3-The working diagram of Hammabit

Figure 4-Composition of Hammabit

Head-It is also called crown because it is like a crown and determines the life of the tool.

Body-refers to the whole under the head

5-manufacturing process of cemented carbide

Figure 6-Types of wear resistant carbide tools

Figure 7-Press Workflow

Figure 5 shows the manufacturing process of cemented carbide, the characteristics of each process are as follows.

. Blended-WC, Co, other raw materials and solvents (hexane, methyl alcohol) are added together.

. Mill ring-Rotates in a cylinder like a carbide ball to ensure uniform mixing between raw materials.

. Press-milled raw material is pressed in a mold after drying.

. Sintering-refers to the bonding between metal raw materials by applying heat, usually work in a vacuum furnace.

Processes relevant to the present invention are compounding and pressing processes. The biggest factors that determine the hardness, specific gravity, and drag force of the tool were the composition (WC, Co) and WC particle size, and the characteristics were compared in Example 1.

4-1 is a typical cemented carbide bit called a button bit used in the drilling equipment can be divided into the head body portion. According to Figure 3 where the contact with the workpiece is the head portion and the body portion serves to fix the cemented carbide bits to the shank. Therefore, the life of the tool can be determined as the head among the cemented carbide bits. The higher the hardness, the more favorable the body, and the longer the material, the longer the life of the tool. As such, the head part is made of a material of high hardness, but the body part is made of a material having high hardness, but is most ideal, and the material properties of the cemented carbide according to the present invention are as follows.

<Example. 1>

Longitudinal ranking: G2> G1> G3

Intensity ranking (Glass force): G3> G1> G2

Hardness is the highest in G2, but when used as a single grade of G2, the hardness is not so low that the tool life does not come out of normal life. On the other hand, when used as a single grade G3, the strength is high but the hardness is also shortened the tool life. In the present invention, G2 having the highest hardness and G3 having the highest strength in the head part are configured in the body part.

The manufacturing method of this structure is made in the press process of FIG.

1) Mold-Mold designed with 18-20% shrinkage

2) Charge G1 raw material (60 Mesh screen) first.

3) Cover G2 raw material (80 Mesh screen) horizontally on G1 raw material and be careful not to tilt too much to one side.

4) Charge the upper punch mold and apply the load 1000-2000 Kgf / Cm ²

5) Raise the lower punch and deodorize the product.

According to the present invention, the lifespan of carbide tools used in mining, civil engineering, and construction work is improved by 1.5-2.0 times compared to the conventional one, and the manufacturing cost of the tool body is reduced by 50% by using soft scrap.

Claims (2)

On a tool of the shape illustrated in FIG. 6 (quantity 10-2000 g) Cemented carbide products by the method of Fig. Cemented carbide products used in claim 1