KR20010060916A - Overlay-welding bare rod containg tungsgen carbide - Google Patents

Abstract

PURPOSE: An overlay welding rod to which a large amount of tungsten carbide is added is provided to manufacture an overlay welding rod having the same abrasion characteristics by using a product substituting carbide powder having a large particle size requiring high manufacturing cost. CONSTITUTION: In an existing tungsten carbide overlay welding rod manufactured by comprising 40 to 80 wt.% of WC, 0 to 10 wt.% of a sum of added amount of Mn, Si and Ni, and 10 to 60 wt.% of Fe containing impurities which is contained in manufacturing Fe, the overlay welding rod to which a large amount of tungsten carbide is added is characterized in that the overlay welding rod is manufactured by using 40 to 60 wt.% of tungsten as a crushed tungsten carbide sintered product.

Description

OVERLAY-WELDING BARE ROD CONTAING TUNGSGEN CARBIDE}

The present invention relates to an overlay electrode in which a large amount of tungsten carbide is added, and more particularly, to an overlay electrode that extends the life of a part by forming a coating layer by oxygen acetylene welding on the surface of a heavy abrasive wear part in an industrial facility.

In general, tungsten carbide has a very good resistance to grinding wear, and the alloy mainly composed of tungsten carbide is used for grinding wear, and the above-mentioned grinding wear is used as a means for extending the life of the component when worn. In acetylene welding, an overlay electrode containing a large amount of tungsten carbide is used for the overlay electrode.

In particular, steel mills are used for wear parts of sinter plants, sintered ore crushers, hammers, scrapers, etc., and tungsten carbide is used by mixing powders having a particle size of 2 μm to 3 μm.

According to Japanese Patent Laid-Open Publication No. 61-219497 related to the manufacture of overlay electrodes described above, it is easy to manufacture a mixture of tungsten carbide prepared by a large-sized casting process and tungsten carbide of a small particle size. In general, it is known to include a wide range of particle sizes in terms of wear resistance.

Tungsten carbide powder of small particle size in the above description can be easily obtained as a material widely used for powder metallurgy. However, carbide particles of large particle size are difficult to obtain in limited use, and the manufacturing cost is high, resulting in an increase in the manufacturing cost of the overlay electrode.

Therefore, the technical problem to be achieved by the present invention is to manufacture an overlay electrode having the same wear characteristics by using a carbide powder substitute having a large particle size that requires a high manufacturing cost to solve the above problems.

1 is an overlay layer organization chart when using a welding electrode according to the present invention

Figure 2 is an overlay layer organization chart when using a welding rod according to the conventional method

In order to achieve the above technical problem, an overlay electrode is manufactured by using a relatively inexpensive crushed tungsten powder in place of an expensive particle tungsten powder, and the weight ratio is WC: 40 to 80%, Mn, Si, In the conventional method of manufacturing a tungsten carbide overlay electrode, in which the total content of Ni is 0 to 10%, the iron containing impurities contained in the production of iron is composed of 10 to 60%, and 40% to 60% by weight of the WC. It consists of manufacturing a tungsten carbide overlay electrode using the crushed tungsten carbide sintered article.

Hereinafter will be described in detail.

WC is the most important component to have abrasion resistance, which is the purpose of overlay welding material, and when it is added below 40% by weight, the wear resistance is sharply decreased, so it is less effective as a wear-resistant material. It is not desirable to break.

Therefore, the amount of WC added was limited to 40 to 80%. In addition, the particle size of WC is known to have a wide range of 2 ~ 3000㎛ It is known that the appropriate size of the reinforcement, such as WC, depending on the size of the abrasive particles and the contact pressure in the wear abrasion, in actual use in general It is desirable to have a wide particle size distribution of the WC because the size is not constant, fluctuates and the contact pressure is not constant.

Therefore, most of the overlay welding material including WC has a wide range of particle size distribution, and in the present invention, a powder mixed with fine WC of 3 to 20 μm and WC having coarse particles of 100 to 300 μm is filled into the electrode.

The mixing ratio of coarse WC and fine WC is known to be influenced by the use environment of the target overlay-grown parts, and when the size of the grinding particles is large, the coarse WC ratio is high, and in the opposite case, the fine WC ratio is high and wear resistance Is efficient.

As a result of associating the above contents with the use environment of the target overlay fabricating parts used in steel mills, the ratio of coarse WC is at least 40% to 60% is considered to have effective wear resistance. Limited to%. Mn, Si, etc., when added as an ancillary in the alloying component, is dissolved in the base and plays a role of removing the dissolved oxygen in the molten steel during solidification and solidifying effect, and may be added below 10% if necessary.

Ni is dissolved in the matrix and stabilizes the austenite phase, thereby improving the ductility of the matrix along with Mn. Therefore, it can add in 10% or less of range as needed.

In the above description, the amount of Mn, Si, and Ni added means 10% or less in total. If necessary, Mn and Si are not added when 10% Ni is added. However, Ni is mainly added and a small amount of Mn and Si is added. Is added.

When described in detail by the following examples.

(Example)

Flux cored wires were prepared using alloy powders with different WC particle sizes and then cut to a certain length to produce welding rods.

Of course, a certain proportion of coarse WC powder was made of crushed tungsten, and overlay welding was performed on the SS400 base material by oxygen acetylene welding using a manufactured electrode. Sand was tested with a diameter of 0.15-0.3mm.

In addition, welding and testing were performed under the same conditions using conventional commercially available electrodes, ie, crushed tungsten, to obtain a comparison of the composition and wear amount of the electrode filler as shown in Table 1.

Table 1 Composition and Wear of Welding Rod Fill

division Fill composition (100% basis, wt%) Fill rate (wt%) Wear loss (g) WC 大 WC 小 Mn Ni Invention One 50 40 2 8 50 0.012 2 42 50 - 8 50 0.012 3 60 32 - 8 40 0.017 Commercial 4 92 3 5 45 0.015 5 92 - 8 55 0.011 6 92 3 5 55 0.014 7 97 3 - 60 0.015

As shown in Table 1, coarse WC was carried out in the range of 40-60% of the fill composition and the total amount of Mn and Ni was added to 10% or less.

When the wear loss, which is a test result, is compared with a conventional commercial material, the wear loss was found to be 0.012 to 0.017g in the embodiment, and the wear loss of the commercial material was found to be 0.011 to 0.015g, indicating almost the same level.

Therefore, even when inexpensive tungsten carbide sintered products are used, it can be seen that the same wear resistance is maintained, thereby reducing raw material costs.

In addition, FIG. 1 is an electron microscope of the overlay layer surface of NO3 and commercially available NO4 in the present invention. It can be seen that coarse tungsten carbide and fine tungsten carbide are mixed in both materials.

The effect of the present invention is to manufacture an overlay electrode having equivalent mechanical properties by using a low cost fractured tungsten carbide sintered product in place of the expensive coarse tungsten carbide produced by the casting process in the manufacture of overlay electrodes with a large amount of tungsten carbide added. Cost reduction effect

Claims (1)

WC: 40 to 80% by weight, Mn, Si, Ni added by weight ratio of 0 to 10%, the remainder is made of iron containing impurities contained in the production of iron 10 to 60% by weight An overlay electrode with a large amount of tungsten carbide, characterized in that the tungsten carbide overlay electrode is manufactured using 40 to 60% by weight of the WC as crushed tungsten carbide sintered product.