KR101496619B1

KR101496619B1 - Chute liner

Info

Publication number: KR101496619B1
Application number: KR20140086570A
Authority: KR
Inventors: 김상권; 이재훈; 여국현
Original assignee: 한국생산기술연구원
Priority date: 2014-07-10
Filing date: 2014-07-10
Publication date: 2015-02-26

Abstract

The present invention is to solve an excessive manual labor of the risk of welding by forming a hole one by one in a welding, and completing with the insertion; and pressurizing a bolt in order to install a conventional heavy chute liner. According to the present invention, the chute liner is manufactured using a light material sheet molded to include embossing and a hole for the bolt, by corrosive-resistance coating the sheet with high chrome, and by combining the sheets in spot welding; and by inserting the bolt into the hole. According to present invention, the installation of the chute liner can conveniently and safely be completed by pressurizing the bolt arranged in advance and fixating the same on a wall.

Description

Suit Liner {CHUTE LINER}

The present invention relates to a construction of a suit liner applied to a conveyor for conveying coal, such as a thermal power plant, and a method of installing the same.

In the thermal power plant, a conveyor system is installed to transport a large amount of coal, and a chute is installed at the turning point of the transportation direction. In the suits, the liner that protects the suits is installed because the coal will be carried using the fall. However, since the sulfur gas contained in the coal and the continuous impact of the coal and the scratching of the coal, the wear of the liner is severe, the chute liner is replaced frequently.

The suit liner is installed on the inner wall of the chute, and since it is made of steel sheet, the weight is considerable. The fixture of the shoot liner is made of a thick steel plate, and a hole is formed by welding to a liner sheet cut to an appropriate size, and is fixed to a hole with a fixing member such as a bolt. The problem is that it is very unworkable that replacement work takes place over a long distance of several kilometers, since all these replacement tasks are done manually in a narrow and harsh environment. Welding work in a harmful environment where harmful gases such as sulfur come out by coal is more problematic because of high labor intensity but high risk of safety accidents.

Further, since the liner is made of iron or ceramics / rubber or plastic, it is also problematic that the replacement cycle is short due to rapid wear. In the case of the chute liner disclosed in Korean Patent Laid-open Publication No. 10-2013-0002421, the above-described problems remain unchanged.

It is therefore an object of the present invention to provide a suit liner made of a new structure and material which is easy to replace and excellent in corrosion resistance and abrasion resistance.

According to the above object, the present invention provides a chute liner sheet made of a steel (Fe) material containing 0.15 to 0.9% of carbon, which is superimposed on a plurality of sheets by welding and the surface of which is formed with a high chromium coating layer, Liner.

In addition, in the present invention, a plurality of thin sheets having holes formed in advance so as to be able to insert a plurality of bolts in the course of manufacturing the above-mentioned shoot liner are aligned and welded together to produce a weight easily accessible to the operator By doing so, the work of replacing the suit liner is sufficient by pressing the bolt fixed to the chute liner against the inner wall surface of the chute.

Further, in the present invention, embossing is formed on the surface of the shoot liner to strengthen the impact resistance by gravel-like coal.

The hardness of the embossed surface coated with chrome is 350 to 420 HV and the flat surface between the embossments is further improved as a welded portion through welding to a hardness of 500 to 900 HV, , The whole part of the corrosion resistance is strengthened by strengthening the hardness characteristics without the shock absorbing function.

According to the present invention, rather than using a thick steel plate, a plurality of thin plate materials are coated so as to provide a suit liner using a lightweight material, thereby facilitating installation and replacement work.

Further, according to the present invention, since the sheet liner itself is formed by aligning a plurality of sheets by welding and forming a bolt insertion hole for wall working, a welding process is not required in the replacing operation, and the bolt is pressed to fix the bolt to the wall of the chute The work is completed and the workability is greatly improved and the safety of the work can be improved.

Further, corrosion resistance is improved by using a material reduced in the weight of the suit liner due to the corrosion-resistant coating applied to the sheet constituting the suit liner, so that the replacement period can be lengthened. The corrosion-resistant coating according to the present invention exhibits a high hardness of 400 HV or higher, a low friction coefficient of 0.4 or less, and a corrosion resistance that is not observed for 24 hours or more for a salt spray test, thereby extending the life of the suit liner.

Further, the embossing is applied to the surface of the inventive strut liner to absorb the impact of fallen objects such as coal, and the flat flat part between the protruded embossings is increased in hardness to 500 to 900 HV through coating and welding, And the replacement period is lengthened.

In addition, the strut liner of the present invention can lower the cost by about 40% by replacing the base material with soft steel by an efficient coating process.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a process sequence for manufacturing a suit liner according to the present invention; FIG.
2 is a perspective view of a sheet constituting a suit liner of the present invention.
Fig. 3 is a schematic view for explaining the coating treatment for the suit liner of the present invention.
4 is a SEM photograph showing a chromium layer coated on a low alloy steel plate according to an embodiment of the present invention.
FIG. 5 is an SEM photograph showing a welding surface in which a plate sheet coated with a high chromium layer is overlaid and welded according to an embodiment of the present invention.
6 is a graph showing the coefficient of friction of a plate sheet coated with a high chrome layer according to an embodiment of the present invention.
FIG. 7 is a microhardness graph of a surface of a coatliner according to the present invention. FIG.
8 shows the results of the salt spray test for each of the specimens manufactured according to the present embodiment.
9 shows the appearance after welding of each specimen manufactured according to the present embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 schematically shows an overall process of manufacturing and installing a suitliner of the present invention, and FIG. 2 shows one sheet 100 constituting a suitliner.

A plate material sheet having a thickness of 2 mm and made of mild steel is relatively easy to process. In the present invention, the sheet 100 formed with the embossing 110 and the hole 120 for fixing the bolt is formed into a metal by the soft steel or the low alloy steel. The embossing is for alleviating a load impact of falling coal or the like, and the hole 120 is for fixing the bolt 200. The position of the hole is preferably near each vertex of the sheet 100.

That is, according to the present invention, a hole for inserting a bolt is formed in advance in a metal sheet constituting a chute liner when the chute liner is manufactured, thereby eliminating the inconvenience and risk of drilling holes in the field as in the conventional case for replacing the chute liner .

In order to produce such a suit liner, a mild steel sheet is first formed into a mold. A mild steel sheet is formed in the form of an embossed shape and a hole formed at a predetermined position.

Next, the molded mild steel sheets are each subjected to coating treatment. That is, the environment in which the shoot liner is disposed is likely to be corroded due to the high concentration of gas including sulfur and impact of the coal. Therefore, it is preferable to carry out a high chromium coating which can improve the corrosion resistance. Since the embossing and the holes are formed as in the present embodiment, pack cementation may be suitable as a method of coating a base material having a simple shape.

Accordingly, the molded mild steel sheet is placed in a chamber and evacuated to about 10 ^-2 Torr. Then, the raw powder containing chromium, the activator and the filler are filled, and chromium at a high concentration is adsorbed on the surface of the sheet by the packementation method And a high chromium coating was performed. Wherein the coating composition may comprise from 5 to 15% by weight of chromium (Cr) powder, from 0.05 to 5% by weight of active agent and from 80 to 90% by weight of inert filler. As the activator, a material comprising a halogen group element is used so as to generate a metal halide gas. This example used an activator of at least one of NH ₄ Cl, NaCl, and NaF. Alumina (Al ₂ O ₃ ) was used as a filler.

The coating process is as follows.

(Cr) or Fe (70 to 80% by weight), Cr (20 to 30% by weight) (ferrochromium (Cr)) by blowing hydrogen (H ₂ ) and argon (Ar) ) Alloy powder is mixed with 10 to 40% by weight of the raw material metal Cr or 5 to 30% by weight of Cr and 5 to 10% by weight of Cr is used as a master alloy. 0.4 to 3% by weight of the metal halide gas is added to react with the active gas to generate the metal halide gas. In this case, if the parent metal is too small, the reaction rate is high, but it is difficult to reuse the chromium raw material after the reaction. Normally, the size of chromium and ferrochromium is 0.1 to 5 mm in diameter. At this time, the size can be selected by changing to the optimum size according to the shape and size of the coated product and the reaction temperature.

This process is a kind of in-situ CVD in which a three-dimensional coating is performed while a diffusion reaction takes place by decomposition / exchange of materials at the surface of the sheet and the inner wall of the hole. As a result of this process, it is formed as diffused form from the surface of the sheet material. It is formed as a compound of chromium and carbon, chromium and nitrogen by controlling the gas of the alloy and the process technology. The chromium content, which is a representative material, is about 20 to 60% A chromium coating layer is formed.

Therefore, even if the base material itself is a relatively light mild steel, it is highly resistant to abrasion caused by sulfur component or falling impact of coal. The coating layer exhibits excellent physical properties with a hardness of about 1500 HV, a hardening depth of about 200 mu m, a friction coefficient of 0.4 or less, an impact strength of 30 J, and a tensile strength of about 1300 MPa.

Three to four sheets coated with a high chromium layer are stacked in this manner to form a suit liner. That is, the plurality of sheets 100 are spot welded and the bolts 200 are inserted into the holes 120 formed in the respective sheets 100 (bolt-in liner production ). The positions of the embossing 110 and the holes 120 are naturally aligned with the correct aligning of the sheets because the sheets are originally molded through the same mold so that the bolts 200 can be easily inserted.

At this time, in the case of the portion to be subjected to the welding process, the strength is further strengthened due to the quenching process after melting. That is, since the flat portion other than the portion where the embossing is formed is the welding surface, the hardness of such a flat portion is 500 to 900 HV, and the hardness of the embossed portion is higher than that of 350 to 450 HV. As a result, the embossed portion relaxes the impact, and the flat portion has high hardness when impacted, and can withstand wear without being worn.

The stitched liner manufactured in this manner is installed in a state where it is contacted with the wall surface of the chute and presses the bolt 200 previously installed at the time of field replacement or installation work so that the operation is very easy, Can be. Furthermore, the weight of the suit liner manufactured according to the present embodiment is 9.36 kg, which is much lighter than that of the conventional suit liner having the same size of 14.01 kg, which further improves the workability. The high chromium coating is excellent in corrosion resistance as in stainless steel, and the embossed portion (110) is also excellent in impact resistance.

FIG. 4 shows a state in which a high chromium layer is coated on a low alloy steel plate according to the embodiment, and the chromium layer is closely adhered to a plate material.

FIG. 5 is a SEM photograph showing the welded joint surfaces between the plate sheets coated with the chromium layer, and it can be confirmed that the welds are well fused so that the interface can not be distinguished.

FIG. 6 is a graph showing the coefficient of friction of a plate material sheet coated with a chromium layer. It can be seen that the coefficient of friction on the surface is distributed between 0.1 and 0.3. It is the measurement of the resultant specimens when the coating material is SS400, SK5M, S45C for 5 hours or 20 hours. These values are greatly reduced considering that the pre-coating value is about 0.7, thereby improving wear resistance.

FIG. 7 is a graph showing the microhardness of a plate sheet coated with a chromium layer. Even if a mild steel alloy material is used, it can be seen that the strength at the surface is 200 to 300 HV / 0.025 g due to the high chrome coating layer and is kept high.

8 shows the results of the salt spray test for each of the specimens manufactured according to the present embodiment. The specimens coated with SK5M and S45C for 5 hours showed the highest corrosion resistance. From this, it can be seen that the excessive coating time may rather deteriorate the improvement of the corrosion resistance, and that the coating process of an appropriate time gives the optimum corrosion resistance.

Fig. 9 shows the appearance of each specimen after welding. Compared with the uncoated specimens, the appearance after welding is excellent.

As described above, due to the improved structure and physical properties as compared with the conventional suit liners, the life span of the suit liners according to the present invention is 24 months or more, which is twice or more than that of the conventional ones.

It is to be understood that the invention is not limited to the disclosed embodiment, but is capable of many modifications and variations within the scope of the appended claims. It is self-evident.

100: sheet
110: embossing
120: hole
200: Bolt

Claims

As a suit liner,
Sheets embossed and molded identically to each other, including holes for fixing member insertion,
Embossing is formed on the entire surface of each of the sheets,
The embossed portion and the hole are formed at the same position for each of the sheets,
The sheets are stacked and aligned, and then joined together by welding,
Wherein the hole is formed such that a fixing member for fixing the chute liner to the chute inner wall surface is inserted.

The sheet according to claim 1, wherein each of the sheets constituting the chute liner has a coating layer containing chromium, coated with a metal mold so as to have embossing and holes using mild steel as a material, Liner for suit.

The chute liner according to claim 2, wherein the coating layer has a chromium content of 20 to 60 wt%.

The chute liner according to claim 2, wherein the hardness of the embossed surface coated with chromium is 350 to 420 HV, and the flat surface between the embossments is welded as a weld treatment portion and has a hardness of 500 to 900 HV.

In a method of installing a liner for a suit,
The liner for a suit is a liner for a suit according to claim 1 or claim 2,
Wherein the installation is completed by aligning the liner for the shoot to a place to be installed and then pressing and fixing the fixing member to the hole for the fixing member previously formed in the liner for the chute.