JPH02303547A - Crushing tooth of sintered ore crushing machine and its production - Google Patents

Abstract

PURPOSE:To improve the durability to high-temp. wear by overlaying the tips of a white cast iron onto the front ends of base materials for fang teeth and receiving teeth and tightly holding the fine pieces of a sintered carbide alloy and/or the sintered polyhedral bodies of a sintered hard alloy on the front end faces and side faces of the tips. CONSTITUTION:The crushing teeth to be mounted to a crushing machine for blooming the ore material sintered for blast furnaces at high temp. are constituted of the fang teeth 7 and the receiving teeth 1. The tips 10, 4 of the white cast iron forming desired shapes are respectively overlaid on the front ends of the base materials for the fang teeth 7 and the receiving teeth 1. The fine pieces 11, 5 of the sintered carbide alloy and/or the sintered polyhedral bodies of the sintered hard alloy are tightly held on the respective front end faces and desired side faces of the tips. As a result, the durability to the abrasion wear at a high temp. is exceedingly improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a crushing tooth for a crusher used for decomposing sintered ore at high temperatures for blast furnaces for steel manufacturing.

BACKGROUND OF THE INVENTION The ore most widely used today for iron and steel production is fine ore for economic reasons. Since it is difficult to charge powdered ore as it is into a blast furnace and smelt it, most of it is sintered in a sintering furnace, and then it is provided after being agglomerated into a desired size. The temperature when sintered ore is discharged is 400-60
The standard temperature is 0°C, and if an attempt is made to crush ore bound in a band shape at this temperature after the temperature has fallen, a large shearing force will be required, which will increase the difficulty.

As the crushing teeth of a crusher, the most widely used type is shearing and breaking by biting between a leading edge and a receiving tooth.

Fig. 4 A 2 shows a single-roll type crushing tooth, the leading edge 7a is manufactured by integral casting of high-temperature wear-resistant casting 1 (for example, 13Cr steel), and the receiving tooth 1a is cast on the base material 2a. It has a cast steel tooth tip 3a that allows cooling water to flow into the hollow part.

However, such a structure cannot withstand the harsh operating conditions of the side bottom and will wear out and lose its crushing ability. Therefore, for the tip of the tip, a wear-resistant tooth tip is placed on the tip of the base material to prevent wear. The method of replacing only the tip of the tooth has become commonplace.

Since the tip of the double-toothed beam catches the high-temperature band between them and tears it, a material with the highest heat and abrasion resistance is required, and various attempts have been made, but the latest material that meets this requirement is "Composite made of sintered carbide alloy and cast iron" (
(Japanese Patent Publication No. 60-11096).

This technology consists of a composite made of a sintered carbide alloy and cast iron, and its characteristics are that the cast iron itself is graphite cast iron with low wear resistance and hardness, and has a carbon equivalent of 2.5
It can be seen that the sintered carbide alloy is adjusted to 6.0 to 6.0, that an intermediate alloy phase or transition zone is formed between the two, and that 20% to 80% of the sintered carbide alloy is in the transition zone.

[Problems to be Solved by the Invention] However, it is impossible for the superhard sintered carbide alloy to completely cover the entire surface, which is prone to wear, and when the cast iron that penetrates the surface is graphite-based, Due to its low hardness and low abrasion resistance, there is a concern that it may lead to deterioration depending on the usage conditions, and the surface may be scratched or hit by hard particles.

This concern is even more acute for abrasion wear caused by frictional flow.

In order to solve the problems described herein, the present invention has created a configuration using materials and combinations thereof that are particularly focused on high-temperature abrasion wear, and has created a crushing tooth for a sintered ore crusher that is most suitable for the usage conditions and its manufacture. The purpose is to provide a method.

[Means for Solving the Problems] The crushing teeth of the sintered ore crusher according to the present invention are crowned with white cast iron tooth tips that form desired shapes on the base material tips of the leading peak and receiving tooth, respectively. The above-mentioned problem has been solved by tightly enclosing strips of sintered carbide alloy and/or sintered polyhedrons of superhard alloy on each tip surface and desired side surface of the tooth tip.

More specifically, the pieces of the sintered carbide alloy consist of crushed bodies, powder bodies, compacted bodies, or a mixture thereof, and at least 70% of the total amount consists of particles with a particle size of 2 to 20 m. Also, sintered polyhedrons of cemented carbide are arranged on the tip surface of each tooth tip at intervals narrower than 20 times its height or 10 times its width, whichever is smaller, white cast iron. is mainly composed of composite carbide due to the addition of alloying elements, and the carbon content ranges from 2.0% to 4.5%.
b) /C is in the range from 1 to 18, and N i
+Mo+Cu was shown to be in the range of 0% to 15%.

In addition, as for the manufacturing method of the tooth tip, white cast iron is added to a sintered carbide alloy layer with a layer thickness of Tctyt and a sintered polyhedral layer of super hard alloy from 50T'C to 180 (1,75+) from its own melting point.
A procedure for capping and fixing a tooth tip cast product poured from a molten state at a high temperature of T>'C on a base body is also disclosed.

[Function] Compared to graphite cast iron, white cast iron is an extremely hard material made of iron carbide and martensite, but in order to further improve its wear resistance, alloying elements are added and melted to improve the structure after solidification. It is well known that a highly hard composite carbide is precipitated on a matrix (mother phase) to increase the hardness of the matrix itself.

However, the most preferable range for this application is 2.0% CM.
to 4.5% (Cr+W+V+Ta+T
It is recommended that the ratio of i ±N b > /C be in the range of 1 to 18. When the ratio is less than 1, the formation of composite carbides is slightly lost, the matrix hardness is low, and graphite crystallization occurs. Moreover, when this ratio exceeds 12, there is a shortage of C for carbide formation, and C is taken away from the sintered carbide alloy, forming a brittle phase at the interface between the two. Also, an appropriate amount of Ni
, Mo.

Addition of Cu is effective in stabilizing the matrix, suppressing precipitation of excessive secondary carbides, and preventing reduction in hardness of the matrix. However, even if 15% or more of N i +Mo+Cu was added, the stability of the matrix would not be improved any further, so the upper limit of the addition was set at 15%.

In addition, in order for the white cast iron molten metal to completely penetrate into the narrow spaces formed between the sintered carbide alloy particles and between the sintered polyhedra of the superhard alloy, the pouring temperature must be lower than the melting point of the white cast iron for the layer thickness Tcm. The temperature needs to be at least 50T°C or higher. In addition, in order to avoid excessive dissolution of the sintered polyhedron of sintered carbide alloy and cemented carbide into white cast iron, the pouring temperature must be in the range of 180°C (1,75+T>'C) below the melting point of white cast iron.

Regarding the properties of the particles, if the particle size is too small, the spacing between the sintered carbide alloys becomes too small, and even if the casting temperature is raised, the white cast iron will not penetrate sufficiently between the sintered carbide particles and the sintered polyhedrons of the superhard alloy. Furthermore, if the temperature is raised too much, the amount of sintered polyhedrons of sintered carbide alloys and superhard alloys melted into white cast iron increases considerably.

If the particle size is too coarse, the amount of melting of the sintered polyhedrons of sintered carbide alloys and superhard alloys increases significantly.

If the particle size is too coarse, not only will the volume fraction of the sintered carbide alloy decrease, but the average interparticle distance cut by the abrasive particles of the interparticle white cast iron base material will increase, resulting in a deterioration of wear resistance. Therefore, 2! A configuration in which 70% or more of the particles are Mi~20 mm is optimal.

The maximum distance allowed for the arrangement of sintered polyhedrons of cemented carbide varies considerably depending on the material of the base material to which it is applied and the conditions of its use. It has been experimentally found that the width should not exceed 20 times the height T or 10 times the width, whichever is smaller.

[Example] (1) Fig. 1 is a front sectional view of a tooth tip 3 crowned on the tip of a base material 2 of a receiver 1 showing a first example of the present invention.

The tip surface of the tooth tip 3 is formed of a carbide layer 5 with a thickness of 15 s formed by sintering tungsten carbide with cobalt as a binder, and the rear base material 4 is made of 3.0%C-15%Cr-
It is supported by white cast iron made of 4%V-3%Ti-2%MO-1%Cu.

In Comparative Example 1, the entire tooth tip of the same shape was made of 2.7%C-28%Cr white cast iron, and in Comparative Example 2, the tip surface of the tooth tip was made of cast steel with 4%C-30%Cr- 2%Mo-2
%Ni welding rod and used in a crusher under the same conditions until it became unusable.

The useful life is recorded as follows:

(a) First embodiment of the present invention 280 days (b) Comparative example 1 60 days (C) Comparative example 2 45 days (2) This is a front sectional view of the tooth tip 3 crowned on the tip of the material 2.

The base material 4 of the tooth tip is 3.2%C-24%Cr-3%W-〇,
It is white cast iron made of 9% Ni-0.5% MO, and the tip surface of the tooth tip is formed with a carbide layer 5 of Bmm thickness formed by sintering tungsten carbide with cobalt as a binder, and the tip surface is close to this tip surface. Outer diameter Bmmφ, inner diameter 2mmφ, height 6m on the side
The same molded bodies 6 of tungsten carbide molded into a regular cylindrical shape of m were arranged in three rows with equal intervals of 12 s. While this tooth tip was actually used without water cooling, the service life was compared with Comparative Example 3, which was constructed in the same way as Comparative Example 2 in the previous section and used under water cooling.

(a) Second embodiment of the present application 340 days (b) Comparative example 3 70 days (3) Fig. 3 shows a third embodiment of the present invention in which tooth tips 9 are covered on the tip of the base material 8 of rabbit meat 7. The base material 10 of the tooth tip 9 is 3.1%C-24%Cr-3%W-1%Nb-1.
%Ta-3%Mo White cast iron consisting of residual iron components,
There is a carbide layer 11 made of sintered tungsten carbide with a thickness of 12 mm on the tip surface of this tooth tip, and a carbide layer 11 with a diameter of 4 mm and a height of 12 mm on the side surface.
Tungsten carbide molded body 12 molded into a cylindrical shape of mm
were arranged in three rows with an average distance of 10 m between centers.

Comparative Example 4 uses rabbit meat of the same shape as 3.0% C-2.
It was manufactured from 9% 0r-1% Mo white cast iron, was used on a trial basis, and its service life was recorded.

(a) Third embodiment of the present application 280 days (b) Comparative example 4 60 days [Effects of the invention] As described above, the present invention creates a tooth tip that has durability in the rear group against abrasion wear at high temperatures. However, when applied as a crushing tooth for a sintered ore crusher, the service life was significantly extended several times over that of a known tooth tip, which had a reputation for having extremely high wear resistance.

Taking into consideration the complicated work required to replace the worn parts of the crusher and the balance with the overall sintering equipment, this method compensates for the soaring unit cost of the tooth tips themselves, and still provides significant benefits.

[Brief explanation of the drawing]

1 to 3 are front sectional views showing different embodiments of the present invention, and FIG.

Claims (5)

[Claims] (1) In a crushing tooth consisting of a demon tooth and a receiving tooth, which are attached to a crusher that blooms sintered ore for blast furnaces at high temperatures, desired shapes are formed on the base material tips of the demon tooth and receiving tooth, respectively. The tips of the white cast iron teeth to be formed are crowned, and the tips of the teeth are closely held with strips of sintered carbide alloy and/or sintered polyhedrons of cemented carbide on the respective tip surfaces and desired side surfaces. Characteristic crushing teeth of the sintered ore crusher. (2) In claim 1, the pieces of the sintered carbide alloy are composed of crushed bodies, granulated bodies, compression molded bodies, or a mixture thereof, and at least 70% of the total amount is 2 to 20 m
The crushing teeth of a sintered ore crusher have a grain size of m. (3) In claim 1 or 2, the sintered polyhedrons of cemented carbide are arranged on the tip surface of each tooth tip at intervals narrower than the smaller value of 20 times or less of the height or 10 times or less of the width. The crushing teeth of the sintered ore crusher are installed with (4) In any one of claims 1 to 3, the white cast iron is mainly composed of composite carbide by adding alloying elements, and has a carbon content of 2.
．． While it ranges from 0% to 4.5%, (Cr+W
+V+Ta+Ti+Nb)/C is in the range of 1 to 18, and Ni+Mo+Cu is in the range of 0% to 15%. (5) White cast iron is applied to the sintered carbide alloy layer with a layer thickness of Tcm and the sintered polyhedral layer of superhard alloy from 50T℃ below its own melting point.
A method for manufacturing a crushing tooth for a sintered ore crusher, characterized in that a tooth tip cast product poured from a molten state at a high temperature of 80 (1.75+T)°C is capped and fixed onto a base body.