JPH05214483A - Material having wear resistance to lump ore - Google Patents

Abstract

PURPOSE:To improve the durability of the material used as a liner, a plate or the like used in a blast furnace of an iron mill and its stock treating equip ment. CONSTITUTION:The objective material having wear resistance to lump ores is constituted of an alloy of, by weight, 3.0 to 7.0% C, 0.3 to 3.0% Si, 0.3 to 1.5% Mn, 15.0 to 35.0% Cr, 3.0 to 10.0% Mo, 3.0 to 10.0% W and 0.5 to 2.0% V, and the balance Fe with inevitable impurities.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an agglomerate mineral wear resistant material having significantly improved durability such as a liner and a plate used in a blast furnace of a steelmaking plant and a raw material processing facility therefor.

[0002]

2. Description of the Related Art A large amount of hard lump minerals collide with and pass through in a blast furnace and a raw material processing facility of a steel manufacturing plant. Therefore, abrasion resistance is very important. Except for the parts that reach high temperatures, high carbon / high chromium cast iron materials are mainly used. Since this material contains a large amount of high hardness chromium carbide, it is often effective against agglomerate mineral wear.

These agglomerate resistant mineral wear materials are manufactured by various manufacturing methods such as those using a high chromium cast iron material as a single casting, those by welding wire overlay, and those by casting overlay with molten metal. ..

[0004]

The conventional high chromium cast iron materials are C2.5-5.5 wt%, Cr15-35 wt%,
Is used as a main component, and some alloying elements (Mo, V, Nb
Etc.) is used. Generally, the durability of the agglomerate mineral wear material is determined by the amount and shape of carbide, the strength of the matrix that holds the carbide, and the wear resistance. That is, firstly, the carbides are destroyed and dropped by collision and contact with the lump mineral, and secondly, the carbides cannot be retained because the strength of the matrix surrounding the carbides is low, and the carbides fall off. In addition, the wear of the base itself will be overlapped and the wear will progress. It is an object of the present invention to solve the above problems and to provide a lump-resistant mineral abrasion material having excellent durability.

[0005]

The present invention provides C3.0-
7.0% by weight, Si 0.3 to 3.0% by weight, Mn 0.3
~ 1.5% by weight, Cr 15.0 to 35.0% by weight, Mo
3.0 to 10.0% by weight, W 3.0 to 10.0% by weight,
It is an agglomerate mineral wear resistant material composed of V-0.5 to 2.0% by weight, the balance Fe, and an alloy which is an unavoidable impurity.

[0006]

[Function] Generally, in order to increase the wear resistance of lump minerals,
The condition is to increase the amount of carbide, but it is necessary to minimize the destruction and loss of this carbide. Therefore, there is an upper limit on the amount and size of carbides. On the other hand, when the strength of the base that holds the carbide is insufficient, or when the wear resistance of the base is lacking and the base wears early, the base cannot hold the carbide and falls off, significantly increasing the wear rate. .. In the end, in order to improve the lump mineral wear resistance of the material, it is important to form a matrix containing as much carbide as possible and having strength and wear resistance capable of holding it.

From this viewpoint, the present inventors have tested the effects of various alloying elements and found that the addition of Mo and W is very effective. FIG. 1 shows the relationship between the added amount of Mo and W and the Shore hardness for 5 wt% C-30 wt% Cr cast iron.
It can be seen that Mo and W significantly increase the hardness. The microstructure is shown in FIG. Here, non-additive materials of Mo and W,
This is a material to which Mo and W are added by 7% by weight each. M
It was found that by adding o and W, a network-like Mo, W-based fine eutectic carbide was formed in the matrix around the chromium carbide, which strengthens the matrix and improves the wear resistance of the matrix. It was also confirmed that the martensite of the matrix became finer by the addition of Mo and W, and as a result, the hardness was significantly increased.

Next, the reasons for limiting the numerical values of each component element will be described.
C is an element that combines with Cr, Mo, W, V, etc. to form hard carbides, but if it is less than 3.0% by weight, the amount of the above-mentioned carbides is insufficient and wear resistance is deteriorated. On the other hand, 7.0
If the content exceeds 10% by weight, carbides are excessively formed and embrittlement occurs, so C
Was 3.0 to 7.0% by weight. Si is an element necessary for deoxidizing the molten metal. If it is less than 0.3% by weight, the deoxidizing effect is insufficient. On the other hand, if it exceeds 3.0% by weight, it becomes brittle, which is not preferable.

Mn is an element necessary for deoxidation like Si, but its effect is insufficient if it is less than 0.3% by weight. On the other hand, Mn is a strong austenite-forming element and has an action of preventing the phenomenon that the matrix transforms from austenite to martensite during the cooling process of the material, so the upper limit of Mn was set to 1.5% by weight. Cr is an element that forms a hard carbide and also forms a solid solution in the matrix to strengthen it. If it is less than 15.0% by weight, the carbide is insufficient, while 3
If it exceeds 5.0% by weight, the carbides are coarsened and excessively generated, so that the material becomes brittle, so the upper limit was made 35.0% by weight.

As described above, Mo and W have the effects of forming a solid solution in the Cr carbide and strengthening them, as well as forming a fine eutectic carbide in the matrix and further strengthening the martensite of the matrix. If it is less than 0.1%, the effect cannot be expected, while if 10.0% by weight or more is added, the effect is saturated, so the upper limit was made 10.0% by weight.

V is an element that strengthens carbides and bases, but if it is less than 0.5% by weight, it has no effect.
When V exceeds 2.0% by weight, V has a strong bonding force with C. Therefore, the upper limit was set to 2.0% by weight because it hinders the formation of Cr carbide and fine eutectic carbide due to Mo and W. If P and S increase in the molten metal, it becomes brittle and its amount is 0.05
It is preferably not more than wt%. Ni, like Mn, inhibits martensitic transformation, and retained austenite lowers hardness and deteriorates wear resistance, so Ni is made as low as possible, and preferably 0.3% by weight or less.

[0012]

EXAMPLES Examples of the present invention will be described in detail below. In this example, a crushing plate (tooth) is manufactured by using the material of the present invention and the comparative material by the overlaying method shown in FIG. That is, a frame is made of ordinary steel material 1, a molten metal 2 adjusted to the composition of the material of the present invention and a comparative material is poured into the frame, and when solidified, an arc heating is applied using a carbon electrode 3 to melt the ordinary steel material 1 and the molten metal. The two are closely attached. By the method described above, the crushing plate of the sintering mill crusher having the components shown in Table 1 and having a width of 200 mm, a height of 189 mm, and a length of 2200 mm was produced using the actual equipment.

[0013]

[Table 1]

The results of using the material of the present invention and the comparative material are shown in FIG. As is clear from this, it is understood that the material of the present invention exhibits durability about twice that of the comparative material, and good results are obtained.

[0015]

As described above, the agglomerate mineral wear resistant material according to the present invention is very effective in improving the durability and greatly contributes to the stabilization of the operation of each facility of the steel factory and the reduction of the maintenance. To do.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between Mo and W contents and Shore hardness.

FIG. 2 is a metallographic micrograph of a comparative material containing no Mo and W, and the magnification is 400 times.

FIG. 3 is a metallographic micrograph of a material of the present invention containing Mo and W at 7.0% by weight, respectively, with a magnification of 400 times.

FIG. 4 is an explanatory view showing a method of manufacturing a crushing plate in the embodiment of the present invention.

FIG. 5 is a graph showing the results of wear tests in the examples of the present invention.

Claims (1)

[Claims] 1. C3.0-7.0 wt%, Si0.3-
3.0 wt%, Mn 0.3 to 1.5 wt%, Cr15.
0-35.0% by weight, Mo 3.0-10.0% by weight, W
An agglomerate mineral wear resistant material consisting of 3.0 to 10.0% by weight, V 0.5 to 2.0% by weight and the balance Fe and an alloy which is an unavoidable impurity.