JPS6056054A - Refining plate material for manufacture of pulp - Google Patents

Abstract

PURPOSE:To extend the service life of a refining plate by using a high-carbon Cr alloy steel dispersed and precipitated uniformly with hard metallic carbide as a material for a refining plate to be used for manufacture of pulp. CONSTITUTION:Plural pieces of split plates 4 knurled with many teeth 2 are attached to the outside circumferential part of a disc 3 to form an annular refining plate 1. Two pieces of such discs 3 are held face to face and in this state the discs are rotated at a high speed in opposite directions. Wooden chips and pulp are supplied into the space between the discs, by which the chips and pulp are loosened and groupd. The plates 1 in this case are manufactured by casting a high carbon teel contg. 2.5-3.5% C, 15-30% Cr, 1.5-2.5% Mo, 0.3-1.0% Si, 0.1-1.5% Mn and 0.5-3.0% Ni. The refining plate for manufacturing pulp in which hard metallic carbide such as Cr carbide is uniformly dispersed and precipitated and which has high hardness and wear resistance, decreases consump- tion of the teeth 2 and has a long life is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refining plate material for pulp production.

As shown in FIGS. 1(a) to (C), 1. The 1-no-fining plate (1) for f7 rep manufacturing has many teeth (2) carved on its surface, and a pair of rotating discs (3).
) are arranged in an annular manner on both opposing surfaces of the wood knobs and 1<).
It serves to loosen the pulp by sandwiching it in between, and is composed of divided plates (4) whose circumference is divided into an appropriate number of plates and which have the same tooth surface. By the way, although conventional refining plates are used, the conditions for using plate materials are vortex.

Because it is a very harsh product, such as being rotated at a rotation speed of 1000 to 2000p, p, m in a humid atmosphere, properties such as appropriate hardness, abrasion resistance, corrosion resistance, and excellent mechanical properties are required. required. On the other hand, when looking at the service life of the plate itself, it cannot be determined immediately from the above properties alone, but must also be determined from the quality of the pulp produced. In other words, wood chips and pulp are loosened and become finer as they pass through the gap where the refining plate (1) rotates at high speed, but the tooth surface (2) of the refining plate (1) If the refining plate (1) is worn out and the same pulp quality cannot be obtained even if the same gap is adjusted, it is determined that the life of the refining plate (1) has expired and the refining plate (1) must be reprocessed or discarded. Conventional refining plate materials use carbon steel (iron-based alloy) containing high chromium because of the conditions under which the charcoal precipitated in the alloy acts effectively to refine the pulp. This is because it has a hardness that matches the standard. However, as is clear from the chemical composition shown in Table 1, the refining plate material that has been commonly used in the past is a hypoeutectic material, and after the initial dendrites form a regular network, A structure is formed in which carbides are precipitated in the gaps between the dendrites, and when the dendrites are used, the dendrites are preferentially worn away, and large independent carbides are lost, resulting in a refining plate ( 1) If the gap between the gaps is small, cut the wood by scraping the wood chips or pulp. Chips and pulp were cut and the service life was exceeded.

1st Table A-1... Rice 2... 9 including casting stress relief annealing
Air cooling treatment after 5θ''Q, 41+ holding As described above, the service life of conventional refining plate materials for pulp production is relatively short (although the development of a material that can be expected to have a long life has been desired).

The present invention aims to solve such problems, and
r 15-a096, C 2.5-8.5%, Mo 1
．． 5 to 2.596, Si 0.8 to 1.096, Mn 0.5 to 1.15, and Ni 0.5 to 8.0%. The purpose of the present invention is achieved by providing the following, and the service life can be extended from approximately 900 hours as cast to approximately 1,400 hours by heat treatment. ~Examples will be described in detail based on experimental examples.

Table 2 first shows the chemical composition of the present invention in correspondence with Table 1 above.

Second surface l...Including casting stress relief annealing=*-2...Holding at 650°C for 4 hours followed by air cooling treatment.Next,
The reason why the composition was determined in this way will be explained.

C 2. The reason why Cr is set at ~8.5% and Cr at 15~80% is that the basic composition is in the Fe-Cr-C eutectic region range, and 15% of Cr is approximately 8.5% of C and 15% of Cr. 80% of
corresponds to about 2.5% of C, but this is because the amount of seven-eutectic solidification outside this composition range is reduced, making it unsuitable as the plate material.

The reason why Mo was set at 1.5 to 2.5% was because It (o is Fe-
In the eutectic region of Cr-C, it is partially dissolved in the matrix, but it is effective in increasing hardness by forming carbides, and if it is less than 1.5%, the target hardness is HRc 54 is not obtained,
This is because the increase in hardness reaches saturation when the amount exceeds 2.5 dollars.

Si is 0.8 to 1.0%, and n is 0.5 to 1.5%.

It is sufficient to add Mn within the usual range used for deoxidation, but Si needs to be added in an amount of 0.8% or more, and if it exceeds 1.0%, ductility will deteriorate; % or more is required and 1
．． This is because if it exceeds 5%, the amount of deoxidized products and the amount of sulfides will increase, making it unsuitable.

The reason why Ni is set at 0.5 to 8.0% is that Ni is added to form a solid solution in the matrix of the material and make the material ductile.
This is because, while it is necessary to add 0.596 or more to obtain this effect, if S and O% are exceeded, ductility will not be improved despite the cost increase.

Note that impurity elements other than those mentioned above, such as P and S, are within normal ranges.

Next, a first example will be described. In this case, the chemical composition is
I made it like the table.

Table 8 Figures 2(a) and 2(b) show enlarged views of the tooth flanks of the refining plate material for pulp production obtained with such a chemical composition. FIG. 2(a) shows a conventional alloy, in which the original dendrites are clearly shown, and the tooth flanks are locally sharp due to non-uniform wear. FIG. 2(b) shows an example of this alloy, which is in the form of eutectic solidification, so that the tooth flanks wear or wear out uniformly, so there is no big difference from the state immediately before use after polishing. These facts also demonstrate the superiority of this material.

Next, a second example will be described. In this case, the chemical composition is
I made it like the table.

Table 4 Conventionally, it is more effective for carbides precipitated in iron-based alloys to be spherical with a diameter of about 50 pm than to be rod-shaped or angular.
Although treatment on carbide spheres is often achieved by prolonged heat treatment, the lifetime of the alloy is still as shown in Table 1. By adopting the alloy according to the present invention as these alloys, a longer life can be obtained as shown in Table 2, but the second embodiment further improves the solidification structure of this alloy. It is.

FIG. 8 and FIG. 4 show the apparatus used in this example. In the figure, (5) is the ladle, (6) is the mold, (1) is the runner of the mold (6), and (8) is the runner that passes from the ladle (5) into the mold (6). The poured melt 8, (9) is in the mold (
6) The mold (6) is used to stir the molten metal (8) poured into the mold (6).
) is an electromagnetic stirring device installed near the bottom of the

Using this kind of casting equipment, the molten metal (8) that will become the refining plate for pulp production is poured into the mold (6).
) is solidified while being stirred from the tooth surface side of the plate using an electromagnetic stirring device (9). The broken line in FIG. 4 indicates the stirring area. The solidified structure of the alloy (refining plate) obtained in this way is finer than that of the first example, and the precipitated carbides are also uniformly dispersed, so that the solidified structure is uniform throughout. By constantly reducing wear and tear under the same conditions, the service life can be greatly extended.

Table 5 shows the results when this example was applied to both the conventional alloy and the present alloy.

Table 5 Rice 1... Including casting stress relief annealing *-2..., Air cooling treatment after holding at 950°C for 4 hours As is clear from the table, by applying this example, the conventional alloy However, this alloy has improved solidification structure and carbide shape, resulting in longer service life.
In particular, the service life is significantly extended.

The alloy of the present invention is mainly produced by precision casting, and has superior castability than conventional alloys, and is also advantageous in producing sound castings.

As described above, according to the present invention, it is possible to perform eutectic solidification without producing primary dendrites as in the conventional method.This eutectic solidification makes it difficult for preferential wear points to occur in the material. In addition, Mo carbide can be uniformly dispersed and the hardness can be adjusted to an appropriate level. Therefore, the service life can be extended to about 900 hours even in the as-cast state, and to about 1400 hours by heat treatment.

[Brief explanation of drawings]

Fig. 1(a) is a schematic explanatory diagram of a rotating disk, Fig. 1(b)
) is a diagram showing the divided state of the refining plate for pulp production, Figure 1 (C) is an enlarged view of the division plate, and Figures 2 (a) and (b) are micrographs of the refining plate material for pulp production. A metallographic diagram showing the tooth surface in cross section, Figure 8 is a front view of the casting device 5, and Figure 4 is 18
It is a sectional view taken from A to A in the figure. (Su... Refining plate for pulp production, (2
)...Teeth, (3)...Disk, (4)...Divided plate agent Yoshihiro MorimotoFigure 1, 2, 2, <c> Figure 2 (Ne?), Figure 3, Figure 4, Procedure Amendment (Eel) Representation 1958 Patent Condyle 164761 Name of the person who manufactures the refining play F material for 1° production (+ Telephone Osaka 06 (532) No. 4025 (main) Name (
680B) Patent Attorney Yoshihiro Morimoto 5゜The number of inventions increases from the scope of claims in the column for the detailed explanation of the invention in the subject book■ column for the detailed explanation of the invention in the specification (1) No. No. 3 on page 3 (The table is corrected as follows.
In the 5th line of the page, add "r weight" between j and "Cr". (3) On page 4, line 7, 13, between all and "chemical composition," add the remaining 9 FeJ. (4) Amend Table 2 on page 4 as follows. Table (5) Table 3 on page 6 is corrected as follows. Table 3 Table (6) Table 4 on page 7 is corrected as follows. Table 4 ■ Patent claims in the description As shown in the attached sheet in the range column, λ Claim 1: By weight, Cr: 15-304, C: 2.5-3
．． 5 t6, M. 1.5-2.54, Si 0.3-1.0%, Mn
is 0.5 to 1.54, and Ni is 0.5 to 3. (196
, a material characterized by being composed of a chemical composition of remaining Fe.
Refining plate material for manufacturing.

Claims (1)

[Claims] 1. Cr 15-80%, C 2.5-8.5%, Mo
1.5-2.5%, Si 0.8-1.0%, Mn 0.5-1.5%, Ni 0. A refining plate material for the production of fuel, characterized by having a chemical composition of 8.0%.