JP3220770B2 - Rolling wheel grinding wheel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding wheel for a rolling roll suitable for grinding a rolling roll made of high alloy steel and having high hardness.

[0002]

2. Description of the Related Art Rolling makers, including steel mills, expect rolls made of high alloy steel having high safety and a long life. This kind of roll is made of a high-chromium, high-vanadium high-speed tool steel alloy steel, and is a material to be ground which is extremely difficult to grind. Therefore, in the case of a conventionally used roll grinding wheel made of general abrasive grains, scratches frequently occur on the roll surface and clogging of the wheel frequently occurs, making it difficult to perform roll grinding suitable for rolling.

[0003] For grinding high alloy rolls, a grindstone composed of a mixture of superabrasive grains and general abrasive grains has been disclosed in Japanese Patent Application No. 61-28 / 1986.
8343. This grindstone has good grinding performance and can efficiently dress and roughen due to the difference in friability between superabrasives and general abrasives.However, the cost is high because superabrasives are used as raw materials. Very high. Therefore, there has been a demand for a grindstone which is composed of general abrasive grains which are industrially used in large quantities without using expensive superabrasive grains and which can be applied to grinding of a high alloy roll.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is a whetstone composed of general abrasive grains, which has a high chromium content and a high vanadium content which are difficult to grind. An object of the present invention is to provide a grinding wheel for rolling rolls that can grind a roll made of a high speed tool steel alloy steel.

[0005]

Means for Solving the Problems To achieve the above object, a grinding wheel for a roll mill of the present invention comprises an alumina-based high crushing abrasive and an alumina-based single crystal high toughness abrasive in a volume ratio. In this case, the high-fracturability abrasive grains are mixed and contained in a larger amount than the high-toughness abrasive grains to form a coarse structure, and these abrasive grains are bonded by vitrified bond at an extremely soft bonding degree.

[0006] Then, in terms of volume ratio, 60-80
% , It is preferable that 40 to 20 % of the high toughness abrasive grains be mixed.

The highly crushable abrasive grains are preferably abrasive grains having a JIS method anti-crushing rate of 20 to 24%, and the high toughness abrasive grains are preferably JIS method anti-crushing rates of 30 to 40%. .

[0008] Further, the grinding wheel for rolling mill of the present invention,
Abrasive grain ratio is 30-40%, and bond degree is C-
E is good.

[0009]

The grinding wheel for rolling mill according to the present invention has a large cutting edge which is naturally generated when the abrasive grains are crushed, and has a long effective cutting edge life longer than that of the GC abrasive grains. High toughness type abrasive grains, 60-80% of high crushability abrasive grains by volume ratio
High by this <br/> and to toughness type abrasive 40 to 20% of the mixing ratio, and high crushing-type abrasive grains crushed during grinding, according to the high toughness type abrasive fulfilling the primary grinding force against The cutting resistance is increased, and the turning property of the cutting blade due to crushing is improved, that is, the cutting blade itself is promoted, and the grinding performance of the grindstone is improved. When the amount of the highly crushable abrasive grains is small, the cutting edge is insufficiently renewed, and the whetstone is apt to cause chattering vibration. When the amount of the highly crushable abrasive grains is too large, the grinding performance is reduced. For grinding high-speed tool steel rolls, 60-80 % of highly crushable abrasive grains by volume ratio
The one having a mixing ratio of 40 to 20 % of high toughness type abrasive grains is preferred.

The vitrified bond grasps the highly crushable abrasive grains and the high toughness type abrasive grains to prevent abnormal falling off of the abrasive grains, and at the same time, forms good pores for escape of the dropped abrasive grains, crushed abrasive grains and chips. Generate. Furthermore, by making the structure coarse and multi-porous, the discharge efficiency of chips, fallen abrasive grains and crushed abrasive grains is improved, and clogging by these chips, fallen abrasive grains or crushed abrasive grains and roll surface scratching are prevented. I do.

Further, by making the degree of bonding extremely soft within the range of JIS indications C to E and setting the abrasive grain ratio to 30 to 40% to coarsen the structure, the cutting blade self-promoting action due to the grinding of the grinding stone is promoted. The cutting resistance applied to each abrasive grain is increased, and the abrasive grains that have lost the effective cutting edge are easily dropped off and crushed.
Thereby, the grindability of the grindstone is improved. Figure 3 shows Bond 1
FIG. 4 is a view showing a crushing mode of a mixed abrasive grain of a high toughness type abrasive grain 2 and a highly crushable abrasive grain 3 combined by the following method.

As described above, the working pressure of the grinding wheel is reduced by reducing the working pressure of the grinding surface of the grinding wheel by reducing the working hardness of the grinding wheel by making the structure coarse and the bonding degree extremely soft to reduce the generation of feed marks. It can also prevent scratches generated during rough grinding when grinding with high load, while grinding while grinding with low load,
It can have a cutting force that can be removed by finish grinding. The combination of the grindstones of the present invention preferably has a sandwich structure shown in Table 1.

[0013]

[Table 1]

[0014]

An embodiment of the present invention will be described below. FIG. 1 is a view showing the shape of a grinding wheel for rolling rolls according to an embodiment of the present invention. This grindstone has a degree of bonding a little harder than D
+ Center disk and coupling degree D stuck on both sides
The center disk had a width of 80 mm, the side disks had the same width of 10 mm, and the diameter was larger than that of a roll of a material to be described later. Table 2 shows the type, working hardness, and binder of the abrasive grains of the whetstone. The abrasive grains are alumina-based and have a volume ratio of a highly crushable abrasive grain of # 60 and a highly crushable abrasive grain of # 80, respectively. , And 35 parts of the same alumina-based high-toughness abrasive grains having a particle size of # 60 and # 80 each having a volume ratio of 15 parts. The binder is vitrified and the abrasive rate is 38. % Coarse structure. Here, the 35 parts by volume ratio means the volume
The same meaning as 35% in the ratio, and similarly, 15 parts in the volume ratio
"A" has the same meaning as 15% by volume.

[0015]

[Table 2]

The alumina-based highly crushable abrasive grains (A1) and the alumina-based high toughness abrasive grains (A
2), as shown in FIG. 2, has a crush resistance of 22% and 30%, respectively, according to the JIS method.

Table 3 shows the specifications of the grindstone for rolling mills of this embodiment. It can be seen that the grindstone for the roll mill of the present embodiment has an extremely soft bond and is in the range of a grindstone having a coarse structure.

[0018]

[Table 3]

In order to examine the performance of the grindstone of the present embodiment, a grinding test was performed with a grinder. The material to be ground subjected to the grinding test was a roll made of high-speed tool steel, mainly composed of Fe, 0.92% of C, 2.39% of Si, and 0.3% of Mn.
%, 4.14% of Cr, 2.22% of Mo, and 1.0% of V
% And W are 0.31%.

The target whetstone performance was as follows.

(1) The same grinding wheel can be used from rough grinding to finish grinding. (2) As grinding efficiency, the removal amount per unit time is 3.0 cc / min or more, and (3) clogging and scratch prevention. (4) Ability to finish with the specified surface roughness, (5) Scratch, feed mark, chatter mark by medium grinding and finish grinding with low load And the grinding method is as follows.

(A) cylindrical traverse grinding; (b)
The grindstone and the roll are rotated in the direction of upcutting. (C) The grindstone has a larger diameter than the roll, and the grindstone rotates at a higher peripheral speed than the roll. (D) Take the tally time to accumulate at the end of the grindstone traverse. (E) cleaning the grinding wheel and the contact surface of the grinding wheel / roll with the grinding fluid and cooling.

The conditions of the grinding test are shown below.

Grinding machine FARREL Grinding fluid Emulsion type Roll size: diameter 460 (mm) Wheel peripheral speed V: 1600 to 1000 (m / min) Roll peripheral speed v: 60 to 50 (m / min) Feed speed f: 2 .0 (m / min)
Grinding time T: 30 (min) Deletion diameter ΔD: 0.1 (mm) Surface roughness: 0.3 (μRa) or less As a result of the grinding test, the grindstone of the present embodiment is the above (1) to (5)
Was satisfied, and it was confirmed to have excellent performance as a grinding wheel for a roll mill.

[0025]

According to the present invention, the grinding wheel for rolling rolls can be used in a volume ratio of 60 to 80% of alumina-based highly crushable abrasive grains.
Mixing ratio of 40-20% of high toughness type abrasive grains of the same alumina
In the coarse structure, it was configured by bonding with vitrified bond with a very soft bond degree, so by using the grindstone of the present invention, conventionally, it is very difficult to grind with a grindstone composed of general abrasive grains. It has become possible to grind rolling rolls made of high-speed tool steel.

In fact, the efficiency is 3 as with the conventional material roll.
With a working time of 0 minutes, a body diameter reduction of 0.1 mm was made possible.
At the same time, it is possible to finish the surface roughness with a predetermined tolerance and to grind the rolling roll so that feed marks, chatter marks and scratches do not remain.

In addition, the grindstone of the present invention uses alumina-based general abrasive grains as a raw material and does not use expensive superabrasive grains as a raw material.

[Brief description of the drawings]

FIG. 1 is a view showing a grindstone in which grindstone members having different degrees of coupling are configured in a sandwich structure.

FIG. 2 is a view for explaining the crush resistance of abrasive grains.

FIG. 3 illustrates a crushing process during grinding of mixed abrasive grains.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Bond 2 High toughness alumina abrasive grain 3 Highly crushable alumina abrasive grain P Cutting resistance applied to high toughness alumina abrasive grain after crushing of highly crushable abrasive grain

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-54-29189 (JP, A) JP-A-63-144963 (JP, A) JP-A-2-106273 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B24D 3/18 B24D 3/00 320 B24D 3/00 330

Claims (3)

(57) [Claims] 1. An alumina-based highly crushable abrasive grain and an alumina-based single-crystal high-toughness abrasive grain are mixed in a volume ratio of the high-crushable abrasive grain.
A roll wheel grinding wheel in which 40 to 20% of the high toughness abrasive grains are mixed with 60 to 80%, and are bonded by vitrified bonds with a coarse structure and a very soft bond. 2. The highly crushable abrasive has a crushing resistance against JIS method.
20 to 24% abrasive grains, the high toughness abrasive grains are JIS method
Abrasive particles with an anti-crush ratio of 30-40%
The grinding wheel for rolling mill according to claim 1 . 3. The abrasive grain ratio of the coarse structure is 30 to 40%.
The coupling degree is C to E in JIS notation.
The grinding wheel for rolling mill according to claim 1 or 2, wherein the grinding wheel is used .