JPH076962Y2 - Reinforcing roll for rolling - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a reinforcing roll for rolling.

[Conventional technology and its problems]

The structure of the conventional reinforcing roll for rolling will be described with reference to FIGS. Each 1 represents a four-high rolling mill, each 2 represents a working roll, and each 3 represents a reinforcing roll. In the case of the conventional body portion 3a of the reinforcing roll 3 as shown in FIG. 5, for example, when the initial surface hardness Hs = 70 is given, its outer radius is
Effective use diameter L in the range from R ₁ to effective use radius R ₂
(About 200 mm), it was hardened as deep as possible to ensure wear resistance. Therefore, the hardness at the effective use radius R ₂ part is given as Hs = 67, and as the hardness of the center O
Hs = about 40 was given. Such a reinforcing roll 3
Is referred to as a high cure depth reinforcing roll.

In the tandem mill as shown in FIG. 2, the reinforcing roll 3 is first set and operated in the seventh stand F ₇ which requires the maximum diameter and the highest hardness. Then cutting opportunity of by connexion surface on the surface conditions of the rolls 3, low hardness, the sixth stand F ₆ may diameter is small, but gradually diverted to fifth stand F _5, the effective use size L As a result of the limited hardness range, there is a limited diversion range. That is, in the high-hardening depth reinforcing roll 3, as can be seen from the table described below, conversion to the fourth stand F ₄ where the degree of decrease in hardness is relatively small is limited, and the degree of decrease in hardness from the fourth stand F ₄ is limited. The conversion to a relatively large third stand F ₃ or later is practically impossible, and the conversion range is narrow. This is based on the fact that when the hardness of the reinforcing roll 3 is higher than the proper hardness in each stage, the working roll 2 may be roughened by the four-high rolling mill 1. For this reason, at present, a different type of low hardness reinforcing roll 3 is used in the four-high rolling mill 1 located on the rear side in the rolling direction, which is normally the third stand F _{3 and} thereafter.

Reinforcing roll 3 of high hardening depth with improved wear resistance
The shortcomings of are summarized as follows.

(A) Since the hardness of the reinforcing roll 3 is fixed to the inner layer portion of the effective use diameter L with high hardness, the divertible range is narrow.

(B) Reinforcing roll 3 is used in the converted 4-high rolling mill 1.
Was too high, which caused rough skin of the working roll 2.

(C) Since the hardening depth of the reinforcing roll 3 is deep, when the surface crack occurs, the inward progress is high and the so-called accident resistance is poor.

(D) In order to obtain a high hardening depth, the heat treatment work required a lot of time and cost.

[Means for Solving the Problems]

The present invention has been made in view of the above-mentioned conventional technical problems, and has a structure in which a pair of working rolls for rolling a rolling material and rotatably arranged outside each of the working rolls are provided. In a tandem mill in which a plurality of four-high rolling mills each having a reinforcing roll supporting the rolls are arranged in series, a predetermined hardness and a hardening depth are applied to the body surface layer of the reinforcing rolls of the four-high rolling mill. After that, each time the roll is regenerated or converted to a desired stand, it is a reinforcing roll for rolling that imparts the required hardness and hardening depth to the surface layer of the body of the roll.

[Action]

According to such a reinforcing roll for rolling, a predetermined hardness and a hardening depth are individually provided to the body surface layer of the reinforcing roll of each four-high rolling mill. That is, the hardness and hardening depth of the body surface layer of the reinforcing roll, the position corresponding to the body surface of the reinforcing roll arranged on the rear side in the rolling direction, the hardness of the body surface hardness or more required at the position is It is given not to be given. Therefore, when the surface layer of the reinforcing roll is used while being machined, a hardness portion lower than the body surface hardness of the reinforcing roll disposed on the rear side in the rolling direction is exposed. After that, a predetermined hardness and a hardening depth required for the reinforcing roll arranged on the rear side in the rolling direction are applied to the body surface layer of the reinforcing roll by quenching, for example, in a low frequency induction heating furnace. The hardness and the hardening depth are also given to the position corresponding to the body surface of the reinforcing roll arranged on the rear side in the rolling direction so that the hardness higher than the body surface hardness required at the position is not applied. Incidentally, after the low hardness portion of the reinforcing roll is exposed, the body surface layer of this reinforcing roll can be given a predetermined hardness and a curing depth required for the reinforcing roll arranged on the front side in the rolling direction, and It is also possible to regenerate the reinforcing roll and use it on the same stand.

In this way, it can be sequentially diverted as a reinforcing roll for any stand. According to such a reinforcing roll for rolling, quenching work is required each time it is diverted, but since this quenching work is to quench only the surface layer portion,
It is relatively easy as a whole heat treatment work.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show an embodiment of the present invention. In the figure, reference numeral 1 indicates a four-high rolling mill. The four-high rolling mill 1 is rotatably arranged outside each of the pair of working rolls 2,2 and the working rolls 2,2, and supports the respective working rolls 2,2 and reinforces the rolls 3, which suppress bending. 3 and. Such a four-high rolling mill 1 is arranged in series with each of the stands F _{1 to} F ₇ to form a tandem mill. In this dandem mill, a pair of working rolls 2 and 2 of each stand F _{1 to} F ₇ are driven to rotate,
The rolling material 4 supplied from the left side in FIG. 2 is sequentially fed in the rolling direction A and rolled to a predetermined thickness.

4-stage barrel 3a of the pair of rolls 3, 3 of the rolling mill 1, 3a has a maximum surface hardness 70Hs at the seventh stand F ₇ as shown in Table, thereafter, the first stand F ₁ The surface hardness is gradually reduced to the minimum surface hardness of 58 Hs, and the outer diameters of the body portions 3a, 3a are gradually reduced as shown in FIG.

First, as shown in FIG. 4, the 7th stand F _7, that is, the body layers 3a, 3a of the reinforcing rolls 3, 3 positioned at the foremost stage in the rolling direction A have a predetermined hardness and a hardening depth which are not shown. It is given by quenching with a induction heating furnace. The predetermined hardness and hardening depth are the sixth and sixth hardness values arranged immediately behind the rolling direction A.
The reinforcement rolls 3, 3 of the stand F ₆ are provided at positions corresponding to the surfaces of the body portions 3a, 3a so as to prevent the hardness higher than the surface hardness (68 Hs) required at these positions. Specifically, the hardness and the depth of hardening of the maximum Shore hardness of 70 Hs and the minimum Shore hardness of less than 68 Hs were applied to the surface layer of the body portions 3a, 3a of the rolls 3, 3 shown in FIG. The depth at which the predetermined hardness and the predetermined hardening depth should be given is a value that changes depending on the magnitude of the rolling load. Using the reinforcing rolls 3 and 3, rolling as the seventh stand F ₇ was performed.

Next, the reinforcing rolls 3 and 3 of the sixth stand F ₆ were diverted from the reinforcing rolls 3 and 3 of the seventh stand F ₇ . At the time of this conversion, the hardness and depth required for the sixth stand F ₆ on the surface layer of the body portions 3a, 3a of the reinforcing rolls 3, 3 were re-quenched using a low-frequency induction heating furnace as shown in FIG. And gave it. This quenching is performed so as to match the hardness of the corresponding working rolls 2 and 2, and may be tempered after quenching in a low frequency induction heating furnace if necessary.

As described above, in the present invention, first, the reinforcing rolls 3 and 3 having the initial hardness and the hardening depth provided to the necessary minimum are manufactured,
Each time it is diverted in the process of operation, it is hardened to give appropriate hardness and hardening depth to the surface layer. For this purpose, it is effective to use a high-output low-frequency induction heating furnace and heat-treat only the required thin layer at a stretch. After the low hardness portion of the reinforcing rolls 3,3 is exposed, the body portions 3a, 3a of the reinforcing rolls 3,3 are exposed.
It is also possible to give the surface layer a predetermined hardness and hardening depth required for the reinforcing rolls 3 and 3 arranged on the front side in the rolling direction, and further, to regenerate the reinforcing rolls 3 and 3 and use them in the same stand. Is also possible.

[Effect of device]

As can be understood from the above description, according to the present invention, the following effects can be obtained.

(A) The predetermined hardness and the hardening depth given to the body surface layer of each pair of the reinforcing rolls of the four-high rolling mill are given so that they can be hardened each time they are diverted to any stand. Therefore, the range of reproduction and diversion of the reinforcing roll is significantly expanded,
There is a merit that complements the demerit caused by the quenching work each time.

(B) Since the reinforcing roll is provided with a hardness that is adapted to the working roll of the conversion destination four-high rolling mill, the problem that the hardness of the reinforcing roll is too high and the working roll is roughened is eliminated.
As a result, the life of the working roll is extended, so that the basic unit of the working roll is remarkably increased, and it is possible to increase it by almost 50%.

(C) Since the hardening depth of the reinforcing roll is relatively shallow, the inward propagating property is low when a surface crack occurs, and the so-called accident resistance is good.

[Brief description of drawings]

1 to 4 show one embodiment of the present invention, FIG. 1 is a cross-sectional view of the body of a reinforcing roll, FIG. 2 is a tandem mill, and FIG. 3 is a reinforcing roll. FIG. 4 is a diagram showing the relationship between the body layer surface hardness of a reinforcing roll and a stand, and FIG. 5 is a view similar to FIG. 1 showing a conventional reinforcing roll body. 1: 4-high rolling mill, 2: working roll, 3: reinforcing roll, 3a: body, 4: rolling material, A; rolling direction, F _{1 to} F ₇ : stand.

Claims (1)

[Scope of utility model registration request] 1. A pair of working rolls for rolling a rolled material,
Rotatably arranged on the outside of each of the working rolls,
In a tandem mill in which a plurality of four-high rolling mills each having a reinforcing roll supporting each working roll are arranged in series,
After applying a predetermined hardness and curing depth to the body surface layer of the reinforcing roll of the multi-stage rolling mill, it is necessary for the body surface layer of the roll each time the roll is regenerated or converted to a desired stand. A reinforcing roll for rolling, which is characterized by imparting hardness and hardening depth.