JPH0471760A - Roll for continuous caster - Google Patents

Abstract

PURPOSE:To prolong the service life of the above roll for continuous caster by arranging plural recessed parts at the fixed intervals to circular direction of the roll on surface of the roll barrel part. CONSTITUTION:Plural pieces of the slit grooves 1 crossing at the right angle to the roll axis and circulating the roll surface in one round at the fixed intervals to the roll axial direction, are arranged on the roll barrel part 2. The roll for continuous caster is constituted so that crack 4 to the roll circular direction developed on the roll barrel part 2 can progress to the roll circular direction only at the roll barrel part 2 between the adjoining slit grooves 1. Then, at the fixed intervals to the roll circular direction on the roll barrel part 2 surface, plural pieces of the recessed parts 3 are arranged. By this method, eccentric resistance and relaxation of heat stress in the roll can be combinedly provided.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to continuous caster rolls.

[Prior Art] Continuous casting machine rolls, such as pinch rolls, are repeatedly subjected to thermal stress due to high-temperature cast slabs under high loads, and as a result, cracks occur and propagate. Among these cracks, cracks that propagate in the roll circumferential direction will cause roll breakage if left untreated.

There would be no problem if there was a roll material that would not cause or propagate cracks in continuous casting machine rolls, but there is currently no such roll material, and currently the only way to extend the life of rolls is to slow down the propagation of cracks. This is the best method.

Conventionally, the following methods have been used to delay the growth of cracks in the circumferential direction of the roll as described above.

(1) Method of machining the roll surface ■ Slit grooves continuous in the roll axis direction are provided at regular intervals in the roll circumferential direction. (Applicable to flat rolls) ■Slit grooves facing the roll axis are provided in a staggered manner over the entire roll surface. (Applicable to flat rolls) ■Spiral grooves with the same winding on the left and right sides are provided on the roll surface.

(2) How to improve the welding direction when overlaying the roll surface ■ Weld in the axial direction and align the direction of the heat affected zone with the roll axis direction.

■Weld in a zigzag pattern in the circumferential direction of the roll, making the direction of the heat-affected zone zigzag in the circumferential direction of the roll.

[Problems to be Solved by the Invention] However, the conventional method of delaying the growth of cracks in the circumferential direction of a roll has the following problems.

(1) Method of machining the roll surface Although this method has the effect of retarding the propagation of cracks, the eccentricity resistance and thermal stress relaxation properties of the roll are poor.

(2) How to improve the welding direction when overlaying the roll surface Although it may be difficult for roll circumferential cracks to pass through the heat-affected zone, it is not effective enough to significantly slow down crack growth. Poor eccentricity resistance and thermal stress relaxation properties.

This invention solves the above-mentioned problems of the prior art,
The object of the present invention is to provide a continuous casting machine roll that slows down the development of roll circumferential cracks and has excellent roll eccentricity resistance and thermal stress relaxation properties.

[Means for Solving the Problems] The continuous casting machine roll according to the present invention has a plurality of slit grooves provided in the roll body at regular intervals in the roll axis direction, perpendicular to the roll axis and going around the roll surface. In a continuous casting machine roll configured such that a crack in the roll circumferential direction that occurs in the roll body can propagate in the roll circumferential direction only in the roll body between adjacent slit grooves, the roll circumferential crack is formed on the roll body surface. This is a continuous casting machine roll that is provided with a plurality of recesses at regular intervals in the direction.

[Function] The continuous casting machine roll according to the present invention is provided with a plurality of slit grooves that are perpendicular to the roll axis and circumferentially around the roll surface at regular intervals in the roll axis direction, so that the continuous casting machine roll according to the present invention can prevent In a continuous casting machine roll configured such that cracks in the roll circumferential direction can propagate in the roll circumferential direction only in the roll body between adjacent slit grooves, fixed intervals are formed on the roll body surface in the roll circumferential direction. A plurality of recesses are provided. For this reason, cracks occur from the midpoint between adjacent recesses of the plurality of recesses provided at regular intervals in the circumferential direction on the surface of the roll body between adjacent slit grooves, and towards both adjacent recesses. It progresses in the circumferential direction while increasing the depth. This is because thermal stress is relaxed both in the roll circumferential direction and in the roll axial direction around the recesses provided at regular intervals in the circumferential direction of the roll body, so initial cracks do not start to generate and grow. It is from. A crack that grows in the circumferential direction while increasing its depth toward both adjacent recesses stops growing near the recess, and when the depth of the crack becomes deeper than the depth of the recess, it begins to grow again. start and cross the recess in the circumferential direction.

Once the crack crosses the recess, the crack will progress in the same way as a normal flat roll, but the presence of the recess will still alleviate the thermal stress acting on the roll. Therefore, compared to the case where there are no recesses on the roll surface, the growth of cracks can be delayed. Of course, since the roll is constructed as described above, it goes without saying that the roll has excellent eccentricity resistance and thermal stress relaxation properties.

[Example] A continuous casting machine roll according to an example of the present invention will be described with reference to FIGS. 1 to 5. FIG. 1 is a side view of the body of a continuous casting machine roll according to an embodiment of the present invention. Multiple slit grooves 1 that go around the surface
is provided so that cracks in the roll circumferential direction that occur in the roll body 2 can propagate in the roll circumferential direction only in the roll body 2 between adjacent slit grooves 1. A plurality of recesses 3 are provided on the surface at regular intervals in the roll circumferential direction.

FIG. 2 is a side view showing the progress of roll circumferential cracks 4 that have occurred in the roll body 2. FIG. The cracks 4 occur at the midpoint between the adjacent recesses 3 of the plurality of recesses 3 provided at regular intervals in the circumferential direction on the surface of the roll body 2 between the adjacent slit grooves 1, This progresses in the circumferential direction while increasing the depth toward roll body 2.
This is because thermal stress is relaxed both in the roll circumferential direction and in the roll axial direction around the recesses 3 provided at regular intervals in the circumferential direction, so that initial cracks do not start to generate and propagate. The crack 4, which progresses in the circumferential direction while increasing the depth toward both adjacent recesses 3, stops growing near the recess 3, and the depth of the crack 4 becomes deeper than the depth of the recess 3. At this point, it starts to advance again and crosses the recess 3 in the circumferential direction. Once the crack 4 crosses the recess 3, the propagation of the crack 4 is the same as that of a normal flat roll, but then the crack 4 crosses the recess 3.
The thermal stress acting on the roll is alleviated by the presence of the roll.

Therefore, compared to the case where there is no recess 3 on the roll surface, the growth of the crack 4 can be delayed. Of course, since the roll is constructed as described above, it goes without saying that the roll has excellent eccentricity resistance and thermal stress relaxation properties.

3 and 4 are side views showing other shapes of a plurality of recesses 3 provided on the surface of the roll body 2 at regular intervals in the roll circumferential direction. As shown in FIGS. 3 and 4, if the shape of the recess 3 is an elongated hole facing in the roll axis direction, even if multiple rows of roll circumferential cracks 4 occur in the roll body 2, the cracks will not be removed. The progress can be interrupted by this slot.

The longitudinal dimension of this elongated hole (p> is expressed as
p may be about 0.8L, the depth of the recesses 3 may be about 5 to 10 degrees, and the pitch of the recesses 3 in the roll circumferential direction may be about 1/10 to 1/3 of the roll diameter.

FIG. 5 is a side view of a roll in which recesses 3 are arranged in a staggered manner. By arranging the recesses 3 in a staggered manner as described above, there is an effect of retarding the propagation of cracks in the roll circumferential direction throughout the roll.

[Effects of the Invention] According to the present invention, the growth of cracks in the roll circumferential direction of continuous casting machine rolls can be delayed, the life of continuous casting machine rolls can be extended, and the roll can have both eccentricity resistance and thermal stress relaxation properties. ing.

[Brief explanation of drawings]

FIG. 1 is a side view of the body of a continuous casting machine roll according to an embodiment of the present invention, FIG. 2 is a side view showing the progress of roll circumferential cracks that have occurred in the roll body, and FIGS. The figure is a side view showing another shape of a plurality of recesses provided on the roll body surface at regular intervals in the roll circumferential direction, and FIG. 5 is a side view of a roll in which recesses are arranged in a staggered manner. 1... Slit groove, 2... Roll body, 3... Recessed part. 1st eye 2nd figure 3rd figure 4th figure

Claims (1)

[Claims] A plurality of slit grooves are provided in the roll body at regular intervals in the roll axis direction, perpendicular to the roll axis, and circumferentially around the roll surface. A continuous casting machine roll configured to be able to advance in the roll circumferential direction only in the roll body, characterized in that a plurality of recesses are provided on the roll body surface at regular intervals in the roll circumferential direction. Casting machine roll.