US3670381A

US3670381A - Rolls and rollers particularly for continuous casting plants, bar deformation plants and for hot rolling mills operated at low rolling speeds

Info

Publication number: US3670381A
Application number: US55830A
Authority: US
Inventors: Rudolf Schoffmann
Original assignee: Voestalpine AG
Current assignee: Voestalpine AG; Voest AG
Priority date: 1969-07-25
Filing date: 1970-07-17
Publication date: 1972-06-20
Anticipated expiration: 1989-06-20
Also published as: BE753625A; GB1310560A; DE2030322A1; ES188324Y; AT291454B; FR2053148A1; FR2053148B1; CH528932A; SE351572B; ES188324U; CS152478B2; CA937788A

Abstract

The invention proposes rolls and rollers, particularly for continuous casting plants, bar deformation plants and hot rolling mills operated at low rolling speeds, in which the improvement resides in that the working body of the rolls or rollers, respectively, is formed by a plurality of segments arranged side by side with play, which segments are provided with key-like projections engaging with correspondingly formed guiding grooves arranged at the roll or roller core. The core may be made of material of high strength, capable of absorbing great bending stresses, and the segments may be made of material resistant to heat and wear. Owing to the division of the working tools into two units and the provision of play between segments, heat cracks and ruptures are precluded.

Description

United States Patent Schoffmann [4 1 June 20, 1972 [54] ROLLS AND ROLLERS 5 References Ci PARTICULARLY FOR CONTINUOUS UNITED STATES PATENTS CASTING PLANTS, BAR 1,618,704 2/1927 Grupe ..29/124 x DEFORMATION PLANTS AND FOR 1,570,231 1/ 1926 Decker ..29/124 X 912,254 2/ 1909 Nash ..29/124 L 0w ROLLING SPEEDS 996,970 7/1911 Burnham ...29/124 X 2,770,082 11/1956 whltesell ...29/124 X [72] inventor: Rudolf schoflmann Linz, Austria I 1,209,736 12/1916 Lueckenbach ..29/124 [73] Assignee: Vereinigte Osterreichische Eisen-Und Primary ExaminerAlfred R. Guest Stahlwerke Aktiengesellschaft, Linz, Aus- Attorney-Brumbaugh, Graves, Donohue & Raymond tria [22] Filed: July 17, 1970 [57] ABSTRACT The invention proposes rolls and rollers, particularly for con- [211 Appl 55330 tinuous casting plants, bar deformation plants and hot rolling mills operated at low rolling speeds, in which the improvement resides in that the working body of the rolls or rollers, respectively, is formed by a plurality of segments arranged side by [30] 93" Apphcauon Prlomy. Dam 7 side with play, which segments are provided with key-like pro- .luly 25, 1969 Austria ..A 7189 jecfions engaging with correspondingly formed guiding a grooves arranged at the roll or roller core. The core may be made of material of high strength, capable of absorbing great [52] US. Cl ..29/;2;1,b29/11 bending stresses, and the segments may be made of mamrial [5 f CI 3 resistant to heat and wear. Owing to the division of the work- [58] new of Search" ing tools into two units and the provision of play between seg- 164/76 282 ments, heat cracks and ruptures are precluded.

12 Claims, 6 Drawing Figures P'A'TE'N'TEDJum [an 3.6 70 3 8 1 sum 10F 2 FIG-I RUDOLF SCI-lFFMANN ATTORNEYS.

SHEET 2 {IF 2 FIG. 5

I PIC-7.6

ngvENToR. RUDOLF SCHOFFMANN BY Mg gm,

m 'zy e his ATTORNEYS ROLLS AND ROLLERS PARTICULARLY FOR CONTINUOUS CASTING PLANTS, BAR DEFORMATION PLANTS AND FOR HOT ROLLING MILLS OPERATED AT LOW ROLLING SPEEDS The invention relates to rolls and rollers, particularly for continuous casting plants, bar deformation plants and hot rolling mills operated at low rolling speeds.

v Rolls and rollers in continuous casting and bar deformation plants are used not only for shaping but also for supporting, drawing, bending and straightening cast bars. They are exposed to specific stresses. As a rule, the speed with which the cast bars are fed, or lowered in continuous casting or bar deformation plants lies between about 0.6 and 1.5 m/min. The speed with which the material to be rolled is pushed into a planetary mill by means of pushing rolls arranged in front of such mill is about the same. As a comparison it should be pointed out that in traditional hot rolling plants therolling material runs through the rolling stands with a speed of between 30 and 600 m/min.

Thus, rollers and rolls in continuous casting or bar deforma-' tion plants and in a pushing stand arranged before a planetary mill are for a far longer time in contact with the bar having a surface temperature of between about l,000 and 'l,300 C than the rollers and rolls in other rolling mills. In operation they are locally highly overheated and exposed to thermal shock stresses as .a result of the necessary cooling. It is therefore imperative that such rolls and rollers be provided with resistance to the formation of cracks and ruptures which might be caused by heat stresses and with adequate strength, including as small a notch sensitivity as possible, and suffic'ient resistance to wear.

Pulling and straightening rollers and rolls for shaping bars have so far been produced from steels with a composition of 0.4 to 0.7 C, 0.5 to L6 Cr, 0.20 to 0.90 Mo and 0.40 V, balance substantially Fe. Rolls with this analysis are well suited as rolls for hot rolling but they have not proved satisfac' tory for use in continuous casting or bar deformation plants; when they are used in such plants substantial chill cracks developed rapidly at the surface and ruptures, particularly ruptures going through the body of the rolls occurred. The reason for such damage lies in the fact that such rollers or rolls According to a preferred embodiment the segments and the roll or roller core are made of different materials. More particularly, the segments may be made of material resistant to heat and wear, preferably of heat resistant steel being composed of 0.15 to 0.30 C, 0.20 to 0.50 Si, 0.40 to 0.70 Mn, 0 to 0.35 P, 0 to 0.035 S, 0.50 to 3.0 Cr and 0.40 to 1.0 Mo, if desired up to 1.5 percent nickel and up to 0.5 percent vanadium and up to 1 percent tungsten, balance iron. The roll or roller core may be made of material of high strength, capable of absorbing great bending stresses, preferably of steel composed of 0.5 to 0.7 C, 0.2 to 0.6 Si, 0.6 to 1.0 Mn, balance Fe.

In order that the construction of the rolls and rollers according to the invention may be more fully understood, it shall now be explained with reference to the drawings, in which FIG. 1 is a longitudinal sectional view of a roll,

FIG. 2 is a vertical sectional view along the line ll-ll of FIG. 1, and

FIG. 3 is an enlarged part of the longitudinal sectional view according to FIG. 1. FIGS. 4, 5 and 6 show similar illustrations of another embodiment'of the invention;

FIG. 4 is a longitudinal sectional view of the upper half of a roll.

FIG. 5 is a vertical sectionalview of the whole roll taken along the line V V of FIG. 4 during mounting, and FIG. 6

- shows the samesectional view (V V) after mounting is are subjected to a different kind of stresses which are not compensated by an intensive cooling, but, on the contrary, even aggravated. Rolls with a high carbon content are sensitive against rapid heating and change of temperature.

The invention is aimed at avoiding the described disadvantages and difficulties by creating rolls and rollers for use'in continuous casting plants, bar deformation plants, and hot rolling mills operated at low rolling speeds, having a long life and durability, and a high resistance against bending stresses, wearing and the formation of cracks.

This task is solved according to the invention in that the body of the rolls or rollers, respectively, is formed by a plurality of segments arranged side by side with play, which segments are provided with key-like projections engaging with appropriately formed guiding grooves arranged at the roll or roller core, respectively.

Advantageously the side faces of the segments are slightly inclined towards each other so that the play gaps are slightly conically widening towards the periphery of the roll.

Suitably the key-like projections are designed to be dovetail shaped.

The grooves may be arranged at the surface of the roll or roller core concurrently and in parallel with the longitudinal axis of the roll or roller and the individual rows of segments may be held together by connecting means, e.g. screws, a holding ring surrounding the roll or roller core, respectively, being provided for fixing the segments; it is, however, also possible to arrange the grooves to be concurrent in circumferential direction of the roll or roller core surface, and to provide at least one further recess extending over the total body length in a direction transverse to said grooves through which recess the individual segments may laterally be slid into the groove and in which recess a holding rail for fixing said segments may be inserted after mounting.

completed when the roll is ready for use.

In FIG. 1 numeral 1 denotes the roll core 1 into whose cylindrical surface grooves 2 are milled to be side by side and parallel to each other in the direction of the longitudinal axis of the roll. These grooves have a dove-tail cross section. They serve for taking up a plurality of segments 3 provided at their bottom sides with dove-tail projections 4 which fit into the grooves 2 in key-fashion. As indicated by the arrows in FIG. I, the segments 3 may be inserted into the grooves 2 with their key-like projections 4 from both sides of the roll. About in the middle of the roll and around its circumference a recess 7 is provided for receiving a holding ring 8 made of two parts which serves for fixing the segments 3. This holding ring need not be arranged in the middle of the roll but may be arranged in any other part of the roll, e.g. at the margin of the roll. Each segment 3 is provided with a bore 5; together, these bores form a longitudinal'canal through which screws 9 are putas soon as one row of segments has been built in. By means of the screws 9 the individual rows of segments which are supported by the holding ring 8 are held together. On both sides of the holding ring 8 segments 3' are arranged which are each provided in the projection 4 with a small angular recess for receiving the holding ring. It is also possible that all segments are provided with such a recess in which case only a single form of segments is necessary for the whole roll body.

In FIG. 1 the roll is shown in a condition during mounting. From the left hand side two segments 3, 3' had been inserted into the upper groove 2. The lower groove is already filled with segments, illustrating the arrangement when mounting has been completed. In the finished roll between each segment and its neighboring segment a play 16 is present, in axial as well as in circumferential direction, so that the segments may freely expand in any direction during operation. Thus, it is practically impossible that cracks may occur; if, in exceptional cases cracks should occur after all, they cannot extend to the core of the roll or roller, respectively and a rupture of the body is therefore rendered absolutely impossible.

The side faces 6, 6' of the individual neighboring segments are slightly inclined towards each other, so that the play 16 between two segments is greater at the surface than at the core. Experience has shown that only some centimeters of the surface are influenced by the great heating of the rolls or rollers, so that the operational demands are absolutely met by such formation. The dimensions of the play 16 depend on the surface temperature and on the dimensions of the individual segments; as a rule, the play will amount to some tenths of a millimeter.

In the modified embodiment according to FIG. 4 grooves 1 1 are machined into the cylindrical surface of the core in circumferential direction of the roll and parallel to each other; segments 12 with dove-tail projections 13 may be inserted into them. FIG. 5 shows the roll when mounting of the segments 12 has not been completed yet. A recess 14 is provided perpendicularly to the circumferential grooves 11 in longitudinal direction of the roll; the width of this recess is somewhat greater than that of the projections 13 of the segments 12. The segments 12 are inserted laterally through the recess 14 into the respective groove 11 and then moved on in circumferential direction (direction of arrows in FIG. 5). When all segments 12 are built in they are adjusted until a rail 15 can be inserted laterally through the recess 14; this rail serves for fixing the segments on the roll core 10. The play 16 between the individual segments is as described in connection with FIGS. 1 to 3. The side faces of the segments are slightly inclined towards each other.

By dividing the body surface of the rolls or rollers into numerous segments which may expand into any direction and are releasably connected with the core, one obtains the advantage that the core of the rolls or rollers practically has an unlimited life and worn segments may simply and rapidly be exchanged. Owing to the division of the roll into body surface and body core, each of these units may be made of the most suitable and qualitatively best material, without having to make do with compromises or less favorable interim solutions. Preferably, the core is made of high-strength, unalloyed material which is capable of absorbing high bending stresses, which material would otherwise be unsuitable for hot rolling rolls in view of its liability to the formation of cracks. By dividing the rolls into two parts as proposed by the invention, the core remains practically free from heat influences emanating from the material to be rolled and only the segments are affected by them. Therefore, the segments may be made of steel which is resistant to heat and wear, the characteristic of strength being not so important for them. The segments may be designed relatively small so as to reduce the costs for the material. If particularly high stresses are exerted on the segments they may be made of a metal ceramic material, e.g. of molybdenum and circonium oxide. Finally, the segments and the core may be made of the same material if the exchange of the segments may be carried out at any time and without having to stop the operation, which may be an inexpensive solution in plants which are not continuously operated. The advantages of the invention thus may be exploited in all cases of application.

What I claim is:

l. A revolving tool particularly for use as rolls and rollers in continuous casting plants, bar deformation plants and hot rolling mills operated at low rolling speeds, comprising a core made of material with a high strength and capable of absorbing great bending stresses, and having a plurality of guiding grooves on its periphery, and a body formed of a plurality of segments arranged side by side with play, the segments being made of material resistant to heat and wear and having keylike projections for engagement with said guiding grooves.

2. The tool set forth in claim 1, wherein said segments have slightly inclined side faces so that the play gaps are slightly conically widening towards the periphery of the tool.

3. The tool set forth in claim 1, wherein the key-like projections are designed to be dove-tail shaped.

4. The tool set forth in claim 1, wherein the grooves are arranged parallel to the longitudinal axis of the tool, the individual rows of segments are held together by connecting means, and a holding ring is provided for securing said segments to the core.

5. The tool set forth in claim 1, wherein the grooves are arranged perpendicular to the longitudinal axis of the tool, at least one recess is provided extending the length of the tool parallel to its longitudinal axis for positioning said segments in the grooves, and a holding rail is provided for securing said se ents to the core.

. The tool set forth in claim 1, wherein the segments are made of heat-resistant steel composed of 0.15 to 0.30 C, 0.20 to 0.50 Si, 0.40 to 0.70 Mn, 0 to 0.035 P, 0 to 0.035% S, 0.50 to 3.0 Cr, 0.40 to 1.0 Mo, 0 to 1.5 Ni, 0 to 0.5 V and 0 to l W, balance iron.

7. The tool set forth in claim 1, wherein the core is made of steel composed of 0.5 to 0.7 C, 0.2 to 0.6 Si, 0.6 to 1.0 Mn, balance iron.

8. A revolving tool particularly for use as rolls and rollers in continuous casting plants, bar deformation plants and hot rolling mills operated at low rolling speeds, comprising a core made of heat-resistant steel consisting of 0.15 to 0.30 C,

0.20 to 0.50 Si, 0.40 to 0.70 Mn, 0 to 0.035 P, 0 to 0.035 S, 0.50 to 3.0 Cr, 0.40 to 1.0 Mo, 0 to 1.5 Ni, 0 to 0.5 V, and 0 to l W, balance iron, and having a plurality of guiding grooves on its periphery, and a body formed of a plurality of segments arranged side by side with play, the segments being made of steel consisting of 0.5 to 0.7 C, 0.2 to 0.6 Si, and 0.6 to 1.0 Mn, balance iron, and having keylike projections for engagement with said guiding grooves.

9. The tool set forth in claim 8, wherein said segments have slightly inclined side faces so that the play gaps are slightly conically widening towards the periphery of the tool.

10. The tool set forth in claim 8, wherein the key-like projections are designed to be dove-tail shaped.

11. The tool set forth in claim 8, wherein the grooves are arranged parallel to the longitudinal axis of the tool, the individual rows of segments are held together by connecting means, and a holding ring is provided for securing said segments to the core.

12. The tool set forth in claim 8, wherein the grooves are arranged perpendicular to the longitudinal axis of the tool, at least one recess is provided extending the length of the tool parallel to its longitudinal axis for positioning said segments in the grooves, and a holding rail is provided for securing said segments to the core.

Po-ww TED STATES PATENT OFFICE CERTIFICATE @F COREC'HUN Patent No. 3, 7 ,3 1 Dated Junev 1972 lnventofls) Rudolf Schoffmann It is certified 'that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 1 line 3 before "0AM" insert --to--'-; and

Col. 2 line 6, "o to 0.35% P" should be --o to 0.035% P",

Signed and sealed this 31st day of October 1972.

(SEAL) AtteSt:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents

Claims

1. A revolving tool particularly for use as rolls and rollers in continuous casting plants, bar deformation plants and hot rolling mills operated at low rolling speeds, comprising a core made of material with a high strength and capable of absorbing great bending stresses, and having a plurality of guiding grooves on its periphery, and a body formed of a plurality of segments arranged side by side with play, the segments being made of material resistant to heat and wear and having key-like projections for engagement with said guiding grooves.

5. The tool set forth in claim 1, wherein the grooves are arranged perpendicular to the longitudinal axis of the tool, at least one recess is provided extending the length of the tool parallel to its longitudinal axis for positioning said segments in the grooves, and a holding rail is provided for securing said segments to the core.

6. The tool set forth in claim 1, wherein the segments are made of heat-resistant steel composed of 0.15 to 0.30 % C, 0.20 to 0.50 % Si, 0.40 to 0.70 % Mn, 0 to 0.035 % P, 0 to 0.035% S, 0.50 to 3.0 % Cr, 0.40 to 1.0 % Mo, 0 to 1.5 % Ni, 0 to 0.5 % V and 0 to 1 % W, balance iron.

7. The tool set forth in claim 1, wherein the core is made of steel composed of 0.5 to 0.7 % C, 0.2 to 0.6 % Si, 0.6 to 1.0 % Mn, balance iron.

8. A revolving tool particularly for use as rolls and rollers in continuous casting plants, bar deformation plants and hot rolling mills operated at low rolling speeds, comprising a core made of heat-resistant steel consisting of 0.15 to 0.30 % C, 0.20 to 0.50 % Si, 0.40 to 0.70 % Mn, 0 to 0.035 % P, 0 to 0.035 % S, 0.50 to 3.0 % Cr, 0.40 to 1.0 % Mo, 0 to 1.5 % Ni, 0 to 0.5 % V, and 0 to 1 % W, balance iron, and having a plurality of guiding grooves on its periphery, and a body formed of a plurality of segments arranged side by side with play, the segments being made of steel consisting of 0.5 to 0.7 % C, 0.2 to 0.6 % Si, and 0.6 to 1.0 % Mn, balance iron, and having key-like projections for engagement with said guiding grooves.