WO2008040844A1

WO2008040844A1 - Method for manufacturing a roll and a roll for fibre-web machine

Info

Publication number: WO2008040844A1
Application number: PCT/FI2007/050521
Authority: WO
Inventors: Jari Liimatainen; Mikko Uusitalo; Markku Kyytsönen
Original assignee: Metso Materials Technology Oy
Current assignee: Metso Finland Oy
Priority date: 2006-10-02
Filing date: 2007-09-26
Publication date: 2008-04-10
Anticipated expiration: 2009-04-02
Also published as: FI20075270A0; FI20075270L; AT506350A2; FI20075270A7; DE112007002160T5; AT506350B1; AT506350A3

Abstract

The invention relates to a method for manufacturing a roll (10) intended for processing a fibre web and a roll (10) a cylindrical roll body (11) of which is constituted by joining together by a joint/joints (12) at least two metallic annular roll pieces (101, 102, 103). Said annular roll piece comprises a centre hole (13) or is without a centre hole and the roll piece comprises required channels such as flow channels (14) or is without said channels. After joining, in addition, the roll body (11) of the roll (10) is thermally treated, into the roll body (11) are constituted required channels, such as flow channels, by machining, and a shell surface (1 Ia) is surface-hardened or coated in the hardness of above 500 HV.

Description

Method for manufacturing a roll and a roll for fibre-web machine

The present invention relates to fibre-web machines, advantageously paper, pulp and board machines.

Particularly, the present invention relates to a roll intended for processing a fibre web, a cylindrical roll body of which is constituted by joining together by a joint/joints at least two metallic annular roll pieces, which roll piece comprises a centre hole or is without a centre hole.

Furthermore, the present invention relates to a method for manufacturing a roll intended for processing a fibre web, a cylindrical roll body of which is constituted by joining together by a joint/joints at least two metallic annular roll pieces, which roll piece comprises a centre hole or is without a centre hole.

The roll described in this specification is a roll used in fibre-web processing devices utilised in manufacturing paper, pulp and board webs and corresponding fibre webs, the roll body of which is single-layered and the roll body of which can additionally be coated.

As previously known, mainly chilled iron or steel has been used as the shell material of metallic rolls.

Significant problems of chilled rolls are the low strength, brittleness and nonuni- formity of the material. Due to low strength and brittleness, the material does not endure high tensile stresses which can be created in intensive heating and cooling situations which are particularly the fault and emergency situations of the fibre- web process. For example, an entry of high temperature from inside the thermo roll via the outer surface onto the web or from the web via the outer surface of the thermo roll inside the thermo roll or the cooling/heating of the thermo roll cause great temperature differences in the shell and particularly in the boundary surface^) of the material layers, whereby different thermal stresses and thermal expansions cause great sheafing forces which can break the thermo roll. For avoiding great shearing forces, modern thermo rolls are cooled and heated slowly. This results in process delays, which increases manufacturing costs and problems.

The nonuniformity and instability of the material of the chilled rolls cause problems in the dynamics of rotating rolls, whereby vibrations, inter alia, "barring" and balancing become problematic particularly in multi-nip calenders. A reason is the thickness variation of a single layer caused by the manufacturing technique, whereby the thermo roll deflects when heated, i.e., a thermo roll well balanced when cool can, because of asymmetric thermal expansion, deflect and be incorrectly balanced in the operating temperature. The instability of the inner layer, which is typically pig-iron casting, causes, again, that e.g. loads (deflecting) during transport and processing produce small permanent deformations (deflections) which are not visible until at the end-use site when the thermo roll rotates (vibrations).

In order to avoid problems occurring in connection with chilled rolls, in more demanding process situations one has increasingly shifted to the use of steel materials. Then, advantages are, inter alia, the better uniformity, stability and considerably higher strength of material characteristics.

In manufacturing rolls of steel, a problem has been the long delivery time of high- tensile roll blanks, such as forged roll blanks, which can typically be even two years.

A general object of the present invention is to remove or at least substantially minimise above-mentioned disadvantages and flaws and to speed up the manufacturing of a roll intended for processing a fibre web. According to an aspect of the present invention, a second general object is to provide a novel and inventive roll the structure of which has been simplified and the manufacture of which has been made more effective.

According to another aspect of the present invention, a third general object is to provide a method for manufacturing a roll intended for processing a fibre web, a particular object being the shortening of the manufacturing time of a steel roll.

These objects are achieved with the present invention the special characteristics of which are defined in the enclosed set of claims.

According to a first embodiment of the invention, it is generally characteristic of the roll that after the joining, in addition

- a roll body of the roll is thermally treated, advantageously stress relieved, into the roll body are constituted required channels, such as flow channels, by machining, and

- a shell surface is surface-hardened or coated in the hardness of above 500 HV.

It is generally characteristic of the method according to the invention for manufacturing a roll that after the joining of roll pieces, in addition

- a roll body of the roll is thermally treated, advantageously stress relieved,

- into the roll body are constituted required channels, such as flow channels, by machining, and

As an advantage of the invention is achieved the speeding up of the manufacturing of the roll from order to delivery. The delivery time of roll pieces to be joined together to constitute the roll, they being advantageously high-tensile weldable metallic material, is considerably shorter when compared with the delivery times of forged products. For the part of other aspects, characteristics and advantages of the invention, we refer to the dependent claims of the set of claims and to the particular part of the following description which depicts in detail but only as examples some advantageous embodiments of the invention and their implementation possibilities.

The invention will next be described by referring to enclosed figures in which the roll according to the invention has been illustrated, without limiting the invention solely to what is shown in the figures.

Fig. 1 is a perspective view of the roll body of a roll according to an advantageous embodiment of the invention as assembled.

Fig. 2 shows a cross-section of the roll body of a roll according to an advantageous embodiment of the invention which body is constituted of three roll pieces comprising a centre hole by welding.

Fig. 3 shows three roll pieces in which channels have been constituted before joining the roll pieces together as a cylindrical roll body.

Figs. 1-3 illustrate a roll 10 intended for processing a fibre web, a roll body 11 of which is constituted of two or more annular roll pieces 101, 102, 103 etc. In other words, the roll is constituted of 2+n roll pieces in which n is an integer which is greater than or equal to 0.

The cylindrical roll body 11 of the roll 10 is constituted by joining together by a joint/joints 12 at least two metallic annular roll pieces 101, 102, 103.

The metallic annular roll piece 101, 102, 103 may, before constituting into the roll body 11, comprise a centre hole 13 or it can be constituted without a centre hole.

After joining the roll pieces 101, 102, 103 into the roll body 11, in addition - the roll body 11 of the roll 10 is thermally treated, advantageously stress relieved, into the roll body 11 are constituted required channels, such as flow channels 14, by machining, and the shell surface 1 Ia of the roll body 11 is surface-hardened or coated in the hardness of above 500 HV.

The roll pieces 101, 102, 103 are advantageously manufactured of steel.

The roll pieces 101, 102, 103 are advantageously manufactured of a weldable high-tensile steel grade.

The joint 12 of the annular roll pieces 101, 102, 103 can be implemented with known techniques, advantageously in the embodiment of Figs. 1 and 2 the joining is done by welding.

The joints 12 of the roll pieces 101, 102, 103 can further be done by bolting (not shown in the figures).

In the embodiment shown by Fig. 3, inside each piece to be joined is constituted before joining a centre hole 13 with a known manufacturing technique e.g. drilling, turning or milling or with a combination of some known manufacturing techniques. After joining, the centre hole 13 can be further processed e.g. with cutting methods.

Naturally, the roll pieces 101, 102, 103 to be joined can also be enclosed when joining, whereby it is additionally possible to constitute required channels 14, e.g. for heat transfer possibly including the above-mentioned centre hole 13, in the roll 10 after the assembly in the stage where roll pieces are joined together. In the second embodiment of the invention, into the separate roll pieces 101, 102, 103 etc. can have been done according to Fig. 3 before assembling the roll body 11 readily flow channels 14 or openings 14 by means of a known manufacturing technique e.g. cutting, drilling, or a combination of some known manufacturing techniques so that, when the pieces 101, 102, 103 etc. are joined together, the flow channels 14 are combined and constitute into the assembled roll 10 the system of through-going flow channels 14.

In the separate roll pieces 101, 102, 103 etc. can be advantageously done before the assembly of the roll body 11 readily possibly required shapes of fastening and/or joint elements (not shown) so that the roll pieces of the roll 10 when joined together the fastening and/or joint shapes, e.g. the holes of fastening or form- fitting joint shapes, fit each other. The joint surfaces 12a of the roll pieces have been machined before the assembly or they are readily adequately smooth so that the assembled roll 10 is tight.

The roll pieces 101, 102, 103 etc. constituting the roll body 11 of the roll 10 according to the invention can be discoid or annular or particularly cylindrical, such as in Figs. 1-3.

The invention was described above only by means of some of its embodiments considered advantageous. This is, by no means, intended for limiting the invention and, as it is evident to those skilled in the art, many alternative arrangements, combinations and modifications of the particular characteristics of the above- mentioned embodiments are possible within the inventive idea and the scope defined by the enclosed set of claims.

Claims

1. A roll (10) intended for processing a fibre web, a cylindrical roll body (11) of which is constituted by joining together by a joint/joints (12) at least two metallic annular roll pieces (101, 102, 103), which roll piece comprises a centre hole (13) or is without a centre hole, and which roll piece comprises required channels, such as flow channels (14) or is without said channels, characterised in that, after joining the roll pieces (101, 102, 103), in addition the roll body (11) of the roll (10) is thermally treated, into the roll body (11) are constituted required channels, such as flow channels

(14), by machining, and a shell surface (Ha) is surface-hardened or coated in the hardness of above

500 HV.

2. A roll according to claim 1, characterised in that the roll pieces (101, 102, 103) are manufactured of steel.

3. A roll according to claim 1 or 2, characterised in that the roll pieces (101, 102, 103) are manufactured of a weldable high-tensile steel grade.

4. A roll according to any one of claims 1-3, characterised in that the joints (12) of the roll pieces (101, 102, 103) are done by welding.

5. A roll according to any one of claims 1-4, characterised in that the joints (12) of the roll pieces (101, 102, 103) are done by bolting.

6. A roll according to any one of claims 1-5, characterised in that required channels, such as flow channels (14), are made into the annular roll pieces (101, 102, 103) before joining them together as the cylindrical roll body (11) for constituting required channels of the roll (10), such as flow channels (14).

7. A roll according to any one of claims 1-6, characterised in that said thermal treatment of the roll body (11) is stress relieving.

8. A roll according to any one of claims 1-7, characterised in that the shell surface (1 Ia) is surface-hardened or coated in the hardness of above 450 HV.

9. A roll according to any one of claims 1-8, characterised in that the shell surface (1 Ia) is temper hardened or induction hardened or precipitation hardened or surface treated in the hardness of above 450 HV.

10. A method for manufacturing a roll (10) intended for processing a fibre web, a cylindrical roll body (11) of which roll (10) is constituted by joining together by a joint/joints (12) at least two metallic annular roll pieces (101, 102, 103), which roll piece comprises a centre hole (13) or is without a centre hole, and which roll piece comprises required channels, such as flow channels (14) or is without said channels, characterised in that, after the joining of the roll pieces (101, 102, 103), in addition

- the roll body (11) of the roll (10) is thermally treated,

- into the roll body (11) are constituted required channels, such as flow channels (14), by machining, and

- a shell surface (Ha) is surface-hardened or coated in the hardness of above 500 HV.

11. A method according to claim 10, characterised in that the roll pieces (101, 102, 103) are manufactured of steel.

12. A method according to claim 10 or 11, characterised in that the roll pieces (101, 102, 103) are manufactured of a weldable high-tensile steel grade.

13. A method according to any one of claims 10-12, characterised in that the joints (12) of the roll pieces (101, 102, 103) are done by welding.

14. A method according to any one of claims 10-13, characterised in that the joints (12) of the roll pieces (101, 102, 103) are done by bolting.

15. A method according to any one of claims 10-14, characterised in that required channels, such as flow channels (14), are processed into the annular roll pieces (101, 102, 103) before joining them together as the cylindrical roll body (11) for constituting required channels of the roll (10), such as flow channels (14).

16. A method according to any one of claims 10-15, characterised in that said thermal treatment of the roll body (11) is stress relieving.

17. A method according to any one of claims 10-16, characterised in that the shell surface (1 Ia) is surface-hardened or coated in the hardness of above 450 HV.

18. A method according to any one of claims 10-17, characterised in that the shell surface (Ha) is temper hardened or induction hardened or precipitation hardened or surface treated in the hardness of above 450 HV.