Method for producing a wear-resistant roller component

Abstract

Described is a wear-resistant roller component for handling abrasive materials where the component comprises a metal body with at least one surface. It is characterized in that a metal template having a pattern of through-going holes is arranged on the at least one surface of the metal body and in that a cover arranged to cover at least a part of the metal template is located at a distance from the metal template to form a gap between the cover and the metal template and in that a powder material suitable for sintering is introduced into the through-going holes in the metal template through the gap and in that the metal body, the metal template, the cover and the material powder are bonded together by means of a sintering process.

Claims

1. A method for producing a wear-resistant roller component comprising the steps of: arranging a metal template having a pattern of through-going holes on at least one surface of a metal body; providing a cover covering at least a part of the metal template and arranging the cover at a distance to the metal template to form a gap between the cover and the metal template; applying a powder material suitable for being sintered into the through-going holes of the metal template by introducing the powder material into the gap between the cover and the metal template; and bonding together the metal body, the metal template, the cover and the powder material in a sintering process, such that the wear resistance of the metal template is lower than the wear resistance of the metal powder after the sintering process.

2. The method of claim 1 wherein the metal template is made from low-carbon steel.

3. The method of claim 1 wherein the sintering process is a hot isostatic pressing process.

4. A wear-resistant roller component for handling abrasive materials comprising a metal body with at least one surface wherein a metal template having a pattern of through-going holes is arranged on the at least one surface of the metal body and in that a cover arranged to cover at least a part of the metal template is arranged at a distance from the metal template to form a gap between the cover and the metal template and in that a powder material suitable for sintering is introduced into the through-going holes in the metal template through the gap and in that the metal body, the metal template, the cover and the material powder are bonded together by means of a sintering process.

5. The wear-resistant roller component according to claim 4 wherein the distance between the metal template and the metal body is at least 3 millimeters.

6. The wear-resistant roller component according to claim 4 wherein the through-going holes cover at least 60 percent of the surface area of the metal template.

7. The wear-resistant roller component according to claim 4 wherein the metal body is a cylindrical roller body.

Description

(1) The invention will now be explained in greater detail with reference to the drawing, being diagrammatical, and where

(2) FIG. 1 shows a three-dimensional view of a wear-resistant roller according to the invention.

(3) FIG. 2 shows a cross-sectional view of the roller shown in FIG. 1, and

(4) FIG. 3 shows two different embodiments of a layout for a wear-resistant layer according to the invention.

(5) FIG. 1 shows a three-dimensional view of a wear-resistant roller 1 produced by the method according to the invention. A tube-shaped metal template 3 and a tube-shaped metal cover 4 are arranged concentrically around a cylindrically metal body 2. This metal body 2 may be tube-shaped as shown in FIG. 2. The outer diameter of the tube-shaped metal template 3 is smaller than the inner diameter of the tube-shaped cover 4 to form a gap 7 between these two parts. The radial extent of the gap 7 must be large enough to allow powder material 6 to flow along the axial direction of the cylindrically metal body 2 when the powder material 6 is introduced into the gap 7. A buffer layer 8 arranged between the metal body 2 and the metal template 3 is optional but may be used to enhance the bond between the parts.

(6) FIG. 2 shows a cross-sectional view through a vertical plane comprising the centreline of the roller shown in FIG. 1. The metal template 3 is made from a steel sheet into which a pattern of holes 5 is cut after which it is either hot or cold rolled (depending of the steel sheet thickness) to form a tube-shaped metal template 3. The powder material 6 is a powder metallurgical steel which is introduced into the gap 7 between the metal template 3 and the cover 4 to fill the holes 5 in the metal template 3. Both the holes 5 and the gap 7 will be filled with the powder material 6. End stops (not shown) at each end of the gap 7 will ensure that the powder material 6 is kept in place prior to and during the sintering process. After the holes 5 have been filled with the powder material 6, the entire assembly undergoes air evacuation and then the assembly is subjected to a sintering process, preferably a hot isostatic pressing process (HIP), where the metal body 2, the metal template 3, the cover 4 and the powder material 6 are bonded together.

(7) During operation of the wear-resistant roller 1 the cover 4 will be worn off rather quickly as it is made from a material with very low resistance against wear. Furthermore, the metal template 3 is made from a material which has a significantly lower resistance against wear compared to the sintered powder material 6 which means that grooves around the sintered powder material 6 will be formed. These grooves will be effectively filled with fine particles of the crushed material. The fine particles are compacted in the grooves entailing an effective retention on the surface. Thereby an autogenous wear protection is established as the crushed material wears against the fine particles in the grooves. As the build-up of the autogenous layer is enhanced by a favourable layout of the sintered powder material it is of great importance that the holes 5 in the metal template 3 are arranged in an advantageous way. The autogenous effect reduces further wear of the roller and also contributes to an increased throughput due to increased friction between the materials to be processed and the materials in the grooves. Thus an optimal texture of the surface of the wear-resistant roller 1 would have significant advantages for the operation given its importance for reducing wear and for increasing the production.

(8) FIG. 3 shows two different embodiments of a layout for a wear-resistant layer. The holes 5 in the two shown sections of different types of metal templates 3 are circular and polygonal-shaped, respectively, but may have other shapes. The shape of the holes 5, which forms the highly wear-resistant zones of sintered powder material 6, and the distance between the holes 5 will depend on the type and size of the material to be processed in order to ensure formation of the necessary autogenous layer which reduces the wear on the wear-resistant roller. Usually the holes 5 cover more than 60 percent of the surface area of the metal template 3.