Method and arrangement for manufacturing a component with hot isostatic pressing, a core, a preform for a cladding, and use of the core

Abstract

A method and an arrangement for manufacturing a component with hot isostatic pressing occurring in solid form, the component comprising a shape opening onto the outer surface. The method comprises forming a sheet metal capsule for metallic powder, and manufacturing a core by arranging around a core centre made of a first material, a form layer made of a second material, the shape of the outer surface of the form layer corresponding to the shape of the outer surface of the opening shape of the component. The core is placed in a spot, where the shape opening onto the outer surface is to be formed, and metallic powder is arranged in the sheet metal capsule, which forms the body part of the component to be manufactured. Cladding material is arranged between the outer surface of the core and the metallic powder, and hot isostatic pressing is performed to simultaneously compact the metal powder and the cladding material.

1 . A method for manufacturing a component with hot isostatic pressing occurring in solid form, the component to be manufactured including a shape opening onto the outer surface of the component, which method comprises:
 forming a sheet metal capsule for metallic powder;   manufacturing a core by arranging around a core centre made of a first material a form layer made of a second material, the shape of the outer surface of the form layer corresponding to the shape of the outer surface of the opening shape of the component;   placing the core in a place, where the shape opening onto the outer surface is to be formed;   arranging metallic powder into the sheet metal capsule, which metallic powder forms the body part of the component to be manufactured,   characterized in   arranging cladding material between the outer surface of the core and the metallic powder; and in   performing hot isostatic pressing in order to simultaneously compact the metallic powder and the cladding material.   
     
     
         2 . The method according to  claim 1 , characterized in placing the core inside the sheet metal capsule before closing and degassing the sheet metal capsule. 
     
     
         3 . The method according to  claim 1 , characterized in arranging in the sheet metal capsule a partition wall separating the cladding material from the metallic powder, which forms the body part of the component. 
     
     
         4 . The method according to  claim 3 , characterized in arranging between the partition wall and the core a powder-like cladding material or a preform including a cladding material and being in the form of a polymer-bonded mat or paste. 
     
     
         5 . The method according to  claim 2 , characterized in arranging on the outer surface of the core a preform including a cladding material and being in the form of a polymer-bonded mat or paste, before the core is placed in the sheet metal capsule. 
     
     
         6 . The method according to  claim 4 , characterized in evaporating by thermal degassing at least most of the bonding polymer included in the preform including a cladding material, prior to the hot isostatic pressing. 
     
     
         7 . The method according to  claim 1 , characterized in
 removing the core centre after the hot isostatic pressing in one piece; and   arranging a new form layer made of a second material around the removed core centre in order to manufacture a new core.   
     
     
         8 . A core, which is suitable for use in the manufacture of a component, which comprises a shape opening onto the outer surface of the component, which core comprises:
 a core centre manufactured from a first material; and   a form layer comprising a second, different material arranged around the core centre,   
       characterized in that
 the form layer is manufactured from a second material, which has a thermal expansion coefficient which differs from the thermal expansion coefficient of the first material of the core centre by at the most 20%, or 
 the form layer is manufactured from a second material, the density value of which is smaller than the density value of the first material of the core centre, whereby the density value is calculated as a ratio of the actual density and theoretical density of each material. 
 
     
     
         9 . The core according to  claim 8 , characterized in that the core centre is manufactured from a material, the density of which is at least 95%, preferably at least 98%, of the theoretical density of said material. 
     
     
         10 . The core according to  claim 8 , characterized in that the core centre is manufactured from an iron-based material, such as steel, especially carbon steel, or from cast iron, or the core centre is manufactured from a Ni-based high temperature material. 
     
     
         11 . The core according to  claim 8 , characterized in that the form layer is manufactured from a material, the density of which is 60-95%, preferably 70-95%, more preferably 80-95%, of the theoretical density of said material. 
     
     
         12 . The core according to  claim 8 , characterized in that the form layer is manufactured from a material, which is inert and thermally stable in conditions of hot isostatic pressing. 
     
     
         13 . The core according to  claim 8 , characterized in that the form layer is manufactured from a ceramic material, such as oxide ceramics, nitride ceramics, carbide ceramics, boride ceramics, beryllium ceramics, or that the form layer is manufactured from graphite. 
     
     
         14 . The core according to  claim 8 , characterized in that the bending strength of the form layer is >75 MPa and/or the compression strength is >140 MPa. 
     
     
         15 . The core according to  claim 8 , characterized in that between the core centre and the form layer is arranged an anti-adhesion layer, the properties of which differ from the core centre and the form layer, and which preferably comprises aluminium oxide or boron nitride. 
     
     
         16 . The core according to  claim 8 , characterized in that an anti-adhesion cladding is arranged on the form layer on the outer surface of the core. 
     
     
         17 . The core according to  claim 8 , characterized in that an open channel is arranged through the core centre, which channel extends from the first end of the core centre to its second end, in order to even out the pressure during the hot isostatic pressing. 
     
     
         18 . A preform for a cladding, which comprises:
 particles of metallic powder of the cladding material, the particles having a size of 0.5-1000 μm; and   a bonding polymer, the amount of which in the preform is 1-50 weight-% of the weight of the metallic powder particles.   
     
     
         19 . The preform for a cladding according to  claim 18 , characterized in that the bonding polymer is selected from a group consisting of polyethylene; polyacrylates; polyisobutylenes; cellulose derivates; polyvinylbutyral; polyfluoroethylene; polyester; polyolefin; polyamide or polyimide comprising a low or high molecular weight component; or phenolic resin, such as epoxy resin, alkyd resin or silicone. 
     
     
         20 . The preform for a cladding according to  claim 18 , characterized in that the metallic powder particles are of a metallic powder, which is mainly for example of a nickel-, cobalt- and titanium-based alloy, stainless steel or a hard metal, for example nickel-chromium alloy Inconel® 625 or nickel-copper alloy Monel®. 
     
     
         21 . An arrangement for manufacturing a component with hot isostatic pressing occurring in solid form, the component comprising a shape opening onto the outer surface of the component, which arrangement comprises:
 a sheet metal capsule for metallic powder;   a core, which can be arranged in connection with the sheet metal capsule   
       characterized in that 
       the core is a core according to  claim 8 . 
     
     
         22 . The arrangement according to  claim 21 , characterized in that it comprises a partition wall, which is arranged at a distance from the wall of the sheet metal capsule, and which partition wall is arranged to define the space meant for the metallic powder between the partition wall and the sheet metal capsule. 
     
     
         23 . A use of a core according to  claim 8  for manufacturing valves, pump casings or ductwork components by hot isostatic pressing.