Powder-metallurgical body and method for the production thereof

Abstract

A powder-metallurgical body and a method for producing such a body. The powder-metallurgical body is formed with a seating base for seating a sealing element to produce a seal with respect to fluids, such as liquids and/or gases. The body is redensified in a low region of the seating base.

1 - 19 . (canceled) 
     
     
         20 . A powder-metallurgical body, comprising:
 a seating base formed in the body and a sealing element seated on the seating base so as to provide a seal with respect to liquids and/or gases;   said seating base having a depth region wherein said body is redensified in said depth region of said seating base.   
     
     
         21 . The body according to  claim 20 , wherein the body is formed with a closed porosity in said depth region. 
     
     
         22 . The body according to  claim 21 , wherein the body is formed exclusively with a closed porosity in said depth region. 
     
     
         23 . The body according to  claim 20 , wherein said depth region is represented by a cross-sectional area formed as product of a material depth proceeding from said seating base and a material width extending substantially parallel to said seating base. 
     
     
         24 . The body according to  claim 20 , wherein said depth region has a cross-sectional area of at least 0.3 mm 2 . 
     
     
         25 . The body according to  claim 20 , wherein, given a material depth proceeding from said seating base of up to 0.05 mm, said depth region has a mean porosity of at most 4%. 
     
     
         26 . The body according to  claim 25 , wherein said depth region has a mean porosity of no more than 2%. 
     
     
         27 . The body according to  claim 20 , wherein, given a material depth proceeding from said seating base of up to 0.5 mm, said depth region has a mean porosity of at most 5%. 
     
     
         28 . The body according to  claim 27 , wherein said depth region has a mean porosity of no more than 2.5%. 
     
     
         29 . The body according to  claim 20 , wherein, given a material depth proceeding from said seating base of up to 1.0 mm, said depth region has a mean porosity of at most 6%. 
     
     
         30 . The body according to  claim 29 , wherein said depth region has a mean porosity of no more than 3%. 
     
     
         31 . The body according to  claim 20 , wherein, given a material depth proceeding from said seating base of up to 1.5 mm, said depth region has a mean porosity of at most 7%. 
     
     
         32 . The body according to  claim 31 , wherein said depth region has a mean porosity of no more than 3.5%. 
     
     
         33 . The body according to  claim 20 , wherein said seating base is a constituent part of a sealing groove for receiving said sealing element. 
     
     
         34 . The body according to  claim 33 , wherein said seating base is a constituent part of a groove base of said sealing groove. 
     
     
         35 . The body according to  claim 20 , wherein said seating base is formed continuously in a circumferential direction of the body. 
     
     
         36 . The body according to  claim 33 , wherein said sealing groove is formed in a region of a front end of the body. 
     
     
         37 . A method of producing a powder-metallurgical body to be sealed by way of a sealing element, the method which comprises:
 forming a seating base of the body for receiving and seating the sealing element with a material elevation;   machining the material elevation to cause the body to be redensified, after the machining, in a depth region of the seating base; and   seating the sealing element on the seating base.   
     
     
         38 . The method according to  claim 37 , wherein the machining step comprises flattening the material elevation. 
     
     
         39 . The method according to  claim 37 , wherein the machining step comprises machining the material elevation by calibration pressing. 
     
     
         40 . The method according to  claim 37 , which comprises providing the body together with the seating base and the material elevation as a powder-metallurgical blank. 
     
     
         41 . The method according to  claim 40 , which comprises sintering the powder-metallurgical blank and subsequently machining the material elevation. 
     
     
         42 . The method according to  claim 37 , which comprise sealing pores on the surfaces of the body at least partially after the material elevation has been machined. 
     
     
         43 . The method according to  claim 42 , which comprises sealing the pores by impregnation with a plastic.