Parts subject to wear which come into contact with metal melts

Abstract

Parts subject to wear, which come into contact with metal melts, are formed with a hydraulically setting high-alumina refractory concrete having a compression strength when cold, measured on dried crude product, of at least 400 kp/cm 2 . The compression strength is at least 700 kp/cm 2 after firing at 1400° C. The refractory concrete has a dimensional stability at 1400° C. of at least plus or minus 0.2%. The refractory concrete contains corundum and active alumina as aggregates, an alumina .[.concrete.]. .Iadd.cement .Iaddend.containing less than 22% lime and, as required, a thinning agent. Up to 5% of the aggregates can be replaced by a spinel-forming substance preferably MgO or MgO-yielding compounds; or up to 5% of the aggregates can be replaced by carbon black, pitch or graphite; or up to 7% of the aggregates can be replaced by chromium oxide. Aggregates under 0.5 mm can be present in the refractory concrete as round grains. Preferably, the refractory concrete is used for slide-valve plates and/or base plates of slide-valve closure members on containers containing steel melts. The moulded parts can be impregnated with tar.

What is claimed is: 
     
       1. Parts .Iadd.of a slide-valve closure means which are .Iaddend.subject to wear .Iadd.and .Iaddend.which come into contact with a metal melt, said parts comprising means for contacting a steel melt and withstanding stresses caused by said steel melt, said means including a hydraulically setting high-alumina refractory concrete, said refractory concrete having following physical properties: (a) a compression strength of at least 400 kp/cm 2  as measured cold on a dried crude product;   (b) a compression strength of at least 700 kp/cm 2  after firing at 1400° C.; and   (c) a dimensional stability of at least ±0.2% at said 1400° C.   
     
     
       2. Parts subject to wear according to claim 1, characterized in that aggregates under 0.5 mm are present in said refractory concrete as round grains. 
     
     
       3. Parts subject to wear according to claim 1, characterized in that said parts are moulded parts impregnated with tar. 
     
     
       4. Parts subject to wear according to claim 1, wherein said parts include .[.slide-valve closure means for a container containing said steel melt, said closure means including.]. slide-valve plates. 
     
     
       5. Parts subject to wear as claimed in claim 1, wherein said refractory concrete contains corundum and active alumina as aggregates, an hydraulic alumina-cement containing less than 22% lime and, as required, a thinning agent to provide a composition having at least 96% Al 2  O 3 , less than 3% CaO and less than 0.5% SiO 2 . 
     
     
       6. Parts subject to wear according to claim 2, wherein said aggregates are in a mixture with up to 5% of said mixture being a spinel-forming substance, wherein said spinel-forming substance is MgO or MgO-yielding compounds. 
     
     
       7. Parts subject to wear according to claim 2, wherein said aggregates are in a mixture, wherein up to 5% of said mixture is carbon black, pitch or graphite. 
     
     
       8. Parts subject to wear according to claim 2, wherein said aggregates are in a mixture, wherein up to 7% of said aggregate mixture is chromium oxide.