Rotationally symmetrical hollow body made a deformable permanently magnetic alloy and its use and production process

Abstract

A seamless, rotationally symmetrical hollow blank formed by a non-cutting operation from a deformable permanently magnetic alloy is provided, said alloy consisting essentially of 5.0 to 20.0 percent by weight cobalt, 20.0 to 35.0 percent by weight chromium, for the remainder iron and impurities caused by melting and/or by chance. The seamless hollow body is suitable in particular for use in hysteresis clutches, hysteresis brakes, and position measuring devices. Furthermore, non-cutting shaping processes for producing the seamless rotationally symmetrical hollow body are provided, with roller spinning being preferred.

1 . A seamless, rotationally symmetrical hollow body shaped by a non-cutting operation from a deformable permanently magnetic alloy substantially consisting essentially of 5.0 to 20.0 percent by weight cobalt, 20.0 to 35.0 percent by weight chromium, iron, and impurities.  
     
     
         2 . A hollow body as claimed in  claim 1 , comprising one or more of the elements selected from the group consisting of Zr, Ti, Hf, V, Nb, Ta, Mo, W, Mn, Si, Al, Ni, Sn, Cu, Zn, Ge, B, and rare earths accounting for a total proportion of the alloy of less than 5 percent by weight.  
     
     
         3 . A hollow body as claimed in  claim 1 , wherein the body comprises a conical form.  
     
     
         4 . A hollow body as claimed in  claim 2 , wherein the body has a conical form.  
     
     
         5 . A hollow body as claimed in  claim 1 , wherein the body comprises a pot-shaped form.  
     
     
         6 . A hollow body as claimed in  claim 2 , wherein the body comprises a pot-shaped form.  
     
     
         7 . A hollow body as claimed in  claim 1 , wherein the body comprises an annular form.  
     
     
         8 . A hollow body as claimed in  claim 2 , wherein the body comprises an annular form.  
     
     
         9 . A hollow body as claimed in  claim 3 , wherein in the circumferential direction a magnetic pattern with different magnetization arranged one behind the other.  
     
     
         10 . A hollow body as claimed in  claim 4 , wherein in the circumferential direction a magnetic pattern with different magnetization arranged one behind the other.  
     
     
         11 . A hollow body as claimed in  claim 5 , wherein in the circumferential direction a magnetic pattern with different magnetization arranged one behind the other.  
     
     
         12 . A hollow body as claimed in  claim 6 , wherein in the circumferential direction a magnetic pattern with different magnetization arranged one behind the other.  
     
     
         13 . A hollow body as claimed in  claim 1  adapted to be used in a hysteresis clutch.  
     
     
         14 . A hollow body as claimed in  claim 1  adapted to be used in a hysteresis brake.  
     
     
         15 . A hollow body as claimed in  claim 1  in a solid gage.  
     
     
         16 . A hollow body as claimed in  claim 15  adapted to be used in a position measuring device.  
     
     
         17 . A process for the production of a seamless rotationally symmetrical hollow body, said process comprising: 
 melting of an alloy and casting the alloy to form an ingot;    hot forming of the ingot to form a thin slab;    hot forming of the thin slab to form a hot strip with a fine-crystalline microstructure comprising an average grain size of <300 μm;    intermediate annealing of the hot strip above a temperature of 800° C.;    cold forming of the hot strip to form a strip;    production of a round blank from the strip;    roller spinning of the round blank to form a hollow body; and    magnetic annealing of the hollow body.    
     
     
         18 . A process as claimed in  claim 17 , wherein the hot forming of the ingot to form a thin slab occurs at temperatures above 1100° C.  
     
     
         19 . A process as claimed in  claim 17 , wherein the second hot forming occurs with a degree of hot forming of more than 90%.  
     
     
         20 . A process as claimed in  claim 18 , wherein the second hot forming occurs with a degree of hot forming of more than 90%.  
     
     
         21 . A process as claimed in  claim 17 , wherein cold forming of the thin slab to form a strip occurs with a degree of cold forming of less than 20%.  
     
     
         22 . A process as claimed in  claim 18 , wherein cold forming of the thin slab to form a strip occurs with a degree of cold forming of less than 20%.  
     
     
         23 . A process as claimed in  claim 19 , wherein cold forming of the thin slab to form a strip occurs with a degree of cold forming of less than 20%.  
     
     
         24 . A process as claimed in  claim 20 , wherein cold forming of the thin slab to form a strip occurs with a degree of cold forming of less than 20%.  
     
     
         25 . A process as claimed in  claim 17 , wherein the round blank produced from the strip are surface-treated.  
     
     
         26 . A process as claimed in  claim 18 , wherein the round blank produced from the strip are surface-treated.  
     
     
         27 . A process as claimed in  claim 19 , wherein the round blank produced from the strip are surface-treated.  
     
     
         28 . A process as claimed in  claim 21 , wherein the round blank produced from the strip are surface-treated.  
     
     
         29 . A process as claimed in  claim 25 , wherein the depth of roughness of the round blank being set to less than 15 μm by means of the surface treatment.  
     
     
         30 . A process as claimed in  claim 25 , wherein the surface treatment of the round blank occurs mechanically.  
     
     
         31 . A process as claimed in  claim 29 , wherein the surface treatment of the round blank occurs mechanically.  
     
     
         32 . A process as claimed in  claim 25 , wherein the surface treatment of the round blank occurs chemically.  
     
     
         33 . A process as claimed in  claim 29 , wherein the surface treatment of the round blank occurs chemically.  
     
     
         34 . A process as claimed in  claim 17 , wherein the alloy comprises cobalt, chromium, and iron.  
     
     
         35 . A process as claimed in  claim 34 , wherein the alloy further comprises one or more of the elements selected from the group consisting of Zr, Ti, Hf, V, Nb, Ta, Mo, W, Mn, Si, Al, Ni, Sn, Cu, Zn, Ge, B, and rare earths accounting for a total proportion of the alloy of less than 5 percent by weight.  
     
     
         36 . A process as claimed in  claim 35 , wherein the alloy substantially consists essentially of 5.0 to 20.0 percent by weight cobalt, and 20.0 to 35.0 percent by weight chromium.  
     
     
         37 . A seamless, rotationally symmetrical hollow body shaped by non-cutting operation from a deformable permanently magnetic alloy having roundness tolerances of less than 0.15 mm for a diameter of about 120 mm.  
     
     
         38 . A body as claimed in  claim 37 , wherein the alloy comprises cobalt, chromium, and iron.  
     
     
         39 . A body as claimed in  claim 37  having a form selected from the group consisting of conical, pot-shaped, and annular forms.  
     
     
         40 . A body as claimed in  claim 37 , wherein the body comprises wall thicknesses of less than 3 mm and diameters of less than 350 mm.  
     
     
         41 . A body as claimed in  claim 39 , wherein the conical and pot-shaped forms have a circumferential direction magnetic pattern with different magnetization arranged one behind the other.