Metal rings formed from beryllium-copper alloys

Abstract

Processes are disclosed for forming beryllium-copper metal rings having a fine and uniform grain structure. A raw BeCu casting is pre-forged and turned to form a BeCu billet. The BeCu billet is subjected to various heat treatment and cooling cycles to obtain/maintain combinations of advantageous material properties. Generally, the BeCu billet is preheated, hot worked via forging, heated again, hot worked again via ring rolling followed by air cooling, solution annealed followed by quenching, and heated a final time followed by air cooling.

1 . A process for making a metal ring from a BeCu alloy, comprising:
 preheating a BeCu alloy billet at a temperature of about 800° C. to about 850° C.;   forging the billet into a ring-shaped preform at a temperature of about 750° C. to about 850° C.;   soaking the preform at a temperature of about 815° C. to about 835° C.;   ring rolling the preform at a temperature of about 750° C. to about 850° C. to form a ring having a wall thickness;   solution annealing the ring at a temperature of about 780° C. to about 800° C., immediately followed by quenching the ring; and   heat treating the ring at a temperature of about 385° C. to about 400° C.   
     
     
         2 . The process of  claim 1 , wherein the preheating occurs for a period of at least 8 hours. 
     
     
         3 . The process of  claim 1 , wherein the soaking occurs for a minimum period of 2 hours. 
     
     
         4 . The process of  claim 3 , wherein the soaking is performed for a period of at least 8 hours if the preform has cooled to a temperature of about 600° C. or less. 
     
     
         5 . The process of  claim 1 , wherein the solution annealing occurs for a period of at least 1.5 hours. 
     
     
         6 . The process of  claim 1 , wherein the heat treating occurs for a period of about 3 hours. 
     
     
         7 . The process of  claim 6 , further comprising starting the about 3 hour period at a temperature of about 393° C., raising the temperature to about 400° C., and heat treating the ring at the about 400° C. temperature for the remaining period of time. 
     
     
         8 . The process of  claim 1 , wherein the preheating and soaking are each performed at a temperature of about 820° C. 
     
     
         9 . The process of  claim 1 , wherein the ring rolling reduces the wall thickness by at least 50%. 
     
     
         10 . The process of  claim 1 , wherein the solution annealing is performed for a period of about 30 minutes for approximately every 25 mm of wall thickness of the ring. 
     
     
         11 . The process of  claim 1 , further comprising air cooling the ring after both the ring rolling and the heat treating. 
     
     
         12 . A metal ring, comprising:
 a BeCu alloy comprising about 1.6 wt % to about 2.0 wt % beryllium, wherein the BeCu alloy has:   a 0.2% offset yield strength of at least 760 MPa;   a Rockwell C hardness of at least 27 HRC; and   a percent elongation of at least 6%.   
     
     
         13 . The ring of  claim 12 , wherein the BeCu alloy comprises from about 1.8 wt % to about 2.0 wt % beryllium, or comprises from about 1.8 wt % to about 1.9 wt % beryllium. 
     
     
         14 . The ring of  claim 12 , wherein the BeCu alloy further comprises from about 0.2 wt % to about 0.3 wt % cobalt. 
     
     
         15 . The ring of  claim 12 , wherein the BeCu alloy further comprises from about 0.2 wt % to about 0.6 wt % lead. 
     
     
         16 . The ring of  claim 12 , wherein the BeCu alloy further comprises an amount of nickel, cobalt, and optionally iron such that the sum of (nickel+cobalt) is about 0.2 wt % or higher, and the sum of (nickel+cobalt+iron) is about 0.6 wt % or less. 
     
     
         17 . The ring of  claim 12 , wherein the BeCu alloy has an electrical conductivity of at least 25% IACS. 
     
     
         18 . The ring of  claim 12 , wherein the BeCu alloy has an average grain size of 0.1 mm or less, or wherein the BeCu alloy has a Rockwell C hardness of 27 HRC to about 33 HRC. 
     
     
         19 . A process for making a metal ring, comprising:
 providing a billet made from a BeCu alloy comprising about 1.6 wt % to about 2.0 wt % beryllium;   preheating the billet at a temperature of about 800° C. to about 850° C. for a period of at least 8 hours;   forming a ring-shaped preform from the billet at a temperature of about 750° C. to about 850° C.;   soaking the preform at a temperature of about 815° C. to about 835° C. for a period of about 2 hours to about 8 hours;   ring rolling the preform at a temperature of about 750° C. to about 850° C. until the preform has a substantially uniform wall thickness, followed by air cooling;   solution annealing the preform at a temperature of about 780° C. to about 800° C. for a period of at least 1.5 hours, immediately followed by quenching in a quench medium;   heat treating the preform at a temperature of about 385° C. to about 400° C. for a period of about 3 hours, followed by air cooling; and,   mechanically machining the preform to form the metal ring having a desired shape.   
     
     
         20 . An amorphous metal casting apparatus comprising a metal ring, wherein the metal ring is made from a BeCu alloy comprising about 1.6 wt % to about 2.0 wt % beryllium, wherein the BeCu alloy has:
 a 0.2% offset yield strength of at least 760 MPa;   a Rockwell C hardness of at least 27 HRC; and   a percent elongation of at least 6%.