Beryllium sheet and method of producing same

Claim 1

IN THE METHOD OF MAKING FLAT BERYLLIUM SHEETS, THE BREAKDOWN ROLLING STEP COMPRISING PROVIDING A BERYLLIUM BLOCK OF SUBSTNATIALLY THEORETICAL DENSITY AND IN THE FORM OF A RIGHT ANLED PARALLELEPIPED OF ACCURATE DIMENSION AND HAVING ITS OPPOSITE MAJOR FACES AND ITS EDGE FACES SMOOTH AND PLANAR AND ITS CORNERS AND CORNER EDGES ROUNDED TO A SHORT RADIUS, SNUGLY EMBRACING THE BLOCK PERIPHERALLY EDGEWISE IN A RIGID FRAME OF METAL RAILS OF WHICH THE THICKNESS NORMAL TO THE PLANES OF THE MAJOR FACES OF THE BLOCK APPROXIMATES BUT DOES NOT EXCEED THAT OF THE BLOCK, AND WHICH ARE WELDED SECURELY TOGETHER AT THEIR CORNERS, PROVIDING ON THE BLOCK SURFACES A COATING OF A COMPOSITION FOR REDUCING OXIDATION AND FACILIATING PARTING, COVERING THE MAJOR FACES OF THE BLOCK AND OF THE FRAME BY APPLYING TO OPPSOSITE MAJOR FACES OF THE BLOCK AND THE FRAME METAL COVER PLATES WHICH ARE SUBSTANTIALLY COEXTENSIVE WITH THE OUTER PERIPHERAL LIMITS OF THE FRAME, BONDING EACH PLATE ALONG ITS ENTIRE PERIPHERAL EDGE TO THE FRAME TO FORM A JACKET, RELIEF VENTING THE JACKET, THEN HATING THE BLOCK AND JACKET ASSEMBLY INTO A TEMPERATURE RANGE OF ABOUT 650*C. TO 860*C. UNFORMLY THROUGHOUT, ROLLING THE ASSEMBLY WHILE IT IS WITHIN SAID TEMPERATURE RANGE WITH AN INITIAL PASS UNDER RELATIVELY LIGHT PRESSURE SUFFICIENT TO CAUSE THE COMPLETMENTARY SURFACES OF THE JACKET AND BLOCK TO BE IN FIRM CONTACT AND PLANAR COFORMITY WITH EACH OTHER THROUGHOUT THEIR EXTENT, THEN ROLLING THE ASSEMBLY, WHILE IT IS IN SAID RANGE, AT A PREDETERMINED PRESSURE TO CAUSE AN OVERALL REDUCTION RATIO NOT TO EXCEED 8:1, CHARACTERIZED IN THAT THE BREAKDOWN ROLLING STEP IS FOLLOWED BY STRESS RELIEVING THE ROLLED ASSEMBLY AT ABOUT 760*C., DEJACKETING THE STRESS RELIEVED BLOCK, CLEANING THE DEJACKETED BLOCK, AND BARE STRESS RELIEVEING IT AT A TEMPERATURE OF ABOUT 760*C.