A method for producing fine-grained beryllium sheet metal with a random crystal orientation

摘要

A method for forming beryllium into shaped bodies comprises casting beryllium to form an ingot of coarse-grained material, working the ingot material to form the shaped body with a fibrous grain structure and subsequently reducing the grain size of the shaped body. The grain size of the ingot material is in the range of 300 to 80 m and the grain size of the refined material is not greater than 80 m . The fibrous grain structure is achieved by warm rolling at a temperature between 200 DEG and 500 DEG C. with less than 50% reduction to avoid fracture. The grain refinement is effected by annealling the warm-worked beryllium at a temperature in the range of 850 DEG to 1000 DEG C. for a time which increases with decreasing temperature and is in the range 15 to 300 secs. In an example, a cast beryllium ingot is rolled at 400 DEG C. to a 50% reduction; flash annealed at 980 DEG C. for 40 secs. to produce a fully recrystallized equiaxed grain structure, then annealed at 700 DEG C. for 19 hours in order to remove any residual stresses and allowed to cool slowly in the furnace and finally warm rolled 40% at 400 DEG C. to a sheet 0.22 inch thick. The beryllium has the following analysis: .Fe-.-.-.-.0.037% .Al-.-.-.-.0.056% .Si-.-.-.-.0.091% .Mg.-.-.-.0.0008% .Mn.-.-.-.0.002% .Ni-.-.-.-.0.004% .Cr-.-.-.-.0.001% .Cu-.-.-.-.0.001% .Be-.-.-.-.to 100%