THE RECRYSTALLIZATION DIAGRAM OF CAST TUNGSTEN

Journal Article · Sat Oct 21 04:00:00 EDT 1961 · Doklady Akad. Nauk S.S.S.R.

OSTI ID:4821329

Savitskii, E M; Tylkina, M A; Pekarev, A I; Gavrilyuk, M I; Zabavnova, A P

Tungsten of technical purity (99.6% purity) was fused in a vacuum arc furnace, and was reduced by 70% by hot pressing and annealed for one hour at l600 C in a hydrogen atmosphere in order to obtain a grain size of 40 to 50 mu . This starting material was deformed 6 to 90% by hammer forging in a hydrogen atmosphere at a temperature of 700 to ll00-C. These temperatures are below the recrystallization tem peraturc. Each sample was then annealed for one hour at temperatures of 1000 to 2500 deg C at intervals of 100 degrees in an electrical resistance furnace in vacuum (l x l0/sup -6/ mg Hg) and in hydrogen. Thin sections were electropolished in 10% NaOH at a current density of 1.7 amps/cm/sup 2/ in order to determine the microstructure and Vickers hardness at a l0 kg loading. A three-dimensional, recrystallization diagram is presented ln which the average grain size is plotted as a function of the degree of reduction (from 0 to 90%) and of the annealing temperature (from l400 to 2500 deg C). The initial recrystallization temperature occurs at 1450 deg C at reductions of 30 to 90%. The optimum annealing temperature for obtaining a fine-grained structure in cast tungsten of technical purity is 1500 to 1600 deg C for reductions of 50 to 90%. A tungsten single crystal 2.5 mm in diameter was prepared by electron-beam zone melting. lt was found that the initial recrystallization temperature of the single crystal. which had been reduced by 70%, was 1100 to l150 deg C, or 300 degrees lower than the initial recrystallization temperature of the technical- grade tungsten. (TTT)

• Research Organization: Baikov Inst. of Metallurgy, Academy of Science, USSR
• NSA Number: NSA-16-005734
• OSTI ID: 4821329
• Journal Information: Doklady Akad. Nauk S.S.S.R., Journal Name: Doklady Akad. Nauk S.S.S.R. Vol. Vol: 140
• Country of Publication: Country unknown/Code not available
• Language: Russian

Related Subjects

ANNEALING
CLEANING
DEFORMATION
FORGING
GRAIN SIZE
HARDNESS
HYDROGEN
METALLOGRAPHY
METALS, CERAMICS, AND OTHER MATERIALS
MONOCRYSTALS
RECRYSTALLIZATION
TEMPERATURE
TUNGSTEN
VACUUM