Recrystallization of High-Melting Metals in Welding and Soldering
Abstract
In the rapid heating encountered in welding, the initial recrystallization temperatures of molybdenum and tungsten rise by 250 and 400, respectively, tending toward some limiting value. For tantalum and niobium, this temperature rise amounts to 120-150 and 170-200. Under the conditions of rapid heating, considerable grain growth is observed in molybdenum at temperatures above 1600. It is of value to shorten the duration of heating only for welding conditions under which the basic metal is heated to temperatures near the melting point. In soldering with working temperatures below 1600, the duration of the process has little effect on the grain size of the ground metal. At higher soldering temperatures, it is advisable to heat with high-frequency currents. Among all of the parameters of the welding heat cycle, that exerting the strongest influence on the processes of grain growth in tantalum and niobium is again the heating temperature, followed in order of importance by the holding times above the recrystallization temperature in heating and cooling. Hence these metals must be welded with heavy currents and at high speeds, or sources that ensure highly concentrated heating and deep penetration (electron beam) should be used.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 09, 1965
- Accession Number
- AD0624909
Entities
People
- G. N. Klebanov
- N. V. Grebtsev
Organizations
- Air Force Systems Command