Physical and Technological Features of the Formation of Welded Joints of Large Thickness in Electron-Beam Welding

Abstract

In this paper, based on the gas-kinetic theory of plasma, a theoretical analysis of the possibility of forming a plasma state in melting channel as a result of the interaction of high-energy electrons of the electron beam with the atoms of the material, being processed in melting channel (in free state) is proposed. Also the assessment of possible impact of this process on the quality of weld metal is given. It is shown that if we take the electron-beam welding of large thickness with formation of a knife-form melting zone, the occurring processes can develop both in the direction of self-organization (synergetic, evolution) and chaotically (it all depends on the set of after-effects, caused by them, and their duration), which is manifested either as autofocusing and melted depth increase (synergy, evolution) or as formation of defects in the center of the channel (in the central part of the weld) in the form of steam and gas cavities of quite considerable size.