Historical overview on Vacuum suitable Welding and fatigue resistance in Research Devices

TL;DR

This paper reviews the historical development of vacuum welding techniques in research devices, highlighting challenges like virtual leaks and fatigue resistance, and discusses how past mistakes impact current and future large-scale projects.

Contribution

It provides a comprehensive historical overview and analysis of vacuum welding methods, emphasizing lessons learned to improve joint quality and fatigue resistance in research devices.

Findings

Welding mistakes have historically led to systematic issues.

Advanced welding methods increase vessel fabrication accuracy.

Past errors can inform better practices for future projects like ITER.

Abstract

New inventions change the approach of vacuum suitable welding for research purpose. With orbital welding, laser welding and robot welding the possibilities increase to fabricate larger vessels more accurately. Despite this development there is still no perfect understanding on how to avoid virtual leaks and how to make such joints suitable for dynamic stress. By recalling its historical development, it is apparent how welding mistakes began occurring systematically and how to avoid them. With ASDEX-Upgrade as an example, it is shown how the attempt to conduct vacuum suitable welding has decreased the fatigue strength. ITER could repeat the mistakes of ASDEX-Upgrade even for unwanted welding (accidental fusing of joints).