Exercise 7 a)

(I) Explain why some welders require preheating. (II) What is the role of the filler material in fusion welding? (III) What are the advantages of electron beam welding compared to ordinary arc welding? (IIII) Describe typical discontinuities (defects) that can occur in welded material and how can these be avoided? (V) Explain what residual stresses that occur in welded structures can lead to. (VI) Describe two of the most important advantages of solid state welding in relation to fusion welding