Design of Mechanical Elements

9Welded Joints

9.1 Introduction

In this chapter, we will use the knowledge of the chapter on design for static strength and apply it to the design of welded joints. Welded joints are connections between mechanical elements in which we melt part of the elements we try to join and simultaneously add a filler material. Upon solidification, the mechanical elements are joined. Welded joints cannot be disassembled nondestructively, which contrasts, e.g. bolted joints that can be disassembled and re‐assembled.

9.1.1 Welding Versus Brazing

We start this chapter by recognizing the difference between welding and brazing.

Brazing is a joining method that is similar to welding, but we do not melt the mechanical elements we attempt to join. Instead, we only melt the filler material that forms the connection between the mechanical elements. Therefore, brazing requires the melting temperature of the filler material to be substantially lower than that of the mechanical elements. However, because we only melt the filler material, the mechanical strength of a brazed connection is negligible (tensile strength on the order of ).

Welding is a joining method in which we melt part of both mechanical elements we attempt to join, in addition to melting the filler material. This melting pool allows both mechanical elements to become “unified” as one new mechanical element. Therefore, the melting temperature ...