What are unweldable aluminum alloys?
By: Tony Anderson CEng. Q – I have heard, on occasion, reference made to some aluminum alloys as unweldable. What does this mean? Are there such aluminum alloys, and if so, what makes them unweldable? A – I shall start by saying that the majority of aluminum base alloys can be successfully arc welded when using the correct welding procedures. However, yes, there are some aluminum base alloys that are sometimes referred to as unweldable. These groups of alloys, which we will further discuss, are typically well known as being unsuitable for arc welding, and for this reason are joined mechanically by riveting or bolting. Before we start examining the various reasons for the poor weldability of these alloys, we should start by considering the term unweldable. This is a nonstandard term which is sometimes used to describe aluminum alloys that can be difficult to arc weld without encountering problems during and/or after welding. These problems are usually associated with cracking, most ofte
