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Are There Specific Aluminium Grades that are Meant for Boat Building?

Blog | 14 November 2018

Straight to the matter at hand, yes, there are specially equipped aluminium grades, which are designed to last longer and function better in boat building applications. Granted, all types of aluminium exhibit a desirable measure of corrosion resistance, but there’s a world of difference between something that resists rust and a metal that absolutely won’t succumb to the influences of an oxidizing environment, right?

All about Aluminium Grades 

Not every alloy is created equal. Let’s assume a certain application wanted a type of aluminium that was workable and machinable. Even if the various grades provide tremendous application diversity, there’s usually a drawback to be taken into account. A natural polished surface looks great, especially on boats, but what if that naturally good looking metal isn’t weldable or heat treatable? For example, grade 2012 has copper as an alloying metal, but it’s designed for wrought applications, not boats. Incidentally, 2xxx aluminium is relatively corrosion-prone. Alternatively, type 3xxx alloys are non-heat treatable, but manganese-alloyed aluminium is highly corrosion resistant. Of course, boating enthusiasts want to know which aluminium grades are marine-capable. They have little interest in metals that won’t satisfy a boat builder’s needs.

Marine-Capable Aluminium 

Primarily, the builder seeks out an alloy that’s been rolled and extruded. A wrought or cast oriented grade doesn’t fit the bill, so they’re quickly dismissed. The workable alloy bends and cuts easily. If there are welds to be made, then the grade also must permit such actions. It’s no good selecting a grade that’s hard to machine, after all. Next, will the alloy prevent all kinds of corrosion, as found in pure lake water or salt-heavy seawater? Lightweight, exhibiting its high strength-to-weight ratio, the hull material comes loaded with impressive yield strength. A water-cutting V-shape won’t deform, but it will easily take a pounding, even when the craft is skipping over the waves at speed. Looking at the numbers, grade 5xxx alloys work best. Select magnesium-backed 5052 graded aluminium when the craft requires moderate-to-high strength hull, plus a corrosion resistant frame. Better yet, and this applies to saltwater vessels, boat builders use grade 5059.

There are a few more options to know about before this post concludes. By adding silicon to the mix, we reach the 6xxx family. These metals, like type 5059, are particularly suited for offshore applications, places where the briny waters exert their worst oxidizing effects. In conclusion, though, that corrosion proof feature isn’t enough. The alloy, especially when it’s used in a larger craft or a fast cruising vessel, must have enough tensile strength to handle the effects of any and all material-deforming waters.

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