Q: Is it possible to join two aluminum castings together with welding rods?
To summarize the answer in a single sentence, the vast majority of aluminum castings, but not all of them, are weldable. It is possible to determine the weldability of a material by looking at two factors. Take a look at the following examples. Consider the chemical composition of the material. Do you believe that it is suitable for welding, or do you believe that it will crack or cause other problems if you attempt to weld them together? aluminum casting alloys are classified into six groups based on the differences in their chemical composition. These are as follows:
They are essentially pure aluminum and can be welded with 1100 filler material with little difficulty, as long as the filler material is clean and free of contaminants.
Compared to wrought aluminum alloys, the 2XX aluminum/copper alloys have a chemical composition that is very similar to that of wrought aluminum alloys 2024.
The 3XX aluminum/silicon/magnesium alloys are similar to the 6XXX wrought alloys, such as 6061, in that they contain aluminum and silicon, but they are forged rather than cast.
The appearance and composition of the 5XX aluminum/magnesium alloys are very similar to that of wrought 5XXX alloys, such as 5083, in terms of both appearance and composition.
Currently, there are no alloys with the designation 6XX available on the market.
All of the 7XX aluminum/zinc/magnesium alloys, such as 7075, are closely related to the 7XXX wrought alloys in that they contain the same amounts of aluminum, zinc, and magnesium in the same proportions as the wrought alloys.
Those who have read my previous columns will recall that, while some wrought alloys in the series 2XXX and 7ZZZ are weldable, the vast majority of them are not. This is particularly true for the 2XXX and 7ZZZ series, among others. A similar situation exists for the casting alloys 2xx and 7xx, which are similar to the one described above. Avoid using them in the same sentence as much as you can in general.
As a result, both the 3xx and 5xx cast alloys are weldable, which is a significant advancement over the previous state of the art. Use 4043 filler for 3XX alloys, and 5356 filler for 5XX alloys when welding these alloys. If you have any questions, please contact us. You will come across 3XX castings in approximately 80% to 90% of all of the castings you will ever come across. There are several 3XX castings, including the numbers 357, 319, and the most common, 356, all of which are 3XX castings.
When faced with a situation like that and not knowing what alloy the casting was made of, was there anything you could have done? As far as I'm aware, there are no straightforward tests that can be used to determine whether or not this is the case. Based on the filler efficiency of 80% to 90% that I mentioned above, I would recommend that you use 4043 as your first choice for a weld filler in your application.
The process that was used to manufacture a casting has a significant impact on whether or not it is easily weldable. Please bear with me as I go into greater detail. We'll concentrate on the three most common processes for creating castings: sand casting, permanent mold casting, and die casting, all of which are discussed in detail below. Creating castings can be accomplished through a variety of methods; however, we'll concentrate on the three most common: sand casting, permanent mold casting, and die casting. Castings can be produced using a variety of casting processes, each of which has its own advantages.
While metal castings are typically not weldable, sand castings and permanent mold castings are both capable of being welded. It is necessary to pour molten aluminum into a mold made of a material with low thermal conductivity in order for the aluminum to cool more slowly than it would have otherwise done so. It is very low in gas content when aluminum is allowed to percolate out any gas that has dissolved in it as a result of the percolation procedure.
It is important to note that die castings differ from other types of castings in several ways. Because the process is designed to be as efficient as possible, cycle times are short, and production rates are high, resulting in high production rates. The liquid aluminum is injected into the mold, which is made of steel and water-cooled, and allowed to cool very quickly after being injected. A result of this is that the trapped dissolved gases within the casting cause them to coalesce and form pockets of porosity throughout it. It is completely possible to weld the majority of the casting together with no problems at all. If, on the other hand, you come into contact with a gas pocket, the weld will spit, sputter, and it may even blow out in your face because of the gas. It is only in this situation that it is possible to grind out the porosity and reweld the joint together again. Depending on the circumstances, it is possible that two or three repair cycles will be required in order to obtain a satisfactory welding result.
When it comes to determining whether or not the casting you are about to weld is a die casting, it is actually quite simple to do so simply by looking at it. Generally speaking, die castings can be distinguished from other types of castings by the following three characteristics:
Significantly smoother than the surface of a sand or permanent mold casting, the surface of the sand or permanent mold casting is noticeable.
A die cast is most likely to have a thin wall, ranging from 1/8 to 3/16 in. thick, and a hollow interior, with the wall thickness ranging from 1/8 to 3/16 in.
When this item is opened, one of its faces will have five or six ejector pin marks on it. This is one of the items distinguishing characteristics. Moving parts in a mold are small steel pins that can be anywhere from 1/8 inch to 14 inches in diameter and are used to hold the mold together. During the opening of the mold, the ejector pins are extended, causing the casting to fall out of the mold and onto the work surface. They only leave a mark on one side of the sculpture, but they leave a mark on the plaster casting as well. The casting was made by die casting if you can see a number of these marks on the same face of the piece of metal.