Aluminum Welding

The aluminum welding technology area has instructions, tips, and product information geared specifically toward welding this lightweight, versatile material.

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Aluminum Workshop: To reheat, not to reheat T4 temper material

December 5, 2014 | By Frank Armao

Q: Three years ago I bought 6061-T4 extrusions for a project. My idea was to weld in the T4 temper and then to improve the strength of the weld by performing an aging treatment after welding. The project sat dormant until now. Will the T4 temper material need to be heat-treated again before...

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Aluminum Workshop: Using 4043, 4643 when welding 6061-T6

December 4, 2014 | By Frank Armao

Q: Most 6061-T6 is welded using 4043 filler wire. If you heat-treat the weld, will the 4043 get stronger? What happens if I use 4643 filler instead of 4043? A: Is the weld heat-treatable? Well, yes and no. Remember, the first step to producing T6 temper is heat treating at around 1,050 degrees F...

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Aluminum Workshop: Tips for repairing cracks

December 4, 2014 | By Frank Armao

Q: What is the best way to repair cracks? Is it better to use GTAW or GMAW? I have heard that sometimes the crack will grow while being repaired. Is this true? Are there any tricks to avoid this? Is repairing cracks in aluminum any different than repairing cracks in other materials? A: Yes,...

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Aluminum Workshop: Charpy V-notch testing—Why not aluminum?

December 3, 2014 | By Frank Armao

Q: In many cases, when I qualify welding procedure specifications (WPS) for steel, I am required to perform testing of Charpy V-notch (CVN) samples, but I’m never required to test Charpy samples for aluminum welding procedures. Why not? A: Charpy V-notch samples are used to determine a...

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Aluminum Workshop: Aluminum-scandium alloys—Strong yet scarce

December 3, 2014 | By Frank Armao

Q: I’ve seen various references to aluminum-scandium (AlSc) alloys. Apparently, the addition of scandium makes aluminum alloys stronger. But I never see these alloys used in common welded fabrication. Why? Can I weld them? A: The major aluminum companies experimented with Sc additions to a lot...

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Aluminum Workshop: Sizing up feedability and conductivity in contact tips

December 2, 2014 | By Frank Armao

Q: There seems to be a lot of controversy about what size contact tip to use for GMAW aluminum. Can you give me any advice? A: The contact tip has two functions. First, it provides guidance for the welding wire. Second, it provides a means of conducting welding current from the welding torch...

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Aluminum Workshop: The ABCs of anodizing

December 2, 2014 | By Frank Armao

Q: What is anodizing? Is it the same as hardcoating, and can I do it myself? Can you weld on anodized parts? A: Anodizing is a process in which a thin, uniform coating of aluminum oxide is formed on the surface of aluminum. Any aluminum alloy can be anodized, but different alloys form anodized...

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Aluminum Workshop: Guidelines for preheating T6

December 1, 2014 | By Frank Armao

Q: We are welding 6061-T6 that is ¼ in. to 1 in. thick. To weld the thicker materials we are preheating to 300 to 600 degrees F. We are not happy with the strength of the welds. Is there something we can do, such as heat treating after welding, to increase the strength of the weld? A: You can...

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Aluminum Workshop: What determines aluminum filler strength?

December 1, 2014 | By Frank Armao

Q: I’m confused about various aluminum filler metal strengths. Does the filler designation tell me anything about the strength of the filler or the weld? I looked in AWS A5.10, the specification for aluminum GMAW and GTAW filler metals, and there are no strength requirements even in there. Why?...

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Aluminum Workshop: Weldability of aluminum mold plate

November 26, 2014 | By Frank Armao

Q: I’m trying to weld some very thick aluminum mold plate. I don’t know what the alloy is. The plate thickness is about 12 in. I’m having lots of cracking problems. Can you tell me what the problem might be? A: In the way of background, most of the molds used for injection or blow molding...

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Aluminum Workshop: Common porosity problems (and how to fix them)

November 26, 2014 | By Frank Armao

Q: I’m having a lot of problems with porosity in my aluminum welds. Can you tell me what’s causing it? A: As we’ve said before, all porosity in aluminum welds is caused by hydrogen, which is very soluble in molten aluminum but insoluble in solid aluminum. Generally, hydrogen comes from two...

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Aluminum Workshop: Explaining the causes of black smoke

November 25, 2014 | By Frank Armao

Q: I get a lot of black smoke on the surface of my aluminum welds. What is it, and how can I get rid of it? A: I can tell you what the black smoke isn’t. It is not soot and it doesn’t contain carbon, as most people think. It is, in fact, a mixture of very fine particles of aluminum oxide and...

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Aluminum Workshop: Addressing arc blow

November 25, 2014 | By Frank Armao

Q: I’m welding aluminum plate and extrusions of various alloys using both GTAW and GMAW. Sometimes I encounter what seems to be arc blow while welding, mostly with GMAW. But since aluminum isn’t magnetic, arc blow shouldn’t be possible. Is it something else? If so, what? A: This is a common...

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Aluminum Workshop: Dissecting a die casting dilemma

November 24, 2014 | By Frank Armao

Q: I weld a lot of aluminum castings. Most of the time they weld fine, but sometimes the weld blows out at me. What’s going on? A: The problem is caused by the casting process. There are three types of casting processes—sand casting, permanent mold casting, and die casting. The molds for sand...

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Aluminum Workshop: Meet tensile strength requirements with the right filler metal

November 24, 2014 | By Frank Armao

Q: I am trying to conduct a procedure qualification test on 5083-0 temper material using 5356 filler metal and gas metal arc welding (GMAW). I have welded a number of test plates, but the tensile samples always fail at a tensile strength of 37 to 39 KSI. The code requires a minimum tensile strength...

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