Hey guys! So for my science fair project I've decided to try welding metals with my Harbor Freight 90amp Fluxcore welder. I've chosen aluminum, zinc, and steel. Obviously I know that aluminum won't bond to steel or zinc but the steel and zinc will weld. I am just looking for some insight as to why zinc will bond to zinc, steel to steel, zinc to steel, but aluminum won't bond to anything with my fluxcore welder. I have been researching and I am pretty sure that it is because of melting temperatures? Also because of it's density? Any help will be appreciated and I will post pics of my final project! Thanks!
Help with a Science Project
- Thread starter JoeyMitch
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Chuck122
Well-known member
I am assuming you are in high school ?
jkwilson
Well-known member
Don't try welding zinc. It is dangerous unless you are properly equipped.
metaleltr
Well-known member
Ok are you going to try to weld pure zinc? Or a zinc coated steel (galvanized) A fluxcore welder is only capable of welding steel properly.
Farmall450
Well-known member
You might want to get a respirator for galvanized...
How in depth of an answer do you want? It is density independent. I hope you enjoy chemistry. Look up welding of dissimilar materials, both AWS and ASM have put out some good articles on the topic.
What is your goal for this project? A specific question to be answered? This can be a very broad topic. Also read up a bit on brazing, which is used quite a bit with dissimilar metals.
What is your goal for this project? A specific question to be answered? This can be a very broad topic. Also read up a bit on brazing, which is used quite a bit with dissimilar metals.
neophyte
Well-known member
The fumes from burning zinc are considered toxic. When burning or melting zinc make sure to have plenty of ventilation, and/or wear a respirator made for zinc fumes. 3M makes several welding fume respirator filters, and masks that are appropriate.
It's possible the problem you're having welding the aluminum to the steel may have to due with the fluxing agent. It's definately possible to bond aluminum to steel, I have aluminized steel baking pans. Cookware companies also make tri-ply and other cookware that in many cases is two layers of steel with a layer of aluminum bonded between them. Other varients are just a layer of aluminum bonded to the the outside of a layer of stainless steel, and copper bonded to a middle layer of aluminum, which is bonded to an inside layer of stainless steel. This episode of How It's Made shows the stainless being boded to the aluminum but it doesn't explain much about it.
It's possible the problem you're having welding the aluminum to the steel may have to due with the fluxing agent. It's definately possible to bond aluminum to steel, I have aluminized steel baking pans. Cookware companies also make tri-ply and other cookware that in many cases is two layers of steel with a layer of aluminum bonded between them. Other varients are just a layer of aluminum bonded to the the outside of a layer of stainless steel, and copper bonded to a middle layer of aluminum, which is bonded to an inside layer of stainless steel. This episode of How It's Made shows the stainless being boded to the aluminum but it doesn't explain much about it.
Thanks for the responses guys. Don't worry, when I weld zinc I use a respirator and have fans blowing everywhere and everything blows right out the garage door. The question I am trying to answer, "Will fluxcore welding bond zinc, steel, or aluminum?" I am definitely going to research it more but I am just wondering as to why fluxcore will only weld certain metals.
Flux core is not a type of base material but a type of shielding. Instead of the gaseous inert sheliding being feed into the mig or tig arc via a high pressure source, the flux burns and creates the shielding, similar to the stick welding process but inside out. You can flux core weld any material that they make proper filler for. The reason they don't make aluminum flux core wire is... Well I'll let you think about it for a bit. Not trying to be an ***, and I will tell you if want me to, but it will give you more satisfaction if you come to the conclusion on your own.
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Chuck122
Well-known member
I'll give you my best guess by saying that I think it has something to do with polarity.
You may recall in chemistry, molecules have charges and they may or may not be polar. Let's say that steel is polar and aluminum is not, then they will not mix together well at all.
I think it is a question of solubility.
Remember, I'm no chemist so this may be pure bs
You may recall in chemistry, molecules have charges and they may or may not be polar. Let's say that steel is polar and aluminum is not, then they will not mix together well at all.
I think it is a question of solubility.
Remember, I'm no chemist so this may be pure bs
jeff g
Well-known member
Hi
Aluminium has a Aluminium oxide layer, a form of rust ( a thin passivation layer of aluminium oxide (4 nm thickness) forms on any exposed aluminium surface ) that has a melting point about 2000* & aluminium melts about 650*
Aluminium is welded with a TIG welder to remove the layer of oxide.
TIG welding
Direct current with a positively charged electrode (DCEP) is less common, and is used primarily for shallow welds since less heat is generated in the base material. Instead of flowing from the electrode to the base material, as in DCEN, electrons go the other direction, causing the electrode to reach very high temperatures.[19] To help it maintain its shape and prevent softening, a larger electrode is often used. As the electrons flow toward the electrode, ionized shielding gas flows back toward the base material, cleaning the weld by removing oxides and other impurities and thereby improving its quality and appearance.
Alternating current, commonly used when welding aluminium and magnesium manually or semi-automatically, combines the two direct currents by making the electrode and base material alternate between positive and negative charge. This causes the electron flow to switch directions constantly, preventing the tungsten electrode from overheating while maintaining the heat in the base material. Surface oxides are still removed during the electrode-positive portion of the cycle and the base metal is heated more deeply during the electrode-negative portion of the cycle. Some power supplies enable operators to use an unbalanced alternating current wave by modifying the exact percentage of time that the current spends in each state of polarity, giving them more control over the amount of heat and cleaning action supplied by the power source.
I hope all this makes sense.
Jeff
Aluminium has a Aluminium oxide layer, a form of rust ( a thin passivation layer of aluminium oxide (4 nm thickness) forms on any exposed aluminium surface ) that has a melting point about 2000* & aluminium melts about 650*
Aluminium is welded with a TIG welder to remove the layer of oxide.
TIG welding
Direct current with a positively charged electrode (DCEP) is less common, and is used primarily for shallow welds since less heat is generated in the base material. Instead of flowing from the electrode to the base material, as in DCEN, electrons go the other direction, causing the electrode to reach very high temperatures.[19] To help it maintain its shape and prevent softening, a larger electrode is often used. As the electrons flow toward the electrode, ionized shielding gas flows back toward the base material, cleaning the weld by removing oxides and other impurities and thereby improving its quality and appearance.
Alternating current, commonly used when welding aluminium and magnesium manually or semi-automatically, combines the two direct currents by making the electrode and base material alternate between positive and negative charge. This causes the electron flow to switch directions constantly, preventing the tungsten electrode from overheating while maintaining the heat in the base material. Surface oxides are still removed during the electrode-positive portion of the cycle and the base metal is heated more deeply during the electrode-negative portion of the cycle. Some power supplies enable operators to use an unbalanced alternating current wave by modifying the exact percentage of time that the current spends in each state of polarity, giving them more control over the amount of heat and cleaning action supplied by the power source.
I hope all this makes sense.
Jeff
Thanks guys! That helps me out a little bit. At first I thought aluminum wouldn't bond with steel wire because of different melting points. Never thought of the polarity and different charges of the metals. Funny because I'm in Honors Chemistry LOL
Outlawmws
Well-known member
Thanks guys! That helps me out a little bit. At first I thought aluminum wouldn't bond with steel wire because of different melting points. Never thought of the polarity and different charges of the metals. Funny because I'm in Honors Chemistry LOL
You need to do some research. The steel MIG wire will weld... Steel
It WON'T weld zinc or aluminum. Not with a steel wire. It will simply fall off.
You can mig weld aluminum with the right aluminum wire and the right shielding gas... and a lot of prep...
You won't generally push aluminum wire through a long conventional MIG cable and gun. They make a special gun for that with a small spoon in the gun. The aluminum wire is to soft to go the length of the longer conventional cable without birds nesting, although they used to sell plastic liners to try...
As for welding zinc, (or zinc plated steel) Don't. Not only are there hazardous fumes to deal with, you also have toxic residue on the materials afterwards.
Honestly, if your teacher ALLOWS the zinc experiment, he/she should be ****** fired. Its bad enough in a commercial environment with the proper gear for welding around zinc plated parts; Letting a kid try it at home is just plain stupid.
Jeff G, there is one gigantic aspect that you missed. The fact that aluminum is mig welded every day in industry with the DC process and a feeder.
Additionally aluminum was initially DC tig welded and still is today in certain applications. With the proper gas (He blends) you actually get a much deeper penetration from heat compared to the same amperage running AC.
Joey, can you please define the question that this project is supposed to solve. If this is your question I'd suggest you go a different route or change it up a bit. See post #9 as to why.
Additionally aluminum was initially DC tig welded and still is today in certain applications. With the proper gas (He blends) you actually get a much deeper penetration from heat compared to the same amperage running AC.
Joey, can you please define the question that this project is supposed to solve. If this is your question I'd suggest you go a different route or change it up a bit. See post #9 as to why.
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Alright guys thanks. Don't worry, the only metal I am going to weld is steel. I wasn't going to actually weld aluminum or zinc.
The question: Will fluxcore wire weld any metals other than steel? If not, then why?
The question: Will fluxcore wire weld any metals other than steel? If not, then why?
Possible, yes, economically feasible or practical, no. Flux core and even dual shielded welding process are mostly limited to ferrous alloys primarily due to mechanical strength of the wire. Now there are self shielded brazing wires for bimetalic joints, but that is a different ballgame.
Chuck122
Well-known member
it depends on how you view the question. I'm pretty sure some other metals could be welded using a flux cored wire but it would have to be a wire made specifically for the metal at hand
if you are asking "will my steel flux core wire work on other metals" the answer is probably not.
don't take this the wrong way but,having done my share of science projects, I'd try to find a project that deals with stuff you can readily explain. the question you are trying to answer deals with chemistry I'm pretty sure you have not dealt with before. the models you have been thought probably cannot explain accurately the "why" of your question.
I'm saying this mostly because it is frustrating to research a subject just to discover later on that it is too complicated and having to find another idea on short notice.