Is steel easier to weld?Which is more brittle/less flexible?
You should not attempt to do any traditional welding of steel to aluminum as they can form a hard and brittle inter metallic compound known as iron aluminide. You would have to employ a process that did not melt either species. Cladding could be an option but you are kind of limited to flat products that are sandwiched together. There is also explosive which does almost the same thing as cladding. Friction stir welding might be possible but I cant vouch for that. The temperature does get pretty hot, so I am not sure what would happen. But any of these suggestions would take specialized equipment not available to the average user. For weight, Al is 2.7 g/cc and Iron is about 7.8 so it is about 3 times heavier for the same volume. How strong either of them are greatly depends on specific alloys and heat treatment. I think some of the strongest aluminum alloys have a yield strength of about 50,000 psi which would relate to a relatively weak steel. For steel, there are alloys that can have yield strengths in the hundreds of thousands psi.
Yes you can, but you really dont want to. Aluminum conducts heat better than steel so the weld would not cool evenly and would be brittle. You would be better off using a bracket or bolt straight on.
Note: the easiest way to join steel to aluminum is to drill holes and BOLT them together...... You cannot WELD steel to aluminum.(except using extreme methods like explosion welding......) For all intents and purposes they are dissimilar metals, meaning they will not bond to each other. Also, aluminum has a much lower melting point than steel. It is possible to join steel and aluminum by *Soldering,* using tin/zinc hard solder. This requires a special flux designed exclusively for soldering aluminum though. The heating process is also a bit delicate as you must avoid overheating the joint. I work as a welder and I've only soldered Al three or four times. Steel is easiest to weld by far. If you set the equipment correctly, a six year-old kid can make a good weld on steel. Aluminum requires special equipment and procedures to weld. It's not easy. The brittleness of aluminum depends on it's alloy content. Most of the aluminum that's used today is not pure, rather it's in the form of aluminum ALLOYS which contain either zinc, magnesium, silicon, or manganese. these elements increase the strength dramatically, but also make it much less ductile. Commercially pure (CP) aluminum is very ductile, but it's also rather weak. Pure aluminum is used to make aluminum foil, as it's so soft and ductile it can easily be rolled paper-thin. The best aluminum alloys can come near in strength to mild steel, but weigh less than half as much as steel. Note that steel itself is an alloy of iron and carbon, Carbon increases the strength of iron in the same way that zinc or magnesium increase aluminum's strength. Most of the commonly used aluminum alloys are somewhat more brittle than mild steel, but not greatly so.
I can't weld steel to aluminum, and generally speaking I'd say the answer is no, however, there are some special procedures that can make a metallic bond between steel and aluminum, it can be done with explosive welding. A lot of multi-ply cookware is made with aluminum sandwiched between stainless steel, there is so much of it that I imagine there is another way besides explosives, but I don't know what. In any case it is not a normal workshop procedure. Steel is often considerably easier to weld, but it depends on the alloy. some steels are difficult to weld and some aluminum alloys are fairly easy, but on the average steel is easier. as far as brittle/ flexible it again depend on the alloy, some steels are less brittle than some aluminum alloys and the other way around. Steel does have a higher modulus of elasticity, so for a given size steel is stiffer, but that is for elastic deformation, for plastic deformation steel often has a higher yield strength, but some of the more exotic aluminum alloys can be stronger than low grades of steel.
