Minor thread drift here on blade selection!!!
A common misconception on band saw blades is to use a coarse pitch blade (Low TPI number like 4 or 6 TPI) for easy to cut materials like wood and aluminum, and use a fine pitch blade (16-20) for tough to cut materials like steel.
That is incorrect. The band saw blade pitch should be selected according to the thickness of the material being cut. There should always be at least 2 teeth engaged in the material for acceptable blade life and cutting finish. Even more teeth for a better finish.
So, if you are cutting a lot of thin material, then a high TPI number is appropriate. theoretically, if you are cutting 0.063 thick material, you should be using a blade with 32TPI or higher. in practice, this is cuts very slow and can even plug up the blade as the teeth are so small, so you can get away with a 16tpi or so blade and still get acceptable blade life and cut finish quality. If you use too coarse of a blade, you get poor finish quality and a very loud cut as the blade teeth are each "grabbing" such a large amount of material. It can even rip teeth off the blade if you get too aggressive.
Conversely, if you are cutting material 2 inches thick, you can use a very coarse blade. theretically, a 1 TPI blade would work, but in practice a blade this course is hard to work with since the teeth are so very deep. A 2-4 TPI blade would probably be more common.
The difference in cutting aluminum and steel is as was pointed out earlier with blade speed.
When cutting aluminum (And even wood) a high blade speed is desirable as it allows you to cut faster as more teeth are going through the material per minute, and there is no consequence about overheating the teeth on the blade with aluminum and wood.
BUT when cutting steel (And other ferrous material) a lower blade speed is needed as you will overheat the teeth on the blade and either melt them off with extreme speed, or just get them so hot they get very weak and lose their cutting edges too quickly.
Some good examples in our shop, when cutting the bar stock for the landing gear legs, we use a 4TPI pitch blade. The material is a very abrasive alloy in 1.5 inch steel barstock, but the blade is running at a relatively low speed. (About 400 Feet Per Minute) We also have some other parts we cut out of 0.25 inch steel plate. Those are cut with either a 16 or 20 TPI blade depending on what is handy at the moment.
We also cut some 1 inch thick plate for making the RV12 legs. We also use a 4TPI blade for those, but it is running as fast as our machine can run. (About 2000 feet per minute according to the chart on the machine).
We do use blades we buy from a woodworking shop for cutting aluminum, but that is only because they have the best prices I have found for big rolls of blades. We weld our own blades for the saw that cuts the aluminum. It is not really that important if the blade is advertised to cut aluminum or steel as long as you have the blade speed set correctly and the appropriate blade pitch for the thickness of material being cut.