We've always been lead to believe the heat treated is harder. So to satisfy your curiosity use one of each as a cold chisel to cut a 16d common nail in half.
#3
primerbulb120
In my experience (mowing 10-12 hrs per week) the heat treated blades do last longer.
#4
RDA.Lawns
Heat treated blades are a bit stronger. I don't own a edger the few accounts I have that would require a edger dosnt justify the purchase of one so we just use a lighter weight trimmer.
There is No benefit unless you count spending two to three the money for a heat treated blade a plus. They sure don't last any longer. You can spend all kinds of money on heat treated blades if you like, you can get them sharpened or un-sharpened. You can buy a 25 pack of heat treated blades form places like Amazon and they cost $44.95 that's like $1.79 each, I can go to the mower shop and buy a 50 pack of un-sharpened Non heat treated edger blades for under $40.00 that's 77 cents a blade that will work just as well and last longer than a heat treated blade. If your mowing as someone else mentioned for 30 hours a week it sure saves on the overhead.
I know from experience the thing that makes the most difference is how thick the blade itself is, because they do make them in varying degrees of thickness... Looking at them sideways the thicker blades are usually 1/8" thick, not sure on the thinner ones but I can tell you the difference is visible. I have found generally the thinner blades to be cheaper and the thicker ones last longer, but in all fairness it's six of one or a half dozen of the other, I do mildly prefer the thicker ones as I have to replace them less but it's a close call in terms of price.
'Rotating' the blade after use so as to 'round' the edge that's still sharp helps save money.
