That blade is "probably" ....made from a small piece of hardenable steel forge welded to a larger piece of less expensive, softer metal to save costs.
I do find it interesting/confusing that the description doesn't mention this process, however. It's described as "HSS" not a composite or combination. see if any of the review mention it... and if there are any issues?
The Powertec phone number:
I hate to admit it, but I called Powertec. They were no help. I sent a PM to the OP with the details. Here is a summary of what the person at Powertec told me:
* We import them and sell them.
* We don't ask the manufacturer about how they make them.
* We don't know why they are made that way.
* There is no technical support person at Powertec who can answer the question.
* Of course they are safe. We have had no safety issues with them, and that's all we care about.
I note that the person at Powertec did not know about the issue. You can't see it in the photo on their website. Once they saw the photos on Amazon, they understood the point of my question, but that was no real help.
In the PM, I speculated
the same as @woodnthings
* They use a harder, more brittle steel for the edge to provide better durability (stay sharp longer) and maybe nick resistance.
* The less expensive steel for the body of the blade lowers manufacturing costs.
* The less expensive steel may be less likely to crack when you tighten it up in the holder. A speck might get sandwiched, or there might be a tiny alignment issue.