I recently ran into a supplier issue and need advice.
I've been ordering 1020 plate from the same supplier for 4 years. I use it to mill parts for fabricated assemblies. The last 2 times I recieved material, the stuff is as hard as stainless. Maybe not quite 304, but I cannot cut it at the same feeds and speeds I've been using for 4 years. Same tooling, same tool holders, tried new tool holders, same machines, same programs, same fixtures. The only thing it can be is the material, the last load was all crap!
My initial worry is that my local supplier just got bought out by a larger supply. I figured they were purchasing the material from another mill, or yard. The salesman assures me that they are using the same mills/yards they have been for 30 years. Even the guys in the shop told me it's coming from the same place and to the best of their knowledge, nothing has changed.
I would be able to inspect the material before I purchased it. I've already inspected the plate for markings or a stamp in the corner that would designate that it would be some other grade than 1020.
My only thought was to purchase a "pocket hardness gauge" and check the hardness of a known good piece from previous purchase, then test what they have on the racks. But a pocket, or portable harness gauge is $1200, didn't want to purchase one unless I have to.
Any input or advice is appreciated.
Unfortunate it seems,
You may try to throw it back at them, by having them supply a "Certificate of Compliance", where they guarantee the quality and so on,
Also research the possible ranges of this material, it may just fall into spec.
You could also have a sample independantly analysed as proof of quality, and reject that batch if it doesn't meet the spec.