As for Chinese products, the Oregon and Carlton LP chains are made in China.
If you read the backs of consumer packages of Oregon chain, they are typically labeled:
"Made in USA", or
"Made in Brazil", or
"Assembled in China from components manufactured in USA or Brazil"
I have no doubt that high quality products can be made in China - look at most Apple and IBM/Lenovo computers, etc. But too often, products are off-shored to cut corners. As for steel, even if 2 companies start with the same raw materials, it is no guarantee of getting the same quality product at the end. Just like giving 2 cooks the same raw ingredients and expecting to get the same quality food.
The Carlton chain is no longer Carlton chain. It is Oregon chain branded as Carlton.
Not sure what you mean by this. Same quality? Same materials? They still have different shapes/profiles, etc. Not sure about Ray Carton's ideas of sharpening cutters after assembling them into the chain, File-O-Plates, etc.
The test for comparing Tri-Link, Oregon, Carlton, STIHL, etc. chains should be based on side-by-side comparisons, user expereince, etc.
Philbert