That was my first thought. This was a few years back, but I knew someone at a large construction company who bought steel beams from China. They soon learned that they had to oversee the testing process on site because they had been receiving good test results and a lot of substandard product.
they typically will start out with US steel as project specs require, then start slipping in the chinese junk with fake mill certs in the shipping documents, ( don't ask me how I know, I have busted them many times and got re-assigned each time )