Many corporations, including those who have had their own steel making foundry as part of the manufacturing process, have simply shipped their technology to China, along with their own experts, to teach the Chinese the steel making process in an effort to get the same exacting standards found in the U.S. and have it done for nearly free.
China has taken this influx of knowledge and will surely use it against us someday. Trump talks tough on China but he never stopped corporations already there from manufacturing. If he really cared, he would have actually done something that neither party can now control. You can't put the genie back in now.
Eventually war will end this relationship and China will nationalize all these factories.