You do not understand predatory trade practices. China is selling steel at a loss so they can take
over our steel market and drive our steel producers out of business.
China is selling crude steel at a loss because their government did a lousy job at central planning. Instead of producing steel to meet demand, they produce steel to hit some artificial production target, and now they are screwed because they can't stop producing steel that no one wants to buy. So they use this steel to build bridges and buildings that collapse.
But let's talk about a real player here - South Korea. They produce roughly 7/8
ths the crude steel that the US produces. But unlike China, they take that crude product and refine it into high quality finished goods like ships, tankers, and oil platforms.
Or how about Japan - a country that is dependent upon ore as well as energy imports. Yet they produce more crude steel than the US. And on top of that, they emphasize specialty steel made to order in quantities that are not available in the US due to the inflexibility of the protectionist mindset of US steel producers.
But back to this imagined takeover of the US market. Let's say that the US stopped producing steel today. There are plenty of players on the world stage that would be more than happy to compete for our steel business with Japan, India, and Russia at the top of the list.