Aircraft are generally not made of steel. Very few components of an aircraft are.
You are generally looking at age hardened alloys - alluminum based, mostly. 7000 series alloys.
Although these are far more finnicky than steel. Steel is pretty straight forward with its various crystalline formations and processes. Still, these pre-industrial societies thrown into a semi-modern factory don't understand what the fuck they are doing - and you get the Steel of Many Colors from them, because they can't hold an alloy consistency to save their lives.
China has gotten better with its aluminum. You have to venture off the beaten trail to find castings that shatter like glass when dropped - but they are still out there. They have the society, now, that should be capable of making decent steel that doesn't have mystery molecules in its matrix. They have schools for that shit over there, now.
Which is cool - they have a massive domestic demand for those products and were just weaponizing their currency and economy against us when selling it here. With the same disastrous effects on their economy as a normal war, ironically enough. The tariffs will, in the long run, be a great thing for China, as well. At least - the Chinese people. Their government system may ultimately have to change, but all things in their due time under the sun.