steel
鋼 centers on the hard, strong metal that is steel.
鋼 combines 金 (metal) with 岡, which likely contributes the sound コウ and may also suggest hardness or a ridge-like quality.
The left side is metal 金, and the right side 岡 looks like a sturdy ridge. Picture a ridge of solid steel: 鋼 is steel.
For コウ, imagine a blacksmith forging steel with a strong, resonant 'koh' sound as the hammer strikes: koh -> コウ.
steel
steel
iron and steel
steel material
steel sheet; steel plate
steel pipe
steel cable; steel wire rope
Shinkou
steel manufacture
mild steel
H-section steel; H-section; H bar; H beam; rolled steel joint; RSJ
I-beam
Wootz steel
chrome-vanadium steel
chromium molybdenum steel; chrome molybdenum steel
chrome steel; chromium steel
silicon steel
Swedish steel
stainless steel
tungsten steel