无钢圈

• 一(one; initial)ASSOCIATIVE
• 尢(disabled person; insufficient)ASSOCIATIVE

From the beginning there was a shortage, so 無 means 'nothing at all'.

• 釒(metal)RADICAL
• 岡(mountain ridge; firm)PHONO-SEMANTIC

Steel is a hard metal, strong like a rocky mountain ridge.

• 囗(surround; square)RADICAL
• 卷(roll; book)PHONETIC

A circle is a closed boundary that wraps around, like a rolled paper forming a complete loop.