When it comes to idioms about iron, the word "iron" comes first. Please help me.

Iron Case: Iron Case: A case or conclusion with solid evidence. Describes that the evidence is conclusive and the case is like a mountain and cannot be overturned.

The iron plate is not easy to change. Yi: change, change. It cannot be changed like an iron plate. Describes the unchangeable and unchangeable.

The iron plate is nailed ①It still means a head-on confrontation. It is a metaphor for being decisive and straightforward in speaking and doing things. ②The metaphor has become a conclusion.

Iron-plate singing voice describes heroic singing.

Iron plate and copper lute describe the bold and exciting writing style. Same as "iron plate and copper string".

Iron plate and copper string describe the bold and exciting writing style.

A monolith is a metaphor for a tightly knit and indivisible whole.

The iron rod ground into a needle is a metaphor that as long as you have perseverance and perseverance, you can succeed in anything you do. Same as "an iron pestle ground into a needle".

The iron pen is selfless, which means that one is writing and judging cases without favoritism.

Iron wall and copper wall are metaphors for things that are very solid and indestructible.

Iron walls and copper mountains are a metaphor for a strong and reliable force.

A heart of iron and a heart of stone is a metaphor for a strong and unmoved nature.

The iron pestle becomes a needle is a metaphor that as long as you have perseverance and are willing to work hard, you can succeed.

An iron pestle ground into a needle. Pestle: a rod used for pounding rice or beating clothes. Grind the iron rod into a fine needle. It means that as long as you have perseverance and work hard, you can succeed in anything you do.

The flavor behind bars refers to the life of prisoners in prison.

Iron Chuo Tong Pa describes the bold and exciting style of writing. Same as "iron plate and copper lute".

Iron is struck with copper and cast with copper. Described as very strong.

A heart made of iron means a heart made of iron. Describes a person's strong character.

Ieguo Golden City is a metaphor for a fortified city.

Iron painting and silver hook Painting: strokes; hook: hook. Describe calligraphy as strong and soft.

Iron Horse Jinge ①Describes the majestic soldiers and war horses. ② It refers to war and military affairs.

The iron face and the sharp teeth are a metaphor for perseverance, hard work and self-motivation.

Incorruptible and impartial, it describes being impartial and strict, not afraid of power, and unsympathetic.

Iron-faced Censor Zhao Bian of the Song Dynasty was the censor in the palace. He impeached powerful people. He was upright and selfless, and was known as the "Iron-faced Censor". Later, it was generally referred to as an official who was not afraid of powerful people, did not show favoritism, and was fair and strict.

A heart of stone is as hard as iron and stone. Describes a hard-hearted person who is not moved by emotions.

Heart of stone still means heart of stone. Describes a person's strong character. Same as "heart of stone".

The flower blooming on the iron tree means that something is very rare or extremely difficult to achieve. The iron tree is native to the tropics and blooms infrequently. Tropical, infrequently blooms. Same as "iron tree blossoms".

Tie tree blooms. Tie tree: also called cycad, is an evergreen tree that blooms infrequently. Metaphor that something is very rare or extremely difficult to achieve.

The iron tree blossoms means that something is very rare or extremely difficult to achieve. The iron tree is native to the tropics and blooms infrequently. Tropical, infrequently blooms. Hua means "flower".

Iron barrel country refers to a solid political power or status.

The iron net coral is a metaphor for collecting rare things.

Treading through iron shoes is a metaphor for traveling long distances and seeking everywhere.

Iron heart and wooden heart are still said to be iron-hearted.

Heart of iron and heart of stone still means heart of stone.

The iron inkstone is worn through. The iron inkstone is worn through. Describes perseverance and perseverance.

Iron prison and copper cage describe a tightly sealed prison.

The evidence is as solid as a mountain and cannot be shaken.

Clang in the Iron: Clang in the Iron: The sound of metal vessels hitting each other. A metaphor for a person with outstanding talents.

Iron mouth and steel teeth are metaphors for being eloquent.