Cast iron and cast copper
The Chinese idiom Ti ě D ǎ t ó ngzhi ù means made of iron and cast with copper. It's very strong. From Li Zicheng.
The origin of Idioms
Yao xueyin's "Li Zicheng" Volume I Chapter 24: "please rest assured, brother, it's not stupid brother who blows around after drinking, my village is really like cast iron."
Idiom usage
It is often used in writing.
Cast iron and cast copper
disappear like snow when hot water is thrown on it - rú tāng guàn xuě
use unscrupulous divisive tactics - bù zé shǒu duàn
not dig a well until one thirsty ---- not make timely preparations - lín kě chuān jǐng
asking for some water and getting some wine - qǐ jiāng dé jiǔ
consider others in one 's own place - tuī jǐ jí wù