Martensitic stainless steel refers to a chromium stainless steel that maintains the martensitic microstructure at room temperature. In general, martensitic stainless steels have higher strength than austenitic stainless steels and ferritic stainless steels and can be strengthened by heat treatment, and have good mechanical properties and high temperature oxidation resistance. 

The steel in the atmosphere, water and weak corrosive media such as saline solution, dilute nitric acid and some organic acids with low concentrations have good corrosive media at low temperatures. 

However, the steel does not resist the corrosion of strong acids such as sulfuric acid, hydrochloric acid, and concentrated nitric acid, and is often used in weak corrosive media such as water, steam, and oil. Since chromium stainless steel can be strengthened by heat treatment, in order to avoid brittleness caused by excessive strength, the correct heat treatment process should be adopted.