A05 is Cr26, which is a common material and belongs to martensitic stainless steel.
Martensitic stainless steel: stainless steel whose mechanical properties can be adjusted by heat treatment, in layman’s terms, is a type of hardenable stainless steel. The typical grade is Cr13 type, such as 2Cr13, 3Cr13, 4Cr13 and so on. After quenching, the hardness is high, and different tempering temperatures have different combinations of strength and toughness. It is mainly used for steam turbine blades, tableware, and surgical instruments. According to the difference of chemical composition, martensitic stainless steel can be divided into martensitic chromium steel and martensitic chromium-nickel steel. According to the different structure and strengthening mechanism, it can also be divided into martensitic stainless steel, martensitic and semi-austenitic (or semi-martensitic) precipitation hardening stainless steel and maraging stainless steel.