How to classify stainless steel forgings more reasonably?

Given the wide variety of stainless steels, there are as many as over 140 types in the GB/T 20878—2007 standard, and approximately 200 types in practical applications. Stainless steel forgings differ in composition, performance, and usage, and there are numerous classification methods.

Next, let's specifically understand the related content in this aspect.
The common classification of stainless steel forging varieties covers:
(1) Classified by chemical elements:
Stainless steel forgings can be roughly divided into: chromium stainless steel forgings (represented by Crl3), chromium-nickel stainless steel forgings (represented by Crl8Ni8 steel), chromium-nickel-molybdenum stainless steel forgings, chromium-nickel-manganese stainless steel forgings, high-nitrogen stainless steel forgings, and high-molybdenum stainless steel forgings, etc.
(2) Classified by structure:
The metallographic structure of stainless steel forgings is closely related to its chemical composition and heat treatment state. If classified based on whether there is a phase transformation when the stainless steel forgings are heated to a high temperature or cooled from a high temperature to room temperature, and the main metallographic structure at room temperature, they can be divided into martensitic stainless steel forgings, austenitic stainless steel forgings, ferritic stainless steel forgings, and austenitic-ferritic duplex stainless steel forgings.
(3) Classified by the content of harmful impurity elements:
Stainless steel forgings can be classified into ordinary stainless steel, low-carbon stainless steel, ultra-low-carbon stainless steel, and high-purity stainless steel, etc., according to the carbon content and the content of harmful impurity elements in the steel.
(4) Classified by corrosion resistance:
Stainless steel can be divided into stress corrosion-resistant stainless steel forgings, pitting corrosion-resistant stainless steel forgings, and abrasion corrosion-resistant stainless steel forgings, etc.
(5) Classified by the usage medium environment:
According to the usage medium and environment, stainless steel can be divided into nitric acid-resistant stainless steel, sulfuric acid-resistant stainless steel, urea-resistant stainless steel, and seawater-resistant stainless steel.
(6) Classified by element conservation:
Due to the preciousness and scarcity of some elements, various countries have researched and produced some steel types based on the conservation of main elements, such as nickel-saving stainless steel, nickel-free stainless steel, and chromium-saving stainless steel, such as Cr-Mn-N and Cr-Mn-Ni-N stainless steel, as well as stainless steel with silicon and aluminum replacing chromium.
(7) Classified by characteristic constituent elements:
Stainless steel forgings can be divided into high-silicon stainless steel, high-phase stainless steel forgings, and high-nitrogen stainless steel forgings, etc.
(8) Classified by functional characteristics:
According to the functional characteristics of stainless steel, it can be divided into low-temperature and ultra-low-temperature stainless steel forgings, non-magnetic stainless steel forgings, high-strength stainless steel forgings, superplastic stainless steel forgings, easy-to-cut stainless steel forgings, and heat-resistant stainless steel forgings, etc.
How to classify the various types of stainless steel forgings? The above eight points are the related introductions. If everyone wants to understand more deeply, they can search for relevant literature materials through Baidu. It is hoped that the above explanations can be helpful to everyone.