Definition of the hottest stainless steel material

2022-08-11
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Definition of stainless steel material

all alloy steels that can resist acid, alkali, salt and other corrosive effects are called stainless steel, mainly iron chromium alloy

The 430/2b and 304/2b mentioned in

are the marks of Japan and the United States on the model and processing method of stainless steel plates. 430 is equivalent to Cr13 of chromium stainless steel in China; 304 is equivalent to 1Cr18Ni9 of nickel chromium stainless steel in China. The surface in contact with the sample is made of sticky soft rubber. 2B indicates that both sides of the steel plate are generally treated and the appropriate surface roughness is obtained after cold rolling. (the polished plate is marked as a)

because 430 does not contain precious metal nickel, and the mechanical properties of the material are far worse than 304. Commonly known as 430 stainless iron, 304 stainless steel. So the price difference between the two is so big. If it is made into a table and placed indoors, it is OK to use 430/2b

stainless steel is generally the general term of stainless steel and acid resistant steel. Stainless steel refers to the steel that is resistant to the corrosion of weak media such as atmosphere, steam and water, while acid resistant steel refers to the steel that is resistant to the corrosion of chemical corrosive media such as acid, alkali and salt. Stainless steel has a history of more than 90 years since it came out at the beginning of this century. The invention of stainless steel is a major achievement in the history of world metallurgy. The development of stainless steel has laid an important material and technological foundation for the development of modern industry and scientific and technological progress. There are many kinds of stainless steel with different properties. It has gradually formed several categories in the process of development. According to the structure, it can be divided into four categories: martensitic stainless steel (including precipitation hardening stainless steel), ferritic stainless steel, austenitic stainless steel and austenitic plus ferritic duplex stainless steel; According to the main chemical composition in steel or some characteristic elements in steel, it is divided into chromium stainless steel, chromium nickel stainless steel, chromium nickel molybdenum stainless steel, low-carbon stainless steel, high molybdenum stainless steel, high-purity stainless steel, etc; According to the performance characteristics and uses of steel, it is divided into nitric acid resistant stainless steel, sulfuric acid resistant stainless steel, pitting corrosion resistant stainless steel, stress corrosion resistant stainless steel, high-strength stainless steel, etc; According to the functional characteristics of steel, it is divided into low-temperature stainless steel, non-magnetic stainless steel, free cutting stainless steel and superplastic stainless steel

it is divided into chromium stainless steel, chromium nickel stainless steel and chromium manganese nitrogen stainless steel according to the main chemical composition; It can also be divided into acid resistant stainless steel and heat-resistant stainless steel according to their performance characteristics; It is usually classified by metallographic structure. According to the metallographic structure, it is classified into: ferritic (f) stainless steel, martensitic (m) stainless steel, austenitic (a) stainless steel, AUSTENITIC FERRITIC (A-F) duplex stainless steel, austenitic martensitic (A-M) duplex stainless steel and precipitation hardening (PH) stainless steel

at present, the trend of gradually developing from non structural parts to structural parts is more and more obvious

ferritic stainless steel

its internal microstructure is ferrite, and its chromium mass fraction is in the range of 11.5% - 32.0%. With the increase of chromium content, its acid resistance is also improved. Adding molybdenum (MO) can improve its acid corrosion resistance and stress corrosion resistance. The national standard grades of this kind of stainless steel are 00Cr12, 1Cr17, 00cr17mo, 00cr30mo2, etc

martensitic stainless steel

its microstructure is martensite. The mass fraction of chromium in this kind of steel is 11.5% - 18.0%, but the mass fraction of carbon can reach up to 0.7 and 6% for building fire prevention. The increase of carbon content improves the strength and hardness of steel. A small amount of nickel added to this kind of steel can promote the formation of martensite and improve its corrosion resistance at the same time. This kind of steel has poor weldability. Steel plates listed in national standards include 1Cr13, 2 Cr13, 3 Cr13, 1 Cr17Ni2, etc

The microstructure of austenitic stainless steel is austenite. It is a stainless steel with austenite structure formed by adding appropriate nickel (the mass fraction of nickel is 8%~25%) to high chromium stainless steel. Austenitic stainless steel is based on cr18ni19 iron-based alloy. On this basis, with different applications, it has developed into chromium nickel austenitic stainless steel series as shown in the figure

austenitic stainless steel is generally a kind of corrosion-resistant steel, which is the most widely used steel. Among them, type stainless steel is the most representative. It has better mechanical properties and is convenient for machining, stamping and welding. It has excellent corrosion resistance and heat resistance in oxidizing environment. However, it is particularly sensitive to the medium containing chloride ions (cl-) in the solution and is prone to stress corrosion. According to the difference of carbon content in its chemical composition, type a stainless steel is divided into three grades: general carbon content (WC ≤ 0.15%), low carbon grade

(WC ≤ 0.08%) and the latest version of the operating system of the hydraulic universal testing machine produced by ultra-low Carey has this functional carbon grade (WC ≤ 0.03%). For example, 1Cr18Ni9Ti, 0Cr18Ni9 and 00cr17ni14m02 steel plates in China's national standards belong to the above three grades. Many countries in the world feel the shortage of nickel reserves. In order to save nickel, manganese and nitrogen were used to replace some nickel in stainless steel as early as the 1940s and 1950s. The grades of steel plates developed and listed in national standards include 1Cr17Mn6Ni5N and 0Cr19Ni9N

AUSTENITIC FERRITIC STAINLESS STEEL

its microstructure is austenite plus ferrite. Stainless steel with ferrite volume fraction less than 10% is a steel developed on the basis of austenitic steel

precipitation hardening stainless steels

can be divided into three types according to their microstructure: precipitation hardening semi austenite, precipitation hardening martensite and precipitation hardening austenite stainless steels. 0cr17ni7a, 0Cr17Ni4Cu4Nb and 0Cr15Ni7M02Al, which belong to precipitation hardening semi austenitic stainless steel, are listed in China's national standard steel plate grades. The microstructure of the steel is characterized by ferrite with austenite plus volume fraction of 5%~20% in the state of solid solution or annealing. After a series of heat treatment or mechanical deformation treatment, austenite is transformed into martensite, and then the required high strength is achieved by aging precipitation hardening. This kind of steel has good formability and weldability, and can be used as ultra-high strength material in nuclear industry, aviation and aerospace industry

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